I have Winchester nickel or Remington brass, and every weight bullet produced.
I need a good fireforming load to make AI brass from 280 Remington brass.

Perry

Copied this from the internet and it's worked for me.
First insert a spent primer (for safety) in an unformed case. Fill the case with Bullseye® pistol powder to the top of the neck (DANGER, never to be fired). Then pour this charge into the pan of your powder scale and weigh the charge. Divide that amount by 10, so that 1/10 of the total volume will become your starting load. Now take that 10 percent load for your case and put it in your normally primed case. It may take some testing to get a load that fully forms the case. Tear a single sheet of toilet paper in quarters, insert one quarter as a wad over the powder charge. Now fill the rest of the case with your inert filler (corn meal, or fine ground hot cereal, etc., dry of course). You will want to place a wad of some sort over the cereal so it does not spill. Bees wax, bullet lube, or toilet paper work, it must be light enough so that the wad can be blown down the barrel without doing any damage.

You are ready to fireform a case. Keep in mind that even without a bullet these loads could be deadly, so use all normal gun safety practices. Pointing in a safe direction fire the first load. If it is not fully formed, bump your 10 percent load by one-half grain at a time until you get a fully formed case. It is possible to generate dangerous pressures if you use too much powder in these inert filler loads, so be careful. The interesting thing about this method is that it will often form cases without any loss to ruptures when a factory load will cause ruptures.
L.R. Wallack wrote this method up for American Rifleman. After describing the method he said, “I then did 10 cases with this load with no splits and all formed nicely. Such success has been practically unheard of, as anyone who has formed cases for this wildcat well knows. I have no hesitation, therefore, in recommending the method.

I've done the following for a couple rifles.

https://imrpowder.com/wp-conte...educed-loads-r_p.pdf

I have found the perfect and most economical way to fire form for my 280 AI. I use Win nickel brass

I use 20 gr of shotgun powder and 2 squares of toilet paper pushed in with a pencil.

Just shoot the whole lot in one go and save $30 to $45 on bullets and get more uniform results from the brass.

Why waste powder, primers, and run the risk of fouling your barrel with foreign matter -- or worse, miscalculating and creating a potential bomb in your chamber? Shoot a normal load and a normal bullet.

It is the chamber and not the brass case which determines the size of the pressure vessel. Simply use your regular .280 Imp load in new, unfired .280 brass (assuming the brass has enough capacity to hold it). It will shoot accurately and right alongside loads in fireformed brass.

If your .280 Imp loads are with a slow powder that overfills the unfired case, then move to a faster powder that will fit in the case. If this load doesn't perform as well as your preferred load with slower powder then use these "fireforming" loads for practice or varmints or small game.

quote:

Originally posted by Stonecreek:

It is the chamber and not the brass case which determines the size of the pressure vessel. Simply use your regular .280 Imp load in new, unfired .280 brass (assuming the brass has enough capacity to hold it). It will shoot accurately and right alongside loads in fireformed brass.

Exactly.

STOP!!!
Using shotgun powders, etc, is a good way to damage something. That is like alchemy.
First thing to do is determine if your chamber is cut longer than a standard 280; some are, mine is, , and if so, you have to have some method of holding your brass back against the bolt face. If not, then fire as normal, like Stone said.
Two methods of fire forming brass, if needed. Form a false shoulder, probably the best method, or jam a bullet into the throat, and fire a min load.

Too bad you're not a cast bullet shooter. You could load cast to form the brass. Good thing about it is you can seat the cast bullet out to head space your case correctly if you do have a long chamber such as some have mentioned here. Too boot you get to shoot some targets with cast!!!!!

This is an interesting thread. Thanks to all those who got me thinking.

Bro and I are re-barreling a couple 22-250AI with longer throats and faster twist for all the obvious reasons.

We decided to chamber a standard take-off barrel exactly the same (as near as possible) and use it to fire minimum yet standard loads for fire forming to save on wear and tear on the custom barrels.

We definitely plan on using minimum yet standard loads since I don't want to damage an action.

We plan on just about melting down the sacrificial barrel. I'll bet the throat is a foot long when we get through forming. haha

Okay, that didn't help you at all but was fun to share anyway.

Zeke

quote:

Originally posted by vzerone:
Too bad you're not a cast bullet shooter. You could load cast to form the brass. Good thing about it is you can seat the cast bullet out to head space your case correctly if you do have a long chamber such as some have mentioned here. Too boot you get to shoot some targets with cast!!!!!

If headspace is an issue just neck 280s up to 30 and then run through 280 AI dies.

My approach is to load a max 280 Rem Manual load with a bullet and use them to hunt with or practice with while fireforming at the same time..I do this most of the time..snug to the rifleings.

but you can use Unique with a tad of pillow fluff then (rice, cornmeal etc) then wax plug, and shoot it..l will have to check on the powder charge with Unique as it slips my mind, but its just enough to blow out the shoulder crisp and clean....

My powder charge of Unique was 22 grs. but start at 20 and work up if that's not giving you a crisp clean shoulder. btw its always best to point the gun up when fireforming without a bullet...