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How do YOU load during fire forming

sacklunch

The Sacklunch Center for Kids Who Can’t Shoot Good
Minuteman
Apr 23, 2023
53
12
Texas
New barrel, first pre-fit, nex box of brass…how do you load for fire forming and what can you achieve prior to load dev after the 100 or so down the tub when that barrel settles in?

Aside from working up to find a max, maybe trying a few different bullets or just taking the time to focus in on fundamentals again, what are some techniques to get you close to that new load vs just but if through 100 rounds of barrel life before beginning?
 
New barrel, first pre-fit, nex box of brass…how do you load for fire forming and what can you achieve prior to load dev after the 100 or so down the tub when that barrel settles in?

Aside from working up to find a max, maybe trying a few different bullets or just taking the time to focus in on fundamentals again, what are some techniques to get you close to that new load vs just but if through 100 rounds of barrel life before beginning?
Since I don't use custom barrels, I like to use somewhat hot loads and not using my best more expensive projectiles (I keep a supply of seconds for this) nor my best powder or primers that may be hard to come by for my first firing towards getting the brass fire formed. After this first firing I'll take case volume measurements so that I'll know how the fire brass volume compares to the previous, which can very often make a difference from previous load performance. I don't consider the brass fully fire formed until they've been fired at lease twice to be sure all the brass has been fully formed to the chamber. The second firing I feel I can go back to my preferred components and begin finding the load that'll work best based on any similar previous barrel and components used. During that first round, I work on my shooting mechanics collect chrono data for the powder I'm using (a good time to test a new powder or new lot of powder, even though velocities might not settle until ~200 rounds). I do not try new bullets until barrel has settled and good data on powder and primers in order not to waste those components.

Since a lot of this is only important to certain level of shooting, it doesn't apply to all. Obviously, if you're just plinking, none of it really matters. For hunting at short distances, I doubt if any of it makes any difference either. But if you intend to shoot .5 or less MOA, especially at long distance, it's good to get the barrel to settle ~200 rounds and to have you're brass in prepped for as much consistency as possible.

Anyway, this is just my approach to it and I'm sure there are many other's who do it all differently for whatever reasons they have. :giggle:
 
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Run a mandrel through just to take any errant dings out of the neck, then prime/charge/seat. Either the load I was using for the old barrel, or a mid range load from a manual. If it's a really new combination for me, I may run a quick charge ladder just to check speeds and pressures.

I really just want something that will let me get some positional shooting practice in during fire forming/barrel speed up.
 
What t rex said. I’ll shoot a local match in the first 200 or so if the mood strikes me, aside from practicing.
 
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Same as above. I don't load anything hot even after first firing of brass. So I don't treat the first firing any differently. Just load what's been working in other barrels, or a common powder/bullet combination that is popular (30.0 varget and 105 berger in 6br for example).
 
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I’m more curious as m going to a shorter barrel in a chambering I have loads for 2 longer barrels already. Debate for me was just shoot a load from another rifle with the same reamer and enjoy it, then tweak after it speeds up. Or that 4” less barrel will change things significantly so may as well start over again.