CamoChameleon
Member
Hello, new to the forum, and not new to guns. I'm having a problem with the AR15 I recently built (my first). I have been having short stroking problems since the start; 20% of my spent casings are ejecting, and it never strips next round from mag. Last weekend, I had a friend help me diagnose what part(s) are the problem. My gun is built on an Anderson 80% lower, with a Hardened Arms 16" midlength freefloat upper, a PSA carbine lower parts kit, and supposedly a "Nitrided Toolcraft BCG", but I have my doubts because it looks to be wearing too fast for nitride, it looks like phosphate, and I got it from Delta Team Tactical <facepalm>. My friend has a PSA 16" midlength on a pistol lower with a Nickel Boron BCG from Brownells. His setup functions perfectly.
We tried various frankensteins of parts from our guns, and these are the results we came up with:
My upper + my BCG = no function
Friend's upper + my BCG = no function
My upper + Friend's BCG = function
My upper + Friend's carrier + my bolt = function
Friend's upper+Friend's carrier+my bolt =function
Friend's upper +my carrier+Friend's bolt=function
My upper + my carrier + Friend's bolt = no function, although the rifle would finally eject reliably and almost pick up the next round, but would jam it into the side of the barrel extention and crush the side of the case.
It seems from this list that the problem is with the bolt carrier itself, except for the result of test #6 above. Since it seems like the carrier is phosphate and thus softer than nitride, I am hoping there is something I can do to fix my current carrier, but otherwise I will just have to buy a new carrier.
Some more info about things I have looked at:
1: Gas block is aligned
2: Gas port is large enough
3: Gas key is solidly tight and properly staked
4: I am trying to contact Toolcraft to see if there is any way to identify if this bolt is really theirs. If so, I will just send it in for warranty replacement or upgrade or something.
5: Problem persists with both .223 and 5.56mm.
6: I have put about 200 rounds through it thus far, with only 10 fully cycling, and those were while using my friend's bolt carrier.
7: Gas tube and gas key are unobstructed.
8: BCG is well lubed with molybdenum grease (sure there's better stuff for long term use/storage, but it is what I had and what my friend is using.)
9: Bolt will support its own weight when standing on the bolt head, so the gas rings are good.
10: BCG is long past replacement period on DTT's policy page. I have been accruing parts for a while now, and I certainly know more about the markets and brands now than I knew at the beginning.
11: I cycled the action manually ~200-300x in the months before this testing.
12: When it fails to eject, you can see brass, so it extracts ok. When filmed with high speed, the BCG comes back just far enough to cock the hammer, but not too much farther than that.
I am at a loss. I can tell you that through this experience I am learning more detail about this system and its operation than I knew there was to learn!
We tried various frankensteins of parts from our guns, and these are the results we came up with:
My upper + my BCG = no function
Friend's upper + my BCG = no function
My upper + Friend's BCG = function
My upper + Friend's carrier + my bolt = function
Friend's upper+Friend's carrier+my bolt =function
Friend's upper +my carrier+Friend's bolt=function
My upper + my carrier + Friend's bolt = no function, although the rifle would finally eject reliably and almost pick up the next round, but would jam it into the side of the barrel extention and crush the side of the case.
It seems from this list that the problem is with the bolt carrier itself, except for the result of test #6 above. Since it seems like the carrier is phosphate and thus softer than nitride, I am hoping there is something I can do to fix my current carrier, but otherwise I will just have to buy a new carrier.
Some more info about things I have looked at:
1: Gas block is aligned
2: Gas port is large enough
3: Gas key is solidly tight and properly staked
4: I am trying to contact Toolcraft to see if there is any way to identify if this bolt is really theirs. If so, I will just send it in for warranty replacement or upgrade or something.
5: Problem persists with both .223 and 5.56mm.
6: I have put about 200 rounds through it thus far, with only 10 fully cycling, and those were while using my friend's bolt carrier.
7: Gas tube and gas key are unobstructed.
8: BCG is well lubed with molybdenum grease (sure there's better stuff for long term use/storage, but it is what I had and what my friend is using.)
9: Bolt will support its own weight when standing on the bolt head, so the gas rings are good.
10: BCG is long past replacement period on DTT's policy page. I have been accruing parts for a while now, and I certainly know more about the markets and brands now than I knew at the beginning.
11: I cycled the action manually ~200-300x in the months before this testing.
12: When it fails to eject, you can see brass, so it extracts ok. When filmed with high speed, the BCG comes back just far enough to cock the hammer, but not too much farther than that.
I am at a loss. I can tell you that through this experience I am learning more detail about this system and its operation than I knew there was to learn!