Rutumbo in a 300 Ultra

[texasdave]

I was at the range yesterday and found that from 90 to 92 grains of powder I was not increasing the bullet speed but by 50 feet. It went from 3090 to 3140 but I was increasing the fireball I threw. It seems to me that I was only burning more powder out front of the rifle. I switched to R22 and at the same 92 grains I increased the speed of the bullet to 3650 and was not throwing a fireball at all. I just wonder what anyone else has found using Retumbo. It seems the powder is too slow for my rifle even though it is supposed to be for large magnum rifles.

 

[D.P.]

what weight bullet and barrel length?

 

[texasdave]

It was a 165 grain bullet and 28" barrel

 

[D.P.]

I think you will find that with heavier bullets the Retumbo will perform well. I am getting ready to load some 200 Accu Bonds useig Retumbo. I don't have much experience with the 300 RUM, But have seen good results in friends rifles with heavy bullets and Retumbo and R-25. In my experience with my 300 win R-25 was awesome with 180 NBT's but when I stepped down to 165's R-22 took over (3430 FPS 26" barrel)

 

[Guest]

I am pushing a 200 gr bullet(Nosler Accubond) at 3200 with Retumbo at 94.5 gr.Retumbo is designed for the heavier bullets...Like rimfire said, stick with R22 for the lighter ones.

 

[sniper2]

Try some WMR if you can find some, great velocity and accuracy!!

 

[JustC]

I have gotten ~3200fps thus far from 89gr of retumbo under a 216gr clinch river with groups in the .2"s (30" 1:10 PacNor select)

For the 200gr SMK,..88.0gr H1000 gave .25moa groupings as well at ~3100fps.

For the 165's,..I think your wayyyyyy tooooo sloooooww with retumbo or even RL25.

 

[texasdave]

Thanks for all the info. I tried Retumbo yesterday using 200 Accubonds and 90 grains of powder. I was beginning to get extractor marks so it looked as though that was as high as I could go. I was only getting a little over 3100 in speed. I was not able to tell if I still got a fireball but I am thinking for my rifle Retumbo is still too slow. At least I am not able to obtain the speed others are getting. Maybe Ill try H1000 or R 25 next.
I did switch to R22 and at 91.5 grains I was getting over 3650 average and und .5 groups. I appreciate everyone input and advice.
Thanks