300 U.M. bullet choice

[257speed]

Helping a friend with handloads, 27"barrel, 1/10 twist, wants to shoot the SMK's, anyone with loads/recomendations as far as 180, 200 or 220? Which will shoot best for this twist. I know what the chart says, so i am looking for some "real world" advice. Thanks

 

[bailey1474]

All should shoot well. I would go w/the 220s and Retumbo. Probably somewhere between 87-89gr.

 

[abinok]

LR and super LR... definately 220s
closer... 200s or 175s
Retumbo and H1000 for powder.

 

[uncleB]

Dont forget to give RL25 a try also.
UB

 

[Boss Hoss]

For that twist the 200 or the 220---Retumbo is good and if you have any WMR it works well with the 200 as well.

 

[budlight]

You said that you know what the chart said. I've been pounding away with a 28 inch barrel 30-378 and I found that it likes the 190 boat tails. They are more pleasant to shoot and make nice groups. I've tried IMR 7828 as the fastest powder and AA8700 as the slowest. Retumbo, h1000, R-25. I even did some experimenting with 80 grains of 7828 topped off with 25 grains of AA8700.

My friend and I have determined that the Weatherby factory rounds must be using a combination of powders to get the chrono speeds and accuracy that we have seen.

My advice is to buy a chrono and use it while bench rest shooting. I've seen 30-50 fps changes in speed go from 1 inch groups down to less than .5 inches. Mixing powder types is not for everyone. But i have seen that accuracy goes up if the same bullet speed is aquired with less pressure. In simple terms I beleive in a full case of slow powder over a 1/2 empty case of hot fast powder.

 

[Michael Eichele]

10 twist you say? I would suggest the 220 SMK for the 10x.

I also second the "dont forget to try RL25".

 

[257speed]

Thanks guys, I too have heard of mixing two powders, but have never known anyone to do it. Not much data for that. Think we will start with the 200's and see.

 

[JustC]

88.0gr H1000 w/200gr SMK
87-88gr Retumbo w/216gr clinch river
rem brass
215M lighter