New vs. Fire-formed brass - load development

[Petersen]

Ya. I'd be more concerned with the barrel breaking in and how that will change. Not so much concerned on brass. But also think about brass being fired once if you turn necks and use bushing dies. Then that will change things a little too. You can do some load development while breaking in, but then fine tune your loads as the barrel gets smoothed out and consistent and you pick how you are gonna reload. Full length size; neck size, bushing dies, etc.

 

[Slowshot18]

Starting load development with virgin brass and barrel is worthwhile to a certain extent. It’s good to get an idea of what your ideal charge weight and seating depth will be.
but as others have stated, once the barrel speeds up you will see an increase in speed.
There will also be changes, although slight, with fireformed vs virgin brass. The virgin brass was sized by the manufacturer, your fire formed brass was sized by your rifle’s chamber and then by yourself with your dies. Now if you’re only using your gun at 100-200 yards for hunting, these differences will not be significant. If you plan on chasing groups on paper or shooting out further, those changes are significant.
I’m obsessed with finding the perfect load and I’m aware that I’m reaching the point of diminishing returns, but to me it matters.

For example, my 20” proof 6.5 cm barrel sped up ~100 FPS near 180 rounds. Before it sped up, my ES was hovering around 12 FPS and I was ok with that because I was on virgin brass still. But I tried shooting a black buck doe at 500 yards with the gun during the speed up process and I shot just over her. I realized what was going on later that day when I was shooting at rocks far away so the rest of the trip I kept all my shots within 200 yards because I did not know what my velocity was.
With the barrels new speed settling in, I did not change the load but I noticed the ES was around 20 FPS and group moved from 1/2”-3/4” groups. I’ve gone outside the optimal range of my node.
I finally have all my brass formed and I plan on doing a final development with the barrel broken in and the formed brass. In other guns, I’ve noticed a difference with formed brass vs virgin, but again, it’s all relative to what you’re wanting to achieve.
BTW, my father in law bought a Ruger American in 6.5 cm and he wanted me to mount his scope, zero it with factory ammo, and put a timney trigger in it. Before shooting it I was skeptical of its potential. But I will be dammed if that gun shoots 1/2” or less groups with factory 140 eldm ammo. It’s a phenomenal gun and I’m sure you will enjoy yours as well!

 

[Wrench]

Ounces make pounds, but it's not going to show up unless you and the rifle are well sub moa shooters.

Brass that is not quite concentric, a chamber that is a fuzz bigger than the brass, bolt slop....many little things contribute to that little pill starting its journey to the promised land.....but most shooters are not capable of the level of accuracy to be able to see the subtle differences.....

So on a hunting rig or steel rig....id sacrifice. 002moa for 100% feed and function every day.

 

[Harvey_NW]

Even when components were readily available I would never waste them or the time fireforming brass for the chamber it's sized to be in without getting something back out of it. The only difference I've ever seen is ES shrink a little.

My personal preference on a new rig is to do the Bartlein break in method, Satterlee test with my seating depth in a general location of where I want to be (bottom bearing surface edge near the neck/shoulder junction is where I like to be, if not limited by mag or chamber length), seating depth test, shoot until something changes. I usually work with a lot size of 100 so after the first 100 I'll prep and double check the formed brass, throw one over the chrono every 20 shots or so to detect velocity change and shoot until it levels off. After I've detected it's sped up and leveled off I'll shoot another short powder ladder around the charge window I was in to retune that speed node, and call it a load until something changes. That's been a really solid process for me.

 

[Wsud]

That's part of what a break in helps with. I wouldn't start load work on shot #1 through a barrel.

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Agreed. I would reccomend a barrel break in procedure prior to a load development or ladder test. As you break the barrel in it helps polish the barrel, removes blems, and smooths out the rifling which will imcrease velocities once the barrel is good.