Verticle Spreading and load development help - where to go from here?

[fnlights]

So I ran a velocity test. I couldn't bring myself to use .2gr increases even though I am sure it is a better method to use. I increased in .5gr and this is what I am getting.

I did not see any pressure at all even up to 77 grains.

Question is, what velocity do you guys get using H1000 and Berger 215's in a 24 in barrel? Is 2,704 sufficient? Velocity literally didn't change much at all from 74.5 to 75.5. Should I use this load and then fine tune seating depth?

At this point, I am thinking that 75 gr is my powder node and fine tune seating depth from there.

 

[PNWdude67]

.080 off the lands? WoW!!!! That's a lot.

Have you tried it? What were your results? We are finding the new hybrid Ogive bullets perform well with some healthy jump in 6mm, 6.5mm 7mm and 30 cal. Or you could just keep doing what everyone in this discussion does and seat .003-.010 off no matter what as it will most likely shoot good. Then watch accuracy deteriorate after 300 rounds and .005-8 throat erosion which consequently changed the geometric relationship of the bullet to lands 160-50% At 50-80 thousandths jump it takes more rounds to see .005-008 throat erosion and the jump % increases much less from the starting point is much less. Some of us are jumping way more than 80 thou. Weatherby had some good practices and one of them was a lot of jump. Berger has some articles on finding jump "nodes" over 100 thousandth off too. We almost always start 50 thousandth off the lands now and we will be adding more freebore to some of our chambers initially based on what we are seeing.

 

[PNWdude67]

View attachment 277186

So I ran a velocity test. I couldn't bring myself to use .2gr increases even though I am sure it is a better method to use. I increased in .5gr and this is what I am getting.

I did not see any pressure at all even up to 77 grains.

Question is, what velocity do you guys get using H1000 and Berger 215's in a 24 in barrel? Is 2,704 sufficient? Velocity literally didn't change much at all from 74.5 to 75.5. Should I use this load and then fine tune seating depth?

At this point, I am thinking that 75 gr is my powder node and fine tune seating depth from there.

I think you are right in using .5 grain increments in a case with 75 grains working loads. We use .2 in the BRA which is 29-30 grains. So percentage wise you are changing your charge about the same

 

[vancewalker007]

View attachment 277186

So I ran a velocity test. I couldn't bring myself to use .2gr increases even though I am sure it is a better method to use. I increased in .5gr and this is what I am getting.

I did not see any pressure at all even up to 77 grains.

Question is, what velocity do you guys get using H1000 and Berger 215's in a 24 in barrel? Is 2,704 sufficient? Velocity literally didn't change much at all from 74.5 to 75.5. Should I use this load and then fine tune seating depth?

At this point, I am thinking that 75 gr is my powder node and fine tune seating depth from there.

You have a great node there at 75. If components we not so tight I'd suggest to start stepping at .2 gr from 76.5 going up and find your rifle's pressure point, you might find a high node in the 76.5-77+ area. But, another say 70fps will not make a big different while hunting.

I say go for 75 and see if you can dial in your groups. You know you're way below your max so even on a really boiling hot day you're going to be safe.

 

[fnlights]

You have a great node there at 75. If components we not so tight I'd suggest to start stepping at .2 gr from 76.5 going up and find your rifle's pressure point, you might find a high node in the 76.5-77+ area. But, another say 70fps will not make a big different while hunting.

I say go for 75 and see if you can dial in your groups. You know you're way below your max so even on a really boiling hot day you're going to be safe.

Agree. I will now fine tune seating depth as needed. Really appreciate all the help! Learned a lot from everyone on here!

 

[drborsos99]

Here's a story from last year about how far off the lands is best:

Bullet Jump: Is Less Always Better?

About 2 years ago, Mark Gordon shared some preliminary research he’d conducted with the Applied Bal...

precisionrifleblog.com

 

[Its204fast]

I load for a 7mm Remmag and found it likes a healthy jump from the case to the lands, I started with Retumbo, then went to H4831 because the group didn't meet my expectations, gun didn't like the H4831, switched back to the Retumbo and worked my seating depth then charge weight to get what I wanted It's at >.75" at 100yds with a 5 shot group. Seating depth I usually find out what the mag will handle then seat deeper from there until it opens up then I work in 0.2Gr increments with charge weight up to max by book or pressure signs which ever comes first.

I know the gun is capable of a better group but I am the weak point. With my .204 I shoot much better, but the 204 has a heavier barrel, a Timney trigger and less recoil, noise and cheaper to shoot.