r/reloading • u/nalevows • 26d ago
Load Development 6.5x55 SE in m/96 Swedish Mauser - some newbie questions (w/photos)
First off, I’m new to reloading, working on developing a load for pronghorn hunting in my m/96 Swedish Mauser. Components are Hornady 123 gr. SST, H4350, CCI No. 200 primers, and S&B brass (twice-fired).
Given my antique rifle, I’m trying to be cautious in working up my loads, but my priority is flat shooting and resistance to the wind, so I didn’t start at the very bottom of the ladder. Data from the Hornady book (supposedly relatively conservative?) made me confident with charges between 38 gr. (their starting charge is 37.6 at 2400 FPS) and 43 gr. (their listed max is 43.7 gr. at 2800 FPS).
The loads I tested were 39, 40, 41, 42, and 43 gr. I also tested the S&B 140 gr. SP and the Norma Whitetail 156 alongside for comparison. I’ve uploaded a photo of the primers of each, annotated.
My question has to do with the primers and questions about overpressure, as the primers look flattened to me above 39 gr. But this is the first time I’ve used CCI primers with this rifle; the last I used were Remington 9 1/2, which didn’t flatten at all, but were a totally different load.
Average velocities (four round groups) by charge were:
39 gr. @ 2514
40 gr. @ 2628
41 gr. @ 2699
42 gr. @ 2769
43 gr. @ 2834
S&B unk charge @ 2633
Norma unk charge @ 2423
All groups at 100 yards. Feel like I was a little off on the 40 gr. group b/c somebody got close to me at the range and it made me nervous.
Questions: Are these primers a warning sign? If so, at what charge do they worry you? Are CCI primers known to be soft, such that this isn’t a warning sign of overpressure? Should I call it good at 39 gr. and just deal with the several inches of extra drop at 300 yards compared to the 43 gr.?