Issue with rifle surfaced during training course, report

[Serpico1985]

I wanted to start this thread to provide everyone with my experience with certain parts that went into my AR15 and issues I had with them. I just took Viking Tactics Basic Carbine course (first course) and a couple issues surfaced.

Info on the rifle:
Upper: N4 Light Recce Low-Profile 16" Upper
Lower: Noveske 2nd run stripped
LPK: Daniel Defense
Other misc parts: BCM gunfighter charging handle-large, replaced noveske bolt with BCM bolt, used a MOE grip instead of A2.

I assembled the lower myself with the help of the error-net. I went slowly and the rifle passed all function tests. Test fired at range with only two rounds in magazine to insure any doubling, trippeling issues would not get anyone killed.

The first issue was the selector. I read that it should work the same when the BCG is locked to the rear as when it’s in battery. This was not the case. It was much more difficult to operate when locked to rear but possible. Also when going from safe to semi the selector was fine and relatively easy. But going from semi to safe (with BCG forward) took much more pressure. Someone told me a quick fix was to put some grease in the channel the detent runs in which I did. After the grease it worked well (until the end of the two day 1200 round class, more later).

The second issue would surface at the VTAC class. At the class every time we would go hot I would start with the BCG locked to rear, insert a fresh 30rnd pmag and hit the bolt release. The round would barley start into the chamber and stop. I could get the BCG into battery by simply banging on the bottom of the pmag vigorously. A couple good whacks and the BCG would fly home chambering the round. The gun was properly lubricated with a generous amount of SLIP 2000. The same thing would happen when the BCG was in battery on a empty chamber and I inserted a full 30rnd pmag and ran the charging handle (by the way I was insuring the pmag’s were seated properly and wasn’t ridding the charging handle). I experienced zero failures to feed (other than above mentioned), extract, eject, etc.

The bolt catch had an indention, scratch or gouge in it and seemed to be wearing faster than I would think would be normal. Dan from VTAC looked at it and observed my failures to feed and thought that it may be an issue with the bolt catch spring. Whatever was causing it, it was clear the bottom of the BCG was dragging on the top of the bolt catch. He slapped his lower onto my upper and I put in a fresh 30rnd pmag and it worked perfectly. He suggested that I file the top of the bolt catch down. When I got home I filed it down and got it to work properly.

By the end of the second day my safety was getting more difficult to operate from semi to safe. When I got home and replaced it I found that all the carbon had gunked up the grease (as expected). After all the grease was a temporary solution to the problem. I replaced the selector with a G&R unit and it worked excellent. It went from safe to semi and back with the same amount of gentle force. I locked the bolt to the rear and operated the selector. I could not tell a difference. It was great.

I then replaced the bolt catch assembly with a G&R unit and it dropped in with a better fit (less front to back wiggle) than the DD unit. It also worked properly the first time as it should with a 30rnd pmag. While racking the charging handle the action also seemed smoother and to spring back into battery more vigorously. I attribute this to the old bolt catch putting constant pressure on the bottom of the BCG.

I am not trying to bash Daniel Defense in any way. I’m just reporting what I found to be the case with my particular rifle.

By the way the class was excellent and I will definitely be taking more classes from VTAC.

My camera is dead and the charger is MIA. If I can find it I’ll take pictures of the parts in question.

Thanks for reading, hope this can help someone some time in the future.

[Heavy Metal]

Is this your first AR?

[Serpico1985]

Yes it is.

[Heavy Metal]

Do you have any friends you could swap uppers and lowers with?

[Serpico1985]

I know a few guys with AR's. Since everything appears to be gtg now what would swapping uppers and or lowers do? Are you saying put my lower on someone elses upper and see if we can create the same malfunction?

[Heavy Metal]

For startes, yes.

It also sounds like your hammer is dragging on the bolt carrier.

[Serpico1985]

I guess I got eager to fix it and didn't stop to think about what you advised. Is there a way I can test the hammer drag you mentioned? Thank you sir.

[Belmont31R]

FWIW I use Colt bolt catches, mag releases, fire control selector, and trigger assembly.


Ive had too many problems with aftermarket LPK's with quality and fitment issues.


One of the pluses to buying a complete rifle is the rifle should be function tested before it gets to your hand so bad parts shouldn't make it to the consumer. In the case of assembling your own lower those potential bad parts will not be found out until you are on the range.


In the future I would also recommend not using an expensive class to test your rifle. It would be a good idea to have at least 500rds through the gun before hand, and any issues worked out before you show up. That way you are not wasting your class time, and the instructor's time trying to diagnose a problem gun.

[CarlosDJackal]

For startes, yes.

It also sounds like your hammer is dragging on the bolt carrier.

Isn't the hammer supposed to drag against the BCG? If there is a doubt then go ahead and replace the hammer and probably the sear.

From what he posted, it sounds like an out of spec bolt catch and safety lever (LPK).

If it is doing what it's supposed to be doing, then I would not worry about it. YMMV.

[JBecker 72]

My home built lower using quality parts and an LMT upper runs flawlessly, but the safety selector is a bit harder to operate with the bolt locked to the rear than when its in battery.
Its not much harder, but it is a noticeable difference.

Is that a problem? Its never caused any type of malfunction.

Sorry to hijack, but it seemed like a good thread to ask in.

[Serpico1985]

Regarding taking up instructors time at classes. Luckily the only time I took from the instructor was on the breaks. I did put a couple hundred rounds through the rifle before the class but did not experience the issue (because I wasn't loading the mags fully) and therefore thought my rifle would be ok. However you are correct, it was a miscalculation on my part but luckily it didn't cause any problems.

JBecker72,

I think the selector should work as I mentioned, the same in battery as locked to the rear. I will of course defer to a more experience mind on that.

[KalashniKEV]

Interesting thread... I'm doing the same upper on the blem lower w/ a CMMG LPK later tonight.

I'm also curious to see if the saftey will move w/ the BCG locked to the rear... in all the years I've spent w/ an AR in my hands I don't think I've ever tried that one.

