Do I need to fire form after market brass? What do you do?

[Matthias86]

I'm new to reloading. I primarily load for my 6mm ARC. With my handloads I pretty consistently shoot .5-.75 MOA with 5 rounds at 100 yards. 6mm ARC brass has been impossible to find so I have only been using once fired Brass from Hornady factory ammo. The brass is already fire formed to my barrel for my first reload.

I just found Starline and Hornady reloading brass. I bought a couple hundred of both to see what I like best. My question - should I use cheap bullets and powder for the first load of the new after market brass to fire form the brass to my barrel, or can I load the new brass with my good stuff and still get good accuracy? What do you guys do with new brass?

Extra info: The gun I'm loading for is a gas gun (AR-15) so my tolerances aren't as tight as a bolt gun.

 

[Tylsmith33]

I have found that with brand new lapua brass in 300 win 243 .22-250 308 6.5 creed and 6.5 prc, that if I run the expander through the case mouth and load it with the usual load it performs extremely well from an accuracy standpoint. Definitely good enough for hunting anyways. I’m not sure how hornady and Starline brass is brand new however. I would definitely run a test on the brass though because if you can get decent accuracy out of that first firing why not take advantage. These days where powder primer and bullets come at a premium I wouldn’t necessarily waste components to just fireform brass especially if you are not shooting competitively. Watching guys fireform the larger ackley rounds and shoot sub moa groups is what turned me to doing this.

 

[Matthias86]

Awesome. I was definitely going to test each brand, but that is definitely good to know. Thanks!

 

[A382DWDZQ]

I think Starline recommends just sizing the neck before firing, not sure on Hornady. I usually do a light chamfer and debur then dry lube neck and size the neck, then check fit with the case gauge, That gets me decent consistency with my seating. You can measure your fired brass at all the different points that get sized & then same for the factory brass and see what the differences are.

 

[Matthias86]

Ok nice. I only have a full resizing die but I don't think it will hurt anything just doing a full resize on it. I do have an annealer so I'm not too worried about working the brass a little more than I have too.

So my Hornady reloading book gives me a "max case length" and a "trim case length" measurement. I have been triming my once fired brass to the trim length. If the after market brass is longer than my usual trim length, should I trim it for the first load or wait until I fired it at least once?

Edit: If I resize the neck and it goes over the max length I will have to trim.

 

[DaveCB]

Edit: If I resize the neck and it goes over the max length I will have to trim.
yes, Its unlikeable, but could happen.
with me the key is consistency. I am somewhat annal. I check make sure each piece of brass has a primer hole and is clear. I full length size and check oal of the brass. If I get a large variance on the length, then I will trim all to the shortest length unless its under minimum length. that piece will be set aside. Always debur. and clean the inside of the necks. Neck tension is always overlooked by new reloaders.

 

[Vern400]

I'm somewhat anal like Dave CB. I'll visually inspect first. Absolutely deburr unless it's Lapua because they drill the flash hole and I haven't found burrs. I have found off-center flash holes, huge flash holes and so on.

Chamber 5 or 10% of your brass and make sure it's nice and slippery in your chamber. You aren't going to find a big difference in an AR in precision by having a few thousands of extra headspace. It does effectively screw up bullet jump just a little bit but probably not enough to be concerned about on the first round.

In your situation, I would not fire form. I don't know what the accuracy life is of a 6ARC barrel. But it's not great. I've got 600 pieces of new Lapua and there's no way I'm going to fire form it. My barrel accuracy life is probably two and a half times what yours is. If you were a benchrest shooter my answer would be different.

I'm always thinking about the real possibility that my next barrel might suck compared to my current barrel . Even with reduced loads you're giving up life.