300 BO and 115 RNFP

[Redleg11b]

I recently resized some 115gr RNFP .313 bullets for a "used to have" handgun down to .309, when I wanted to try them in my 300 BO for a plinking load. I already have 500+ so I figured I might as well just use them. Barrel is 16.25" and 1:7 twist.

I tried 3.7 gr Trailboss and got an ES of 60 fps @ average velocity of 950fps. COL is 1.755", Win SR primers, LC converted brass. I think some of the problem may be the mixed stamp, but still all LC, brass. I also had some loaded with 3.5gr Trailboss and had velocities from 890 fps to 964fps.

The 3.7gr load had 4 of 5 rounds touching at 25 yards, I did pull one left pretty bad though. The other load was so bad, I am definately not working in that direction.

In the collective opinion, would an increase to 3.9gr potentially fix the issue, should I try different powders, or is this light of a bullet just not worth it?

I was thinking about moving up to a 140-170gr cast down the road for a similar cost plinking load that will hit metal plates with a wee bit more authority if I cant get something more consistent figured out withthis weight. Primary use are holes in paper, bouncing cans, steel plates, demo for suppressed shooting (have a take apart can, not worried about shooting lead).

[DDriller]

You need to use a full case of Trailboss (approx. 4.5 gr. at that seating depth) with that bullet. I would use a different powder and get them up to 1500-1600 fps with a COL of 2.1.

[Redleg11b]

I was hoping to keep them subsonic for the giggle factor, but if they need to move faster to be more accurate, that is not a problem either. At my current seating depth, the lube groove is just inside the case mouth, I'm not going to seat them longer. I may just have to go to a little heavier bullet to get a cheap subsonic plinker. I have some .309 XTPs that I was going to load to about 1800 fps for typical rimfire distance vermin control. I need to work on something for them later.