Load developing multiple barrels cut from same reamer

[MikeMcCasland]

Hey Guys,

I figure there's a few of you F-Class and BR veterans out there that have gone through this, so wanted to see if you'd do anything different.

Overview: I've currently got 3 barrels in circulation that are all cut off the same reamer; they're setup to shoot the 200.20x bullet. I have an additional 4 barrels cut from the same reamer that I need to do rough load development on, and I'd like to be smarter and more methodical about how do approach things.

All four of the new barrels will be shooting the 200.20X, but I still need to source bulk quantities of the same lot for those new tubes. That said, I have a few boxes of 20X bullets that are of varying lots, and really don't do me much good from a match shooting perspective; I was planning to use them to roughly identify powder nodes in these new barrels.

The plan:
1.) Load up ~40 rounds with crappy/low cost 30 cal bullets, and burn off excess powder 'breaking in' the rifle. (i.e. I just want the barrel at or close to speed when I start deving).

2.) I have a rough idea of where the 20X likes to shoot from my other three barrels; I was going to seat it in the same ballpark as those guns (.010-.015 off) for my testing.

3.) Run the ~4-5 ideal powders I have on hand through them to determine which one the barrel likes best. My plan was to start at charges that would get me 2600, and work up to 2670ish.

4.) Pull barrel until it's ready to have dev finished (seating depth testing) with the correct lot of bullets.

Anyone of yall with a bunch of barrels done something like this, or do ya'll just dev them 1 at a time when you're ready to shoot them?

If it matters, these are 2x 5R barts, 1x Krieger 4-groove, and 1x Brux of unsure rifling type. All 1:10 twist.

I'm really just trying to make sure I do this in the most cost effective/efficient manner. Secondly, I've got the spare time now, so I'm trying to make good use of it.

Thanks,

Mike

 

[David Christian]

@MikeMcCasland, your process seems good.

I run 2 different .284 rifles, with 2-4 barrels each, all cut from same reamer. I don’t start load dev until they have been properly broken in and have 200 rounds down them. I fire form a lot of brass over this time, run mini tests on stuff, burn off extra odd lots of bullets, primers and powder.

in the end, all of my barrels end up liking almost the same powder charge and seating depth. Meaning, I can jump to my fine tuning steps and can skip all the coarse testing.

 

[ballisticxlr]

I have 3 otherwise identical barrels in 6XC all from Columbia River Arms blanks that live on 3 otherwise very different rifles all cut with the same reamer to identical case head protrusion distances +/- .0002 to my gold master (a solid brass gauge that exactly matches my chambers and my sizing die). All 3 barrels are set up for zero headspace. I found that whatever load one barrel liked, the others were always totally ok with. Keep in mind that my standards are for 10 rapid fire shots to go into under .75" max, .5" is the goal but I don't have to hit that goal for the games I play.

I ran the first barrel for 10 rounds of break-in and then 50 rounds of load development with various powders to get a good idea of MV:charge weight returns. Almost all of the first powder testing loads made accuracy spec so then it was about charge weight, burn rate (I prefer powders on the slow side of the available options), and MV. Once I selected my powder I ran around 25 more development loads with that powder to get case fill as close to 100% as possible without getting pressure. Once I had the powder charge I ran seating depth in pretty coarse increments from near touching to big ol' jump which tuned the group size to its minimum. Then I ran 10 shots of break-in for the other barrels before and shot 20 rounds of the developed load for confirmation and to get my zero set. All 3 guns perform essentially identically in group size and accuracy though one of them is just the tiniest bit more accurate than the other two. Keep in mind the barrels I use are broke in within 10 rounds and I only ever shoot one kind of bullet from them and those bullets are coated with HBN from first shot to last shot.

Rifles are a wood stocked flat back Savage 110, an MDT chassis stocked modern Savage 10FPSR and a chassis stocked Howa 1500.