Problems with cycling on new 20in upper. PICS [Archive]

Devildog1988

03-04-12, 19:07

I traded my 16 inch upper for a 20 inch upper. I was told its a BCM upper but not sure. Its 1/7 twist 5.56. Its on a lower with an A2 stock and a KX3 muzzle break. The BCG is from my Stag. I experienced failure to cycle with the tulammo steel case(I know its bad but I had a box left over that I needed to get rid of). Failure to properly cycle with 45 grain brass cased and some failure to feed with 55 grain brass cased. Also double feeds with both. I think that that there was not enough gas pressure to push the bolt all the way to the rear for proper cycling (and was thinking about maybe clipping the buffer spring by a few links to lessen the tention. NO LONGER GOING TO CLIP SPRING ). I plan on cleaning the upper, lower, and BCG thoroughly, and clip the buffer spring and trying again. Any help or advice I can get would be appreciated. Thanks for your time.

http://img820.imageshack.us/img820/1765/1001582u.jpg
By devildog1988 (http://profile.imageshack.us/user/devildog1988) at 2012-03-05

http://img806.imageshack.us/img806/6697/1001581.jpg
By devildog1988 (http://profile.imageshack.us/user/devildog1988) at 2012-03-05

http://img850.imageshack.us/img850/8312/1001580r.jpg
By devildog1988 (http://profile.imageshack.us/user/devildog1988) at 2012-03-05

Rmplstlskn

03-04-12, 19:19

What buffer do you have in there?

I personally would never snip coils on any spring to get functionality. You have a problem somewhere, work it out, don't rig it....

Rmpl

jmart

03-04-12, 19:21

Clean and lube as you state. Also, before doing any spring surgery, you may want to try some higher powered ammo first to see if that improves functioning. If you've been running laquer-coated steel cased ammo (sorry, I'm not familar with Tula), then give the chamber a good scrubbing with a chamber brush and get out all the gunk and make sure there's no built up laquer or other case coating, sometimes that can retard extraction.

if upper is truly a BCM, then I'm betting the gas port is drilled to spec. I'd be real hesitatnt to go clipping springs until you take care of the other items first. If a thorough cleaning and ammo change cures your ills, then you may have to settle in on a class of ammo for proper functioning. or get a separate "softer" spring dedicated for the lower-powered stuff. But you may find that in tuning your spring to run properly on the low end, it's under-sprung for NATO-class loads.

Fried Chicken Blowout

03-04-12, 19:23

I don't own a dog, but I'll still treat you right...

Keeping in mind that you are dealing with a rifle length gas system I would look at how clean everything was. Was it lubed properly? Is the buffer spring old? What buffer are you using? Any chance the gas block is misaligned or loose? Any chance your gas rings are warn? Does it hand cycle okay? Is the gas key loose? What is the condition of the mags? Was the issue all from the same mag? Will it run with M193? Did it lock back the bolt on the last round of the mags? I have no doubt that it won't cycle 45gr ammo. You may have to play with your setup to get that to happen. Full boat 55gr ammo would be concerning.

I have some 55gr match loads (light 3-gun hand loads) that run great in my mid-length and carbine length gas guns, but won't run my 18" rifle length gun. Check out the other stuff and see what you come up with. I wouldn't start cutting the buffer spring.

N2CH_556

03-04-12, 19:33

Clean thoroughly, and lube until sloppy, dripping wet.

Then, try some true 5.56x45 NATO ammo (e.g., M193 or M885) and I'm sure you'll find it runs just fine. Since the BCM gas port is in-spec (and not-oversized/over-gassed like other commercial uppers), you may encounter some issues running weak, under-powered .223 ammo. BUT it should run the hot stuff perfectly.

You may also want to check the lower. Does it run with other uppers just fine, or with similar problems?

ETA: although no break-in is required, after a few hundred rounds of 5.56 NATO it may start to function with steel cased .223.. maybe. Good luck.

