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Posted: 2/25/2008 3:41:29 PM EDT
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Hi, long time lurker here. Finally decided to get an AR 15 after many years of wanting one. It is a New Armalite 16" mid length with heavy bbl (750). M4 stock, A3 flat top upper. I've read the postings on short stroking here and everywhere else I could find the info. I'm stumped! It is definatly short stroking. Ammo tried: Wolf 55gr hp M193 (white box, headstamp PPU Winchester Q3131 Rem UMC 55gr FMJ 3 rounds of winchester supreme 55gr ballistic silvertips Handloads Lake City brass, Win sm rifle primer, 23, 24, 25, 26 gr of Varget, sierra 55gr hpbt, and 55gr spitzer. 110 rounds with 110 short strokes. 3 different mags, all USGI green followers, 1 changed to orange mag pull follower Checked bbl port, gas tube, key, rings, follower and spring length. Gas tube had irregular burn mark. Round on front of the tube, but the back of the port was long and extented to the rear stopping where the gas block ends and didn't extend on the tube past the gas block. Other thing I found was bc dragging on the hammer when the hammer is in the cocked position. Hammer has a where mark on the left side the length of the hammer face and 1/16" wide. Anything else I should check or just send the thing back to Armalite? It is only 2 weeks old with warrenty. |
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It will extract but not pick up the next round from the mag and also won't lock the bc back on the last round. It will cock the hammer but still an empty chamber. Pulling the charging handle to the rear, I can feel the bc contact the hammer and drag on it (hammer in the cocked position) Is this drag enough to cause the bc to lose momentum and not fully cycle? Or do I need to be chasing a gas problem? |
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Factory gas block, Have used all the ammo listed in my 1st post. I currenty have some PPU M193 left, anc can always hand load some more. Is is an Armalite 15A4C www.armalite.com/ItemForm.aspx?item=15A4C&Category=8e8e5de6-5022-483e-812b-822e58014822%20&ret_url=Categories2.aspx?Category=8e8e5de6-5022-483e-812b-822e58014822 |
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I have an Armalite M15A2 and it would short stroke on everything but XM193. I swapped out a buddy's bolt carrier and it fed everything including Wolf. The gas key turned out to be a bit loose and I torqued it down and restaked it. Now it feeds everything but short strokes 50% on Wolf. A big improvement. I am going to get a new gas key and screws, lap the bottom of the key and give it another try before getting a different bolt carrier. |
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I hate to mess with it due to the warrenty, but.........just got off the phone with Armalite. They said to shoot 62gr or heavier ammo. If it would cycle them, then they wouldn't do anything "free" under warrenty. They said they would work on it to be able to fire any grain bullet, BUT if it will cycle 62gr+ before sending it in, they would have to charge me shop labor and parts (if any). What a crock!! Also said (of course) if I did anything but field strip and clean (read: don't mess with anything that needs a tool to take apart) then the warrenty would be void. Anyone in West KY or Southern Ill that has a bolt carrier to loan me for a few rounds....give me a shout Thanks fsj_man. |
I was able to cycle SS109 62gr fine except for some Bosnian stuff. After getting the key properly torqued it fired that stuff as well. If you are short stroking on XM193 or Q3131, after a break-in period, then I would insist that Armalite rectify the problem. This 62 gr check is BS. |
That is normal. The hammer has to be pushed on down below the trigger sear catch and the disconnect catch to assure that the disconnect works. The face of the hammer rides on the skid on the bottom of the bolt carrier when the BCG is back. Before your telcon with Armalite hits the "industry" forum and Bill and Mark go after someone to string him up, do you know who you talked to at Armalite that gave you the 62 gn story? I don't think they intend for word to get out that the Armalite rig will not operate with XM193 (55gn). |
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Problem Found!! 1st off, THANK YOU TO ALL THAT REPLIED. Very helpful info. Problem is the magazine riding too high, putting too much pressure on the bolt. This was noticed placing a full mag in on a closed bolt. Had to push the mag in and could feel the rounds compressing the mag spring. I held the mag placing my thumb on the trigger guard to put downward pressure on the mag.........waaaalaaa, it fires, feeds, and locks the bolt to the rear on an empty mag. Mags are marked .223 Cal / 5.56 mm NHMTG S/42 HARTFORD, CT Now, Do I replace the mags, replace the mag catch or remove a very small amount of material from the top of the mag catch? Any other thoughts appriciated THANK YOU again for the help |
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It's usually those pesky mags. Put those aside. Beg, borrow, steal, buy some old straight 20's aluminum with alloy follower if possible. Restore your confidence that there are mags in this world that work. Then, and only then work your way back up to the 30's. By the way, make sure you hose down the bolt and bolt carrier with CLP and pat it lightly to take off drips. The idea of running those items "lightly" lubed has changed lately. |
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