Regarding the bolt catch, I would have tried a USGI mag before I took a file to it. It sounds to me like the PMAG might have been the culprit. My original batch PMags were tight in my lower and non-DF. I also had the idea that the catch was improperly located b/c you had to slap them to death to get them to lock. I later ran them in a SAW on the range and it chewed the lips.

Not too scientific, as I wasn't going to use them outside the gate...

I'm a WECSOG master, but I always try every possible configuration to diagnose a problem before I remove metal from a gun.

[pezboy]

Same Serpico1985 from M14tfl.com?
I would try different mags in the rifle and see if that fixes the problem. I've had some mags that would work in one rifle and not in another. Your lower may hold the mag slightly different than the instructor's causing drag while chambering a round. Also, more lube and an un-notched hammer may help. I can't help you out with the selector.
Dustin

[Belmont31R]

None of my AR's have any issues rotating the selector with the bolt locked back. This is with Colt and KAC/LMT selectors.

[ColdDeadHands]

None of my AR's have any issues rotating the selector with the bolt locked back. This is with Colt and KAC/LMT selectors.

Same here; LMT Complete Lower with Noveske Light Reece Upper and complete Noveske Recon...the Selector works in any position of the bolt.

[JBecker 72]

my selector is the same way, it is just a little bit harder to rotate with the bolt locked to the rear. :confused:
it has over 2000 rounds through it.

[Serpico1985]

Pezboy, I am on M14TFL as same name. I tried a couple of usgi alimnum mags at the class too and the rifle did the same thing. Although I should have tried a few more mags just to be sure. Instructor initally thought the same thing as yall about pmags.

Well, whatever, it's fixed now, just have to take it to the range to be sure.

I didn't know if anyone else had any issues with the Danile Defense parts kit or if I was solo on that.

Camera battery still MIA. I'll see if I can use my camera phone to show wear.

[KalashniKEV]

Also when going from safe to semi the selector was fine and relatively easy. But going from semi to safe (with BCG forward) took much more pressure.

I feel like I owe you an apology! Although I didn't say anything about it yesterday, I was thinking that perhaps the safety was not fully inserted (i.e. selector side gap) but since you would come up way short on the other side I didn't want to insult your intelligence. (I was thinking the detent wasn't riding in the proper channel)

Last night I had the EXACT same problem! Upon completion of assembly w/ a CMMG LPK, functions check allowed the safety to move from SAFE to FIRE with normal effort, but it almost wouldn't go back to SAFE after I thumbed the hammer back. Upon examining the part, I'd say that instead of the little dimple to allow the detent to rest, this selector had a pretty large, deep recess.

Luckily I had a spare Stag selector and detent, which I replaced them with and everything was perfect after that.

I wonder if there is a batch of horribly out-of-spec selector levers going around?

[brianc3]

There is some conversation on AR15.com about this very issue, there seems to be a problem with the CMMG LPK, in specific the safety selector.

[brianc3]

There is some conversation on AR15.com about this very issue, there seems to be a problem with the CMMG LPK, in specific the safety selector being out of spec

[Heavy Metal]

If the selector is out of spec, it can push down on the trigger bar which will push up on the Hammer contact which will cause the hammer to bind against the carrier.

[KalashniKEV]

If the selector is out of spec, it can push down on the trigger bar which will push up on the Hammer contact which will cause the hammer to bind against the carrier.

The issue here is with the detent recess.

It's like a peg going into a hole on the FIRE position, or a dowel preventing your selector from moving... crazy!

[Serpico1985]

Heavy Metal,

With regards to your comment about the out of spec selector causing hammer drag. Are you suggesting that that is the problem I was having? If so how could that cause the wear on the bolt catch? Would the bolt catch not still be an issue even if the selector was also?

Thanks.

[thopkins22]

Removed so as to avoid generating bad information.

[sickpup]

folks,

please read

http://www.ar15.com/forums/topic.html?b=3&f=4&t=484476

regarding the cmmg lpk

[Serpico1985]

Hey guys. I know it's been a while since I made the original post but I would like to give an update and show some pictures since I am still having one of the two original issues.

Here is what the jam looks like, shitty picture, I know:

http://i54.tinypic.com/2uo2t5k.jpg

It starts forward but stops after only a small amount of movement. The tip of the round is already starting to feed and is angling slightly up. I shot yesterday and had the same issue. The first round of a fully loaded mag (I used pmags and new BCM mags) would fail to feed. To get it to feed I simply slammed the bottom of the magazine once or twice and it feeds. I have never had a failure to feed once the initial round has fed.

Some photo documentation:

This is the original bolt catch from the DD LPK. I started filing on it at class but you can still see the gouge mark. It got replaced with a G&R bolt catch after the class but the feeding problem persists.

DD mag catch:
http://i54.tinypic.com/2iros2o.jpg

Here is the new G&R mag catch after firing roughly 100 rounds (couple days ago) no gouge just a very small amount of surface finish removal:
http://i55.tinypic.com/2u6cs9y.jpg

Here is a pic of the original DD hammer:
http://i55.tinypic.com/16ixxfa.jpg

Over head shot:
http://i52.tinypic.com/2nh3gxv.jpg


So a quick summery. Built the rifle using DD LPK, went to class, had issues feeding first round of fully loaded mag, had issue with stiffness of safety selector and it's operation with bolt locked back. Got back from class replaced the mag catch and selector with G&R units. Safety selector problems gone. Gun still having issues feeding first round of fully loaded mag (pmags, BCMs). During the last range session the gun started off clean and dripping with Slip 2000.

Thanks in advance for any advice. I have digital calipers and other measuring tools if y'all need exact measurements.

[ForTehNguyen]

youre not loading the pmags to 31 are you? They actually can fit 31 rounds but its tight and I can imagine that first round causing drag on feeding. That extra play is needed to be able to load a fully loaded 30 round pmag on a closed bolt, a problem USGIs had (military recommended loading to 28 in the past).