Devildog1988

03-04-12, 19:56

Thanks for all the help so far guys. I forgot to mention when I got it, the guy gave it to me pretty dirty and I didnt clean it before firing. To answer a few questions.

Rmplstlskn- Your right, Ill take more time and fix it right.

Jmart- Today is the first time I have fired it and the guy I got it from said less than 100 rounds but we didnt get into what kind of ammo was fired through it. Ill clean it up and run some of my green tip through it.

Fried Chicken blowout- First off you should get a dog lol jk. The rifle was pretty hanous and I didnt get a chance to clean it before I fired it. It was lubed properly, I generously added Rem Oil before and during firing. The buffer spring and buffer are both new. I dont think the gas block is misaligned because its secured with the taper pins. The gas rings where gtg, I checked them during firing. The issue was the same with all my PMAGS and a bushmaster mag. I did not tr M193 ammo, and the bolt did not lock to the rear after the last round.

N2CH 556- Ill clean it and lube it. Then Ill run some green tip through it. The lower does good with every other upper I tried it with. When firing I tried swapping it and found that the 20 inch did run slightly better with a milspec 6 position stock.

Bonez556

03-04-12, 19:57

There could be a few things that could be causing. First thing is always make sure it is propery cleaned and lubed. If you rin it dry you will definately start having issues. And second, if you have a rifle length gas system on that 20" gun the cheaper steel cased ammo isnt hot enough to properly cycle the action. I ran into this same issue on one of mine. I changed almost everything before someone told me that it wouldnt cycle that cheap stuff. I swithed to a better ammo and it cycled fine. I hope you get it figured out.

Devildog1988

03-04-12, 20:05

Thanks Bonez556. Ill quit using the steel cased. I plan on cleaning it and only running heavier grain bullets with more pow. Do you all think it would help if I get a used buffer spring, might not have all the tension? My buddy offered to give me one.

TacMedic556

03-04-12, 20:10

Would you mind posting some photos of the upper on both sides and the stamp on the barrel? If it is a BCM it should have some identifying markings. Would be nice to know which upper you are dealing with for sure.

MistWolf

03-04-12, 20:15

Devildog, you mentioned a problem with double feeding. A double feed is when two cartridges are stripped from the magazine and that is a magazine problem. Get rid of that magazine.

If your problem is that an empty case is extracted but not ejected before the before the bolt strips the next cartridge from the magazine, that is a failure to eject and/or a short stroke. If this is the case, after cleaning and lubing your BCM, load a single round in the magazine and fire it to see if the bolt locks back on an empty magazine. If it does not do so consistently (you may have to perform this test several times) your rifle is short stroking. Gas leaks, underpowered ammo, too heavy a spring rate, too small gas port sizes and misaligned gas blocks all contribute to short stroking. Start with trouble shooting the easiest items first. Check for signs of gas leaks around the gas block at the barrel and gas tube. Borrow a known good action spring and buffer. Clean and lube the rifle. Try good standard 5.56 ammo.

While checking your rifle by loading and firing single rounds, it will become obvious if the ejector is working.

Good luck and let us know what you find. Hopefully it's something as simple as the rifle needing a good lubing

Col_Crocs

03-04-12, 20:32

^I agree. Also, you mention using a used BCG from another weapon? I dont know what level of use it has seen but you might want to go over it as well -- Gas rings in particular.

RichDC2

03-04-12, 20:58

Losing the KX3 on a 20" can't hurt;)

Iraqgunz

03-04-12, 23:27

1. Get rid of the silly KX3. It's not needed on this rifle.

2. Do you have a fixed FSB or did someone screw with it?

3. Try some decent M193 or similar ammo.

Devildog1988

03-05-12, 19:26

TacMedic556- Got pics up.

Mist Wold- The mags only had problems when firing with that rifle. The bolt does not lock back to the rear after the last round. But when I match the same lower to a carbine upper it does so I dont think the problem is in the spring.

