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RL 15 for 308 Win. 168gr SMK
- Thread starter Rob96
- Start date
Case capacity varies more, brand-to-brand, in .308 than in most chamberings, and this can vary the maximum charge about a grain to a grain and a half. So it is important to specify the case. Primers also affect it. I can tell you Hornady publishes 44.3 grains as maximum for their similar 168 grain bullet using Hornady/Frontier brass and Federal 210 primers (mild side). 2.800" COL.
Alliant publishes 45 grains as a recipe using the similar Speer 168 grain match bullet in an IMI case with a CCI 200 primer. 2.800" COL
My records show 45.4 grains in a Winchester case (Winchesters are on the large side) over a Federal 210M primer did well with the Sierra 168 grain MatchKing. 2.800" COL.
As with all load recommendations, you should knock 10% off and work up slowly in your own rifle, while watching for pressure signs. That allows for differences in the powder lot you bought and in your gun's chamber and throat dimensions. Both affect pressure.
Alliant publishes 45 grains as a recipe using the similar Speer 168 grain match bullet in an IMI case with a CCI 200 primer. 2.800" COL
My records show 45.4 grains in a Winchester case (Winchesters are on the large side) over a Federal 210M primer did well with the Sierra 168 grain MatchKing. 2.800" COL.
As with all load recommendations, you should knock 10% off and work up slowly in your own rifle, while watching for pressure signs. That allows for differences in the powder lot you bought and in your gun's chamber and throat dimensions. Both affect pressure.
My goto load for this combination is 42.2 grains of RL-15, Win brass, 168 SMK and CCI LR primers. COAL is 2.791" for a 15 thousandths jump in a Savage Model 12. I've experimented with up to 44.0 grains, with no pressure signs but diminished accuracy.
For what it is worth, Sierra (5th ed.) lists a starting load of 38.8 grains and a max of 43.6 grains, using Federal brass and primers, another Savage Model 12, and a COAL of 2.800" and with a recommendation of 42.0 grains for best accuracy.
For what it is worth, Sierra (5th ed.) lists a starting load of 38.8 grains and a max of 43.6 grains, using Federal brass and primers, another Savage Model 12, and a COAL of 2.800" and with a recommendation of 42.0 grains for best accuracy.
azredhawk44
Moderator
Just FYI:
2.800 is the max OAL because of the fact that the .308 can be chambered in an M14 rifle, and the magazine will only accept bullets that are less than 2.800 in length.
If you're shooting a bolt gun, you might be able to get away with more, and benefit from that.
Also, gotta agree on the case capacity issue. I've got some stuff that is headstamped ".308 Win" from makers that are typically associated with producing 7.62 NATO circle-cross stamped ammo. Prvi Partisan, Magtech and GGG are 3 examples of this brass. They are thicker cases than most other .308 and should be downloaded about 1.0-1.5gr since the internal capacity is less.
2.800 is the max OAL because of the fact that the .308 can be chambered in an M14 rifle, and the magazine will only accept bullets that are less than 2.800 in length.
If you're shooting a bolt gun, you might be able to get away with more, and benefit from that.
Also, gotta agree on the case capacity issue. I've got some stuff that is headstamped ".308 Win" from makers that are typically associated with producing 7.62 NATO circle-cross stamped ammo. Prvi Partisan, Magtech and GGG are 3 examples of this brass. They are thicker cases than most other .308 and should be downloaded about 1.0-1.5gr since the internal capacity is less.
Curiously enough, the IMI brass that Alliant uses in their 45 grain load is the heaviest I have (186 grains; IMI Match). Winchester is the lightest (156 grains average in my last buy). Remington ran around 168 grains at last measure, Lapua ran 171 grains, and new Lake City Match was at about 180 grains.
I should have mentioned that my 45.4 grain load was for a Garand chambered in .308, so it is for a 24" tube and a chamber that's not especially tight. I looked at my M1A records, and it liked the charge a grain lighter, at 44.4 grains. Also 2.8" COL. As mentioned earlier, the 2.8" number is just the max for universal magazine and feed compatibility. Nothing to stop you from going either up or down if your gun and feed requirements permit it. Just be prepared to rework the loads at any change in seating depth, as that affects pressure. My numbers are all more than 10 years old, as I got into the mouse gun phase around a dozen years ago.
I should have mentioned that my 45.4 grain load was for a Garand chambered in .308, so it is for a 24" tube and a chamber that's not especially tight. I looked at my M1A records, and it liked the charge a grain lighter, at 44.4 grains. Also 2.8" COL. As mentioned earlier, the 2.8" number is just the max for universal magazine and feed compatibility. Nothing to stop you from going either up or down if your gun and feed requirements permit it. Just be prepared to rework the loads at any change in seating depth, as that affects pressure. My numbers are all more than 10 years old, as I got into the mouse gun phase around a dozen years ago.