Start off with that I have a J&T Complete AR15/M4A3 with 14.5 barrel with phantom 5C2 flash hider. Thousands of rounds down the tube and NEVER had any malfunction/misfire of any sort until today.

My buddy and I installed my gear today that I had received. The PRI flip up sight, vltor modstock, Magpul MIAD grip, samson rail, phantom flash hider, cqd dieter grip PRI big latch on the charging handle and so on.

We went to test fire, and we had some problems. It would fire the first round, but for some reason the bolt would 'stick' half way to the rear and not eject the spent casing. Well from this point, my friend and I switched out EVERYTHING possible to try to find the problem, I switched out my lower, charging handle, switched out bolt assemblies, then we even alternated each others bolts with different bolt carrier groups.  Tried different magazines, different ammo. I tried my bolt, bolt carrier group, charging handle, and lower in my friends bushmaster and he fired it just fine.

We also would chamber a round and drop the magazine. During these trials the gun would fire and eject the round just fine 8/10 times, the last two times it stuck at the exact same spot it had before with a magazine in.

A couple points through the afternoon, the bolt assembly was literally STUCK in the receiver. It would not move when trying to change out assemblies, I had to pull with ALOT of force to get it out. This scared me the most, what would have the power/hooking capability to keep the bolt assembly stuck in the receiver like that?

We manipulated everything in both of our guns to eliminate the problem, and the only thing we couldn't swap out was the gas tube.

When removing my gas tube from my A2 assembly, we tried using pliers, and then hitting the pliers with a hammer to slowly remove the gas tube. This did not move it at all. So we had to cut the A2 front sight in multiple spots so we could then 'grind' our way with a grinder to the hole in the A2 sight and then proceed to push the gas tube out with a push pin instead of trying to pull it.

the only things we could possibly think of was that the gas tube could be pinched somewhere just enough somewhere along the line and not getting enough gas to blow back the bolt assembly? The new vltor stock buffer and buffer spring are too tight? The plunger possibly is keeping the buffer from moving back during recoil, interfering with the bolt assembly? The latter is probably not the case since my lower worked on my buddy's upper.

need some help :)
Let me know what you think..

UPDATE

Another AR15 member, slickbt, and I took it apart today and noticed that the plunger that keeps the buffer and buffer spring in the stock was protruding just a little bit TOO much. So I cranked the stock down one more turn into the lower, to insure that plunger was depressed where it should have been.

With the bolt assembly becoming stuck in the upper, its hard to think the gas tube and th gas key on the bolt carrier would cause such a lock up that it would take a 22 year old man to use all of his 'manhood' to pull on the charging handle to get it undone.

SO, hopefully when I get a chance to shoot it next everything is fine, if it isn't, its the gas tube.

Is your new gas block aligned with the barrel's gas port correctly? If the two holes are mismatched, you will experience short stroking.

Quoted: Is your new gas block aligned with the barrel's gas port correctly? If the two holes are mismatched, you will experience short stroking.

We took it apart and reinstalled it, and from what I remember it was lined up correctly. That would make sense for the short stroking, but for the bolt assembly locking up on multiple occasions points to another related or totally different problem?

I tried my bolt, bolt carrier group, charging handle, and lower in my friend's bushmaster and he fired it just fine.

If it wasn't for the fact that your lower shot fine with your buddy's upper, I'd say that you have a problem with your new stock set-up which is causing the bolt carrier to hang up.

Quoted: I tried my bolt, bolt carrier group, charging handle, and lower in my friend's bushmaster and he fired it just fine. If it wasn't for the fact that your lower shot fine with your buddy's upper, I'd say that you have a problem with your new stock set-up which is causing the bolt carrier to hang up.

Roger, and the problems persisted with his lower combined with MY upper. Consider myself a smart person, and we though we narrowed it down to almost everything.

ttt as I stare at my brizz0ke gun.

Sounds like stock and buffer issue.

Rick

btt

Guys, I'm virtually certain this is a problem with the charging handle being out of spec.  My friend had the EXACT same problem happen with his.  I'll have him post here about it.

