Issues - M4 upper with Adams Arms Kit

Being that I haven't used up most of my personal days, I took today off to get a few things done... one of which was to sight in my 5.56mm. Had a few issues at the range...



Just a basic picture of the rifle. It is a DPMS lower, which I built, with the Spikes M4 upper that was sold with the Adams Arms piston kit. I picked this up back in July of 2009, and haven't shot it until recently (really, it has just been something I've been putting off). Everything in that picture is the same, except a DPMS 1 inch stock extension (I live in New Jersey). I have an H buffer in it. Today, I used three different PMAGs that RifleGear pinned to 15 rounds. Quick breakdown of what I felt was relevant... any other specifics needed, I'll answer them as quickly as possible. Ammo that has been fired up to now has been Remington/UMC .223 (a 200 pack of .55 grain metal case; total fired through the gun is 78 rounds).

About a month ago, I took the rifle to the range to attempt to sight it in. Fired five rounds when my girlfriend called and needed me to pick her up at work (battery took a dump in the car). I did not clean the rifle since I wanted to get it sighted in somewhat soon as possible. I do think I had one round that did not get loaded into the chamber (pulled the trigger on an empty chamber), but not 100% on that. I used a CProducts lanced 20 to 15 round magazine at that time.

Fast forward to today... I get to the range and start by zeroing the red dot at 25 yards (indoor range, being I rather get it in the ballpark instead of spending all my time outside... in the cold ). So, I start with the same pack that I fired the first five rounds from. It took me about 30 rounds before I was happy where the rounds were landing... all of which, the gun functioned 100%. I messed around with the last magazine (killing off that first 50 round pack), then began to load the second pack into magazines. Right now, I have 22 rounds left in that pack, so within the 28 rounds I fired, I had quite a few problems (to be fair, there are also six rounds in that group of 22 that are pretty dented up when I thought I had the bolt locked to the rear... which I don't plan on firing). I began having the round get caught up on the way into the chamber, with some (I only took notice on maybe two, which I took a picture of) that the rear of the case got underneath the bolt. I wanted to get some clear pictures of what occurred, being I'm far from an AR gunsmith. Also, I'm far from a photographer... especially one-handed with my iPhone.





Also, I had a few instances where the bolt closed on an empty chamber (two or three... also within those 28 rounds). Being I recently shot my SKS, I first thought it weird that UMC had hard primers. Opened the gun up, and nothing was in there. Took this picture of a skid mark on the top round of the magazines right after one of those occurrences. This may have also occurred in the first time out to the range, but I really didn’t take notice.



Any event, I just wanted to get some ideas on what is occurring... especially before I decide to clean the gun up and go back to the range to try it again. Some added info, these shots were either with me standing (unsupported) or leaning against a range bag. I checked to make sure there were no external forces on the magazine. The magazines were locked in place, and I did not ease the bolt home while loading (did not have any issue loading, only when a round was fired). The lower is my only one, being I have this upper, a Spikes .22, and a .410 upper (the latter was never fired on it, but I did shoot the lower with the .22).

At first, I thought it was the H buffer... but then I wondered why it functioned fine in the majority of the shooting. I thought about not cleaning, but if the upper has issues with that low of a round count between cleanings, I may look into another platform (pretty much not considering that, since I cannot see it occurring). So, I'm stumped on this. Almost chucked the rifle downrange towards the end of my time at the range, which is why I just packed it up and went home (and I'm also sure that was partial reason behind why I have the six dented rounds... being pissed off doesn't really improve problem solving).

What makings are on the upper and the barrel? Have you talked to Adam's Arms about it yet?

Try a new magazine. Get one of those 20 round older Colt magazines...they work great... try that first

It is a Spikes receiver and an Adams Arms barrel... I bought it off the Spike's website (there were a handful of sales prior to you guys dropping the piston line, which I got it during one). Markings on the receiver are just the spider on the rear part of the rail (forward of the buffer tube). The barrel has “Adams Arms Comp Elite 5.56 1:8 6049” right under where the rod sits (12:00 on the barrel).

Did not contact Adams Arms. Just looking to see what the possibilities are and if it is something stupid that I'm overlooking.



