Just Learnin
Well-Known Member
Hey guys, finally got to do some load work-up this morning. I'm shooting a 338 snipe-tac made by Dave Viers (specs posted down in Gun Photos). I used H50BMG powder, 300gr SMKs (boron coated), and WLRM primers. I waited about 3 minutes between shots, putting the rifle and ammo in the shade between shots. Shots were made round robin, i.e. one 135gr, one 136gr, etc. It was sunny (mirage was pretty bad so you gotta cut me a little slack for the group size ) with a light (est. 2-5 mph) left to right breeze. Temperature ran from 45* at the start to about 50* at the end and elevation of 2621 (no humidity reading, forgot the Brunton). Distance to target was 235 yards and I used an Oehler model 35P chronograph. Group size is center to center.
135gr
1 3113fps (sighter/fouler shot)
2 no reading
3 no reading (shots 2 and 3 almost touching)
4 3134fps
es = 21fps
group size = 1.7" or 0.72moa
136gr
1 3134fps
2 no reading
3 3128fps
es = 6fps
group size = 1.52" or 0.65moa
137gr
1 3157fps
2 3150fps
3 3169fps
es = 19fps
group size = 1.38" or 0.59moa
138gr
1 3171fps
2 3174fps
3 3179fps
es = 8fps
group size = 1.62" or .69moa
139gr
1 3193fps
2 3208fps (1st two shots touching)
3 3208fps
es = 15fps
group size = 1.05" or 0.45moa
140gr
1 3218fps
2 3225fps
3 3232fps
es = 14fps
group size = 1.17" or 0.50moa
I thought about fine-tuning the upper spectrum, say 138.5gr, 139gr, 139.5gr, and 140gr. Maybe 5 shots each to gather a little more chrono data? The load at 139 sure looked promising to me, except for the first shot being 15fps slower...
Any thoughts or comments? Thanks! -- Don
135gr
1 3113fps (sighter/fouler shot)
2 no reading
3 no reading (shots 2 and 3 almost touching)
4 3134fps
es = 21fps
group size = 1.7" or 0.72moa
136gr
1 3134fps
2 no reading
3 3128fps
es = 6fps
group size = 1.52" or 0.65moa
137gr
1 3157fps
2 3150fps
3 3169fps
es = 19fps
group size = 1.38" or 0.59moa
138gr
1 3171fps
2 3174fps
3 3179fps
es = 8fps
group size = 1.62" or .69moa
139gr
1 3193fps
2 3208fps (1st two shots touching)
3 3208fps
es = 15fps
group size = 1.05" or 0.45moa
140gr
1 3218fps
2 3225fps
3 3232fps
es = 14fps
group size = 1.17" or 0.50moa
I thought about fine-tuning the upper spectrum, say 138.5gr, 139gr, 139.5gr, and 140gr. Maybe 5 shots each to gather a little more chrono data? The load at 139 sure looked promising to me, except for the first shot being 15fps slower...
Any thoughts or comments? Thanks! -- Don