From the accurateshooter.com 6PPC page
[h=2]Fire-Forming Cases[/h] [h=3]There are three basic methods to form 6PPC cases.[/h]
Method 1
Fire-Form with Pistol Powder, No Bullet:
With this method, you load a case with pistol powder, seal the case mouth with wax or modeling clay, and then just shoot off the charge. There are many variations on the theme, using different loads of powder and various fillers, but we suggest just loading the case with Bullseye up to the neck, top with wax (NO BULLET of course!), and forget the fillers. This will produce very consistent cases, particularly if you use a dedicated fire-forming barrel with .002-.003″ shortened headspace for a good crush fit. It’s sensible to set up the fire-forming barrel with a no-turn neck, so you can neck-turn
after fire-forming. If you are using a chamber with normal headspace (such as when fire-forming with your match barrel), we recommend you run an expander down the neck to get an outside diameter just equal to the chamber size. This helps with crush fit, and seals the chamber, reducing blow-by. For example, if you have .010″ neck thickness, and a .262″ neck, you want to expand the neck inside diameter to .242″ (after springback). Since there is no bullet in place, the case-neck will go in the chamber even with this tight clearance. Note: you can buy expanders in various diameters, but you may have to turn down the diameter slightly to get just the right amount of expansion.
WARNING: NEVER USE the FIRE-FORMING PISTOL POWDER in YOUR REGULAR LOAD WITH BULLETS–THIS CAN BE EXTREMELY DANGEROUS!!.
Method 2
Fire-Form with 6mm bullet and Full Load:
The second method is to fire-form with a 6mm bullet in place using your regular rifle powder. To save wear on your precious match barrel, again, this can be done with a dedicated fire-forming barrel. It’s fine to use a “throw-away” PPC barrel that has lost its accuracy, but you want to make sure the chamber is the same as your match gun, or your fire-formed rounds may not fit. You expand the brass with a 6mm expander, then turn the cases to fit your chamber. (You may wish to leave the very end of the neck a couple thousandths larger than the rest of the neck so you get a crush fit–you can then make a final neck-turning pass after fire-forming). Load a full charge, seat the bullets into the lands, and shoot. After initial fire-forming you’ll want to shoot the cases one or two times in your match barrel to get a final perfect fit. Most shooters will then uniform the primer pockets, and some will ream the flash holes. Some shooters like to do a final neck-turning pass after fire-forming. Once you do the case prep you prefer, the cases are ready for competition.
Method 3
Load with .222 Bullet in 6PPC Chamber:
The third method, loading a 220 Russian normally and shooting it in a 6PPC chamber, is less well-known but reportedly works well. Start with a 6mm fire-forming barrel chambered like your match barrels. You simply take the 220 Russian case, fill it with a normal charge of rifle powder (H322, Benchmarks, VV N133), and seat any inexpensive .222 bullet. Chamber the round and fire. This will blow the shoulder forward
and expand the neck to your exact chamber dimension. The .22-caliber bullet just sails down the oversize bore (don’t use your match barrel for this!). Reports are that this results in very uniform necks. After fire-forming, expand the neck and turn to your desired diameter. The only negative in this process is that you will be wasting bullets, so use cheap ones. Also, you’ll need some kind of .22-caliber seating die. By contrast, with the no-bullet/wax-plug method you can basically fire-form at the bench with no tools other than a primer seater and a powder dipper. Thanks to K. Highfield of Sydney, Australia for this tip.