Can't... I live in New Jersey, which has a 15 round magazine restriction.

get a 10 rounder and not the same brand as the one you are using

Considering this, I decided to go back to the range and use the CProduct magazines instead of the PMAGs... interesting results.

First two CProduct magazines ran 100%. So, I loaded all six magazines (three PMAG and three CProduct) to try again. The only issues with the PMAGs were none of them locked the bolt back, and the third one had a few of the above failures (two or so). Moved to the CProducts, thinking that they would work perfectly. NOT AT ALL! Same issues in those as I had with the PMAGs (if someone was videotaping my earlier shoot and this past one, the PMAGs and CProducts would give about the same footage). From what I'm gathering, the gun functions fine cold... but after 45 to 60 rounds, it begins to have these issues. Again, I'm going through a lot of the basics and not seeing anything caused on my end.

Shy of that, it is a very accurate upper. I'm very impressed at what the barrel is capable of, especially when I stopped worrying about accurate shots to pay more attention to the function.

I have resources on my end where I could try a different bolt carrier group, buffer spring, buffer etc..to help me diagnose the problem. If you pull back on the charging handle can you manually cycle the gun every time (go through 15 rounds? Or does the round hang up entering the chamber? Did you check the feed ramps and chamber to see how it looks??

For each magazine I picked up, I always loaded them up to 15 to make sure it is complient for the state (Magpul dummy rounds). To unload them, I always did that that... and never had an issue. I did notice that one PMAG had a hard time to load the 15th round, which I asked RifleGear about (they said it was fine).



I didn't notice any defect prior to shooting (no issues on either the barrel extension or the receiver, and there isn't anything for the rounds to catch on). When I got the upper, I went over it pretty well.

However, I haven't looked at them after shooting. Either tonight or tomorrow I'll take a look and see if there are any marks that look out of the ordinary (leaving in a little bit, and not going to get all dirty taking it apart).

Maybe your fully loaded mags are a problem have you tried just loading 3-5 rounds. also bolt looks dry. lube that sucker up.

Is the gas block an adjustable unit? If so do you have it adjusted to the fully open position? If it is closing on an empty chamber that sounds like short-stroking which is indicative of too little gas or too heavy buffer or spring. This could also be the cause of your poor feeding. Just a thought...

Didn't have time to check the feedramps, and really don't feel like doing it know. I'll pop it open sometime tomorrow.



I pulled the magazine out anytime I had a failure, cleared the jam, then put the magazine back in. Sometimes I slid the unfired round into the chamber, closed the bolt, then put the partially loaded magazine in. Other than occurring as the gun heated up, I saw no other pattern to it.

In regards to the bolt, I oiled it with Slip 2000 EWL prior to going to the range the first time (when I cut it short to pickup my girlfriend). Stuff usually stays lubed for a good period of time with that, but I didn't add any extra since then... a possibility.



It is always at full open (12:00). Pinned barrel, so not going to be using a suppressor any time soon.

Like I mentioned before, I have been shooting a box of UMC .223s. Wanted to use them first, being I was given them maybe a year or so back. I do have an American Eagle (if I remember it correctly; black cardboard box) box of 5.56mm (55 grain, either a 200 or 250), so I’ll try that out next. Could an H buffer really cause issues with .223 loads? .223 isn't something I'm planning on using a lot, but at least I'd have an idea on it if that is the case.

As it sits now, I am definitely going to use what was said. I likely won't get out to the range until between Christmas and New Years, but I'll clean it in the next few days and lube it up prior to shooting.

So you are trying to cause a slam fire hazard with cheap commercial ammo?

No matter how many rounds you fire on a range trip, whether it is 1 or 1000, you clean your weapon afterwards. Once oil or lube is exposed to hot carbonized gas it will begin to break down over time and become ineffective. There is no CLP type oil or lube out there that will say you are good to go between firing sessions for any length of time with their lube or else they would face the wrath of lazy gun owners everywhere demanding the company replaces their firearms. They will advertise round counts of how much it is good for, but that is for a single session. The basic rule of weapon maintenance still applies. Your weapon is well overdue for a serious scrub down.