Rich- I love the look of the KX3

IraqGunz- I like the KX3 and I think that if anything it is helping because its designed to create more gas pressure. The front sight is fixed, I see no signs that it was ever removed.

ryan

03-05-12, 20:29

Ok you like the "beer can" and extra weight it adds to the wrong place on a rifle , fine to each their own.

Take it off and test fire without it, if the rifle functions without it, throw it in the river, if the rifle still has issues screw it back on.

Devildog1988

03-05-12, 21:49

I added it because it supposed to use the gas created more efficiently to cycle the bolt and also reduce recoil for follow up shots. Ill take it off though and see what happens.

Update- I cleaned the heck out of it and it was filthy. The worst I have ever seen. Im hoping that all the muck in it was creating resistance and kinda bogging down the bolt. I put the rifle away with the bolt locked to the rear to maybe loosen up the new spring for next time I go shooting. Next time I go shoot Ill take some green tip, shoot a few rounds and if I still see no difference Ill take off the KX3 and put on a bird cage. Am I forgetting anything else?

TacMedic556

03-05-12, 22:03

There are no markings on the barrel or upper to indicate it is a BCM. Interesting. Hopefully the true experts on here can figure it out.

ryan

03-05-12, 22:05

I would put new gas rings on the bolt just for insurance ( they are cheap) and a known good bolt carrier with you to the range if you have one ( if you dont, you need a spare anyway).

Devildog1988

03-05-12, 22:09

I hope someone can help me figure out who made the upper then. I need an extra bolt carrier.

ryan

03-05-12, 22:21

http://m4carbine.net/showthread.php?t=5357

That is a start anyway, Iraqguns or Robb Jensen would be the ones who would really know, it does not look like my BCM but I'm not sure.

Devildog1988

03-05-12, 22:38

So I think the brand is CMP. or IDK.

SMETNA

03-05-12, 22:40

OP,

You mentioned RemOil back there somewhere. Although its not likely causing your issues, it's a bad lube. One of the worst in fact. The only redeeming quality is that it's cheap.

Many here swear by Froglube or Slip2000 Ewl. Hell some even use synthetic engine lube. Any of these will be an improvement of varying degrees over RemOil.

Heavy Metal

03-05-12, 22:41

There are no markings on the barrel or upper to indicate it is a BCM. Interesting. Hopefully the true experts on here can figure it out.

Aren't those marking Colt?

Iraqgunz

03-05-12, 22:48

That is a Colt barrel, not BCM. Basically someone has sold you a Frankenupper.

Devildog1988

03-06-12, 08:54

Thanks Smetna, Ill try wd40 or regular clp.

Heavy Metal Iraqgunz- Thanks for IDing the upper. Ive never owner a franken rifle. Any drawbacks?

Heavy Metal

03-06-12, 09:04

hotrodder636

03-06-12, 09:20

That is a Colt barrel, not BCM. Basically someone has sold you a Frankenupper.

Not a 100% here but I don't think your upper was actually ID'd, just the barrel...

Devildog1988

03-06-12, 09:39

K Ill take off the KX3 :angry: lol. Anyone here wanna trade a muzzle device for a KX3?

Devildog1988

03-06-12, 09:47

Since I have a 20inch barrel, Is there a certain type of buttstock I need to stick to?

Iraqgunz

03-06-12, 12:34

You should stick with a standard rifle stock or you should go with the Vltor A5 system.

Since I have a 20inch barrel, Is there a certain type of buttstock I need to stick to?

Devildog1988

03-06-12, 12:38

Thx Gunz, Ill keep what I have now then, minus the KX3. Im going to replace the gas tube with a Spikes Tactical Melonite gas tube.

Iraqgunz

03-06-12, 12:42

Why? Is there something wrong with it now?

Thx Gunz, Ill keep what I have now then, minus the KX3. Im going to replace the gas tube with a Spikes Tactical Melonite gas tube.

