Just starting off

[ReAX222]

I loved the idea of 300 whisper and I am making it my first AR. I found an upper on another forum and I am ordering a lower next week for. I also ordered the 3 die set and some 220gr bullets. The next week I am going to be modifying cases, I am going to pick up a pipe cutter and cut some 223 brass down. I expect my dies in weds/thus, so I have time to work on it.

However, this is my question. I am going to gander mt soon and want to pick up some 221 cases, but will I need a different powder? I have about 5 pounds of unique and a half a pound of w231 on hand, but I haven't found load data for either. I also have some Titegroup and bench mark, but I am not crazy about them like I am my Unique.

The upper is a 16" model 1 sales, the gas block is more than 8" from the receiver according to the previous owner. This is only a plinker, but I want it function flawlessly. I plan on changing out the gas block to an adjustable and if I have to ream out the hole to 0.120".

[dksd39]

you can find tons of load info searching past threads- here is one page I used to get started-
http://www.accuratereloading.com/300whisper.html

[ReAX222]

I may have some No 7 sitting around, but most of those seem like supersonic loads. Do you know of a link with more sub sonics?

Basically I just would like to find some ideas for starting loads that will cycle an AR. I don't know yet if I can run 4-5 grains of unique, but unless I can verify it can't work, it's going to be my starting load when I get my rifle assembled.

[pug]

I don't think unique is slow enough burning to cycle an AR but you can give it a try. 5gr would be good for a magnum pistol case but with the 300/221 higher case volume I think it may be a squib load so make sure the bullet comes out before squeezing a second round off. It usually takes me at least 7gr of pistol powder in a small rifle case to get the bullet out and thats sometimes under 800 fps.