Sub sonic 300 BK load data

[usmcpmi]

Has anyone found a sub sonic load that will cycle in the ar platform?
Thanks...

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[OldCurlyWolf]

You may have to change springs and/or gas porting

 

[usmcpmi]

You may have to change springs and/or gas porting

Yes Sir...understood. Looking for a starting point- type of powder- bullet weight range, etc.

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[popper]

For a 220 gr bullet, 7-8 gr 1680 should do. Or about 5 gr hp-38. Look at Hogdon reloading web site for real data.

 

[Eastexasrick]

My load. Standard buffer and spring. Gas block wide open.
220 gr Sierra Pro-Hunter round nose. 11.5 gr 1680. WW standard small rifle primers. 2.260 OAL.
Chrono shows average 1123 @ 3 feet from the muzzle. Our other East Texas member installed his suppressor to test. No crack, no problems cycling.

This load is listed in the Lyman #51.

 

[usmcpmi]

Thanks for the input. Settled on Hornaday 190 gr. sub sonic partition bullets. 9.6 gr. H110.
So far no problems cycling or feeding.
I have loaded up some 200 gr. with 9.2 gr. H110. Going to try those next.

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[usmcpmi]

Supposed to be running 1050 fps. The 190's seem to be about half the report of a .22 short.
The steel plate is much louder than the round.

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[lonestardiver]

Seems to me I am running about 9 gr os H110 with my 220gr bullets. No chrono but with a suppressor, it is fairly quiet.


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[Deavis]

You can cycle almost every
properly gassed gun at subsonic velocities with 1680 or CFE BLK. It is easier with 220s but you can do it down to 150gr reliably with those two. Suppressed helps but not necessary.