450 bushmaster data

[540guns]

I'm looking for load data for my 450 bushmaster I need data for a 300 grain xtp-mag. I can find data for it just not for the powder I have. I need data for one or more of the following. Winchester autocomp, reloader 17, retumbo, tight wad or alient ar comp. Any will work but I want to use the autocomp. Any suggestions would be great thank you.

[Hoot]

I'm looking for load data for my 450 bushmaster I need data for a 300 grain xtp-mag. I can find data for it just not for the powder I have. I need data for one or more of the following. Winchester autocomp, reloader 17, retumbo, tight wad or alient ar comp. Any will work but I want to use the autocomp. Any suggestions would be great thank you.

Welcome aboard bud. While those are excellent powders for other calibers and I especially like AR Comp myself, none of them are acceptable choices for this caliber. When a shoe is way too small or big, you just can't make them work for you since you can't change your foot to match them.

Hoot

[pitted bore]

540guns-
Welcome!

You may have already discovered that there are three reliable sources of tested loading data for the 450B cartridge. For a 300-grain bullet, the list of usable powders is pretty short.

From Western: #9, Enforcer, 4100, 5744, and 1680
From Lyman: 4100 , Enforcer, Lil'Gun, H110, IMR4227, and 1680
From Hornady: #9, Lil'Gun, Enforcer, H110, W296, IMR4227, VV-N120, and 1680

The five powders you list bracket these, with tightwad and autocomp on the too-fast side, and Reloder 17, Retumbo, and AR-Comp on the too-slow side. With some of these you may be able to develop a load that might persuade a bullet to actually come out of the barrel safely, but the bullet will be too slow for almost any use, and the load almost certainly won't make your action function properly.

We're all in about the same boat with regard to powder supply. As of two minutes ago, ammoseek.com listed a source for IMR-4227.

We hope you continue to participate in the forum and report your hand loading results, both successful and not so good.

--Bob

[Hoot]

To add to Bob's list, Alliant 300 MP, though its a lot like W296.

Hoot

[pitted bore]

Hoot-

Alliant 300-MP, as I discovered a couple of months ago with some preliminary trials, is a wonderful powder for 300-grain bullets with the 450B. Further work awaits the end of snow season.

In my post above, I was looking at only published test data, which may be the best recommendation for those first attempting handloading for the 450B. If I've overlooked any reliable pressure-tested loads using other powders including 300-MP, I'll be really happy to learn about them.

--Bob

[540guns]

Could the auto comp work if so what grain should I start at

[Hoot]

Could the auto comp work if so what grain should I start at

Again, too fast.

Look at this Burn Rate chart and try to stay between numbers 70-80.

Hoot

[540guns]

I found some Imr 4227 any body have some starting data for that

[pitted bore]

I found some Imr 4227 any body have some starting data for that

Apologies for a tardy reply.

With the 300-grain XTP Mag, Hornady #9 shows a starting load of 30.5 grains and a max load of 33.9 grains, with velocities from a 16" barrel of 1500 and 1700 fps, respectively.

--Bob

[540guns]

Ok thank you what would think it would be on a 20 in barrel