Finding the sweet spot ?

[c3pppo]

I had an interesting experience today while shooting some handloads and could use some help.

I'm shooting a Savage .308 1:10 twist, using 168 gr. Berger VLD bullets, Winchester fire formed brass with Federal Match primers.. The cartridge is loaded to the maximum length the magazine will take, just under 2.89 COL. The powder is H4895.

I had loads made up at 41 gr., 42 gr, and 43 gr. of powder.

I zeroed the scope at 200m with the 41 gr loads and was getting good groups, holes touching. Then I switched to the 42 gr. loads. This produced the same grouping a bit less than an inch higher. Then I switched to the 43 gr. loads. This produced good groups , but they were 3 inches higher than the groups at 41 gr.

So, I'm trying to figure out what's happening here. I don't have a chronograph, but my intuition tells me that the 43. gr loads have significantly higher velocity than the other loads, thereby causing the large increase in elevation. But why is there such a large change between 42 and 43 grains and hardly any change between 41 and 42 gr.?

Which leads to the question; should I be spending my time loading at 41-42 grains looking for the best grouping, or should I explore the area around 43 grains. It seems to me that for longer range work the higher velocity would be advantageous so spending time testing for the sweet spot at 43+ grains would be in order.

Your thoughts ?

 

[CyaN1de]

Accuracy is #1, Velocity is #2

If you can find the higher velocity accuracy node then you get the best of both worlds. I would go with the best accuracy over the best velocity if push came shove.

 

[sunray]

Like CyaN1de says, accuracy is more important.
Forget about where the group hits when working up loads. Shoot for group only.
"...holes touching..." Doesn't get any better than that with a hunting rifle. Sight in with the 41 grain load.

 

[pockets]

If the higher powder charge groups as well, it will have a higher FPS, giving you a flatter trajectory. Running your OAL, powder, and bullet on Quickload, it predicts a speed of 2500 for the 41gr. load, 2550 for the 42gr., and 2600 for the 43gr. You should be able to run that bullet at 2600 easily. You should be able to go all the way up to 45.8 gr. with that bullet and your OAL. But, work up watching for pressure signs. The FPS were calculated with a 24" barrel. If you have a 26" the speeds should be approx. 40 fps higher.

 

[c3pppo]

Thanks guys. I'll experiment a bit at the higher load levels and see what happens. BTW, the rifle is a Savage 10 BAS, not a hunting rifle by any means, unless you like lugging 16 pounds around in the bush. It has a 24" barrel, so thanks for the numbers, pockets. Something to play with.