Feeding Problems w/ 6.8 Upper -Help

[musashi666]

Ok guys here is my story... grab some popcorn and a Coke...

I bought a custom 6.8 Upper from a reputable dealer. Got it after waiting many weeks and loved it. Until I brought it to the range. When I drop the bolt release the round jams up in the feed ramps (M4 ramps) and pushes the bullet back into the case. When I pull the C-Handle back and release, it slams the bullet even further back into the case. Repeat as above again and the round chambers but is waaaay seated back into the case & honestly dangerous to shoot.

After I fire the 1st round, usually rounds feed properly but it still has malfunctions. I am using CProducts mags (6 of 'em).

I contacted the dealer and he said "sounds like mag issues. Probably not the upper because everything on the upper is pretty straightforward." So, I contact Larry @ CProducts, send him my mags, he is testing them now but there seems to be zero problems with the mags. (BTW, CProducts has been GREAT at working with me. They have been very professional and helpful!)

I called the dealer re: my upper on Friday but have not recieved a call back yet.
It is a CMT upper /M4 feedramps. Everything looks ok.

What could it be? I understand the dealer about the upper but what are some possible problems? I'm upset that I have ruined lots of expensive 6.8 ammo w/ this upper & I still have problems. I've shot about 200 rounds w/ it so far. V-Max bullets feed fine, everything else jams.

HELP me Obi-Wan Kenobi, you are my only hope! :(

[Nitrox]

CProducts has put out a lot of bad mags over the last two years. If it were me I would try some other brands regardless of what CProducts tells you is going on with their mags.

[Derek_Connor]

I also agree. Different mags would be the very first thing I would try differently. Do you use any of the Magpul anti-tilt followers? Did those come w/your Cproduct mags?

If you can't answer this question, I'll understand, whoever built this precision upper for you, did they test fire it for functioning?

[AR15barrels]

This seems to be a very common problem.
One solution that has worked good is to tweak the mag lips so that the bullet tips actually hit the feedramps.
It's common for the bullet tips to hit low.

Here are a couple pictures of what you want to end up with:

http://www.ar15barrels.com/tech/68front.jpg
http://www.ar15barrels.com/tech/68front2.jpg


Basically, you bend the front of the lip about 0.020" upwards, tapering back to no change at the rear.
This raises the bullet tip about 0.040", making it hit the feedramps properly.
I suggest either 4" crescent wrench or needle nose pliers, whichever you are more comfortable with...

[musashi666]

The mags DO have magpul followers.

It kind of bothers me that I may need to modify and tweak my mags simply to get them to function. I like the price of the CProducts mags but if they don't work properly...

PRI would be the only other option and they charge 2X as much for a mag and I still hear of people bending the feed lips on their mags as well.

This is quite frustrating. Thanks for the repsponses guys. When I get the mags back maybe I'll try bending the lips.

[C4IGrant]

It is really hard to troubleshoot these issues over the internet. Have you loaded one round into the mag and chambered it?

I would also get somone to load the weapon for you so you can actually watch the round getting stripped off the mag and see what it is doing.

You could try a PRI mag, but from what I hear, they have a lot of issues with their mags (at double the price of a C Products 6.8).


C4

[musashi666]

It is really hard to troubleshoot these issues over the internet. Have you loaded one round into the mag and chambered it?

C4

I agree. It's hard to know what I have tried or how experienced w/ the weapon I am.

I have the feed problems w/ 1 round loaded, 3, 5, 15, 25, it does not matter how many rounds are in the mag it still jams while feeding.

And I totally agree about the price of the PRI mags.

So fellas, is it POSSIBLE that the problem could be the upper? No one has mentioned that yet. I'm not sure how it could be but I'm not an expert which is why I ask.

Thanks guys.

[C4IGrant]

I agree. It's hard to know what I have tried or how experienced w/ the weapon I am.

I have the feed problems w/ 1 round loaded, 3, 5, 15, 25, it does not matter how many rounds are in the mag it still jams while feeding.