Devildog1988

03-06-12, 12:50

The tip of it that mates with the bolt is a little serrated. IDK if it makes a difference but it couldnt hurt to replace it.

Devildog1988

03-06-12, 13:23

Anyone want it? Trade for a different muzzle device. TRADED FOR A ARES ARMOR EFFIN A COMP

http://img27.imageshack.us/img27/6099/1001583b.jpg
By devildog1988 (http://profile.imageshack.us/user/devildog1988) at 2012-03-06

dennisuello

03-06-12, 13:55

I put the rifle away with the bolt locked to the rear to maybe loosen up the new spring for next time I go shooting.

All coil springs loosen up by cycling them, keeping it compressed won't do squat.

Devildog1988

03-06-12, 14:15

I disagree. I was a custodian in the armory for a while and the ORDO told us to make sure all bolts are sent home when we take weapons in because they loose tention if they are locked to the rear for a long time.

Devildog1988

03-06-12, 15:14

I traded the KX3 for an effin a comp.

Col_Crocs

03-06-12, 17:23

Could you post a pic of your gas tube? Also, there's no need for the melonite treated tube. Standard ones work just fine.
Have Checked your BCG yet?

Devildog1988

03-06-12, 17:40

Yea I checked the bolt, inside and out, everything is good. Ill post a pic in a bit.

Devildog1988

03-06-12, 17:48

You can kinda see how the tip of the tube is not really neatly rounded off like otheres. Its sharp and jagged looking. I put a melonite gas tube in my carbine, looks and functions well.

http://img585.imageshack.us/img585/9013/1001587k.jpg
By devildog1988 (http://profile.imageshack.us/user/devildog1988) at 2012-03-06

http://img846.imageshack.us/img846/9462/1001586y.jpg
By devildog1988 (http://profile.imageshack.us/user/devildog1988) at 2012-03-06

Devildog1988

03-06-12, 17:51

That looks really jagged and nasty.

RichDC2

03-06-12, 19:07

IMHO if you are using this rifle for ANY type of self/home defense I would take it to someone knowledgeable in AR's for a complete inspection and learn as much as you can as well (on this site) before you change any parts. You do not know who built it, what parts were used and how well it was put together. Not something to trust your life on. Good Luck!

Devildog1988

03-06-12, 19:23

Ive asembled several ARs and can do pretty much anything when it comes to them Ive just never owned a 20 inch and though I might get some help from some of M4C members.

Snake Plissken

03-07-12, 14:33

I can already see it is not a BCM of any sorts because the interior of the upper does not have the characteristic BCM blotching from their lubing operation. I actually have a 20" M16 upper from BCM and none of the markings match up. As IraqGunz said, it's a frankenupper for sure.

If the gas tube is being chipped in that fashion it appears the gas key is not aligned with the tube upon the bolt carrier moving forward after returning. Potential causes I can imagine are an improper taper of the end of the tube, improperly staked and out of spec gas key and/or bolt carrier, the bolt carrier in an out of spec receiver allowing too much slop, or an out of spec gas key. Consensus of this: replacing the gas tube will probably end up with the same thing that it is now if the bolt carrier and gas key or receiver are bad.

Get a photograph of the bolt carrier. All I can suggest at this point is get this upper running and sell it and then buy a BCM (or other quality manufacturer)....or sell it for parts (separating parts yields greatest costs) and then buy a BCM (or other).

Devildog1988

03-07-12, 14:44

Hey thanks. Ill take apart the whole upper and see what I can find. :mad:

BUBBAGUNS

03-07-12, 14:47

From the pics of the barrel you posted, I looks like a colt barrel to me. My Colts have the same markings.

BUBBAGUNS

03-07-12, 15:05

Since I have a 20inch barrel, Is there a certain type of buttstock I need to stick to?

You should be able to use you standard A2 or a collapsable stock. If that is what you are asking.