Quoted: Guys, I'm virtually certain this is a problem with the charging handle being out of spec.  My friend had the EXACT same problem happen with his.  I'll have him post here about it.

Never had a problem before this, I also used my charging handle in my friends rifle, no problem.

I be interestd to hear from your buddy on what exactly happened before and after fixing..

Neither did he, in fact it first surfaced at a carbine competition and caused exactly the kind of binding you're mentioning.  I'm IMing him right now.

Quoted: Neither did he, in fact it first surfaced at a carbine competition and caused exactly the kind of binding you're mentioning.  I'm IMing him right now.

Appreciate the help, I have a new gas tube arriving today, going to replace that and test fire.

After winding down the stock one more turn, I cycled rounds through it continuously and it didn't stick at all after 50+ cycles, so as of nw, the 'binding' problem is done, just have to diagnose and eliminate the short stroking

Ok, this may or may not be your problem, but as Victor mentioned, My gun exhibited a similar problem as yours. My charging handle was out of spec. If you look at your bolt carrier there is a little lip infront of the gas key. The charging handle hooks on that little lip and pulls the bolt carrier back, causing the Cam pin to rotate and unlock the lugs of the bolt from the chamber. The end of my charging handle was too short. It barely would hook the lip on the bolt carrier. After some rough use at the competition, it finally skipped over the lip and locked against the Cam Pin. With the Cam Pin held in place by the Charging handle, there is no way to unlock the lugs to open the bolt. No matter how hard you pull on it. I had to smack the charging handle to get it to go back into place, and then open the bolt. But the damage was done. The little bit of the charging handle that hooked the lip there was had been worn off and now, when I tried to pull my bolt back, even if the lugs weren't engaged, the handle would skip over the lip and bind against the top of the reciever  and the bolt carrier.

My advice is to take out your bolt carrier, put the charging handle over the gas key and make sure it hooks the lip on your charging handle solidly.

If that isn't the problem. Then I'd go with what you are thinking about the buffer tube screwed in to far. I too put in a VLTOR stock on my weapon. I screwed the buffer tube in a little to far. It didn't cause the problems you are describing but it did make it impossible for me to connect my upper and lower at the rear pin.

Quoted: Ok, this may or may not be your problem, but as Victor mentioned, My gun exhibited a similar problem as yours. My charging handle was out of spec. If you look at your bolt carrier there is a little lip infront of the gas key. The charging handle hooks on that little lip and pulls the bolt carrier back, causing the Cam pin to rotate and unlock the lugs of the bolt from the chamber. The end of my charging handle was too short. It barely would hook the lip on the bolt carrier. After some rough use at the competition, it finally skipped over the lip and locked against the Cam Pin. With the Cam Pin held in place by the Charging handle, there is no way to unlock the lugs to open the bolt. No matter how hard you pull on it. I had to smack the charging handle to get it to go back into place, and then open the bolt. But the damage was done. The little bit of the charging handle that hooked the lip there was had been worn off and now, when I tried to pull my bolt back, even if the lugs weren't engaged, the handle would skip over the lip and bind against the top of the reciever  and the bolt carrier. My advice is to take out your bolt carrier, put the charging handle over the gas key and make sure it hooks the lip on your charging handle solidly. If that isn't the problem. Then I'd go with what you are thinking about the buffer tube screwed in to far. I too put in a VLTOR stock on my weapon. I screwed the buffer tube in a little to far. It didn't cause the problems you are describing but it did make it impossible for me to connect my upper and lower at the rear pin.

Thanks for the info, I looked at the gas key and charging handle to ensure the chaging handle is engaging correctly, no wear marks or cuts on either  parts

I think my problem was that the stock wasn't wound down tight enough, allowing the  buffer 'plunger' to stick up too far in the receiver causing the buffer/spring to catch when te BCG was pulled to the rear.

It is a little tight now when putting it back together, but it was actually nice to eliminate some of the play between the upper and lower.

long story short, with some reassembly and gunsmith advice, it was the PRI set screw front sight/gas block. PRI had excellent customer service, they swapped the the set screw with the clamp style front sight out next day it arrived. assembled it, took it to the smith to double check my work and fired it in his bullet trap. All is well.