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Ahh, the much awaited update....
First of all, some people may think I decided to ignore everyone's advice. That's not true. Many people gave good advice. A few threw in some anti-piston and anti-A5 advice, which I did choose to ignore. I wasn't going to just get rid of either one in order to "fix" this problem. I wouldn't call that fixing the problem, I'd call it building a new gun. My next new gun, which will have nothing to do with this gun, is going to be a DI AR with standard carbine RE chambered in 300BLK.
Anyway, there were 3 specific suggestions that I did choose follow.
1) Swap uppers/lowers with a functioning rifle.
2) Use some better ammo.
3) Lighten the buffer.
So the story goes like this...
1) Friend with functioning AR was completely willing to come to the range with me and swap parts. Unfortunately, other things kept getting in the way, so this never actually happened (yet).
2) Ordered 250 rounds of Lake City M855.
3) Ordered a standard carbine buffer and a kitchen scale. Upon receiving the scale, weighed my buffer, and it weighed 6.8oz (HAHAHAHA). Apparently the guy I ordered the Vltor parts from sent me the heaviest buffer Vltor makes (A5H4, all tungsten weights). Anyway, removed 2 of the tungsten weights and replaced with 2 steel weights from the carbine buffer, bringing the weight down to the 5.3oz it should have been as an A5H2.
Result:
Loaded 25 rounds of M855 into 30rd PMAG. All fired, all cycled no problem, bolt locked back on empty mag.
Loaded 30 rounds of the old Independence XM193 into various magazines. All fired, almost all ejected (some rather weakly, landing 6-12 inches away), 1 cycled the next round, none locked the bolt back on empty mag.
Loaded M855 into various magazines, 1 failed to feed, the rest fired and cycled fine.
Came home, did a quick inspection of the buffer tube, and didn't see any real damage other than some scratching all around on the inside... very minor looking.
So it sounds like it was, and still is, a buffer weight issue. I'm going to change the last tungsten weight to steel and it should function fine with all my ammo. If it needs to be lighter than that, I'll need to order a new A5H0 buffer, because the last tungsten weight in mine is the one with the spring attached (which I guess I could swap for steel one without a spring, but I have no more steel weights anyway).
Thanks for all the help guys!
Last edited by gwilki2; 08-22-13 at 21:32.
Über heavy buffer.
Makes perfect sense.
Would definitely cause short stroking.
Black River Tactical
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BRT OPTIMUM Barrels - 16" MPR, 14.5" MPC, 12.5" MRC, 11.5" CQB, 9" PDW
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BRT MicroPin Gas Blocks - .750" & .625"
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The scratching is from the fact that the carrier isn't(and can't with a short stroke piston) operate the way it was designed to.
The gun as designed was an inline piston gun...the carrier ran nice and neat straight to the rear because the forces acting upon it were nicely centered inside of it.
Piston conversions change where the piston is. Instead of being centered inside of the carrier, it moves to the front of the gun and drives an op rod into the area where your bolt carrier key used to live(I realize you probably know this part.) When it's impacted off center, with the relatively short and small bearing surfaces, the carrier tilts as it's driven rearward into the receiver extension.
The good news is that to my knowledge this hasn't led to many serious issues, and the world is okay if not perfect. The bad news is that your inner engineer will now have to deal with something that's not working as designed, and the worse news is that it's due to a "fix."![]()
Last edited by thopkins22; 08-23-13 at 00:47.
"That thing looks about as enjoyable as a bowl of exploding dicks." - Magic_Salad0892
"The body cannot go where the mind has not already been."
Glad you got it working. So it turns out that the stock A5 system wasn't to blame... fancy that.
Yeah, he thought it was stock A5H2 buffer when it was really the A5H4. That's like installing a H3 buffer thinking it's a H. The stock A5 buffer worked...
Last edited by bruin; 08-26-13 at 16:12.
He's still having some issues that needs to be resolved before calling the rifle good, those failures to extract are a concern and the scoring inside and around the front of the buffer tube may not be carrier tilt but bad fit between the bolt and buffer tube.
We are all inclined to judge ourselves by our ideals; others, by their acts.
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