How do you fine tune a load by adjusting seating depth? What amount of adjustment are we talking about? 0.001, 0.002, etc.? In or out?

Go to Berger bullets website, there you will find Walt Bergers personal method. Basically start in the lands, and back off in .040" increments, when you find the best one adjust +/- .005" and you are finished. Powder charge first, then seating depth.

Hope it helps.

For what purpose? If it is hunting loads, stop at 0.030 lead with ammo fitting magazine comfortably & feeding easily. I am of course assuming that you are happy with the bullet & the accuracy. All my hunting rifles will shoot 1 inch groups or there abouts at 100 meters with this kind of "fine tuning".

I am not a target shooter.

quote:

Originally posted by craigcampbell:
How do you fine tune a load by adjusting seating depth? What amount of adjustment are we talking about? 0.001, 0.002, etc.? In or out?

IMO, you can't even reliabley seat a bullet that little. I use 0.015"+/- increments (1/64"). 0.005" is 1/128" of an inch. Most bullet ogives/noses are not kept to that tight a tolerance, maybe a match bullet, but not most hunting bullets IME.

Hey Craig, Try 0.010" difference with 2-3 loaded at each Seating distance. Like 0.010" Off-the-Lands, 0.020" OtL, 0.030" OtL, 0.040" Otl, and 0.050" OtL. One of those should narrow it down for you.

Don't forget that you need to be "shorter" than the inside of the magazine, so Off-the-Lands may need to be changed to Fit-the-Magazine.

Best of luck to you.

Hey Hot Core,
I used your mentioned methods of detemining OCL and than converting OCL to ODL. I then used the Creighton Audette load development method. Trimmed all my brass to 2.490" and loaded 168 Matchkings kissing the lands. Shot varying loads between 69.0 and 71.0 grains this weekend and came up with three loads to test further. Hope to go within the next few days. Keeping my fingers crossed. I have to say the Creighton Audette method is so beautifully simply and so far appears to be effective. Great advice. Do you see any reason why I couldn't test my three new loads at 100 yds as oppossed to 300yds? Wind this weekend may be an issue and our 100 yd range is really well protected. Thanks again.

Hey Craig, There are two potential problems, but they can be ignored if need be:
1. Same as before, it can be more difficult to determine which Group is actually the "Best" Load, due to the close proximity of the Holes.
2. If you can "see" the Holes as you are shooting, it often adds a mental Stress Level that can result in a poor shot. When unable to see the Holes, that Stress just can't happen.
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The following appears to be contradictory to what I said above about using 3-shot groups. But, once I think I've located what appears to be the Best Harmonic and the best Seating Depth, I often go to a whole bunch of Cumulative 1-shot Groups from a clean, lightly lubed, cold barrel. This is very time consuming and may take a couple of days. But, it is my time to use as I desire, so that is what I do. After a shot and cleaning, I shoot other rifles while the barrel continues to cool.

Every few years I re-run a "Blind" P-FLR vs. Neck Sizing Test to verify the P-FLR is still the most accurate for me. I have a buddy hand me the Cartridges, so I do not know which ones I'm shooting at any particular time.

And while I'm doing this Blind Test, I normally have 15, 18, or 20 Cartridges all loaded the same for each type. For the Blind Test, I prefer a larger quantity, just to save time and I do not clean between each shot. If I know for sure I created a bad shot, and if it goes outside the Group, then I note it was "me" rather than the Load.

The larger number of shots are significantly more relevant than only a few. It just takes longer - a lot longer - so I do not get the barrel hotter than I prefer. Even more time with the Cumulative 1-shot Groups from a clean cold barrel.
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The trick is to find a Method that gives you confidence in "your" Final Load, regardless of the number of shots. Many ways work well and you can always "Stack" Targets you shoot in the future to verify the Group is not shifting.

Best of luck to you.

Hey HC

OCL, ODL, Audette, PFLR, clean after every shot?

You forgot the warnings about strain gauges, OCW and "thingies"! Don't forget to tell cc the trick of filing down the shell holders.

But I do agree with what you said about .010", although most of the time if I start at .030" off and vary the powder charge I come up with a load that is just fine.

Hey Woods, I went for the phone to call you yesterday and then I realized it was past noon. Figured you would be in the Fully Secured mode by then.

I save that Filing Shell Holders trick for "special" people.