[Serpico1985]

No. 30 rounds, top round is on the right side and you can push it down a little bit. I just unloaded a couple to double check.



EDITED TO ADD:

Not sure if this was in the OP but while at the class the instruction swapped lowers with me (his lower, my upper) and it fed the top round fine. I could feel a difference when releasing the bolt catch on his lower, the gun fed smoother and faster.

Also, this rifle isn't in use, it's just a training rifle. I don't consider it GTG until it gets this bug worked out and goes another 500-1000 trouble free.

Thanks again for any help

[Iraqgunz]

Have you considered sending the lower to Noveske and have them look at it? I think that may be the issue.


No. 30 rounds, top round is on the right side and you can push it down a little bit. I just unloaded a couple to double check.



EDITED TO ADD:

Not sure if this was in the OP but while at the class the instruction swapped lowers with me (his lower, my upper) and it fed the top round fine. I could feel a difference when releasing the bolt catch on his lower, the gun fed smoother and faster.

Also, this rifle isn't in use, it's just a training rifle. I don't consider it GTG until it gets this bug worked out and goes another 500-1000 trouble free.

Thanks again for any help

[Serpico1985]

Iraqgunz,

Honestly I havent considered that. Thank you sir. I guess I've been assuming it was my error on assembly and/or parts tolerance stacking. But now that you mention that I will defiantly consider it. I would like to exhaust all other avenues first so that I don't pay shipping both ways (easily close to $100) to find out that it was a $5 part. I would defiantly defer to the knowledge base on this forum, if y'all say send it back I'll do so.

[wingo]

my dd safety lever still had a bit of a edge around the divit holes no amount of lube would fix. after tedious work with several grains of sand paper i made the chanel semi-correct. ill never stray from CMT/colt again. i still may order a correct part. never had your problem, but ill look on that rifle.

why did you replace the Noveske bolt carrier?

[Serpico1985]

wingo,

Almost forgot to mention that, thanks. I replaced the bolt with a complete BCM unit for no good reason. The bolt carrier is Noveske.

Edited to add: The BCM bolt has been in the rifle since the beginning. I've got around 1600 rounds through the rifle now. I know over time the bolt lugs settle into the corresponding lugs in the upper receiver extension (at least I've read that). Is there any chance that could be the issue? If so is to too late to throw the Noveske bolt back in and give it a try?

[Heavy Metal]

With regards to the round hanging on the upper, are you riding the charging handle or letting it slam home from full compression?

I I have a trick I do to all my barrels prior to install. I take a small diamond dust file and bevel the corners on the 5 and 7 o'clock cut-outs in the locking recess(barrel extension) and I polish the feed ramps below and this area too with a felt bob on a dremel and jewler's rouge. I assure this area is a smooth as a babie's bottom.

Also, check your recoil spring assembly.

[Heavy Metal]

And that's a Bolt Catch, not a Mag Catch.

[Serpico1985]

Heavy Metal,

With regards to riding the charging handle. When loading I always have the bolt locked to the rear, insert full mag, ensure mag is seated by firmly tapping the bottom a couple of time, press bolt release, round hangs up, hit bottom of mag once or twice, bolt slams home and chambers round. There have been a couple times where I would insert the full mag with the bolt closed and cycle the BCG with the CH. Same thing would happen and I would make extra sure to not ride the CH.


With regards to beveling the corners of the receiver extension. This is a Noveske chrome lined barrel. I would imagine the barrel is chromed in this area as well. Would there be issues with attempting to file that area, even a little bit?

I looked at that area on my rifle and it appears to be pretty smooth. I don't notice any significant step where it transitions from the receiver feed ramps to the barrel feed ramps, but this is just a uneducated observation.

Bolt catch, mag catch, I was typing fast.

Thanks again.

[scottryan]

Honestly I havent considered that. Thank you sir. I guess I've been assuming it was my error on assembly and/or parts tolerance stacking. But now that you mention that I will defiantly consider it. I would like to exhaust all other avenues first so that I don't pay shipping both ways (easily close to $100) to find out that it was a $5 part. I would defiantly defer to the knowledge base on this forum, if y'all say send it back I'll do so.


You said the Noveske lower was a cosmetic second.

I don't believe the issue with this lower is purely cosmetic.

Companies just don't have piles of items to give away at a discount just because they have an irregularity in the finish.

The first thing you should have done was replace the entire LPK with Colt parts from SAW or Brownells.

[Serpico1985]

The lower came stripped with the upper during a promotion from noveske. I also realize that 'parts aint parts'. I thought it was a safe bet going with a DD lpk based on their reputation. It may still be a gtg lpk if the receiver is out of spec on some area. Noveske plainly states on their website that the 2nd run lowers are dimensionally correct and suffer only cosmetic blems. So I don't really feel like I took a risk or rolled the dice with the lower. It may just be out of spec.

[Serpico1985]

Allright. I'll contact Noveske about it and see what they say. I'll let everyone know what they say.

[az doug]

What happens if you download the mags to 28 rounds?

Also, what buffer and spring are you using?

[Serpico1985]

If I download to 28 rounds it will load as it should. If I remember correctly its a carbine buffer spring. I'm not sure which buffer, standard heavy buffer I think. I did research and bought whichever one everyone generally recommended for a midlength rifle.

[ForTehNguyen]

strange problem, have you tried it with a different buffer spring that is known to work?. Perhaps when it is loaded to full there isnt enough spring force to feed the top round. The top round is the tightest bullet on the stack when its full obviously, so maybe there is an issue there.

[Serpico1985]

I hadn't considered that. The buffer spring was bought new from Rainer arms. So your saying I should try another carbine buffer spring?

Let me ask another question. Does anyone think that the issue I was having with the original bolt release getting beat up has anything to do with the failure to feed I'm having?

Thanks

[az doug]

If the bolt catch is somehow creating drag on the bolt carrier it could be an issue.

