SmallCaliberCentral

Many of you have made the observation that RL 15 can be temp sensitive. I get very decent groups with 29gr. of that powder using Winchester brass/#7 1/2 primers/39gr Sierra BK's @ 2.320"OAL in my CZ 527 with a heavy varmint barrel in 204 Ruger with it in the summer. Recently, I've been loading brand new Winchester brass with that same load and it shoots decently but not quite as good as I'm used to. I've noticed the brass is not very concentric in the necks(perhaps I should have neck sized it prior to loading). Do you think it'll shoot better once I fireform it? We are down to the sixties now and it rained last night. How much could that affect the groups? This summer I was getting half inch groups at 200yds, today I got between 1" and 1.5" groups at 200yds. I'd like to try 8208 powder but since I have over 5 pounds of RL15 I'd like to use the RL15 up first. BTW-do any of you have any reloading recipes for RL15 for 223cal for 40gr VMax, 50g TNT/Sierra BK, or 55gr FMJ's?

Sounds like the group size is a matter of non-concentric necks. If you haven't loaded them, neck size the cases. Otherwise, fire form them and then neck size only. When they don't chamber easily, then use a body die and bump the shoulders back .002".

As for the temperature sensitivity, it's the warmer temps that matter to me. They'll shoot at higher pressures so, if you're loaded hot you could have problems.