And I totally agree about the price of the PRI mags.

So fellas, is it POSSIBLE that the problem could be the upper? No one has mentioned that yet. I'm not sure how it could be but I'm not an expert which is why I ask.

Thanks guys.

I am guessing that you have tried all 6 mags and they all exhibit the same problem?


C4

[musashi666]

Correct sir. I tried all 6 of 'em. All had similar results. I even tried some standard 5.56 mags loaded w/ 1-3 6.8 rounds... jams.

[AR15barrels]

It is really hard to troubleshoot these issues over the internet.

Please load all 6 mags with at least 5 rounds.
Lay them all side by side, on their backs so the bullets are pointing upwards.
Take a picture of this and post it here or email it to randall@ar15barrels.com.

What I want to see is the location of the bullet tips in relation to the front of the magazine.

If the bullet tips are sitting low, that's absolutely the problem.
The mag tweak helps uppers with or without M4 feedramps, but you have to raise the bullet tips a little more for non-M4 ramped uppers.

Here are a couple side view shots.

http://www.ar15barrels.com/tech/68magfix.jpg
http://www.ar15barrels.com/tech/68magfix2.jpg

Notice how the round is sitting higher afterwards.
That's about how the rounds should look sitting in the mag.
The ones that were lower were having feeding problems.

[musashi666]

The mags are w/ Larry @ CProducts right now. When I get them or some new ones back I'll take some pics for you.

So EVERYONE here that has read this thinks that the problems I am having are 100% mag related?

[C4IGrant]

The mags are w/ Larry @ CProducts right now. When I get them or some new ones back I'll take some pics for you.

So EVERYONE here that has read this thinks that the problems I am having are 100% mag related?


I do not. I highly doubt that all 6 mags are bad (especially shince Larry is using them without issue). Since you get the same thing with USGI mags, then I think it is your upper (most likely you BCG).


C4

[DocGKR]

As I posted previously, we've seen problems with our C-Product magazine dimensions--some are very tight fitting in our Colt mag wells. On the other hand, we have not had any failures to feed with our PRI mags in Barrett, MSTN, and PRI uppers nor in our 6.8 mm Robinson. I suspect Randall's advice is quite relevant to your problem and his council should be carefully considered...

[AR15barrels]

I have been at the range with a customer having problems with his C products mags.
He had about 10 of them, maybe it was an even dozen.
ALL had the same problem.
As I tweaked a couple of them with needle nose pliers (not the optimum tool for the job), the problems went away.
The bullet tip absolutely MUST hit the feedramp in order to feed.
If it's hitting low, you will have problems.

Look at your upper.
Are there little copper marks just below the feedramps from where the bullets were getting jammed?
That's the tell-tale sign...

[CProducts]

CProducts has put out a lot of bad mags over the last two years. If it were me I would try some other brands regardless of what CProducts tells you is going on with their mags.
__________________

That certainly a very broad, general statement. Is this first hand experience or something you have heard? And in your mind, what is a lot?

We have tested the magazine in question in a Bushmaster without problems. Tuesday we are going to Stag Arms and do some testing there. As I have told the customer as well as anyone else who has a problem with one of our products...after we test it if we are wrong we will admit it and make the correction, and replace the defective magazine at no charge. Since we have introduced the 6.8 we have had a hand full that had a problem and everyone was the follower hanging up.

Larry
C Products

[Nitrox]

Larry,

My intent is not to insult you but I think it is not truthful to suggest that CProducts didn't have a lot of problems with the initial magazines. In addition, people who bought the bad mags were promised 2 good in exchange for 1 bad...and the promise was not kept. The mags I bought ended up getting thrown away rather than deal with CS.

The picture above clearly demonstrates the problem which is the feed lips, not the followers.

Like I said, try other mags before it is decided it is not a mag related issue.

And to answer the question: And in your mind, what is a lot? An entire production run.

[AR15barrels]

The picture above clearly demonstrates the problem which is the feed lips, not the followers.



