SBR 11.5" gas piston

Talk about the AR15 style rifles chambered in 450 Bushmaster.

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Re: SBR 11.5" gas piston

Postby WEAZELWACKER » Thu Feb 25, 2016 1:20 pm

Just got back from doing a test fire. Only fired three rounds to make sure everthing worked well, will take it apart tonight and inspect/ clean. Everthing looks good so far, no signs as far as issues go. Didnt have to ajust my gas block or anything fire and cycled really well. Cant wait to get some better range time and see how good it groups, and what kind of velocity it will have.

Compleat build list-
Seekins SP223 lower
Gibbz Side Charging Upper
Blackhole Weaponry 9.5" barrel
Geissele G2S trigger
Ultra Compact Stock - LWRCI
Extra heavy buffer from heavybuffers
Samson hand rail ( modified anti rotation tabs)
Grizzly Gunworks muzzel brake w/ noise redirector
syrac adjustable gas block
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Re: SBR 11.5" gas piston

Postby WEAZELWACKER » Sat Mar 12, 2016 6:32 pm

Just a follow up. Got more range time today. Sighted in iron sights at 25 yards for a 2 inch group. Pushed it to 100 yards and had about a 10 inch group. Only real issue with this build so far is the Samson rail would slide forword due to recoil. Not a big issue because of my muzzle device having two screws that held the rail in place, but without it the rail would have eventual feel off.
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Re: SBR 11.5" gas piston

Postby WEAZELWACKER » Fri Dec 28, 2018 10:37 am

Image



Its been a few years gents, and I am now passed what has to be close to 1000 rds. This thing is the love of my life (Don't tell my wife), however I'm looking to take this to the next level.



Image



This is the bullet I'm looking at right now. Plan is sub sonic, and pair it with a Silencer Co. can. I was looking at Lil'Gun for my powder but it seams like several folks have strong opinions for, and against it.
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Re: SBR 11.5" gas piston

Postby plant_one » Fri Dec 28, 2018 11:32 am

that doesnt look like a gas check bullet, so unless you plan to add one - lil gun is probably not gonna be a good choice for subs. being as it burns a little on the hot side (temp wise) it tends to lead to gas cutting and can cause some awful leading - even with a coated bullet. it'll burn stuff like powder coat or hitek right off the base of the projectile. i had lead spraying out the end of my barrel when testing some mild supers (sub 1500 fps) in my 300 blk. no bueno. it was a PITA to get it off the bayo for my magnetospeed. thank god the "blast shield" caught most of it.

[edit]this is an absolute big huge giant problem since you're discussing using a suppressor. if you get a small spray of lead out of your barrel every shot, you're gonna have a lead brick strapped to your barrel in short order as your can fills up. this is why rimfire cans are *usually* user serviceable - to clean the small spray of lead that comes out the end of the bore every time you pull the trigger out of the can so you dont end up with a loud, expensive, paperweight. [/edit]


id recomend something like 4227 or 1680 for better choices for subs. besides the temp difference in the burn itself, those two tend to generate more gas volume than lil gun does, so you'll probably have an easier time of getting them to cycle for you as well.


good luck with your subsonic project!
Last edited by plant_one on Fri Dec 28, 2018 11:44 am, edited 1 time in total.
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Re: SBR 11.5" gas piston

Postby plant_one » Fri Dec 28, 2018 11:41 am

also - typically cast bullets are usually 0.001-0.003 larger than a typical jacketed bullet so that they seal well to the bore. i'd probably want to look at a mold that dropped a 0.454 - 0.455 bullet and then size them down *if needed* with a sizing die.


im sure the folks over at castboolits would be able to help you select something that would fit your needs well.

http://castboolits.gunloads.com/forumdi ... -Reloading

one of the sticky's regarding boolit sizing
http://castboolits.gunloads.com/showthr ... ullet-size
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