I'm currently using .338 Lapua cases (neck sized only), Federal large magnum match primers, 98.5 grains of RL33 with Berger 300 grain OTM tactical bullet, COAL of 3.71 to work in my TRG42 magazine. Measured Pro Chrono velocity of 2,715 fps with chronograph centerline between posts of 18 feet, which gives a 2,722 fps muzzle velocity at 70 F and 2,100 elev. Ambient temp at Usery Mtn Range was 70 deg F, at 2,100 ft elevation. No signs of high pressure in my rifle at 70 deg F and bolt was easy to work. Plotting a very basic ammo temp to velocity on this load gave me the following (fps values shown are only for understanding the effect of ammo heat on pressure and velocity and are not tested) : Ammo Velocity
Temp. nearest to
(deg F)
0 Deg 2631
10 Deg 2636
20 Deg 2644
30 Deg 2654
40 Deg 2665
50 Deg 2680
60 Deg 2699
70 Deg 2722
80 Deg 2751
90 Deg 2787
100 Deg 2832
Some cloverleaf groups at 100 yds, under 1/2 MOA on a windy day. Pretty consistent velocities seen, but while chronographing any rounds sitting in the warmed rifle chamber indicated higher velocities, and I had to get ammo and rifle consistent temp for consistent velocity. I had multiple rounds indicate 2,715 fps on chrono @ 18 ft, with some slightly higher or lower. Bore and cases were very clean after shooting. Very rough values of 4,933 ft lbs muzzle, 2038 ft lbs 1,749 fps @ 1,000 yds and -26.7 MOA sighted at 100 yds in my typical hunt conditions of 70F at 3,500 ft elev.
Be aware of ambient temps and weapon chamber temps. Signs of high pressure were not observed in my ammo in my rifle, but always start off at least 10% lower or as indicated in your load data. As always, you must adjust your loads, for your rifle, for temperatures outside of that at which you chronographed at as high temps will affect chamber pressures and can be dangerous.
I will be trying N570 when I can ever get any. Good luck on your loads and happy shooting.