[Deersniper]

I've tried some 155 Sierra Match at about 2950, like the manuals suggest, but they aren't accurate out of my Stevens .308. Has anybody slowed them down to 2600 -2750 with Varget, BLC-[2] or RE-15? I may rework some out of my old 150 gr CorLockt loads
42 - 44 gr does wonders with 150 gr bullets out of my rifle.??????

[samuel]

I don't use 150/155gr but douse 165/168br but looking in the Sierra load book they are around 2700fps with a 150/155gr.That would lead me to believe that would be appropriate for their bullets.With the 168gr MK I am using 45gr of IMR 4064 for about 2700.Thats 1in12" twist. ,,,sam.

[Bart B.]

Sierra's 155-gr. Palma bullets will shoot very accurate out of any good barrel decently chambered for the .308 Win. at most any muzzle velocity from 2000 fps up to 3100. !:10 twists will do well at the lower muzzle velocities and 1:13 or 1:14 at the higher ones.

Three things help get the best accuracy possible.

One is the proper extruded powder needs to be used; Varget or IMR4895 have proved excellent. None of the ball powders tried by the US Palma Team folks developing loads for the prototype 155's they got to test did well. Even though the most uniform pressure, muzzle velocity and metered powder charge weights were had with ball powders, they were the worst for accuracy.

Another is the barrel. Groove diameters shouldn't be larger than .3077" and .3075 has worked very well. Bore diameters can be .2980" to .2995" with good performance. Chambers with shorter than normal throats help if OAL is 2.800" otherwise just seat the bullet out to touch the lands.

And finally, the case. Full length sized fired cases give best accuracy. Use a bushing die such as RCBS Gold Medal or Redding S Full Bushing with a bushing diameter a couple thousandths smaller than loaded round neck diameter. 155's have a diameter of aboutr .3084" so you double your case neck wall thickness, add that to .3084 then subtract .002" for the bushing diameter to use. New cases have virtually the same accuracy when their necks are resized to hold the bullet uniformly. A conventional full lengths sizing die can be used but its expander ball may bend the case neck as well as be a bit small; use an expander ball diameter of about .3078". Set the die such that the fired case shoulder will be set back about .002". All types of neck sizing has never been consistantly successful.

Using a 155 in a load that worked well with 150's may do well if the charge is cut half a grain or thereabouts. I'd give it a try.

[Deersniper]

Thanks Bart B, I'll go back down on the charge to 42 and work up. My 150 CorLockt gets touching holes with 42 gr varget or 43 gr RE-15.

[Bart B.]

Deersniper, the load first used with the 155 in a .308 was 45.3 gr. of IMR4895 in a Winchester case with a Fed. 210M primer. Tested under 3 inches at 600 yards.

Later the same charge weight of Varget did just as well.