New rifle, virgin brass...too soon for load development?

[Vandy321]

First time reloader. Have learned a ton on here about the process.

Need to know where to go from here.

New, unfired custom build.

Have 150 pieces of prepped brass:
Body sized, primer pockets uniformed and flash hole deburred, necks trimmed and turned, chamfered and deburred. Neck sized and mandrel expanded to .002 tension. Ready to prime and start load development....but

With a new rifle, new barrel, and virgin brass...what next before I can start load development? Proof has an 11 shot break in. Do I do that first, and screw around to fire form 50 pieces and THEN start load development? Or do I break in and do load development with virgin brass... I understand accuracy wont change much when fire formed, but velocity will likely increase.

What's the best way to crack that nut?

 

[LawnMM]

What caliber?

As a general rule, I'd suggest at least 150rds on the barrel prior to load development.

Take what's prepped, pick a mild load, and go enjoy it. Do load development after you fire the 150.

 

[Vandy321]

300wm, 26" proof CF, ADG brass, berger 215s at a COAL of 3.565 (.020 off to start), .002 neck tension. Planning to start at 72gr H1000 and go from there.

Not sure I have that much time, trying to work up a load for a hunt 2nd week in Oct...and I'm away from home about 50% of the month for work.

Aside from speed changes, any other reason to wait that long?

 

[RegionRat]

If the design comes close to a standard, there is no reason to put it off very long.

Once you fire the bbl break in rounds, you should know on inspection if you are lucky or not.

If the case volume isn’t significantly affected by that first cycle, you can get to work and the bbl should settle within the first 50 rounds if it has been hand lapped and chambered by an expert.

Occasionally, there is a chamber reamer and bbl that don’t get along and a bbl will take longer, but in some circles that bbl will get passed for a different one. If you think about it, do you really want a bbl that is significantly affected by 200 rounds?

Sometimes, this impression is due to a wildcat situation or one where there is a chamber fit issue and it takes that many rounds to work the brass and settle on the accuracy nodes.

Having a good initial idea of what should work with a particular design helps minimize the round count associated with break in and load development. Many match shooters don’t believe in break in at all...

 

[Deleted member 10043]

Just work up a load and shoot. Don't waste 10% of your barrel life with your dick in your hand. It's bullshit right up there with breaking in a barrel.

 

[Olen_4504]

You can still do load dev and find your velocity node with virgin brass/new barrel.

once the barrel breaks in and you move to 1x + fired brass - you may just need to re-adjust your powder charge to get back down into that node.

you can still gain valuable information doing load dev early. just know you will probably have to tweak things slightly once everything is broke in. sometimes you won't!

 

[Deleted member 10043]

Or just true the ammo and if accuracy is fine call it. Nodes are right up there with wasting ammo fucking around with the barrel. Colossal waste of time.

 

[bsekf]

Should be able to do the Berger CBTO test while fireforming.

 

[Precision Underground]

It really depends on how much your brass grows when fired and how much your barrel speeds up. I always load 25-30 mild loads to get the barrel going and then start developing. Just don’t set the load in stone and make up 200 of them until you are sure it will shoot the same after 100 rounds or so and with 1x brass as it may need adjusting.

 

[____________]

My process with new brass.

Anneal
Full length size
expander mandrel


My load on my last barrel was 41.7. I load ten each 41.5, 41.7 and 41.9. I then test to see the accuracy at 800 and velocity. I choose one. In two hundred rounds I redo the test expecting to increase my charge weight about .3-.5.


Previous barrel new brass was 41.3, at 200 load testing lead me to 41.7.

I want an accurate load with virgin brass and a new barrel. When the barrel speeds up (about 200 rounds), I want to adjust my load again (through testing).

I will add, that any load sub half MOA should suffice. No need to burn the barrel out trying to find a load.

Right now, I have less that 100 rounds on two new barrels and I know my load for each. I will shoot that until I'm at 200 rounds. Then I will test the loads again with a slight increase.

 

[Vandy321]

Thanks fellas. I think I will find a an initial zero while doing proofs barrel break in (11 rounds) and run the berger CBTO test while I fire form.

I dont see it as a waste of barrel life as trigger time is trigger time which I desperately need anyways.

Also gives me time to find a Kestrel before I started with an OCW

 

[clcustom1911]

Based on my 6.5CM Proof barrel experience...

I did load development #1 after 200 rounds through the barrel. .... 41.5gr H4350 under a Hornady 147 ELDM was moving at 2680fps with a 20 shot SD of 9 ans sub-3/4 MOA all day long. In 75 degree weather.

At about round count 500 on the barrel That exact same load (same jug o powder, same lot of bullets, primers, same chrono, etc) sped up to 2750. In 80 degree weather.

I know H4350 is very temp stable and shouldn't shift 70 FPS in a 5 degree increase in temp. I've dropped half a grain and I'm back down to 2685 or so.

I think my barrel sped up on me after the initial break in.