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Posted: 5/19/2011 7:34:08 AM EDT
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Took the new blackout build out yesterday and ran some rounds through it. Functioned perfectly, except I had 1 small problem. After the last round, the bolt won't lock back. I am running a collapsible stock with a regular carbine buffer. It cycles shells just fine, it just seems like it doesn't have quite enough power to recoild enough to lock the bolt back after the last shell.
Anybody got any ideas? What about removing a coil or two from the buffer spring. Would that help at all? I don't guess they make any lighter weight buffers than a regular carbine buffer. 
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Quoted:
What rounds were you shooting? What is your gas port size? What is the gas port position? Were you using a suppressor? What kind of gas block are you using? I was running factory Remington 220 gr subsonics. Not 100% sure on the gas ports size, but it is in the carbine position. The barrel is a Wilson Combat 16". I was running it with my suppressor, and I am just using a regular low-profile gas block. I have read that sometimes with the carbine gas port location, the 300 might have a problem locking back on the last round. Not a huge problem, just wanted to know if there was an easy fix. |
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Quoted:
Quoted:
What rounds were you shooting? What is your gas port size? What is the gas port position? Were you using a suppressor? What kind of gas block are you using? I was running factory Remington 220 gr subsonics. Not 100% sure on the gas ports size, but it is in the carbine position. The barrel is a Wilson Combat 16". I was running it with my suppressor, and I am just using a regular low-profile gas block. I have read that sometimes with the carbine gas port location, the 300 might have a problem locking back on the last round. Not a huge problem, just wanted to know if there was an easy fix. Since it was a factory subsonic load you won't be able to increase the powder charge so you have a couple options. You could open the port a bit. The factory 16" 300BLK barrels don't have an extremely large port to keep the gas flow down when shooter supersonics. It is difficult to find that perfect happy medium with two dramatically different gas pressure curves so that is likely where you're running into problems. I prefer the pistol gas port position on 300BLK's because it is a bit more forgiving but the carbine position has advantages, especially with supersonics which is what most people will shoot most of the time. The other options would be to try removing a coil or two from the spring, going to a lighter mass carrier, removing a coil from the bolt catch spring, or trying a different magazine with a stiffer spring. Your last option would be to live with it. If it functions fine other than just that one issue, it is up to you whether that is something you can live with. Does it lock open on supersonics? ETA: Forgot to mention you could also try some different recipes reloading your own subs. You might find it likes heavier bullets, like the 240gr SMK, a bit better or a slightly different powder. One of the reasons the 300 Whisper didn't have much loaded ammo available was that rifles were very unique and liked different things. The 300 BLK has standardized alot of that and made it less of an issue but your rifle might just like a load that is different than Remington's factory offering. |
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Not sure of the wilson barrels but the noveske, aac, CMMG, Delta arms and most other manufactures have figured out the correct port sizes to run with the blackout. In your configuration you should have a good chance of locking it back without the suppressor but with the suppressor on you should have no problem locking the bolt open.
This means your gas block isn't properly aligned and may be cutting off some of the flow to the bolt, Gas is leaking out from the gas block (not tight enough), Gas is leaking from under the key carrier (bolts aren't screwed down/staked properly), not giving the riffle a solid shoulder during firing or not properly lubed. If none of those are the problem then most likely the port size is too small and needs to be opened up. I run a noveske 8 inch with a spike tactical 9mm buffer. I have had 220 grain subs cycle and lock my bolt back all the way down to 658 fps and Noveske is known for keeping their port sizes a little on the small side to favor supersonic over non suppressed subsonic. I also run a Delta arms 10 inch with the same buffer and have no problems cycling and locking back every round I have fired. A properly built barrel/rifle with factory ammo and a suppressor attached should not have to have any of its springs cut or change any regular buffers out! |
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Quoted:
Not sure of the wilson barrels but the noveske, aac, CMMG, Delta arms and most other manufactures have figured out the correct port sizes to run with the blackout. In your configuration you should have a good chance of locking it back without the suppressor but with the suppressor on you should have no problem locking the bolt open. This means your gas block isn't properly aligned and may be cutting off some of the flow to the bolt, Gas is leaking out from the gas block (not tight enough), Gas is leaking from under the key carrier (bolts aren't screwed down/staked properly), not giving the riffle a solid shoulder during firing or not properly lubed. If none of those are the problem then most likely the port size is too small and needs to be opened up. I run a noveske 8 inch with a spike tactical 9mm buffer. I have had 220 grain subs cycle and lock my bolt back all the way down to 658 fps and Noveske is known for keeping their port sizes a little on the small side to favor supersonic over non suppressed subsonic. I also run a Delta arms 10 inch with the same buffer and have no problems cycling and locking back every round I have fired. A properly built barrel/rifle with factory ammo and a suppressor attached should not have to have any of its springs cut or change any regular buffers out! Good points about checking the gas block and carrier key. Also check the gas tube and the gas rings. |
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Did you ever figure this out? Just curious. This looks like a great / fun AR cartridge. Well, yes and no... 
I decided i didn't like the 16" barrel with the suppressor hanging off of it. (Too darn long) I have an SBR lower, so I went ahead and had the barrel cut down to 10". After getting it all back together, it runs like a champ. Only think I can think of is maybe the gas tube was not 100% aligned the first go round. |
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