Reloading 7mm PRC

I have an 8lb jug of N570 and was curious if anyone has experience using this with some 180 class Berger's in the 7prc. The lack of information I've found online leads me to believe this combo is not worth pursuing. Any information is appreciated.
Compressed a little. Use a drop tube and it will work. I've tried it on 195's in the 7PRC and 7 Saum. Both work great with it. N568 also works well also but will be 40 to 60 fps slower. But It does work and works very well.
 
I am slowly transitioning away from magnum primers because I have experienced a few pressure spikes during hot temperatures here in Texas. No issues in colder temps, but I like to practice year around.
I ran these two lots just for you.
Both lots:
67.9gr N565
175gr ABLR
Once-fired Peterson Brass
2.640" CBTO
First 5-shot lot using White River Large Rifle Magnum Primers
Velocity average: 2832fps with ES=10 and SD=3.8

Second 5-shot lot using White River Large Rifle Primers
Velocity average; 2819fps with ES=21 and SD=7.7

Target set at 203 yards, no MOA adjustment on scope. Alternating shots. WR LR on right, Wr LRM on left.
WR test.jpg
 
I ran these two lots just for you.
Both lots:
67.9gr N565
175gr ABLR
Once-fired Peterson Brass
2.640" CBTO
First 5-shot lot using White River Large Rifle Magnum Primers
Velocity average: 2832fps with ES=10 and SD=3.8

Second 5-shot lot using White River Large Rifle Primers
Velocity average; 2819fps with ES=21 and SD=7.7

Target set at 203 yards, no MOA adjustment on scope. Alternating shots. WR LR on right, Wr LRM on left.
View attachment 602857
The magnum primers produced much better groups and tighter fps.
 
I ran some 160 monos with N565 at 71.5gr with an sd of 2.6 shooting 3179.6 fps for 2 separate 5 shot groups. Group was about .8 moa. I was using GM215M primers. Everything was pretty good, but I was at pressure and wanted to back off. I decided to try large rifle primers and also dropped the charge weight. Using GM210M primers and 71.0 gr of n565 got me 3088.2 fps and an sd of 4.4 for a 5 shot group. It was about a 1 moa group.

I'm going to try using the LRM primers at 71.0 gr for 5 shots and also try the LR at 71.4gr to see what I come up with and compare velocities. I'd be a lot happier if I was around 3/4 moa or less for 10 shots.
 
Wouldn't pressure spikes be associated more with powder/temperature than the choice of primer?
I'd think so.
Especially if you are on the edge. Might not realize that part until the mercury gets up enough though.
 
DAG NABBIT! After questioning accuracy for the last few days, I fingered out my scope was moving! So I cleaned up the rings and tube with alcohol and socked it down good and hard. Harder than I'd like to, but it's not a crusher. the rings are really precise and smooth. But I wasted a few/30 rounds and had to re-do a good bit of load development.

I settled in at 69.3gr N565 with the 175 ABLRs seated to a 2.6700" BTO, or roughly 3.340" COAL. This is the worst of three 3-shot group at 500yds. A touch under 3", and a velocity average of 2895fps for the 9 shots. SD of 3.6 and ES of 7. I used 2x fired Peterson brass untrimmed and bumped 0.001", with a 0.312 neck bushing in the Forster FL die. I'll run with this load!! I need to have some bullets left for hunting. Next I have to set zero.

Note that my cast iron manhole cover is starting to crack - mostly due to the earlier 340 Weatherby slams, LOL!
69.3N565.jpg
 
Top