In Larry's defense, the first two pictures above (single mag pictures) are of a PRI mag.
I am not sure what brand the two mags in the 2nd pictures are as those pictures came from someone else.

I don't own any C-products mags.
It's not because I don't want them, but because I can't get them...

[Stephen_H]

I have have had basically 100% reliability with my CProducts 6.8mm Mags. Not so with the PRI mags I had (stress had because I got rid of them in leu of all CProducts 6.8mm mags). I would try mags from a different manufacturer.

Something I would also consider is changing out the buffer to something heavier. If the bolt/bolt carrier are moving too fast I have found that the cartridge may not be in an ideal mag position when it is picked up by the bolt.

HTH

Stephen

[musashi666]

I am using a Bushmaster lower w/ an A2 stock and rifle buffer. That's the heaviest buffer there is I believe.

[AR15barrels]

Here is Slash's buffer chart:

http://www.ar15barrels.com/tech/buffers.jpg

[Sean King]

Any chance this *might* be an ammo issue? The reason I ask is I am new to 6.8 as well. What ammo is the original poster using and has he tried any other types?

I bought 11 CProducts mags over the 4th of July sale (and got a free one with my LW upper). I will tweak the feed lips as needed (unless Larry says not to).

I also recently bought 1200 rounds of SSA's new Extreme (small rifle primer) 6.8 SPC from Art. The tips of the bullets are EXTREMELY blunt and I'm a little concerned that they won't feed at all. The only reason I mention the tips is that I know with my Dad's Colt A2's, we had problems feeding anything that didn't have very pointed tips.....although I'm sure his uppers didn't have M4 feed ramps.

I'm waiting on SBR paperwork before I can actually assemble this upper on my lower, but I'm curious as to other's opinions.

Thanks for any advice.

Sean

[AR15barrels]

I also recently bought 1200 rounds of SSA's new Extreme (small rifle primer) 6.8 SPC from Art. The tips of the bullets are EXTREMELY blunt and I'm a little concerned that they won't feed at all.

Congratulations.
You have 1200 of the main reason mag lips need to be tweaked.
I believe that those blunt noses contribute to feeding problems that we see in the 6.8.
Personally, I have never experienced feeding problems with any 6.8 upper during test firing and I test fire every barrel I build, but then I have only test fired with remington ammo.

It's a sad state we are in where everyone buys the absolute cheapest ammo and then frets about their rifle not working well when they work great with better ammo.

You know how the QC triangle goes, you can have it cheap, you can have it fast or you can have good quality, pick any two...

[Sean King]

Congratulations.


It's a sad state we are in where everyone buys the absolute cheapest ammo and then frets about their rifle not working well when they work great with better ammo.



Cheapest???? At 58-59 cents a round, it's about the same as Remington (since you can get 20 for $11.79 or $.5895 cents per round from SG or any other number of vendors).

The reason I bought SSA was b/c just about everyone on Arf.com was saying how Remington's brass was too soft in the tacked 6.8 thread and many people were writing glowing reports of the SSA ammo and that they wouldn't be buying Remington.

Please check the attitude until you have the facts of my particular situation. I wasn't trying to be cheap.....perhaps I bought unwisely based on hype, but how was I to know any better? ***EDIT*** I will add that the friendly exchanges between you and Art in the 6.8 pinned thread don't make it readily apparent that you have a distaste for his "cheap" ammo.

Sean

[C4IGrant]

Soft tip or wad cutter type ammo will give any weapon troubles (whether it is a 1911 or an AR). AMMO sounds like it is the issue. Got any other ammo you can try?


C4

[AR15barrels]

Cheapest???? At 58-59 cents a round, it's about the same as Remington (since you can get 20 for $11.79 or $.5895 cents per round from SG or any other number of vendors).

The reason I bought SSA was b/c just about everyone on Arf.com was saying how Remington's brass was too soft in the tacked 6.8 thread and many people were writing glowing reports of the SSA ammo and that they wouldn't be buying Remington.

