Experimenting with 308 and Magnum Primers

[powereng]

I know this has been debated a million times, but I thought I'd share my results with you guys. After using CCI BR-2's for all my load development for kicks I decided to try some Federal 215M's I had lying around.

My accuracy node using the BR-2's has been set at 42.6gr of Varget. This node has been great in terms of accuracy (.4 moa) but a little under powered compared to my zeroing cartridge of 308 FGMM 175gr SMK's. The BR-2's and 42.6gr of Varget typically shoot .2mils lower than my rifle zero. When I tried the 215M's I reduced my power charge to 42.0gr of Varget. This resulted in a +.1mil elevation change, closer to that of my zero and reducing my groups size to a little under .3moa. I also found that this combination also keeps me in my accuracy node longer over different charge weights. I ran my OCW test from 42.0 to 43.0 grains of Varget with no pressure signs what so ever.

From here I going to make two assumptions. One that the +.1mil elevation change is a result of higher pressure from the Varget being ignited faster by the 215M's. The second is that my rifle likes the harmonics of this new pressure, resulting in a more even accuracy node.

Comments and suggestions welcome.

 

[scorpion168]

Nice! What gun,barrel length? I bought 100 to try in my Savage bolt .308. 24" barrel.

 

[buffybuster]

I use Magnum primers for EVERYTHING. Keeps things simple. It "might" cost me some accuracy, but I have not been able to notice. Just work your loads up and it's no problem.

 

[powereng]

Nice! What gun,barrel length? I bought 100 to try in my Savage bolt .308. 24" barrel.

AI AE MKIII, 20" factory barrel, w/ thunderbeast muzzle break.

 

[turbo54]

You should expect a change in POI with different loads.

If your rifle is zeroed at 100 yards with ammo X, you can't assume ammo Y is going slower because ammo Y prints lower at 100 yards.

 

[powereng]

You should expect a change in POI with different loads.

If your rifle is zeroed at 100 yards with ammo X, you can't assume ammo Y is going slower because ammo Y prints lower at 100 yards.

I'll buy an ounce of that. I really need to get these loads on a chronograph.

 

[Turd in the Pool]

I use them in 308, 6.5-284 and have popped a bunch in 22-6mm in the past.

Found them to lower the SD and ES in all 3.