Minimum Loads

[alorton]

I'm working up a load for my 300/221 AR. I'm loading 240SMK's using 2400 powder. Sierra's manual lists 9.4gr of powder as the minimum load and goes on to suggest not loading below that minimum. At that level, I'm getting 1180 FPS. I want to get down to 1050 but also don't want to get into issues with detonation. What would you all suggest?

I'm guess I'll need to drop a full grain before I get where I want. I'll work my way down, but if I can't get that low safely I guess I'll have to switch powders. Are those minimums to prevent bullets from getting stuck (the Sierra data shows a MV of 950 FPS with that load) or is it getting to low for the case capacity?

[amafrank]

I think we started out with 8.2gr of 2400 in the 300 and that put us right around 1000fps in the 16" bbl. I don't think detonation is a problem when the case is nearly full and that load of 2400 is not quite case filling but isn't on the low side either. Just keep an eye on the powder volume and remember that the 240gr bullet will fill quite a lot of that case.

Frank

[alorton]

I did some digging and found SSK's load info that also showed using less than 9 grains of 2400. I am just relatively new at this and didn't want to assume anything and get myself into trouble.

I tried 8.5 grains of 2400 today behind a 240SMK. I got exactly what I was looking for. Low of 997 fps and a high of 1051 fps. All the rounds cycled my AR and would lock it open on an empty mag as well. I think I've found my subsonic load.

Thanks for the help.