I have a Winchester M70 Youth Ranger I won in a raffle that I restocked with a Ramline I had on hand. Tag on the rifle said it had a 1 in 12" twist. One of my favorite loads uses the 165 gr. Speer Hot Core at 2610 FPS. The load is consistently at .75" or slightly less if I'm having a good day at the range.
I'd purchased one of those one book/one caliber manuals for the .308 Win. and there was data for bullets up tp 220 gr. in weight. FWIW, later issues of the manual no longer have data for 220 gr. bullets.
It seems that the highest velocity was reached using W760. The starting load was 42.0 gr. for 2177 FPS at 42,000 C.U.P. and the max load was 44.0 gr. for 2295 FPS at 46,900 C.U.P., interesting. Just for spits and grins I decided to play with the data and had some 220 Sierra RNs on hand, nothing better to do so why the hell not?
Way back when, it seems the 30-40 Krag was considered a better elk round than the 30-06; probably based on bullet construction of the day. Seems loads ran from 2000FPS to 2200 FPS depending I guess on the time frame the round was loaded.
Well, I loaded up a test series starting with 42.0 gr. and loaded three round with a .0.50 gr. increase for each of the next three rounds until the max mentioned above. The result? Three shots with an average velocity of 2320 FPS and a .375" group.
Next trip to the range with a full 20 rounds loaded up I shot four 5 shot groups the smallest .80" and the larger 1.10". Seems to me that if the old 30-40 was so good on elk then the .308 at 2300 FPS with the same weight bullet should work just as good.
I'll probably never have to use that load as most of my elk hunting has been with shots somewhat farther out, most averaging right around 250 yards. Still, it was interesting to see just what a .308 would do with that heavy a bullet. I also believe I could tweak that speed up some as pressure signs were not there when I reached the book max. Not seeing a need I just moved one.
Paul B.
