300PRC load improvement question

[tstanek]

Hi there,
I would like to ask you for advice regarding my 300 PRC load with 215 Hybrids. I use Reload Swiss RS76 powder, which should be very close / similar to H1000 in burning velocity. Loading 80,5 Grs to Lapua Brass, induction annealed, FL sized with Wilson bushing die, run with mandrel afterwards. Fed LRM primers. COAL is 3,7 inch (94 mm), which represents 0,010 jump in my rifle. I'm getting consistent velocities I'm satisfied with, mean is 2831 fps, SD 5,9 and ES is 13, no pressure signs at all. But grouping is no good, I'm getting like 1,5 MOA groups approx., maybe little less, but over 1 MOA for sure. How would you proceed with the load dev. / to improve the grouping now? The thing is that my current stash of bullets is getting thinner, and there is really no chance, or hope to get a new batch of these Hybrids in the foreseeable future. So I would really appreciate a component-saving approach if possible. In 3 weeks I have the opportunity to shoot in the 1 km range, which is very rare here in Czech republic, so I want to be prepared for that. But as I said the load isn't really on the point calling it satisfactory. How would you refine the load now? I also have Cortina Tuner Brake which seems to have some ability to shrink the groups, but obviously the current load is far from being almost-optimal to just fine tune it with a barrel tuner. Any advice, or ideas on that would be really appreciated. Thanks a lot in advance!
T.

 

[moondog]

On my second 300PRC barrel shooting 215s. Both liked them into the lands around..006, both shot better at higher velocity.

 

[Precisionhunter417]

What length and twist is your barrel. Im having alot of success with 300 PRC and your accuracy expectations are low. It should be 3/4”-1/2” with the right load and using quality components.

 

[tstanek]

I have 26 inch barrel with 1:9 twist.

 

[LCazador]

Bad groups great ES generally means wrong powder. How are you measuring pressure? You should be measuring head diameter of brass so you have a more accurate measure of pressure. I would suggest a seating depth test to see if groups get better. Are your groups horizontal or vertical?

 

[drop_point]

I would find touch point, back up 0.006", 0.012", 0.018" and see if any of those shoot better.

 

[OmegaRed]

My speed with 215's, Lapua brass, H1000 is right at 2900. 24" barrel

.016 jumped from touch. That said, none of that matters for you. You have to work up your own load.

When I was short on components, I shot 1 shot at half grain intervals for rough powder charge at different targets. Overlaid all those onto the same target to see POI. I got a 1 grain wide node where POI was the same. Then went to seating starting at .020 off touch.

 

[10XSHOOTER]

Hi there,
I would like to ask you for advice regarding my 300 PRC load with 215 Hybrids. I use Reload Swiss RS76 powder, which should be very close / similar to H1000 in burning velocity. Loading 80,5 Grs to Lapua Brass, induction annealed, FL sized with Wilson bushing die, run with mandrel afterwards. Fed LRM primers. COAL is 3,7 inch (94 mm), which represents 0,010 jump in my rifle. I'm getting consistent velocities I'm satisfied with, mean is 2831 fps, SD 5,9 and ES is 13, no pressure signs at all. But grouping is no good, I'm getting like 1,5 MOA groups approx., maybe little less, but over 1 MOA for sure. How would you proceed with the load dev. / to improve the grouping now? The thing is that my current stash of bullets is getting thinner, and there is really no chance, or hope to get a new batch of these Hybrids in the foreseeable future. So I would really appreciate a component-saving approach if possible. In 3 weeks I have the opportunity to shoot in the 1 km range, which is very rare here in Czech republic, so I want to be prepared for that. But as I said the load isn't really on the point calling it satisfactory. How would you refine the load now? I also have Cortina Tuner Brake which seems to have some ability to shrink the groups, but obviously the current load is far from being almost-optimal to just fine tune it with a barrel tuner. Any advice, or ideas on that would be really appreciated. Thanks a lot in advance!
T.

Ahoj "T". where in the Czech Rep is the 1000km range? I lived in Pardubice for some time and only got to shoot at a local pistol range.. Dekuji G Pribyl.