Many LEO's load their mags to 28 rounds, mainly because they are easier to insert on a closed bolt, but also for the reason you describe. Yes, I am aware that HK and P-Mags will compress the rounds a little farther than GI mags making them easier to insert when the mag is fully loaded. Even so many LEO's only load them to 28 rounds.

There are many factors involved here. Obviously more pressure is being applied to the bottom of the carrier than the buffer and "buffer spring" can overcome. This pressure comes from the fully loaded magazine, the height the magazine is held at, the hammer spring (for the short duration the hammer is applying pressure to the bottom of the carrier)... Again, several factors. I would try the upper on someone elses' gun that has a lower configured similar to yours. If it works on their lower then I would try their buffer and buffer spring in your lower. Absent that I would buy an extra power buffer spring and possibly heavier buffer.

[bkb0000]

if it was me, i'd do the following:

-pull my bolt-catch spring and make sure it's really a bolt-catch spring, replace if at all questionable
-check bolt-catch protrusion- i don't know what the max end is, but the only weapon i have with me right now just mic'd to .2125".. so probably any higher than .2200, maybe a little more, may indicate an out of spec lower
-install a different buffer spring and try again
-install an XP spring and try again

i've had XP springs make non-functional guns into functional guns. this is almost always simply compensating for something else being screwed up, but that's what they make them for.

[Serpico1985]

Great info bkb000. I will try what you said. Like I said before if it has to go back that's fine, I would just like to exhaust all othe avenues first. I also don't like the idea of using stronger springs to overcome out of spec tolerances, but I would like to get the gun to run correctly first.

[az doug]

If you suspect the bolt catch you may want to try it with the bolt catch removed. Just leave it off when you remove it to check the spring as bkb0000 recommended. This may help isolate where the problem is.

[ForTehNguyen]

im not seeing how a bolt catch would interfere with feeding the first round. Springs can be defective, more rare tho. Just worthwhile to check.

[bkb0000]

im not seeing how a bolt catch would interfere with feeding the first round. Springs can be defective, more rare tho. Just worthwhile to check.

if it's dragging the bottom of the carrier, it'll slow it down enough to stop it, slow it down, prevent lockup, etc. bad catches/springs and/or out of spec lowers do cause failures to feed. if it's only dragging a little, it'll only effect the first round, because the carrier does not have the additional inertia of cycling during firing.

weird things happen with this platform from time to time- and m4c is where they're gonna pop up.

[az doug]

im not seeing how a bolt catch would interfere with feeding the first round. Springs can be defective, more rare tho. Just worthwhile to check.

I tend to agree, but he did have unusual gouging on his original bolt catch and his new one has some surface finish removed in the same pattern as the gouging on his original. It appears that the bottom of the bolt or carrier is contacting/riding across the top of the bolt catch. Unknown if this is occurring all the time, or just when the bolt is released from the bolt catch. Why not eliminate the bolt catch as the cause of his malfunction just to give him peace of mind?

[Serpico1985]

Testing now. Will report back shortly

[Serpico1985]

Ok did some tests sans bolt catch. I backed the bolt catch pin far enough out to remove the bolt catch:

http://i54.tinypic.com/oqlzrn.jpg


I noticed a wear mark on the top rear of the mag well that looked odd. I don't know if this is a normal wear spot so I snapped a picture. I can feel a slight dip where the mark is so it isn't just surface finish removal:

http://i52.tinypic.com/1252nf5.jpg


I then fully loaded 3 PMAGs and 3 BCM mags. I made sure the rifle was plenty wet with slip2000. I loaded the first 30rd pmag, made sure it was fully seated by striking the bottom a couple times and tugging. I pulled the CH to the rear, paused, let go, round fed fine. Also note I had the rifle angled down pointing towards the ground (about 45degrees). I did this with other two pmags and switched to holding the gun parallel with the ground, they all fed fine. I then used the first BCM mag and holding it parallel to the ground it fed fine. I tried the second BCM mag and help it upward at about a 45degree angle towards the ceiling (about the angle you hold the rifle when reloading), it hung up like it's been doing:

http://i53.tinypic.com/xcvtq0.jpg

I used the last BCM mag again holding it upward and it hung up. I then went back to the PMAGS (topped them off) and did all three of them. 2 out of 3 PMAGS failed to feed when holding them upward toward the ceiling:

http://i51.tinypic.com/14cfehk.jpg

http://i56.tinypic.com/68zbe1.jpg

On a side note the PMAGS I used were previously lent to a friend who used them in a a VTAC class with a S&W M&P rifle. They worked fine and he didn't have any issues at all.

So is it safe to say that it isn't the bolt catch at this point? Does this indicate there is something "bigger" wrong with the rifle, like lower/upper tolerances, feed ramps, etc? Remember when at the class I used the instructors lower on my upper and it fed fine when I tried out a few different fully loaded mags.

I guess next thing to try is a stronger buffer spring. I don't have any spares, can someone advise a good choice for that?

Thanks for all the help guys.

[spamsammich]

Did you actually measure the buffer spring to make sure it is within spec?

[CarlosDJackal]

This is starting to sound like an out of spec receiver. Try someone else's lower and upper to see if it happens again and to which receiver.

If it happens to your upper, try another lower. If it happens again, then your upper may be the suspect.

If it happens to your lower, do the same. If it happens again then your lower is suspect.

[Serpico1985]

Ok guys. No I didn't measure the spring. Can you advise me how to do that and I will.

I will try to get a few guys to bring their ar's to work to try what you said, swapping them to try and figure out if its the upper or lower.

[Serpico1985]

37 to 38 coils, right at 3 inches completely compressed...

[ForTehNguyen]

there was a tolerance on the lengths of the spring, I cant remember what it was off the top of my head. I think carbine buffer springs are suppose to be around 11-11.5 inches uncompressed? Rifle buffers are longer around 14.

edit: I measured some of my carbine buffer springs that are known to be reliable. They were 10.5", 11", 10.75"

[Serpico1985]

Uncompressed it is 10.8 inches. I slipped the spring over a wooden dowel and measured that way....