Please check the attitude until you have the facts of my particular situation. I wasn't trying to be cheap.....perhaps I bought unwisely based on hype, but how was I to know any better? ***EDIT*** I will add that the friendly exchanges between you and Art in the 6.8 pinned thread don't make it readily apparent that you have a distaste for his "cheap" ammo.

Sean

In general, I would try a few boxes of each ammo to see how it works BEFORE I bought a case or more.
Hopefully, you have no feeding trouble with the extreme bullet.
This has not been the case for many people though.
I have helped a lot of people tweak their mags.
Most of them are not even my customers.

I did nothing to give the extreme bullet it's reputation.
It earned it on it's own merits.
I have no problem with Art's ammo and we are on good terms.

I just really don't like that extreme bullet.
Art's been screwed by it a little too because it can't hold up to max pressures like traditional jacket & core bullets can.
When pushed to max presures, the tail of the bullet would obturate into the neck relief and then sometimes leave a copper ring which elevates pressures in subsequent rounds.
The solution was a longer throat that would support the tail of the bullet while it obturates.
By the fact that large quantities of this ammo made it to market quickly, the barrel makers were forced to re-work chambers so that the extreme ammo would be safe.
That's where my animosity towards that bullet stems from.
I'm sure it's a love/hate relationship for Art too, having to deal with complaints and make appropriate reductions in pressure/velocity to make it safe for everyone.

For the record, I have not had any problems with Remington ammo and that's what all my test firing is done with.

[Sean King]

In general, I would try a few boxes of each ammo to see how it works BEFORE I bought a case or more.
Hopefully, you have no feeding trouble with the extreme bullet.
This has not been the case for many people though.
I have helped a lot of people tweak their mags.
Most of them are not even my customers.

I did nothing to give the extreme bullet it's reputation.
It earned it on it's own merits.
I have no problem with Art's ammo and we are on good terms.

I just really don't like that extreme bullet.
Art's been screwed by it a little too because it can't hold up to max pressures like traditional jacket & core bullets can.
When pushed to max presures, the tail of the bullet would obturate into the neck relief and then sometimes leave a copper ring which elevates pressures in subsequent rounds.
The solution was a longer throat that would support the tail of the bullet while it obturates.
By the fact that large quantities of this ammo made it to market quickly, the barrel makers were forced to re-work chambers so that the extreme ammo would be safe.
That's where my animosity towards that bullet stems from.
I'm sure it's a love/hate relationship for Art too, having to deal with complaints and make appropriate reductions in pressure/velocity to make it safe for everyone.

For the record, I have not had any problems with Remington ammo and that's what all my test firing is done with.


Randall,
Thanks for the explantion. I apologize if my reply was a bit curt. The truth is: I'm a complete newb to 6.8 and I made the apparently ignorant assumption that the ammo issue was good to go regardless of who was making it. Not until AFTER I ordered my upper did I find out about the discrepancies with the SAAMI spec and I had no idea that the Extreme would have the blunt tip it does. Knowing what I know now, I was extremely stupid to buy a 1000 rounds (there was a billing error and I had Art pay the overcharge to me with more ammuniton) without first trying it. Coming from a .223 or 5.56 background, I didn't foresee any real issue as this first thousand was just to break in the rifle and most brass cased 5.56 is decent enough for this purpose. Apparently not so for 6.8.

In any case, thanks for the education. I guess the old saying still holds true. "Education is what you get when you read the fine print. Experience is what you get when you don't." This is going to be an expensive "experience" for me if the Extreme won't feed in my upper.

Thanks for the reply.

Take care,
Sean

[AR15barrels]

Randall,
In any case, thanks for the education. I guess the old saying still holds true. "Education is what you get when you read the fine print. Experience is what you get when you don't." This is going to be an expensive "experience" for me if the Extreme won't feed in my upper.



