Optimum Powder Charge Then Set Bullet to Land Distance or Vice Versa

[max]

I always thought that to find the best load you established the best powder charge first using the OAL published in the manual, then adjusted the bullet to land distance to fine tune it. While browsing the web I found that others do the reverse. Was I wrong all along?

[jlcpls]

I've never done it any other way than charge 1st, than OAL.

[tammons]

The way I have done it in the past is for normal match type loads is to set the bullet at the lands and work the load then fine tune the bullet seating depth.

All loads vary but in general I have found that flat tail bullets do best jumped around .015 and VLD bullets do better jammed about .015, but that's just in general. Now for flat tail bullet especially light bullets I usually start out .015 jumped.

For barnes bullets I start out at the barnes recommended jump.

[Elkbane]

On "target" guns with "target" bullets that I'm probably going to shoot jammed into the lands anyway, I do the OCW testing with them jammed. That way you establish safe max load with jammed bullets and don't have to deal with pressure issues you might face if you find a node at, near or above published max, and then find later you need to jam the bullets for optimum accuracy.

For hunting guns, I start out with SAAMI length, find the powder OCW powder charge, then monkey with seating depth. Both methods work. Just depends on what intentions you have for the load / rifle combo.
ELkbane

[1Shot]

...Powder then OAL...Ask Mike CTX...lol.. ;)

[brianinca]

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For hunting guns,
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I never bother to fiddle with seating depth, I so often get sub-MOA with OCW high nodes I just stop and be happy. I CERTAINLY would never start with seating depth, you're changing pressures surely but nothing in comparison to a 1 gr difference between a chaos node and an accuracy node.

With having to go with non-lead bullets for hunting two years ago, my predisposition to stop when I get to 1 MOA or better for hunting just solidified. I'd never shoot a deer at 500 yards, so why would a 2.5" CEP matter to me?

Regards,
Brian in CA

[Hammer]

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Do them simultaneously.

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[jlcpls]

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Do them simultaneously.

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I knew that was coming.

Practically speaking, given the variables of bullet type, seating depth, powder type, powder charge, brass type, how formed, and primer, how many trials would you need to determine best repeatable accuracy, assuming shooter error was eliminated?

[Hammer]

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I like shooter error. I see it all the time. It is fun to discuss the other shooter's error at dinner. Especially if it is an in-law.


With bullet seating depth and powder charge levels as the only two variables and with five levels of each, that would be 25 groups. This is how the very best benchrest shooter in the world does it.


Adding more variables, the total number of experiments does not go up materially.

With 30 variables, could do it in 32 experiments. Did a sniper ammunition development project years ago that had all the factors you mentioned plus more (like which rifle was being used). Completed the whole test in one day.

Repeated it on other days to confirm that it wasn't a fluke of one day.

It did repeat.


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