[mowmer]

I regards to the lower being out of spec.. I found this sticky in the NFA section. Has some specs on what the lower should be.


4. Check all the pin holes to see if they are in spec. Trigger/hammer holes are .154” and takedown holes are .248”. The tolerances are +/- 0.001”. Anything more than that is out of spec. I don’t care what any blueprints say. You can take 100 lowers and measure them yourself. You will come up with these numbers.

5. Measure the magazine well. A good magazine well will measure .900” at the front and back and .970” at the slot. If you are less than this, you may have magazine drop free problems.-scottryan

[az doug]

Re-install the bolt catch and try your test again. If it functions the same then the bolt catch is eliminated as being a contributing factor. If it gets worse then the bolt catch may be adding to the problem. Personally I think the issue will be resolved with an extra power buffer spring.

[Iraqgunz]

Off the top of my head the proper length (per the TM) is 10 1/16 to 11 1/4 inches. I think the issue here is the lower receiver.

[Serpico1985]

I'll put the bolt catch back in and re-try when I get home.

I will also get on the horn with Noveske tomorrow and see what they say. Thanks for all the help guys.

[bvmbandit]

If the issue is with the lower being out of spec, then when a round fails to feed what does it do after the rear take down pin is pulled? Does the round feed then?

Scott

[Serpico1985]

Sorry, I don't understand what your saying...

[bkb0000]

i think he's suggesting you allow it to malfunction, and while malf'd, pull the takedown pin and see if that drops the bolt.

seems to me like you'd just bind the carrier up in the receiver extension- but i've never tried it.. so maybe he knows something i dont know.

[Serpico1985]

Ok. Thanks.

I have a call into Noveske right now, waiting on Joel to call me back.

[Serpico1985]

Spoke to Joel with Noveske. He stated it sounded like a out of spec LPK causing the hammer to drag on the bottom of the BCG robbing the BCG of enough inertia to feed the top round. He gave me a test to try. I should clean the face of the hammer, mark up with sharpie, cycle the action a few times and see if there are rub marks on the hammer. He also said it may very well be an out of spec lower receiver causing the above hammer drag. He recommened that I use a H1 buffer which I belive I already have in there and to lightly lube the buffer spring. he also said to ensure that the spring was in-spec.

I'm at work now I'll try the test when I get home. Joel was a nice guy and easy to deal with. He made it clear that if there is an issue with the lower itself, they would take care of it.

[AR15barrels]

How high is your cocked hammer protruding from the lower?

It's normal for the hammer to rub on the bottom of the carrier during cycling as the carrier is what causes the hammer to be cocked.

However, if the hammer or lower is out of spec, the hammer can cause excessive drag and that is a problem.
Sometimes it's only a little bit of metal that needs to be relieved to fix the problem.

The picture below shows how much was required in one case:

http://ar15barrels.com/tech/hammer-mod.jpg

[Serpico1985]

I have calipers and will take measurements when I get home as well as the marker test. I understand what your saying as far as the BCG must contact the hammer to cock it. Thanks for the info on relieving the hammer somewhat. I did not know that. I’ll try up post an update on what I find tonight.

[carbinero]

If you are replacing the buffer spring, why not use an eight dollar Colt one from SAW? I wouldn't switch from one unknown to another, when you are trying to nail down a problem. Best wishes: I feel confident the Noveske will be a winner once you iron out the issues.

[Serpico1985]

Roger that cabinero, If I need a new spring I guess I can't go wrong with a known quality maker like colt.


I did the bolt rub test when I got home. I cycled the action about 10 times, the hammer never dropped....

http://i53.tinypic.com/14kjdyq.jpg



Here's my next question. If the above rubb marks indicate that the hammer is rubbing on the BCG when cycling, which is not a good thing, how do I determine if it's an out of spec hammer or out of spec pin hole locations?

I have digital calipers, I have a set of gage pins from .061" - .250" so I can take some pretty exact measurements if need be. I guess the easiest answer would be to use a known in spec hammer and see if it's still rubbing, is so it must be the lower. I wasn't sure if someone had measurements for the pin hole locations on the lower relative to the top of the receiver.

The trigger pull on this bad boy is pretty horrible, I would easily say in the 10lb range so replacing it would be my pleasure.

Thanks again for all the help guys, I really appreciate it.

[ForTehNguyen]

if your trigger pull really does feel real heavy, I would recheck the installation of your LPK.

[az doug]

I personally do not like hammers that are notched on top. I like the hammers that are radiused at the top, like a F/A M-16 hammer. (No, I am not advocating using a F/A hammer unless it were properly modified. I use semi auto hammers with the same profile.) I do not have tangible proof, but I believe the notched top creates more drag on the bottom of the bolt carrier as the bolt carrier moves forward.

Also, I would get an "extra power" buffer spring. I believe this will alleviate your problem. The extra power spring should be able to overcome the pressure the hammer is placing on the bottom of the bolt carrier.

JMHO

[Serpico1985]

Sure I can recheck my work no problem. I can take the lower apart and make sure it is installed correctly. Is it possible for the lower to be assembled incorrectly and still function correctly for 1500+ rounds? Other than the feeding issue the gun hasn't experienced any malfunctions (I know, thats a big laugh, "other than the fact that is won't feed right it works %100").

Would there be any value in removing the fire control parts and leaving the mag catch in and testing feeding of the gun? If it feeds then it is defiantly the hammer right?

Also, I am a little confused. Doesn't the BCG have to be in contact with the hammer? The trigger is pulled the hammer drops, gun fires BCG starts moving to the rear and pushing the hammer back to re-engage the disconector/trigger. The hammer is pushed back enough to reset, hammer is still in contact with the BCG, if it wasn't it wouldn't be able to re-set right????

Maybe I'm over-thinking this whole thing.

[bkb0000]

you're right, and that's actually a good idea. pull the hammer, see if it happens. maybe pull the bolt catch, and see if it happens from a manual charge

[ForTehNguyen]

Im finding it hard to believe the trigger pull is that heavy. Have you compared the trigger pull to a working AR?

