new loads

[RICHCAS]

when working up new loads , I was at the high end and was increasing by .2 of a gr. my jump from 66.2 grains to 66.4 showed my average fps drop by 30. the chrono doesn"t lie. the rifle is a model 70 win in 264 win mag. it has happened before. Anyone have an answer.

 

[Mikecr]

I've never seen more powder cause less velocity.

 

[bman73]

Not a hot enough primer to ignite all the powder uniformly would be the only reason I can think of that happening. Mind you I would think that it would take a change of more than .2 of a grain to see a drop in MV that much. Mind you I have been surprised before and I'm sure I will be again as well

 

[RICHCAS]

Thank you BMAN73.
I was considering federal 215m but used up leftover wlrm. I will switch over and see what the difference is. The problem had me confused. You at least came up with a possible answer. lightbulb

 

[devildogandboy]

could you be more specific about the bullet weight, primer and powder? are you using all the same brass(manufacturer)?