Troubleshooting reload for 300 Winchester

[RSP]

Hey, all! I could use some comments to help troubleshoot a new Ramshot load for a 300 Winchester.

There was no IMR 4350 available when I went to buy more power, so I am trying some Ramshot Magnum. I put 80 grains behind a 168 gn Hornady Match HPBT, with a CCI-250 primer, and just tried firing it out of my Wincehster Model 70 hunting rifle (which I've had for 35 years, Leopold 4x scope). I can normally group around 1.5" at 100 yd with the gun, but that load was all over the place, at least a 6" diameter circle with 5 shots, both left-right and vertical stringing. Just for kicks (and to make sure I wasn't having a bad day) I put three of my old 180 grain Normas ahead to 72 grains to IMR 4350 (same primer), and got the expected 1.5" group.

Any ideas what could be going wrong?

 

[Moman]

Have you tried doing work up loads in .5 gr increments? Different bullet with this powder? Sounds like your gun is where it should be but may not like this powder/bullet combination. Mix it up a little but do work up loads.

 

[RSP]

Have to admit that I haven't worked up much else, afraid that I am spoiled rotten with this rifle - everything else I've ever feed it (normally a bullet change with the same IMR 4350 powder) has always grouped at least respectably.

I checked my bullet supply last night, and have some 165 grain spitzers. I'll try those at the same powder load, and then begin moving away from the 80 grain load.

Thanks for the reply!