300BlkTalk

200 gr is about the most you will get away with. It depends on the shape and length of the bullet. A short or round nose bullet will stabilize easier. The best bullet is the 200gr Lapua subsonic.

I don't think anyone needs to feel sorry for Kevin. He made millions selling AAC. As well there is no need to worry about the future of our favorite round. 300 Whisper has been around for nearly 25 years and it had a large following as a wildcat. It isn't about to die now. The most interesting thing...

Using a slower powder makes sense. But then you say you've used AA#5, which is a relatively fast powder.

True and the AA#5 didn't work as well so I no longer use it.

H322. The trick is not to use a faster powder but a slower powder to produce a longer gas pressure dwell time. The downside (because there is no free lunch) is that these are not the quietest loads. I also used AA#5 but it is not as reliable and tends not to lock the bolt back on the last round even...

There is no specific "speed of sound" per se. There is a transonic range over which the sonic crack begins to be generated.

To stay under this range in all conditions I try to stick to velocities between 975 and 1000 fps.

I had asked that same question of 300blk and was told that it would not work. He said you need at least a 220 grain bullet to get it to cycle properly. The lighter bullets need too much velocity to get the bolt to cycle properly and then they are no longer subsonic. Just goes to show he isn't nearl...

Someone needs to do some sound testing to discover which powder is the quietest.

The Lapua 200gr subsonic bullet is by far the best subsonic bullet I have used. They are very accurate and easy to work with. Not really surprising as they are Lapua and they were specifically designed for subsonic flight. We even got them stable in a 1:12 twist barrel.

Yes it can be done and yes they do light. It just takes the correct choice of powder. However they won't stabilize in a 1:10 barrel. I have run them in a 7" barreled AR and gotten reliable cycling and last round lockback.