PSA 300BO not working right.

[Tackleberry41]

Local shop knows me as the guy to call when they get a weird old gun or a problem gun. Somebody had brought in a Palmetto state 300BO rifle. Fed fine, it was cycling. Often would not cycle, then ripped a case in half and left the rest inside the chamber to be dug out. Not going to shoot it suppressed or use subsonic ammo.

Seemed odd to me it would be sold w a 16in barrel and non adjustable pistol gas system. My bet is on to much gas supersonic. It was a trade in gun, and more than likely the previous owner had issues and just got rid of it vs fixing it.

Question was the fix. Not going to bother w subsonic, so a carbine gas system? Or just an adjustable block?

[marek313]

I have PSA 300AAC upper with 16" barrel and pistol gas system. No problems at all unless you form your 300 brass out off .223 brass thats too thick. Thats the only time I had rounds stuck in the chamber but once fired I had no extraction issues there neither.

Look at the extraction pattern and that should tell you if its over gassed. 1-2pm extraction is good but 4-5pm is too much gas. I had that issue with my PSA 5.56 upper but not the 300 one.

[Texas by God]

I can't say whether or not pistol gas system is your problem but I have put together 4 300s on carbine gas system with 16 inch barrel and they run flawlessly. I only use supersonic ammo as well.

Sent from my SAMSUNG-SM-G930A using Tapatalk

[Earlwb]

Well you could try an adjustable gas block and see if it works Ok with it or not.

[osteodoc08]

Was the case that separated steel? Reload? Does the headspace pass the go/no gongauges? Is it a factory upper or parts upper put together by someone?

[Smoke4320]

Check the chamber for roughness.
This has been an issue on several psa rifles.

[Tackleberry41]

It was a remington brass case, factory ammo, they are not a reloader. No idea on gauges, shop has none. Not something I carry around all the time. I stopped in for a soda and shoot the breeze 'hey glad your here'. I asked what another gun to make ammo for? Last gun I bought there was a Swiss Vetterli.

Used gun, no idea on who did what. Guess it will be shipped back to PSA to see whats wrong. I was not impressed w the bold head at all. Almost like the locking lugs were peened. Who knows what the previous owner might have done to it. Plenty of bubbas out there.

Just seemed odd w a 16in barrel and non adjustable pistol gas system.

[2wheelDuke]

Pistol gas systems on 300blk aren't uncommon at all. Adjustable would make more sense, but that's not common for factory guns that I see.

The idea is supposed to be that it can run subsonic or supersonic just as well. I've seen some factory rounds that seem horribly overgassed in a pistol length carbine though.

[jmort]

I believe AR pistols run pistol buffers is the ATF and the arm braces made to fit them. You can run 300 BO sub-sonic from around 8.5" on up

[Boolit_Head]

Pistol gas is more versatile and I don't have much problem on my 7.5 inch barrel. I do run a adjustable gas system just to cut back the gas when suppressed. The carbine gas length are finicky beasts but if you would be happy finding one load that it shoots well and that's it they would be ok. New barrels can be had for reasonable prices if you want to change something anyway.

[jmort]

At less than 8.5" sub-sonic heavy bullets are problematic.

"...here was my day yesterday with this barrel and the v7 6.5". cut and paste from another thread

velocity data: 70 deg F
barnes rangeAR 90gr
v7 2154, 2164, 2195, 2111, 2207
r2b 2116, 2070, 2110, 2116

barnes ttsx 110gr
v7 1975, 1961, 1972, 1978, 2001
r2b 1917, 1916, 1937, 1920, 1925

Federal copper 120gr
v7 1779, 1799, 1798, 1792, 1802
r2b 1735, 1739, 1723, 1732, 1748

fiocchi 220gr
v7 797, 798, 828, 806, 824 cycled unsuppressed, no lock back
r2b 838, 828, 849, 822, 838, did not cycle unsuppressed"

AR15.COM

[DCM]

If they are running supersonics on a pistol length gas system an adjustable gas block should cure the problem. Too much pressure too fast.
Running subsonics with a carbine length gas system in this caliber will not function at all with out a suppressor, and may not function with a suppressor.