Good to know, I've been setting my Hammers back at 0.10 and after several primers and powders I still don't have anything to write home about so I'm going to do the Berger Test and see what happens.
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Bullet seating depths
- Thread starter 17remhunter
- Start date
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Call Steve at Hammer bullets. Really helpful.
I hope he has an idea, I've tried FL and NK and nothing is going good at the moment, but like I said I've been 10 off the lands on all the load so maybe jumping the bullet a little will help. I recrowned the barrel today, but it started raining so I have not tried it out. Something has to give or it'll be time to try something else on this action other than the barrel I have.
Mikecr
Well-Known Member
On the graphs, more or less powder/load density affects those up peak amplitudes, but the optimum seating as shown in pressure troughs is likely due to best throat interface. That's where bullets slide straight down the bore with no rattling around to begin.
No matter the load, optimum seating is always right where it is (independent of load).
No matter the load, optimum seating is always right where it is (independent of load).
Steve, recommended that I back it up 30 and give that a try, then 20 since the 10 isn't producing any good groups.
Hard rock
Well-Known Member
Have you tried crimping ? The hammers also like more interference or neck tension .0035 too .004 if your .010 off lands and not working out seat too the front drive band and try that kind of opposite of touching lands and going deeper . This way at least if things tighten up you may be good to go and it will give you a idea if closer or farther from the lands is what is going too work . It might also save you some componites
Sending156s
Well-Known Member
Yes, when you touch the lands there will always be an initial pressure spike that would not otherwise be there. The amount varies with different powders & different calibers to much to give you a number. Does it shoot better or worse? Only testing will show you. If you are going to jam, work slowly up to max & minimize your brass sizing. You would want your brass filling the chamber to keep bullet concentric with bore.
Modify the Berger test to .10, .30, .50. Why….because there will be a good spot closer & further back. Use the closest and as your throat erodes fall back on the further node.
Could you possibly email me the spreadsheet. I've been trying to work one of these up with miserable results.
My experience has been that seating depth effects group size. Different rifles, bullets, loads etc all react differently to seating depth changes. All of my rifles, except my lever actions like .018-.021 off the rifling. I find my best node with combinations of brass, primers and charge weight. then I muck with seating depth. Its amazing how I've found something that I thought was a node that didn't become a node until I tweaked the seating depth. My .270win likes .020 off the rifling, that was with a 150gr NP. Out of necessity I had to move to a 150gr ABLR and had to go to .017 to get an exceptional group out of it. Other things, like neck tension, neck thickness add to the equation also, once I had a concentricity issue throw me a curve too.
