Failure to cycle subsonic ammo - Best options?

[kuroTexan]

I know you don't have a Noveske barrel, but they noted on their website that their barrels may not cycle subsonic ammo unsuppressed. This might be your problem and not your buffer.

[rjacobs]

Don't know what type of buffer it is because it is not stamped on the buffer anywhere like I have often seen. I do know that it is from Slidefire Solutions. I have a call in to them to find out what type of buffer it is. I ordered the buffer and spring set from them in order to be able to occasionally shoot my 5.56 upper with their system. I assume they require the extra power buffer spring since that is what they sent to me. I still have the standard spring and will try swapping that with the extra power spring to see if subsonic cycling can be achieved. If so, that is no big deal to swap out springs for different shooting situations (as you mentioned above). Will keep you posted on progress as others may also be having similar issues..... Thanks all for replies.....

If its unmarked, chances are its a C buffer. But that would be ridiculous to run a C buffer with an extra power spring. Its just not the right way IMO to get things to run right. But when you said slidefire solutions it made sense because those guys dont know what they are doing anyway with their ridiculous product.

[BLKinator]

Spoke to Slide Fire today. It is in fact a C buffer. I've already swapped the springs so should be GTG now. Will confirm once I have a chance to run a few sub rounds through. Thanks again all.....

[ncorry]

What does a C buffer weigh? I see a wide range of "C" buffers advertised and the ones that list a weight it seems to vary quite a bit.

[300Blk]

82-85 grams or so.

[rbthntr64]

Guys,
New here, but not new to gun building. I am working with a colleague who is making CNC 300 BLK barrels for the AR, and Krinkov platforms. The AR rifle I am working with has a .128 gas port in the barrel and will not cycle with the Remington 220 subsonic ammo, and hand loads using 10gr of IMR 4227. Velocity on the chrony was averaging 1060 fps. We are going to try a shortened spring as well as a lightened (63g) buffer that has had one of the tungsten pucks removed. I saw a small improvement when we tried a prototype Krinkov four piece flash hider, but not enough for reliable function. Later today going to try out the buffer change. Also changed powders to A1680, as recommended here. Went up to 11gr for the 220's, and 20gr for the NOS BT 125's(sonic with the original carbine buffer and spring)

[robrob]

.128 is as big a gas port as I've ever heard used. Mine's .125 (1/8 inch) on my 16 inch carbine gas AR. Your rifle should cycle with 11gr of 1680 & 220gr bullet. Make sure the BCG is wet lubed and try another BCG to see if that has an effect. Then look at the gas rings, gas block alignment and gas tube to BCG alignment.

[rbthntr64]

What are you guys using to lube the BCG? In 20 years of service in the military, we only use a very light application of CLP. I realize that this application is different, so what do you guys recomend?

[300Blk]

It turns out that the Army teaching a light application of CLP was proven bad a few years ago in extensive dust/sand chamber testing. Heavy CLP is much better. But that is not your problem. You are probably using a mid length or rifle length gas, which does not work.

[Artful]

or in oz.




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