[sjohnny]

I'm pretty new to all this (I only have about 100 rounds through my first self built AR) but this looked like a red flag to me. Is this normal wear or is this an indication that the lower may be out of spec:
http://i52.tinypic.com/1252nf5.jpg

[Serpico1985]

Trigger pull...

Ok, probably not 10lbs, I guess I exaggerated. Probably closer to 7-8lbs. It is a little be heavier than my stock M&P .40, which should be 6.5-7lbs. I have a trigger pull gauge but it only goes to 4.5lbs. Sorry for the confusion. I don't have access to any other AR's at the moment to compare it too.

[Serpico1985]

Ok, I am about %99 sure that its the hammer dragging the carrier causing the issues. I pulled all the fire control parts (hammer, trigger, disco) and left the bolt catch out. It fed excellent from topped off mags. I added the bolt catch back and still left out the FC parts and it fed just as good....

[Serpico1985]

sjohnny,

I would like a answer on that too. Doesn't look right.

I spoke to Joel again and advsied him of the rubbing. He said to sent it in and they would look at in and fix it.

[bvmbandit]

I have noticed that on some of the LPKs the hammer pin hole was drilled/machined off center to where it should have been. So you may want to take a look at the hammer itself and see if you can find anything that does not look normal where the pin goes through...ie hammer pin hole off center...

In regards to my previous post, yes I was suggesting pulling the rear take down pin to alleviate pressure on the lpk only, not to bind the carrier. It looks as if you may have found the problem after all.

Scott

[wingo]

Is it the camera angle or do the marks on the hammer look like they are at an angle? Honesly the hammer looks to be in canted to the side(might be the pic or my eyes also). Im not sure what part that is on the side of your reciever, but maybe take that off also and use the stock hammer pin.

[Serpico1985]

It's the camera angle. That part on the side is the Boonie Packer Redi-catch. I did not have that part on the rifle when I went to the VTAC class and still had the failures. The redi-catch doesn't affect the rifle at all, it just replaces the hammer and trigger pins.

Noveske told me to send the rifle in and that it didn't have to go through and FFL. I called my local AFT office to confirm this, they said no problem. I'm gonna try to get it to UPS tomorrow before work. Joel said it should be a 1-2 day turn around.

I'll let y'all know the outcome.

[DBR]

One small thing comes to mind. The notched hammer presents a relatively sharp edge to the bottom of the bolt carrier. Are there any finish flaws on the bottom surface of the bolt carrier where the hammer rides? If there are it may act like a ratchet when the bolt tries to close.

[Serpico1985]

I just looked at the bottom of the BCG and found a strange wear mark.

http://i56.tinypic.com/15d2kg0.jpg

http://i51.tinypic.com/huo84w.jpg

Would this be where the hammer is rubbing? Could it have something to do with the bolt catch that was marred and replaced?

I didn't get to ship it today but picked up a box and will get it out Monday.

[DBR]

That surface is where the hammer rides as the bolt opens. The bolt is supposed to rub there. The hammer might be bouncing back after it is cocked and peening that spot.

It looks to me like that might catch the top edge of the notch on the hammer as the bolt was closing. You should try another bolt carrier if possible before you send it back.

[Serpico1985]

I shipped the rifle back to Noveske today via UPS. I lucked out and there was a gun guy working behind the counter. He hooked my up with a free box that was 5x smaller than the one I picked up to ship the rifle in and saved me on shipping.

I included 3 of each pmag and bcm mag, and a letter explaining all the issues I've been having. I wouldn't expect the Noveske folks to remember every conversation they have over the phone.

It should get there Tuedsay (next tuesday). Of course I'll let everyone know what the problem was.

[Darkop]

I shipped the rifle back to Noveske today via UPS. I lucked out and there was a gun guy working behind the counter. He hooked my up with a free box that was 5x smaller than the one I picked up to ship the rifle in and saved me on shipping.

I included 3 of each pmag and bcm mag, and a letter explaining all the issues I've been having. I wouldn't expect the Noveske folks to remember every conversation they have over the phone.

It should get there Tuedsay (next tuesday). Of course I'll let everyone know what the problem was.

I had the exact same problem you have described (except for the mark in the web of your lower from the bolt catch) This was with a Noveske 10.5 upper.

After checking each LPK part and finding them in spec and checking magazines and springs in magazines I finally checked the buffer spring for length. It was at minimum spec. I had an extra Wolff X-power carbine spring in my parts kit. I replaced with that and it has run without any problem since.

I belive your problem may be two fold. First the bolt catch/release, because of the marks left on your lower, I would replace that. Then I would replace the buffer spring with a known good spring.

I am old LEO and have always loaded my mags, including pmags to 28 rds to reduce problems with bolt closed reloads.

I have no doubt that the Noveske crew will find the problem and it will be corrected ASAP. I have 4 of their 5.56mm guns and one 7.62. I absolutely run the piss out of them and feed them crappy ammo and they just keep running.

Let us know the final outcome.

Until that day,
Darkop

[Serpico1985]

Darkop,

I replaced the original bolt catch that was marred up with one from G&R and it is good to go so far, no marring. I sent in the old one for them to look at.

I figured a extra power buffer spring would fix the problem but would only be a band aid. I'm sure noveske will figure it out. My department is considering allowing patrol rifles and I would like to be able to get this thing back and take it through another class before that.

Thank you for the insight. I appreciate it.

[az doug]

I understand your concern, but I do not think an extra power spring is a band-aide, I think it would fix the problem. I also think Noveske will fix it and may be the better fix.

Good luck.

[Serpico1985]

az doug,

Ok I hear what your saying. Here's my thinking, tell me if I'm wrong. I am thinking of this kinda like a 1911. Lets say you've got a feeding issue and rounds are hanging up. So you go out and upgrade to a 18lb recoil spring and the problem goes away. Now the original root problem is likely something to do with the feed ramp being out of spec or the barrel's feed ramp, or timing, etc...any number of issues more serious than an under power recoil spring. The recoil spring is a band aid of sorts.