This explains why the first photo looks like the round is crooked. And yes, with cheap underpowered commercial ammo from Remington, many bad things are possible.

If the UMC is underpowered then going with a lighter buffer while using this kind of ammo may help too then. I have never fired UMC rifle ammo but I do periodically have issues (bolt over base) with Wolf (it was given to me as a gift so I'm working through it). I just chalk it up as a symptom of using cheap ammo, clear the jam and go on shooting but I have thought about getting a lighter buffer for use whenever I take the cheap stuff out.

Took the colors off since it really bothered my eyes...



Actually, I tried to keep the gun going... being I wanted to see the malfunction and/or the cause. The bolt was closed with the magazine out, and the muzzle was already on target... so, if a round did decide to go off, wouldn't have bothered me much (it would have used up one more of the "cheap commercial ammo" that I wouldn't had to messed around with).

But thanks for the safety tip, for my lack of not stating my reasoning in my post.



Well, which is it? The ammo isn't something I bought, but was given (I actually never purchased any .223 or 5.56mm ammo, as of yet). I usually do keep very good care of my weapons, but between work and getting stuff ready for Christmas, I did not have time. There was not any buildup in the gas block area, so I decided to get the sight on target, then clean it afterwards.

I am very taken back by the underlined part. I didn't buy your product so it would be replaced for any small issue (if it warranted it, I know you guys would fix it). I bought your product for the fact that you guys actually are on these forums and helping your customers. I nowhere demanded a refund or a replacement (obviously, you can't replace something that you discontinued), and even stated in a post that I was looking for guidance on how to resolve the problem (specifically why I stated I'll post any other needed info). I posted this for help, no more (you guys offering to swap it out), no less (attitude for asking help). I've recommended your products on various forums, due to the support you give your customers, so I'm hoping that this post was either due to you having a bad day or misreading my posts...



So, talking about buffers, how does yours compare to the standard options (H, H2, H3)?

I have to pick up some stuff for my M&P, so if I'll probably just pick up a standard buffer from MidwayUSA. Don't know where the original is at, and at $10, it isn't a huge investment.

I could be wrong but I don't think that he was talking about you in specific in that undelined passage. I think that it was more of a general statement.

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Greyguy is correct. I was speaking to CLP makers and consumers in general. My post was offering possible suggestions as to the cause of your issue. Maybe I shouldn't have started off the slam fire reaction, but I was just going top to bottom through your post based on the information provided.

Sadly, even in the firearms world there are those that try to work the system to get something for nothing. It is not a statement about or directed at you. I was just illustrating that the makers do not, and they they do not, claim their lubes can last through multiple shooting sessions over uncounted periods of time.

As for the difference in the T1/T2/T3 buffers and your heavy H series buffers, the difference is in the ballast material used within the buffers –– and the total gross weight (T2 does not weigh the same as H2). The T series buffers from ST use a tungsten powder filling, except in the case of the T3 (where a tungsten weight is used). Tungsten is a denser metal that provides more weight per volume than standard inserts. Plus, since it is powdered, provides an almost fluid motion to the shifting weight inside the buffer that compliments the recoil impulse of semi auto rifles. And some people like the lack of "twang" from the ST buffers too. These reasons are why other noted makers of AR's use the ST-T2 buffer in their rifles.

For the UMC, yes, it is underpowered and what they call "dirty" ammo. A lighter buffer can help address this to some extent, as long as the remainder of your gas system is free flowing and void of obstructions.

No problem.



I'll probably order a T1 sometime after Christmas. The standard buffer is on the way from MidwayUSA, so I'll see how that works and see how much difference between it and the T1. It should be here on the 24th... hopefully.



I think I shot less than 150 rounds, and it wasn't that bad (Wolf in my SKS was about twice as bad, with less rounds). I didn't clean the barrel or the hole in the gas block, but the rest of the gun wasn't that bad (I'll probably hit the piston and rod another time with solvent when I finish it up).

I was planning on picking up a bulk pack of M855 from Brownells, but I cannot use that at the indoor range I'm a member at. The M193 is backordered, so I'll probably just order it after Christmas...

PMC's .223 ammo is pretty well pressured. You can get it for a good price from AIMSurplus.

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