Home Forums Reloading Big Game Rifles 7mm-08 with Big Game and Mag primers??

I've read several times on here about the virtues using magnum primers with Big Game powder in 7mm-08 so I have a few questions. I know it can improve accuracy, but how much? If I'm getting 2" groups with 140 Accubonds, is it likely that the magnum primers will shrink my groups to 1" or close? Is that asking too much? This rifle shoots many other bullets to sub-moa, but doesn't seem to love the 140 AB. I did get some adequate 1.25" groups with other powders, but velocity was too slow for my liking.

I have another load with 120 TTSX and Big Game that shoots just under 1 MOA consistently at 3150 fps. I was thinking of trying the Mag primers to see if I can shrink that to 1/2 or 3/4 MOA which was easily done with RL15 (but slow), so I know the rifle is capable. Is that feasible? Do I need to back off the load and work up again for safety? I'm at 50 grains now, so well below the acceptable max.

Mag primers did tighten my 7-08 groups when using Big Game. It would be worth a try IMO. Just curious......did you try Varget with those AB's?

I did try varget but not much yet. Gonna try more soon. Shot a decent 1 3/8" group at 41 grains (2735ish) and I have some loaded at 42 grains but haven't had time to shoot in a few weeks. Definitely was better than most of the other powders I tried but not sure if the velocity will be what I want.

I bet you find a sweet one around 2800. Hope so anyway.

country 20boy,

I've seen group size cut in half by the use of magnum primers with Ramshot Big Game, and not just in the 7-08. My first experience with the powder occurred shortly after it was introduced over 15 years ago, when a .220 Swift went from shooting 1-1/2" groups to sub-3/4" groups just by switching from a standard to magnum primer. Same powder charge, same bullet, same brass.

Thanks John. Definitely will give it a shot.

Worth trying mag primers in Hunter too?

Loaded a couple of sets of 4 last night with CCI magnum primers. Hope to shoot them this weekend. Wish it would cool off....

Yes



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Just curious countryboy- are you using unprepped brass or the premium stuff? I found that even if I didn't uniform primer pockets, just using a flashole deburring tool (for cases like Rem/Win/Fed,etc) cut my groups very significantly. I also use BR2 primers in standard cases, but I like Fed 215M in magnum cases. Of course, Nosler/Norma/lapua/RWS don't need deburred as their flash holes are made differently. I never saw a real benefit in primer pocket uniforming unless the pockets weren't deep enough and/or the rifle was a high dollar custom action...regular sporters couldn't benefit from the smaller tolerances....like using racing oil in a Ford pickup- the idea is nice, but the truck doesn't know! ha Good luck to you pard!

So are all flash hole deburring tools the same? Is one better/simpler than the other? I'm curious, and want to look into this further.

Hornady brass, but thanks for the tip.

NTG- they all are about the same. I started out using Sinclair International stuff in the 80's and just stayed with them. I use their primer pocket uniformer even on subsequent loadings as it makes them nice and clean....I'm persnickety, ha.
Another thing, even with new brass, set aside any round that shoots a flyer (that's IF you were holding your mouth right when it went off! :)). Weigh them against the others later and separate if needed, use them for sighters, etc.

Update. I shot a couple groups this weekend with mag primers and 140 ab. Groups got a little worse.....
I think I'll just hunt with my 120 ttsx load this yr......