Iraqgunz

03-07-12, 15:44

Sorry to tell you this, but the ORDO was wrong. Springs lose life from cycling not being under pressure.

I disagree. I was a custodian in the armory for a while and the ORDO told us to make sure all bolts are sent home when we take weapons in because they loose tention if they are locked to the rear for a long time.

Devildog1988

03-09-12, 17:10

Update-

Went shooting today after taking off the KX3 and putting on a Effin A compensator. I did as everyone suggested and the rifle cycled a whole lot better. I cleaned the heck out of it, switched from rem oil to wd 40 (saw a big difference), used new PMAGS, and made sure the gas rings where good to go. Everything was gtg except that I still had a few double feeds, 2 if I remember correctly. Also the bolt was still not locking to the rear after the last round. Was using 55 grain brass cased ammo. I can see now where the KX3 was messing up my cycling. Ill post pics up soon of the new set up. I wasnt able to replace the gas tube yet though because it seems that all websites are not carrying the Spikes melonite tubes in rifle length. To be honest though, Im kinda over the 20 inch barrels and I think Ill move down to midlength.

RichDC2

03-09-12, 17:42

The melonite gas tube will be of no benefit to your rifle. Can you specify the brass cased 55 grain ammo, it can be the culprit to your problems if it is low powered.

Devildog1988

03-09-12, 17:54

Its 55 grain Hornady V Max. I reloaded it with 25 grains of benchmark, max is 25.6 grains. The Melonite gas tube is more heat resistant and resists corrosion better. also the finish is non reflective. I can see the shiny gas tube through the top of my magpul handguards.

An Undocumented Worker

03-09-12, 19:04

It looks like the gas tube that is currently in there was struck squarely with the gas key, replace it with a standard gas tube and make sure it is properly aligned. Make sure the gas key is tight, if it came loose at some point it could have caused the damage to the gas tube if that is the case the seal between the key and the carrier may be suspect. Also check the barrel nut to see if it is pushing the tube to one side or the other. It may not hurt to pull the FSB and make sure everything is good there.

tonyxcom

03-09-12, 21:17

The Melonite gas tube is more heat resistant and resists corrosion better. also the finish is non reflective. I can see the shiny gas tube through the top of my magpul handguards.

The melonite tube is of no value to you if you can't get one to replace your damaged one, leaving you with a malfunctioning upper. Why get frustrated with 20" barrels if looks are more important than fixing an undergassed upper.

We are talking about a $13 dollar part here. Who cares if it corrodes over the next several years. And since when did a gas tube need to resist heat?

Devildog1988

03-09-12, 21:38

Take a look with at a full length rifle with magpul handguards. the gas tube is like a mirror, reflects so much light, pretty much saying here I am, shoot this way. (in a SHTF scenario) If i can get the melonite tube I will. Everything on ARs is preference right?

tonyxcom

03-09-12, 21:46

Sure, I just prefer mine to work first, look the way I want second.

If you want melonite, get it. We said our peace and don't really care if you still want it. But your previous post gave me the impression that you wouldn't even bother replacing it if you couldn't get a melonite one.

ryan

03-09-12, 21:48

If you have gotten close enough to see my gas tube in the situation you describe you have much bigger problems, get what's available get several.

RichDC2

03-10-12, 00:59

Paint is your friend

Jaysop

03-10-12, 02:06

J_Dub_503

03-10-12, 02:37

SMETNA

03-10-12, 03:38

Instead of using wd-40, use some motor oil or firearm lubricant. There is now way possible that you could get your rifle lubed properly with wd-40. After you spray it on the aerosol evaporates and leaves an extremely thin layer of oil. Use something with a higher viscosity and run it wet and you'll have a lot smoother action.

Thank you. I gave it the old college try, but then he came back talking about Water Displacement formula 40 (worse than RemOil as lube), and I gave up because he obviously didn't grasp the concept of real lube vs random grocery store liquids. Plus, the shiny gas tube betraying your position comment . . .