Am I wrong to think that the rifle should be correct and in spec and not want to settle for a extra power buffer spring? My thinking is that if the rifle is in spec it will run better under unfavorable conditions, like dirty, or with a spring that's on the end of its life cycle.

I'm not arguing with you, I'm just relativity new to AR game and am always looking for more insight. Thanks.

[bkb0000]

as i said earlier- XP springs can be very useful for "fixing" guns that have hiccups. if it makes a gun work that wouldn't otherwise, and you've well tested it for reliability, there's nothing wrong with that.

[az doug]

Your asking the wrong guy as I run 18 lb recoil springs in all my 1911s and extra power buffer springs in most of my ARs. Eventually all my ARs buffer springs will be changed out. 16 lb recoil springs in a 1911 was a compromise to used for light and heavy loads. 14 lbs is the standard for a Gold Cup. Anyway we are off on another subject.

I do understand your point.

[Serpico1985]

Anyway we are off on another subject.


Agreed, this thread is a little long in the teeth for spring, LPK or out of spec lower issue.


Lighter 14lb-15lb recoil springs can be used with a small radius firing pin stop and a full 23lb mainspring/hammer spring and normal/standard duty loads. That setup was the original design of the 1911 and relatively quickly changed to make hand cycling the slide easier. It can also help keep the slide and barrel in battery while the bullet is exiting......side topic for another thread.


I appreciate all the info everyone's give me in the thread.

[Darkop]

Darkop,

I replaced the original bolt catch that was marred up with one from G&R and it is good to go so far, no marring. I sent in the old one for them to look at.

I figured a extra power buffer spring would fix the problem but would only be a band aid. I'm sure noveske will figure it out. My department is considering allowing patrol rifles and I would like to be able to get this thing back and take it through another class before that.

Thank you for the insight. I appreciate it.

I realize that you have sent your gun back to Noveske but wanted to state the following.

All AR platform weapons are not the same, just like many look alike items in life.

Depending on what ammo you shoot or if you switch back and forth between different ammo brands and weights (like I do) regularly and which magazine you run makes a big difference in how the gun operates. A lot has to do with different dimensions in the gun, IE: gas port size, gas system length, buffer weight, buffer spring strength etc. Some times a one way approach doesn't work all the time. I see several times a day on this site where some one will say run a carbine spring and H buffer "thats all you need". Some times, do to unknown reasons, a gun just doesn't run well even though we set them up "Right" and we have to change a few things until they do run correctly.

Please do not take this as a lecture, I just don't want you to be "afraid" to try different set ups on your gun just because it doesn't run setup like we "think" it should or what is the "norm".

That Noveske 10.5" upper I spoke of in my last post gets run with all kinds of cheap crap ammo, with and without a suppressor on it. I just tried different setups until it ran perfectly with crap ammo, with and without the can. I doesn't mean it was "out of spec" just that it needed a heavier spring to move the BCG forward with enough force to strip that top round from the mag and slam it into the chamber, lock the bolt and repeat for several thousands of rounds.

Anyway I know that Noveske will find out what is wrong and you will have something tangible that will run great and will last a life time.

CAN WE SAY THAT ABOUT MOST THINGS IN LIFE?
Back to lurk mode

Until that day,
Darkop

[az doug]

Do you carry an original 1911, not A-1, 1911? Do you use ball ammo and original magazines for self defense? Why not an original 1905 as designed by J. M. Browning? A 20 inch barreled 1/14 twist AR as Stoner originally designed? The fact is we evolve, even though some may argue that I have not, and designs can be improved upon. I do not buy into the “as originally designed“ theory. I am glad that I am not driving a Model A.

[Serpico1985]

Do you carry an original 1911, not A-1, 1911? Do you use ball ammo and original magazines for self defense? Why not an original 1905 as designed by J. M. Browning? A 20 inch barreled 1/14 twist AR as Stoner originally designed?

No
No
No
No


The fact is we evolve, even though some may argue that I have not, and designs can be improved upon.

Absolutly agree %100.



I do not buy into the “as originally designed“ theory. I am glad that I am not driving a Model A.

I agree. I wasn't trying to say the original 1911 set-up was the best and no improvement was needed. I was tryign to say some folks perfer that set up (small radius FP stop, full 23lb mainspring, lighter 14lb-15lb recoil spring) as they claim it has different recoil characteristics that they favor/prefer.

I think we're on the same page az.

[1_click_off]

Is the face of the bolt behind the case? Meaning is the bolt pushing down on the shell instead of pushing on the back of it? Once you slap the mag it raises the case just enough for the bolt to push it forward and not down? Do you have a picture of the jam from a view that we can see the face of the bolt and the back of the shellcase?

[Heavy Metal]

I just looked at the bottom of the BCG and found a strange wear mark.

http://i56.tinypic.com/15d2kg0.jpg

http://i51.tinypic.com/huo84w.jpg

Would this be where the hammer is rubbing? Could it have something to do with the bolt catch that was marred and replaced?

I didn't get to ship it today but picked up a box and will get it out Monday.

Check your fire control group and see if the tail of the hammer is making a groove in the tail of the disconnector and the trigger near the back of the disconnector.

[Serpico1985]

I just got off the phone with Joel at Noveske. He checked the rifle out and determined the feeding issue to be a under power buffer spring. He also recommened a H1 buffer for my rifle (midlength 16"). He stated the buffer spring I had was in spec, he meausred it and counted the coils but said it was just weak. He put a H1 buffer and a new spring inthe rifle and said it fed great even with 31 rounds in the pmags. He also said that the hammer drag wasn't excessive wasn't an issue.

Also, he checked headspace on the BCM bolt I've been using and advsied that it was barely in spec (close to max headspace spec) and recomended I use the issued bolt.

So I went ahead and bought a buffer spring, H1 buffer and the rifle and parts went out UPS today.

