7mm max cream of wheat fire forming

[ZSteinle]

Anyone have a load they want to share for fire forming 7mm max. I have some green dot I can burn through. Was thinking maybe start at 8 grains and go up from there.

 

[GLTaylor]

It will probably take a bit more. Don't be bashful. I use 20grs of Bullseye, with NO cream of wheat - just tissue and get good initial forming.

 

[LongBomber]

Just for refernece info only, I use 11gr of green dot to fireform a 260ai case, so you prob have a bit of room to go up. In the edge ai I used 17gr of green dot.

 

[ZSteinle]

Just for refernece info only, I use 11gr of green dot to fireform a 260ai case, so you prob have a bit of room to go up. In the edge ai I used 17gr of green dot.

Thanks for the reference on capacity vs powder charge

 

[ZSteinle]

Just for refernece info only, I use 11gr of green dot to fireform a 260ai case, so you prob have a bit of room to go up. In the edge ai I used 17gr of green dot.

Are u using powder only or powder with a filler on top?

 

[Predator 22]

Start low and work up. When I formed 6.5ss I got a little carried away trying to get pretty much fully formed and had several cases split mid way up the body. And before anyone asks I had a good bit of tension on the bolt close from a false shoulder.

 

[MagnumManiac]

Rule of thumb is to use a fast pistol/shotgun powder and 1/3 of a normal max load average for the parent cartridge.
Personally, I use Universal topped off with COW and a twist of TP.
All improved chambers should have negative headspace of .003-.005" to get good fire formed brass WITHOUT the need for false shoulders and other unnecessary ducking about.

Cheers.

 

[deweyduck]

Shotgun powder for my 7mm RM? I need more info on this. I have some 7 mag Nosler brass to fireform and I have about 4 lbs of Hodgdon Clays powder that I no longer use so it would be a great help to avoid wasting my H4831SC. And what's up with using a twist of toilet paper or cream of wheat as a filler? Help me out here please with this great idea I've never heard of.

 

[just_jon]

I have fire formed 1000s of improved rounds using the the 1/3 rule of thumb with Green Dot. The COW method saves barrel wear and is less expensive . I've not fire formed 7RM using this method, but use 19 grains in 280 to fire form 280AI. 7RM H2O capacity is roughly 25% higher, so somewhere in the 23 grain range should work.

 

[GLTaylor]

There are 2 methods to initially fire form without shooting a bullet down the barrel. Both still require a full pressure load with a bullet to finish forming the case and get good, sharp shoulders and full case dimensions.
Cream of wheat (or grits) is placed over the powder charge as a filler. Others can recommend a charge - probably around 10grs or so. Cap the case mouth with tissue or bar soap. Fire the case and clean inside and out.
The other method is to use a very fast pistol powder ( I like Bullseye). Just place the powder charge in the case and cap with tissue. Hold the rifle somewhat elevated and fire. For an '06 sized case I use 20gr. You'll get about 90+% forming. Much less messy, but doesn't smell as good!

 

[FEENIX]

Anyone have a load they want to share for fire forming 7mm max. I have some green dot I can burn through. Was thinking maybe start at 8 grains and go up from there.

That is probably a safe starting point and then adjust accordingly. "My" unwritten rule is ~15-20 percent of the parent case powder capacity, For instance, if .30-06 has 58g powder capacity, 15% is 8.7g, and 20% is 11.6g. I use Winchester WSF in COW forming my .30 Gibbs 11g, fill COW to the shoulder area and then stuffed it with cotton balls.

From L-R
- .35 Whelen virgin brass
- After resizing with .30 Gibbs die to establish false shoulder
- After 11g of WSF COW forming
- After resizing with .30 Gibbs die

Good luck!

Ed

 

[LongBomber]

Are u using powder only or powder with a filler on top?

Sorry been away at work, I run COW filler on top.

 

[Seabeeken]

I use 15 grains of red dot for 7x57ai, 250ai, 280ai, 257ai, 243ai. I use coffee instead of COW. Reason being, COW burns and was all stuck in the shoulder of the cases and had to be dug out with a pick. It also stinks when burnt. Coffee is already burnt and doesn't stink. It cleans out of the bore easier also

 

[bdpayne2000]

It will probably take a bit more. Don't be bashful. I use 20grs of Bullseye, with NO cream of wheat - just tissue and get good initial forming.

I also much prefer no COW on top just tissue paper and get good results.