300 RUM with 200gr MKS range results

[rhouser]

I have added this data in an edit (thanks to Joel Russel for pointing out iin his reply that t was missing).

Powder was Retumbo.
Remington Brass fireformed and necksized only.
CCI Large Rifle Magnum primer.
Remington 700 with factory 1:10 26" barrel.
Sierra 200gr MK's

Range trip 1:

I shot 3 rd sets at 90 to 94 grains over my old olher 35 set at 10 feet from the barrel.

94 gr : High-3063fps Low-3028fps ES-35 Avg-3051 and SD-20.

91 gr best accuracy: High-2920fps Low-2912fps ES-8 Avg-2916 and SD-4

Range Trip 2:
I went back to the range with loads 90.6 to 91.6 grains to find best load in the 91 grain load range:
91.2 grains resulted in a .3 in center to center group at 100.

I shot 3 at 95grs that I had left from the first round but no chono. Two went in same hole (literally) the third was up and over by almost 1 inch at a 100. I may have pulled it.

Issues: Best accuracy so far is the 91.2 grains, but, I am only getting 2930 +/ with the load. I will play with primers and seating length, but, the accuracy is decent and the SD and ED are great. (Of course, I can't hunt this bullet).

The 94 gr load chono'd 3063 high and 3028 low with no pressure signs.
The 95 gr load had no pressure signs but I didn't have my chrono when I shot it. If I extrapolate from my 94 grain to the 95 grain, it should be averaging at least 3080. I still have no pressure signs. How fast are people pushing the 200 gr bullets? If I read pressure signs, I can go up from here, but, I am already at the MAX velocities that I find for the 200 gr. Anybody making 3200 with a 200 gr?

Thanks rc

 

[Joel Russo]

In one of my RUMs, I get a comfortable 3225 fps with a 200 gr AB, with acceptable hunting accuracy at extended ranges. 92.5 gr Retumbo, 28" barrel.

What powder did you use?

 

[rhouser]

I can't believe I left that out.... I will edit my first post.

Powder was Retumbo.
Remington Brass fireformed and necksized only.
CCI Large Rifle Magnum primer.
Remington 700 with factory 1:10 26" barrel.
Sierra 200gr MK's

At 92.0 grains, I chrono'd 2977 average at 10 feet from the muzzle on an 8 foot rail 3 trap Ohler.

At 93.0 grains I chrono'd 3000 average.

What brass and primer are you using?

 

[Joel Russo]

Sounds like you're a bit slow, but the increase in velocity between 92 and 93 grains is about right.

FED 215M, and the crappy REM brass.

If your ES is low, and you accuracy is acceptable, use the turrets on the scope.....

 

[cinch]

200 Accubond, Remington brass, 95gr Retumbo, CCI-250, 27" Lilja = 3290 in a 5 shot average

 

[rhouser]

Joel, at 91.2 gr, my ES = 8, my SD = 4 and the group at 100 was .3 center to center. I agree that I am slow, so I will probably load and chrono up to pressure signs. If my Chrono isn't lying, then I may end up above 95 gr in looking for the 3200 fps. I am not hung on it, accuracy over velocity in my book (within reason).

Joel you are shooting a 28" and Cinch is shooting a 27" barrel. With my 26" and Retumbo, I may be losing 30 fps per inch? That still should have me with 60 FPS or so of you and Cinch.

I have some 200gr AB's I can try. I will reload to my 91.2 and see if the groups stay and the velocity changes. I don't have any Federal 215M's , only CCI's, but, that is a sign of the times. I will work up the 200 gr AB's to pressure signs or to max velocity with accuracy.

thanks rc