Poper
Member
I have 2 different rifles chambered in .308 Win. One is an old Remington 788 carbine (18 ½” bbl.) chambered in .308 Winchester which I acquired new in 1982 that has seen moderate use and still looks new, and a Ruger Hawkeye in .308W (new this spring) with a 22” bbl.
I have been working up loads for the Ruger using 150gn Speer SP, Varget, RP 9 ½, and Winchester brass. The final best grouping load ended up being 44.8gn Varget with these components.
I prefer to find the load a particular rifle likes before I chronograph them. (It reduces the likelihood that I will shoot the chronograph or the sky screens.) I have had sky screens shot twice. Once by me and once by another fellow I allowed to “shoot a couple over your chronograph?” I won’t do that again. But I digress.
Because I was going to shoot 3-10 round strings from the Ruger over the chronograph, I thought, “Why not shoot 3-10 round strings from the old Remington, too?” It probably wouldn’t group as well (it didn’t) nor run as fast (it didn’t) but it would be an interesting exercise. So I loaded additional ammo for the heck of it.
From Sunday’s range session, the chronograph showed the Ruger’s velocities averaged 2944 f.p.s., Extreme Spread was 44.22 f.p.s., Standard Deviation 12.14 f.p.s. and it was grouping 1 ¼” to 2” for 6 - five round groups.
The old Remington velocities averaged 2579 f.p.s., Extreme Spread was 167 f.p.s., Standard Deviation was 78.56 f.p.s. with 6 - five round groups from 2 ½” to 3 ¾”.
Definitive results? Nahh. But interesting, just the same.
I was not surprised by the lesser velocities and overall performance of the Remmy 788. Its muzzle blast is considerably greater than the longer barreled Ruger, which is probably due to the amount of powder still burning when the bullet exits the barrel. When fed its preferred load of IMR4064 and 165gn Hornadys, it is a little slower, but will group right around an inch if I stay off the caffeine.
Though I report the group sizes here, it was not the purpose of the range session. I lay the oversized groups to two different reasons: 1) The shot strings were 10 consecutive rounds in as many minutes which did not allow the barrel to cool in the 100+ degree Az weather; and: 2) I was not shooting for tight groups – I was sending lead quickly downrange for the primary purpose of chronograph data.
Fun stuff!
Poper
I have been working up loads for the Ruger using 150gn Speer SP, Varget, RP 9 ½, and Winchester brass. The final best grouping load ended up being 44.8gn Varget with these components.
I prefer to find the load a particular rifle likes before I chronograph them. (It reduces the likelihood that I will shoot the chronograph or the sky screens.) I have had sky screens shot twice. Once by me and once by another fellow I allowed to “shoot a couple over your chronograph?” I won’t do that again. But I digress.
Because I was going to shoot 3-10 round strings from the Ruger over the chronograph, I thought, “Why not shoot 3-10 round strings from the old Remington, too?” It probably wouldn’t group as well (it didn’t) nor run as fast (it didn’t) but it would be an interesting exercise. So I loaded additional ammo for the heck of it.
From Sunday’s range session, the chronograph showed the Ruger’s velocities averaged 2944 f.p.s., Extreme Spread was 44.22 f.p.s., Standard Deviation 12.14 f.p.s. and it was grouping 1 ¼” to 2” for 6 - five round groups.
The old Remington velocities averaged 2579 f.p.s., Extreme Spread was 167 f.p.s., Standard Deviation was 78.56 f.p.s. with 6 - five round groups from 2 ½” to 3 ¾”.
Definitive results? Nahh. But interesting, just the same.
I was not surprised by the lesser velocities and overall performance of the Remmy 788. Its muzzle blast is considerably greater than the longer barreled Ruger, which is probably due to the amount of powder still burning when the bullet exits the barrel. When fed its preferred load of IMR4064 and 165gn Hornadys, it is a little slower, but will group right around an inch if I stay off the caffeine.
Though I report the group sizes here, it was not the purpose of the range session. I lay the oversized groups to two different reasons: 1) The shot strings were 10 consecutive rounds in as many minutes which did not allow the barrel to cool in the 100+ degree Az weather; and: 2) I was not shooting for tight groups – I was sending lead quickly downrange for the primary purpose of chronograph data.
Fun stuff!
Poper
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That ended that session! 
