300 blk with 240 gr SMK's (subsonic load)

[in812]

Anyone have any load data for 300 blackout with 240gr sierra match king bullets ? subsonic loads 1:8 twist 10.5" bbl

 

[AllenM]

I dont have 240 data but for 220 SMK's I was using 9.6 of H110 I had tried a couple of powders that were recommended as being quieter and they were a little quieter but none of them were as accurate as the H110 so I stayed with H110 because it wasnt worth the trade off to me.

For 240 gr I would try around 9.5 and tune from there

Also, but not related to your question.
I did an interesting experiment. I tried was loading the bullet in backwards so the blunt end of the bullet was facing out. I did this based on some info I read about the military trying this with subsonic amm to increase the contact area and increase impact damage maybe to keep the bullet from tumbling also since the heavy end was formward. Not sure about the last part. If you try this reduce your powder alot and work back up. maybe 40 percent. I did not write down that data.
It acually worked real well and accuracy was very good. I just could not get them to cycle well in an AR.

 

[Aszerigan]

240's are going to be heavy in an 8" suppressed barrel. But, 9.5gns of H110 is a good starting point.

I'd recommend Lil' Gun for AAC Subs. It's higher pressure for cycling the bolt, and I've found it to be less temperature sensitive.

 

[xtremegunnr]

yeah 9.5 grains would be good. They are gonna be pushing it for length in the magazine.

 

[in812]

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