.308win & 155gr #2156 Sierra's need some help

[manitou210]

Trying to help good friend find a load for F class gun he had made up
Action Barnard
30" Barrel 1/10 twist
Brass Lapua (uniformed primer pockets)
Primers CCI Benchrest
I have tried many powders,Varget, H4895, RL 15, VT 540, Benchmark, IMR 4064.
Most of these powder will shoot in .2s & 3s in my Hart 1/12 twist with Sierra 168gr but dammed if I can get these 155gr MK to shoot
3/4" best to 1.5" at 100y, tried kissing, right out to 25& 30 jump. I think twist is to fast for 155gr????????
He cannot use bigger bullets rules allow only 155.5gr max for FT/R class in Canada

 

[msnations]

If you want to stick with the 2156s I'd recomend picking a powder and playing with a significant range of seating depths (cover .030 on to .060 off in .015 increments). Tried soft seating? My 13 twist hart likes them lightly jammed...

-Mark

 

[distinguished]

Guns of the week- week 59, trials winners home built .308 Palma rifle. Used a 1-10 twist. Your bullets may not be going to "sleep" at 100yds. I suggest trying at a longer distance, at least 200yds.

 

[spclark]

The new 2156 works fine in a 1:11 Broughton 5R I use for Palma. Other suggestions notwithstanding, you might want to try either the Berger 155 VLD or Lapua's 155 as they're longer than the 2156 & hence may be more suited to the faster twist.

Last year I was astounded to find jumping the 2156 as much as .060" didn't seem to affect performance. I started at .010" off & at 200 yards testing the results improved the farther they were jumped.

 

[Laurie]

I doubt if it's the 1-10" twist in itself. It may be the barrel dimensions are such it just doesn't like the Sierrra, in which case the Berger 155.5 FB or Lapua Scenar may shoot better.

You've omitted one powder that I would always try in .308 with 155-175gn bullet weights, Viht N150. It doesn't always give as high MVs as some, but in my experience is hard to beat for accuracy in most barrels and bullet models. Although N140 is the usual powder of choice for TR loads on this side of the Atlantic, I've had far smaller groups with N150 in some four or five barrels / rifles to date.

Laurie,
York, England

 

[xtightg]

Hi I am using the 30 cal Dyer HBC-BJD 155grain Palma projectiles, Lapua brass. I tried the felt pen seating depth set up in my Sako TRG 22 1:11 twist to just missing the lands, resulting grouping all touching almost one hole at 100 yards. Got me a Hornady seating depth gauge set up I have 0,063" jump !!! I thought I was just missing. Tried closer as per all the advice still shoots best with the big jump !!!. My powder is 47.5 grains ADI AR2208 I think this is Varget you best check this out , Federal 210 primers. Velocity 26" barrel high 2898 fps low 2861 fps average 2885 fps, ES 37, ED 10. No pressure signs or bolt lift or brass issues. 300 yards 60 x60 500 yards 60x 60 900 yards 59x60 first try seams to work for me. Standard Sako TRG 22, Schmidt and Bender PMII 5-25x56, Sinclair F/Class bipod with their rail adaptor and rear bag.
Be careful work loads up safely per the manuals this works ok for me in New Zealand maybe not you. Have fun ;D