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Discussion Starter #1
I am having problems with my 300 blackout. I am running a 8.5 barrel upper suppressed. When shooting 208 hornady amax ammo sometimes the bullet does not fully seat into chamber. I have to use the forward assist to get the bolt to go all the way. Does not happen every time but to often. Happened about 5-6 times out of about 50 rounds shooting today. I am not sure if I need to add an adjustable gas block or a heavier recoil spring/lighter buffer or what. The spent cases look ok besides a slight scratch all the way down them that seems normal and the rim of the case has a dent inward as does every 300 bullet I have ever shot seems to have, indicative of the round I suppose. It always fails in this manner. Everything is fine it just does not always slam the next round all the way home into the chamber. Any advice appreciated.
 

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Discussion Starter #6
Everywhere I look someone is saying subsonic 300 is unreliable unless shooting suppressed, so I only shot it suppressed.
definition of disappointment: waiting 9 months to shoot something and find out it is unreliable. I got to figure this out. I feel like the ammo is not the problem. The hornady 208 amax are supposedly the best subsonics to shoot. Should be at over a dollar a round....
 

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I would say you want to try a heavier buffer. But don't quote me on that. Whatever the solution is I'm interested.
 

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Discussion Starter #8
Would the heavier buffer make it have more force to shove the bullet into battery? Maybe there is not enough gas pressure shoving it back I thought but that does not make sense either because it always picks up the next round just does not go all the way in. With the silencer on there it should generate more pressure anyways, hence people say shooting suppressed makes it more reliable.
 

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Would the heavier buffer make it have more force to shove the bullet into battery? Maybe there is not enough gas pressure shoving it back I thought but that does not make sense either because it always picks up the next round just does not go all the way in. With the silencer on there it should generate more pressure anyways, hence people say shooting suppressed makes it more reliable.
Hang in there, don't get disappointed -- i think the lighter the buffer, the faster it will move!
I've always heard common switching blackout you need to switch out buffer when under the 10 inch.
 

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Really its the only thing I can think of. Its not short stroking with the carbine buffer or you would know. So with a heavier buffer - as long as the bcg cycles fully- it should help push the next round into battery.
 
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Who is the manufacturer of your upper and did it come that way?
 
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Discussion Starter #14
also he says the scratch on the bullets could be a sign of one of the lugs on the bcg rubbing it to much to polish the lug in question that the scratch could being caused could be just enough resistance to keep it from slamming home. He is going to write back and give me the low down on what different weight buffers etc. do also. It is a cmmg complete upper I bought about a year ago. the lower is a psa I built from scratch and form 1
 

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Sounds like a solid plan. It wouldn't hurt to throw in another buffer as well or instead on your next range visit. If you have one laying around. Faster isn't always better. Sometimes there is no substitute for weight.
 

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Discussion Starter #16
I am concerned that with that 2x spring though a different weight buffer maybe needed to keep from causing another problem which I assume would be short stroking and not picking up the next round
 

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I am concerned that with that 2x spring though a different weight buffer maybe needed to keep from causing another problem which I assume would be short stroking and not picking up the next round
Only one way to find out brother. If it is not going to work with either the spring or heavier buffer you will know right away. You certainly won't have to burn two magazines before you find out.
 
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Sounds like a solid plan. It wouldn't hurt to throw in another buffer as well or instead on your next range visit. If you have one laying around. Faster isn't always better. Sometimes there is no substitute for weight.

Yep, you are right!!! But buffer is cheap enough to buy,and try. Return if not working. Can't hurt. Enough $ invested
 

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Discussion Starter #20
Well I will order both from midway they have fast shipping. Hopefully that way I can try it again this weekend. In the mean time I will clean, oil, and polish the bcg lugs. The bcg lug fix can be verified without shooting it.
 
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