Thanks to everyone that helped. I feel like a learned a few things and can't wait to get to another class.

And yes, if a few of you guys want to say "I told you so" I can't argue. :sarcastic:

[bkb0000]

glad you got it sorted out. problems can be tricky to diagnose, especially when you build your own. just tolerance stacking alone can leave you with an assembly of good parts- but a weapon that doesn't work.

we're mighty lucky to exist in a time where there is a huge selection of quality parts to chose from. a home-built gun from quality parts and assembled correctly is unlikely to give you problems. the opposite was true back when i first started building- it was basically a given that the weapon wouldn't work right off the vise. you put it all together, file-fitting parts a lot of the time, and took your tools with you to the range for the first test-firing, and probably even the second.

good on Noveske for helping you out with that, also- a lot of manfers would just tell you you're on your own.

[az doug]

A little premature as you have not got the new spring installed and tested yet, but glad it is going to work out.

[Serpico1985]

Rifle back from Noveske with new buffer spring and h1 buffer it feeds with authority from all my mags topped off. Even with 31 rounds crammed into the PMAGS!

Thanks for everyone that helped me out. I appreciate it.

[ForTehNguyen]

so it was a bad buffer spring? good to hear its running

[Serpico1985]

Yep. Bad spring. It was in spec for length and # of coils but just weak. New spring and everything feeds great.

The folks at Noveske where great, same day turn around (my rifle was in their shop for a total of 3 hrs.), they sent me two new springs and a H1 buffer and didn't even charge me for return shipping (I didn't expect that since the problem wasn't with anything that was there fault)!

[86K5]

I am not calling into question Noveske's quality or people but I would still be concerned with the excessive wear on the original bolt catch and the receiver behind the bolt catch. I also see, in this case, this recoil spring as a band-aid. Relates to having trouble driving a nail? Get a bigger hammer. It would be one thing if the wear marks were not there and it was just having trouble stripping a round from the mag but... I am sure it is one of the problems but not the only. Think about this, not only is the bolt grinding on the bolt catch excessively, what is causing the wear on the receiver? There should be nothing contacting that point. The heavier spring is only providing more force against the drag created by the rubbing. Also, thinking about the mag. How does slamming on the bottom of the mag a few times make it chamber. I say the banging would make the BCG bounce a small amount to lessen the drag and allow it to chamber. I could be completely wrong, and I hope I am, but in this case I don't think so.

[Todd.K]

We replaced with a standard carbine spring.


This
http://i54.tinypic.com/2iros2o.jpg

Is probably caused by this (Notice the device attached to the bolt catch)
http://i52.tinypic.com/2nh3gxv.jpg

The bolt catch was probably pushed up slightly by the above device. During firing the BCG cycling would run into it and slam it back down, the "wear" spot is actually from the bolt catch impacting the lower at that point.

[shadow65]

Thats what I thought and the first thing I noticed. I've gotten awayfrom all the add ons. Some cause more problems than they are worth. But they sure look good.

[Serpico1985]

Hey sweet, a Noveske rep is in this thread! Thanks guys, y'all's turn around time seems like it would be pretty hard to beat :)

Just to clarify when I attended the VTAC class my rifle didn't have the "device" on it. The device is from Boonie Packer and I think is called the "redi-catch". If I'm not mistaken one of the moderators here, maybe Jay Cunningham, had one on his rifle and did a review of it, use to have it bookmarked. Anyway the redi-catch replaces the hammer and trigger pins. When you are not pressing on the redi-catch it is not in contact with the bolt catch at all (there is a gap between the two pieces). You press down on the lever and it rotates into the bottom of the bolt catch rotating it out to catch the bolt. So when firing I don't believe it would affect the bolt catch at all, I could be wrong, wouldn't be the first time.

During and after the class I noticed the heavy wear marks/gouges on the bolt catch (remember without the redi-catch installed). No one really had any good ideas what was going on. When I got back from the class I replaced the bolt catch with one from G&R and added the redi-catch. Since I've been back from the class I have fired about 200+ rounds with the redi-catch installed and other the failures to feed never had a problem. There aren't any gouge marks on the bolt catch now.

Just wanted to clarify that.

edited to add: I'm going to the range tomorrow to test fire/re-zero. Do y'all have some tips or things to look for while I'm there? Any tests that might be helpful in figuring out if there still could be an issue? I can take a camera with me.

[Serpico1985]

Went to the range today and only had time to put 90 rounds through the rifle. Didn't have any issues with feeding the fully loaded mags.

When I got home I started looking at the faint line that is on the new bolt catch. I locked the bolt to the rear and looked at it and found that the area of the bolt that is wearing on the bolt catch. When it was locked back I could see that the line leads straight to the second bolt lug rotating counter clockwise from the extractor. I pulled the bolt and look at the back side and found the following:

BCM bolt (1500 rounds on it along with the old damaged bolt catch):
http://i53.tinypic.com/e7chzo.jpg

Noveske bolt:
http://i56.tinypic.com/2a619qc.jpg

New G&R bolt catch, about 300 rounds on it:
http://i51.tinypic.com/11qrbk3.jpg

Redi-catch, notice the gap between the bolt catch and the redi-catch as I advised in my last post:
http://i54.tinypic.com/2ag14eo.jpg



It's hard to tell from the photo's but there is a wear mark on the rear of the bolt on the second lug rotated counter clockwise from the extractor. Its on the rear facing corner of the lug, the part that would touch the colt catch as the BCG is being locked to the rear on the last round. The BCM bolt has a more prounced "ding" (about 1500 rounds on it) than the Noveske bolt (as of toady 90rounds plus whatever was fired at the factory) but they are there. I looked closely at the other lugs and while they had a slight radius they defiantly didn't have the rub mark thats on the 2nd lug.

The wear on the new bolt catch doesn't seem to be getting any worse. I guess If I wanted to test is I could load a bunch of mags with one round to simulate the BCG locking back and see if the wear increases.