SmallCaliberCentral

So I went out to shoot my Cooper 204 yesterday with the new Nosler BTLF 32 gr yesterday. I used my typical 26.5 gr of reloader 10x and remington primers. I setup a new chronograph (Competition Electronics) to record a few velocities. First three shots came in at 4,219, 4246, and 4,287. I inspect the cases and saw a slight primer crater/dimpling and a shiny smudge on the back of the case. I fired the next shot and the velocity jumped to 4,314. At this point I decided to hold off. In the past I would get velocities in the range of 4,050 to 4,100 feet with Sierra 32 Blitzkings.

I'm assuming the "longer" bullet is the culprit as I never had any primer issues. I was planning on loading up a lower powder charge beginning at 25.5 gr to see what velocities that would register. Nosler's website doesn't list reloader 10x as a powder for the 32 gr nor does Alliant have any 204 reloading data.

Any help would be greatly appreciated.

I find staying below 25 gr of 10x works for me. Above that I start showing pressure, in my gun anyway. As for Alliance they do show varmint powder as the one they show 204 loads for. Check out thier website and load info. Bill K

Bill:

Cut the load down to 25.25 gr of 10x and got three shots into a 1/4" group. It was 90 degees and the velocities were still 4,100ish...little confused if the hot weather raised velocity to the same area as a 1.25 grains less powder?

BJ

Heat , humidity etc etc all make adiff. Aliant shows no load data online for the 204 and 10x. I do my test loadsfrom min to max inhalfgrain increments. When i see what shoots best I ajgust from that in tnthe grain increments for the Holy Grail formy barrel. Stay safe Sorry for words running together my spacebar works when it wants to.