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Posted: 1/15/2016 7:15:36 PM EDT
| Built a .300 for shits and giggles to be fired un-suppressed. Any recommendations on the type of buffer/spring I should use? Took one out of my 16" carbine and she wouldn't cycle the .300. Any help would be appreciated. |
| If I read your post correctly, your rifle will not cycle with a standard 3.0 oz carbine buffer and standard carbine spring? Are you using sub-sonic, weak ammo? If not, you probably have a gas leak somewhere. Check your gas block/FSB alignment, or maybe your gas key on bcg is loose and leaking. |
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Quoted:
In my 9" AAC, I run the standard gas block, Sprinco white-hot spring, H3 buffer, FA WMD carrier and a Reliabolt...runs nice and tight wth supers and subs; suppressed or not. Good to hear. I built my 10.3" 300BO BA Hanson barrel with a Sprinco White-Hot spring. FA Aim c158 bolt nitride bcg with H2 buffer....may go lighter to an H buffer. How do you like the Hot-white spring? Supposed to be better for short barreled 300 SBR. |
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I threw a 16" Franklin Armory upper with a fixed sight base onto a Stag Arms lower with a Timney 4lb trigger, standard rifle buffer spring/buffer and A2 stock. Ran perfectly on everything from Remington 120 gr. on up. It may be longer than the most efficient length for the .300, but it's a nice, accurate setup. OP, there's something not right about your setup. Generally, there are three factors that affect cycling; gas, buffer spring and reciprocating weight (buffer and BCG). If that's the Franklin Armory nickel boron BCG that you have, it's likely a little heavier than a "standard" AR BCG, but that's usually not enough by itself to keep the rifle from functioning, as demonstrated by my rifle described above. Assuming that you're running either a standard carbine or rifle buffer tube/spring/buffer, I'd be looking at the gas block and tube first for leakage. If not, I'd return to a standard buffer spring and buffer and see if that runs. The next thing I'd consider is enlarging the gas port a drill size at a time until the rifle functions. |
| 9" Ballistic Advantage barrel, heavily fouled older Spikes NIB BCG, carbine spring and buffer. I rarely ever lube or clean this rifle except for cleaning the bore, barrel extension and bolt face. No failures with subs and supers, suppressed and unsuppressed, so far. |
| I would say your gas port is to small or your using suns or weak supers. I'll suggest a lighter buffer spring or cut your current one. Try the Spikes spring. Don't go havier on the buffer. Your setup is very unique and I have no ideas why or who would make a 18 300blk barrel. |
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Quoted: Good to hear. I built my 10.3" 300BO BA Hanson barrel with a Sprinco White-Hot spring. FA Aim c158 bolt nitride bcg with H2 buffer....may go lighter to an H buffer. How do you like the Hot-white spring? Supposed to be better for short barreled 300 SBR. Quoted: Quoted: In my 9" AAC, I run the standard gas block, Sprinco white-hot spring, H3 buffer, FA WMD carrier and a Reliabolt...runs nice and tight wth supers and subs; suppressed or not. Good to hear. I built my 10.3" 300BO BA Hanson barrel with a Sprinco White-Hot spring. FA Aim c158 bolt nitride bcg with H2 buffer....may go lighter to an H buffer. How do you like the Hot-white spring? Supposed to be better for short barreled 300 SBR. I was suggested the white-spring by one of the guys from Sprinco...very good CS...it is the only other spring I have tried in my BLK when I was trying to get my setup to run properly. In the beginning I had major cycling issues that turned out to be an out of spec AAC carrier. Although to me, the white-hot spring feels "tighter." It's as though the movement of the buffer, BCG, bolt and spring move in harmony with each shot that much better is the best way I can explain it. My ejection point is at 4'oclock every shot... I don't have any other springs to compare it to, but I know the white-hot spring is perfect for my 300BLK SBR... |
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I didn't see it if it's already stated, but is the barrel drilled for carbine or pistol gas? Even 16" barrels in 300 Blackout work better with pistol gas.
My 8" upper (pistol gas) runs just dandy with a standard carbine buffer. The problem should not be that your buffer is too heavy. Make sure your gas block is properly aligned, make sure there aren't any blockages in the gas tube, and that you're using good quality ammo to test with. Remington's 120 grain OTM commercial stuff is made by Barnes and is very good stuff; it's my "testing standard" round for 300 Blackout. |
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Both my 300 blackouts (8.5 and 10.5" Rainier Arms Match Barrels) run supers and subs both suppressed and not suppressed using carbine spring and buffer. Thought about changing to a heavier buffer but everything runs great so...if it's not broke why "fix" it?...
Both barrels are pistol gas with pinned low pro gas blocks non-adjustable. |
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8.5" - Spikes t2 buffer standard c spring. Will shoot some subs without suppressor, subs and supers with suppressor all day long.
16" - SOTA barrel, c gas, c buffer and standard spring. I only shoot supers with it when hunting, runs with or without a suppressor. |
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