Re: 168 gr. Match BTHP Load(s) suggestions
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Grump</div><div class="ubbcode-body">With 4064 in .308, 41.5 to 42.5 gr should do it.
My barrel with 42.5 gives 2560-2600 fps from an M1A with 168s, right there in the spec for M852 (2550 at 78 feet, +/- 30 fps, about = 2560-2620 fps at 10 feet).
Then there is the old reliable 41.5 IMR-4895 load, again in military brass. I suspect it goes a bit slower, like 2530-2550 at 10 feet, but that was the one which for years we said, "if your rifle won't shoot this load well, it has a problem".
Work up and believe your chronograph AND your targets. I suspect that Win brass might take a full grain more of powder to reach the full-spec velocity, but you are the one responsible for your safety. </div></div>
adkmtnman,
Grump's suggestion of IMR4895 powder is an excellent one in commercial brass though only a light starting charge. I like 44.2 grains of IMR4895 with the same assembly details as the H4895 load for a very similar 2,730FPS out of my varmint barreled Rem700. These are both 1,000 yard capable loads in my early '70's vintage (my first high-power bolt gun) Rem 700 which for some 40 years has always preferred 168 grain bullets.
You can get to 2,800FPS using RL-17 but by many reports this is not a very temperature stable powder and on a warm day will be over-pressure. Both H4895 and IMR4895 seem pretty heat insensitive and I have used both for some time here in southern California mostly in the hot (70F-120F) weather though not so much in the cold (lower than 50F). Varget is also very popular powder choice in terms of temperature insensitivity but Varget seems to be inconsistent lot to lot which is why I buy it in the 8lb. jugs! Hodgdon BL-C2 is another good powder that can give you a speed boost due to it's density and softer hit when ignited. Using about 46.0 grains of BL-C2 will get you close to the same velocity as the Hodgdon 4895 and IMR 4895 powders above.
My personal favorite powders for .308Win (all easily loaded to safely produce higher velocities and consistently accurate rounds) using 168 grain bullets are IMR4895, IMR3031, H4895, BL-C2 and Varget. All of my pet powders seem to produce slightly more modest pressures by weight when compared with other commonly used powders for .308Win. The slightly lower energy powders ignite softer and produce more gas slower than higher energy powders which IMO is why they tend to produce more velocity and accurate loaded rounds. Combining a softer primer it seems like you can get more velocity from the same components because you can use slightly more powder to increase the volume and duration of high gas pressure to work on accelerating the bullet down the barrel.
Remember, start 10% below current loading manual maximum charge weights and work up from there looking for pressure signs. If you shoot inside 600 yards you will probably see more consistency from modest powder charges and velocity.
HTH!
