Boyd Heaton or any one else with experience
with Retumbo powder. I`ve tried some in my 308 Baer and it gave me great groups at 1140yds. with 216 Clinch River bullets. But, after about 20 rounds, during cleaning there was a good bit of solid streaks of carbon( I guess) coming out on the patches. Also, on the end of the muzzle was a coating of this carbon or whatever that was thicker, blacker, and tougher than I have ever witnessed before. This stuff had to be soaked for a while to be a able to scratch it off with my finger nails. Is this normal for this powder? I like the groups that it`s producing but not the clean-up. The primers being used are 210 Match. I`m wondering if this situation could be helped with 215 Match primers somehow with the burning. I just figure the 210`s would be better with the extreme spread. Any explanations?
Also do any of you use magnum primers with low extreme spreads (215 Match)?