If the Extreme won't feed in your upper and mags as it comes, look at where the ammo is hitting and tweak the mag lips accordingly.
It's really that simple and it's not a big deal.

[SuicideHz]

I built an upper over the last two weeks for a friend who just moved up and got into AR15s. I used an LMT upper I had along with a brand new CMMG barrel with M4 extensions. We got through 30 rounds before having a FTF every other round. It appeared the left ramps didn't line up so I cleaned them up with a battery powerd teenie weenie dremel. I cleaned up both ramps. Then every round jammed while loading manually.

Eventually that same night I realized that the ramps were not the same as on my WOA SS barrel- my ramps widen as they approach the bore. The CMMG's do not and it was the narrow channels for the bolt lugs that were still very sharp from being so new that were grabbing every round and holding onto them.

Check your jackets for deep grooves on each side.

I ended up using 800 grit sandpaper wrapped around a 1/8" dowel to slowly polish the ramps in the upper and extension by hand.

It seemed to do the trick.

My pre-ban Labelle's didn't jam as bad as his new midwayusa stoner (c-products) mags but they still had a few. Problem was totally gone the next day using the c-products mags.

[Sean King]

If the Extreme won't feed in your upper and mags as it comes, look at where the ammo is hitting and tweak the mag lips accordingly.
It's really that simple and it's not a big deal.
Well, like I said, I plan to try that first (unless Larry says not to).....

I talked to Art today about the issue and he is willing to swap out the unopened Extreme for me if I can't get it to work in my upper. THAT, IMO, is excellent customer service. On the plus side, Art said he's just run 500 rounds of Extreme through a LW 10.5" upper and had no problems whatsoever.....hopefully, I'll fair as well.

I appreciate your time Randall. Thanks again for the advice and the education. You've helped me a lot.

Sean

[AR15barrels]

I talked to Art today about the issue and he is willing to swap out the unopened Extreme for me if I can't get it to work in my upper.

Art's a stand-up guy.

I fully expected that he would offer to credit you for un-opened ammo if it does not run in your upper.

Start out with the mags JUST AS THEY COME first to have a baseline.
Don't go making changes just because I said to.
Get a performance baseline before you determine if changes are even necessary.

[Sean King]

Art's a stand-up guy.

I fully expected that he would offer to credit you for un-opened ammo if it does not run in your upper.

Start out with the mags JUST AS THEY COME first to have a baseline.
Don't go making changes just because I said to.
Get a performance baseline before you determine if changes are even necessary.


Will do. Thanks again. :)

Sean

[CProducts]

Well, like I said, I plan to try that first (unless Larry says not to).....

My advice with any C Products magazine is DO NOT mess with the feedlips, you are only asking for trouble. With all due respect to Randall, that is not good advice. Randall will you accept responsibility for anything that happens to that individual who takes your advice? And, Randall, you posted you could not get my product, please explain that or call me to discuss.

Now to the problem of the 6.8 magazines that do not work. Just so everyone reading this knows how we work, I took the magazines in question, which we fired flawlessly, to Stag Arms. They tested them without failure. That is an independent test. It is, as discussed, most likely an ammo problem or the rifle.

We will return the magazines to our customer at no charge.

Larry
C Products

[AR15barrels]

Randall will you accept responsibility for anything that happens to that individual who takes your advice?


<lawyer speak>
My advice stems from my own experience.
In my experience, there were no problems making a small adjustment.
Of course, someone could surely screw up things, but that's their responsibility to do it the right way.
If they are not capable, then they should not attempt the procedure.
</lawyer speak>



Randall, you posted you could not get my product, please explain that or call me to discuss.


I'm in CA.
I don't have a High Capacity Magazine dealers permit.
I also don't have any mag bodies to trade-in.
Can you take some worthless AK mags in trade?

[Sean King]

Guys,
I certainly didn't mean for my question to start any sort of problem.

I completely understand that any modification of Larry's mags will be my problem, not CProducts or AR15Barrels.

Again, thanks for taking the time to reply.

Sean