Problems with my new AR Short Stroking

[Theloss52]

I posted this on Sniper central as well, so I'm just copy pasting what I have from that if you all don't mind.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Hey guys,

I just built a new AR-15 car at the end of this last year. DD barrel and upper, YHM rail with a BCM bolt carrier and charging handle make up the upper. The lower is RRA with there two stage match trigger, and a vickers buffer tube create the lower. I am using nothing but the new magpul Pmags. I am using an Acu-wedge as well, just making sure to note that.

when I fire my rifle, it will not load the next round, jam the next round, duble feed, and not ketch when the last round if fired from my rifle. I have just over 1k rounds threw it now, and have had no problems tell the last month. I did install the Acu-wedge the last month, just to note that.

I took the rifle to the in-town AR guy, and he said everything looked really nice. He thought the gas system looked perfect, with no leaks and plenty of air flow. The bold looked good, and the gas rings are good. He said the bolt was sliding perfectly, and the locking lugs and everything where working perfectly (I had cleaned the out of the rifle thinking it might be dirty). he said the barrel looked good, and the buffer spring as well. He did not see any reason as to why it would be having these problems, but one thing, and ill note that later here.

There is a small amount of carbon build up around the gas tube, but after looking at other rifle (mine and my friends) every one had it, so the tube and gas block must just leak a little no mater.

I have NEVER shot wolf out of the rifle, and only shot PMC (or PCM, I forget), and ammo my friend makes for us (he is a licenced relaoder, and we only use good brass, powder, ext...)

The in town guy (Tim) can only think that the Acu-wedge is making the bolt rub and "chatter" in side the buffer tube. Ill be heading to the range here today and try taking it out, placing it back and a few other things.

I keep the rifle REALLY clean, and I do run it wet (not to wet though). mostly use rem oil, although I have used a few others at times.

Any help would be so cool guys, I'm getting really frustrated with this. As I said, I'm heading to the range today, so hope I get a few ideas to try here before I leave.

Thanks,
Stephen</div></div>

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I know the acuwedge is cut right (I did it myself), but It is the main thing I'm going to test. I'm packing up now to head to the range.

I do have an upgraded extractor, with the "crane o ring" (I think its called). Its a full mil spec rifle, so it could be the added preshr from the wedge is making the bolt drag in the tube.

Ill get pics up as soon as I can, having problems getting them copied off my phone. I might try and get a camera from a friend to do it.

Ill let you all know how it works,</div></div>

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">one round in each mag, did not ketch with the acu-wedge in. shot the next one with the wedge out, and it did ketch. Shot 3 more shots in 3 more mags and the bolt ketch worked on every one. Then every mag after that did not ketch even with the acu-wedge out of the rifle. After a few rounds, they started jamming again.

I checked the buffer spring, and it is to spec. I'm out of ideas, if you guys could help.</div></div>

Please help guys,

Thanks,
Stephen

 

[ARsR4ME]

Re: Problems with my new AR Short Stroking

I had one short cyle and turned out it was the gas tube were it mets in the bolt gas key. Take the chargeing handle out and slide the bolt close with your finger and listen for that sound of the tube hitting the key. It shouldn't hit when going into battery. The only other thing I would suggest is put your upper on another lower with different mags and test it then.

 

[K_4c]

Re: Problems with my new AR Short Stroking

check to see if your gas block is lined up (might of backed out of position).... had that happen to me once.

 

[jwn8552]

Re: Problems with my new AR Short Stroking

Yeah, it sounds like you have a gas problem. Check your bolt carrier, look at the gas key. Is it straight? If not it may have worn your gas tube off at the end so you aren't getting enough pressure to cycle. Look at the gas tube, does the bulge at the end look the same all around? I realize you can't see between it and the reciever but if you look from the stock end you should be able to see.
I guess you are seeing a common problem here.

 

[steve123]

Re: Problems with my new AR Short Stroking

I just fixed my AR today.

It wasn't getting enough gas even though I tried to align the gas block hole and the hole in the barrel perfectly.

So I used one drill bit size larger and re drilled the hole on the gas block.Also I beveled the hole on the barrel with a center drill.My gun functioned flawlessly today and I can feel the bolt cycling all the way now.

Steve

 

[Theloss52]

Re: Problems with my new AR Short Stroking

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: steve123</div><div class="ubbcode-body">I just fixed my AR today.

It wasn't getting enough gas even though I tried to align the gas block hole and the hole in the barrel perfectly.

So I used one drill bit size larger and re drilled the hole on the gas block.Also I beveled the hole on the barrel with a center drill.My gun functioned flawlessly today and I can feel the bolt cycling all the way now.

Steve </div></div>

I found that thats exactly whats happening. The DD barrels are seem to be drilled at 58 hundredths of an inch, and its seems like it needs to be about 63 hundredths of an inch.

I'm trying to get a hold of a few different guys, and see what it will take to get this done for me. I don't have the time, or the work space to do it my self, or i would.

If you know exact specs on what size this needs to be, please let me know. There must be something different with the DD bolts that can use the lower presher and still get the power needed to reload each round.