New Brass load development or fireform first
- Thread starter Raydee
- Start date
I always fire form my brass before starting load development.
dusterdave173
Silver $$ Contributor
I don't understand "takes several firings to fully fire form to your chamber" I mean--when you re size it after each firing?? I just don't understand when you are squeezing it back--please explain what all is happening I am a rookie
dusterdave173
Silver $$ Contributor
I have seen folks get stunning results with new Berger Lapua factory loads and that is first fired brass--I am guessing that is a great combo of correct bullet for twist--that loves the chamber on that rifle? No work up--new brass--no seating depth testing just bang and OMG look at those groups
I have 500 new Starline and 200 new Lapua that I am about to get started on in two new barrels so I am very interested in this thread--I hope I don't have to burn 3 rounds of primer, powder and bullets in each to start getting best results ( all 223 )
I have 500 new Starline and 200 new Lapua that I am about to get started on in two new barrels so I am very interested in this thread--I hope I don't have to burn 3 rounds of primer, powder and bullets in each to start getting best results ( all 223 )
It actually does take a few firings to fully form to chamber
Brass rebounds back a lot on first firing
Less on second.
Third I can usually measure the datum to base and get a good number to set setback.
I test this with packing tape on base.
That number of firings I’m sure can change from various factors in the system but always I just size the body only on first sizing and even the growth of datum length from touching the body only won’t make brass tight to chamber shoulder on second shot.
I found this out years ago when I neck sized a lot.
TheCZKid
Silver $$ Contributor
This thread is interesting to me too, as my most recent load development has been with 20 Vartarg. I've created about 1500 pieces from LC 5.56, and needed to know a good load for "never shot" brass to get good results for a season or two of sage rat shooting. I can't imaging fireforming 1500 pieces and using up my components, and also the barrel life, with just fireforming. Thankfully I found a couple really stellar loads for my first firing. I might have to change my load a bit for once or twice fired brass, I'll have to wait and find that out.
Ned Ludd
Silver $$ Contributor
With .223 Rem brass, primer pocket life may a concern, especially if it will ultimately be used for loads with heavy bullets, such as in F-TR competition. For that reason, I would suggest running a substantially reduced load for the first firing. 45K psi pressure (or even a little less) is more than enough to expand the brass and push the shoulder forward, even if it doesn't fully complete the fire-forming process on the first firing. That way, you're not starting the process of killing the primer pockets during fire-forming.
I typically work over the primer pockets/flashholes, then prepare virgin brass using a bushing die followed by an expander mandrel to set the final neck tension (interference fit). I trim/chamfer as a final step, which is often mostly chamfer and very little trim before the brass has been fire-formed. Brass prepared in this manner can be used to work up a load and can shoot very, very well. I often use such fire-forming loads to practice. Below is an image for three 15-shot targets at 318 yd in fairly ugly wind conditions with no flags using a mild load with Hornady 75 ELDMs in prepped virgin Norma .223 Rem brass. An old pizza box regained new life as a target, serving quite admirably. But again, you don't want seriously cut into the primer pocket life of the brass during the fire-forming process, which can be easy to do with .223 Rem brass if you're not careful.
I typically work over the primer pockets/flashholes, then prepare virgin brass using a bushing die followed by an expander mandrel to set the final neck tension (interference fit). I trim/chamfer as a final step, which is often mostly chamfer and very little trim before the brass has been fire-formed. Brass prepared in this manner can be used to work up a load and can shoot very, very well. I often use such fire-forming loads to practice. Below is an image for three 15-shot targets at 318 yd in fairly ugly wind conditions with no flags using a mild load with Hornady 75 ELDMs in prepped virgin Norma .223 Rem brass. An old pizza box regained new life as a target, serving quite admirably. But again, you don't want seriously cut into the primer pocket life of the brass during the fire-forming process, which can be easy to do with .223 Rem brass if you're not careful.
Andy Work
Gold $$ Contributor
We should have asked the OP what his goal is, that makes a difference. If you are trying to get the ultimate accuracy out of your rifle for competition, there are a lot of things that make a difference. It is a common practice to shoot new brass until you feel resistance closing a stripped bolt. Then size the brass so the shoulders are pushed back about .002". A lot of shooters don't want to feel any resistance when lowering the bolt. Some like to feel just a bit when the bolt is half way down. You can get good groups and kill groundhogs without doing all this, it just depends what your goal is.
You shouldn't need anywhere near 500 cases.
Pick the best 50 or so as measured, and fully fire form them before body sizing.
Good time to have a custom sizing die made out of a few FF'd cases.
You shouldn't have to FL size cases until they have gone where the chamber will eventually put them.
I say this because it's important that the cases stabilize, and that won't happen until you let it happen.
Pick the best 50 or so as measured, and fully fire form them before body sizing.
Good time to have a custom sizing die made out of a few FF'd cases.
Your chamber is your best die, and nothing truly undoes the chamber sizing with fire forming.
You shouldn't have to FL size cases until they have gone where the chamber will eventually put them.
I say this because it's important that the cases stabilize, and that won't happen until you let it happen.
dgeesaman
Gold $$ Contributor
I think all of this depends greatly on how much forming is in the fire forming.
If the brass simply needs to go from saami specs to your chamber then one firing should be very close. I will do a rough load development step on virgin brass here but take the results with a big grain of salt.
If you’re talking about making Dasher brass from 6BR, the yes a few firings are required to get the full brass volume.
Also, unless you have a sizing die that’s well matched to your actual chamber, fireforming never really completes. So if you’re just mashing out .223 to work in multiple guns don’t worry about it.
David
Last edited:
This is the practice I have always followed. I found that I can get fairly close if not spot on with new cases. I just don't push the shoulder back after the first few firings until I need to, but I do FL to zero to .001 bump.
Work up a load and shoot, once you have FFed your brass just tweak your load and carry on.
dryhumor
When an old man dies, a library is lost forever...
I’ve gotten too thrifty to fireform a lot of cases… I might do 20-30, maybe.
I use new and find a decent load, and use that load until I’ve shot all of it. Or, I change bullets powders and primers when I do it. That way, once formed I can have several combinations that are close to work with.
A chronograph can be your friend if you don’t have one.
I use new and find a decent load, and use that load until I’ve shot all of it. Or, I change bullets powders and primers when I do it. That way, once formed I can have several combinations that are close to work with.
A chronograph can be your friend if you don’t have one.
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.