barnbwt
member
- Joined
- Aug 14, 2011
- Messages
- 7,340
Could someone who has one of these verify the amount the piston is able to travel? By which I mean, how far back it can move when the carrier is to the rear before it comes to a stop against the upper receiver.
I'm using one in my AR-that's-not-an-AR build with one of those big chunky free-float tube barrel nuts, and the piston is short stroking as well as hammer-drilling a hole through the nut, slowly. I suspect the ~1/4" of travel it currently has is less than required, so it is both slamming into the soft aluminum barrel nut under force, as well as unable to cycle the bolt completely. I plan to drill out the barrel nut however much is needed, but I don't know how much is needed, lol.
Right now, when using the normal/full gas setting, I get nice consistent ejection, and the hammer resets, but it's not quite getting far enough back to snag the next round in the mag (let alone pick up enough momentum to shove it out the mag reliably)
Summary of the build for those interested;
-Freebie billet 80% lower ("phantom firearm")
-PSA cheapie LPK & stock/tube, from back when they were 25$ during the '13 Banic
-Carbine length standard weight buffer (going to an empty/light one did not fix the issue)
-Adams Arms rifle-length piston conversion
-Cheap Chinese free-float tube & barrel nut
-Homebrew 6.5 Grendel barrel from a chambered, unprofiled Sarco blank, .104" gas port (large)
-Lilja Grendel bolt & barrel extension (they just market them)
-Gibbz Arms side-charging upper (non-reciprocating handle type)
-At some point, I'll fabricate a telescoping buffer spring assembly to replace the sproing
-Nikon Prostaff 3-9x40 scope on extra tall cheap pic-rings
-Those steel ASC mags that score the hell out of the brass but are the only option
-123gr AMAX, Lapua brass, CCI primers, 28.1gr 8208, 2.25OAL
So yeah, total mutt of a gun with a random smattering of nice and incredibly cheap parts. Bears almost no functional resemblance to the AR at this point apart from the trigger group and bolt head, lol. Barrel shoots quite well for 50$, though the chamber neck is way too generous so it'll be getting replaced or set back & rechambered once I scrounge up a reamer. The thing is murder on steel; the FMJ PPU cheap stuff that got recalled recently (for being too fat at the case head & tending to tie up the gun in my case, while also operating at too-high a pressure) will put 1/8"x1/8" craters in AR500 at 150yds. Once I can get the gun cycling, I think it will be in the 1-2MOA range --I'm not really trying for groups at this time, as the malfunctions are too distracting.
TCB
I'm using one in my AR-that's-not-an-AR build with one of those big chunky free-float tube barrel nuts, and the piston is short stroking as well as hammer-drilling a hole through the nut, slowly. I suspect the ~1/4" of travel it currently has is less than required, so it is both slamming into the soft aluminum barrel nut under force, as well as unable to cycle the bolt completely. I plan to drill out the barrel nut however much is needed, but I don't know how much is needed, lol.
Right now, when using the normal/full gas setting, I get nice consistent ejection, and the hammer resets, but it's not quite getting far enough back to snag the next round in the mag (let alone pick up enough momentum to shove it out the mag reliably)
Summary of the build for those interested;
-Freebie billet 80% lower ("phantom firearm")
-PSA cheapie LPK & stock/tube, from back when they were 25$ during the '13 Banic
-Carbine length standard weight buffer (going to an empty/light one did not fix the issue)
-Adams Arms rifle-length piston conversion
-Cheap Chinese free-float tube & barrel nut
-Homebrew 6.5 Grendel barrel from a chambered, unprofiled Sarco blank, .104" gas port (large)
-Lilja Grendel bolt & barrel extension (they just market them)
-Gibbz Arms side-charging upper (non-reciprocating handle type)
-At some point, I'll fabricate a telescoping buffer spring assembly to replace the sproing
-Nikon Prostaff 3-9x40 scope on extra tall cheap pic-rings
-Those steel ASC mags that score the hell out of the brass but are the only option
-123gr AMAX, Lapua brass, CCI primers, 28.1gr 8208, 2.25OAL
So yeah, total mutt of a gun with a random smattering of nice and incredibly cheap parts. Bears almost no functional resemblance to the AR at this point apart from the trigger group and bolt head, lol. Barrel shoots quite well for 50$, though the chamber neck is way too generous so it'll be getting replaced or set back & rechambered once I scrounge up a reamer. The thing is murder on steel; the FMJ PPU cheap stuff that got recalled recently (for being too fat at the case head & tending to tie up the gun in my case, while also operating at too-high a pressure) will put 1/8"x1/8" craters in AR500 at 150yds. Once I can get the gun cycling, I think it will be in the 1-2MOA range --I'm not really trying for groups at this time, as the malfunctions are too distracting.
TCB