Pistol powder to fireform 300 rum??

[Mram10us]

I've seen other use unique and other pistol powders to fireform smaller cartridges with cream of wheat (cow). My question is, can I use a bit of trail boss or blue dot (my only pistol powders on hand) and stuff a bit of toilet paper? Thanks.

 

[JKB57]

what are you trying to fireform 300 RUM from or to

 

[Mram10us]

what are you trying to fireform 300 RUM from or to

Forming 300 rum to a 35deg, wider case. Already do it with light loads and 165 or 180s, but would prefer to do it out in the shop

 

[David Emerson]

I have used unique to fireform 338 lapua improved. But I cannot answer for other powders. Now this is weird and I cannot explain but I used unique and cream of wheat to make 300 weatherby from 300h&h. It formed a visible ring in the chamber ahead of the case head. So I quit the cream of wheat. Gun still extracted fine and it did not bother but it bothered me. And no it was not from overpressure. I forget how many grains of powder but I just melted wax to make a plug in the neck

 

[Mram10us]

I also did the wax thing ff 300 Weatherby to 30stw, and got wax all over in my barrel Took lots of heat and cleaning but it still shoots great. Really surprised it didn't hurt the barrel

 

[David Emerson]

In my case the cream of wheat scrubbed it out I guess. I don,t remember it being a problem.

 

[Mram10us]

Started experimenting. I took it from 6gr trail boss with 2 patches pushed down in to the case. No effects on brass. Meaurements are the same but the primer pushed back due to headspace (normal).

Just tried 12gr with a square of toilet paper folded twice then rolled like a bullet into the case neck. It sticks out enough to keep the case against the boltface. Brass seems to be slighty affected, but not totally fireformed.

I found a reduced load of 18gr(min) trailboss for 300wm with 150gr bullets on the imr website. Seems I need more resistance

 

[Ckgworks]

In my rather limited experience in fire forming cases with COW, it seemed like it made a big difference if the COW was packed tight, and filled the case from the powder to the case mouth. In my mind this made since......The COW has more opportunity to expand the case rather than just relaying on the explosion of the Powder to force the case out. I was always to nervous to play with other packing material as I was worried about them hanging up and creating too good of plug.

Here's a BAD Idea for you: Use your reamer to make a insert for a single shot 12 gauge....COW form to your hearts content without wear on your barrel. Just make sure no one mistakes it for a chamber adapter . Maybe leave the exit too small to chamber a loaded case in it, and stamp the heck out of it......I can just see that thing ending up in a "Gunsmith Estate sale" someday.......

 

[David Emerson]

Started experimenting. I took it from 6gr trail boss with 2 patches pushed down in to the case. No effects on brass. Meaurements are the same but the primer pushed back due to headspace (normal).

Just tried 12gr with a square of toilet paper folded twice then rolled like a bullet into the case neck. It sticks out enough to keep the case against the boltface. Brass seems to be slighty affected, but not totally fireformed.

I found a reduced load of 18gr(min) trailboss for 300wm with 150gr bullets on the imr website. Seems I need more resistance

How about your charge of trail boss and then fill to the bottom of the neck and then take a candle and make a wax plug to the top of the neck? If it is not forming well keep adding more powder until you get the pressure up enough to form well? It takes more than you think. When forming improved 338 lapua I was using blem 250 bullets and I had to get up over 30 gr of unique to get a good shoulder

 

[David Emerson]

How about your charge of trail boss and then fill to the bottom of the neck and then take a candle and make a wax plug to the top of the neck? If it is not forming well keep adding more powder until you get the pressure up enough to form well? It takes more than you think. When forming improved 338 lapua I was using blem 250 bullets and I had to get up over 30 gr of unique to get a good shoulder

Sorry, I left out to use cream of wheat

 

[Bravo 4]

I am no expert...
But I wouldn't have imagined using trailboss without a bullet to get enough pressure to blow the shoulder out. To produce subsonic loads with a bullet I will usually fill the case to where it is about to compress and then work my way down till I hit the point where it's consistently subsonic. I've used greendot with COW to fire form my Snipetac brass and it pressures up quick! Takes around 22 grains. If I tried the method I use for sub loads with greendot it would be like putting dy-no-mite in the chamber. Would fireform my rifle into a hand-grenade.

 

[Mram10us]

I stopped at 15 until I get some cow. Might even use the imr reduced loads with trail boss. Thanks for the input guys.

 

[J E Custom]

I would recommend using a hydraulic die if you don't want to shoot reduced loads.

Squib loads are very dangerous and normally don't do a good job of fire forming the first shot.

If the head space is good just go with a middle of the road load for the parent case/cartridge and you will be fine and you won't take a chance of firing a squib load.

The case will have to expand to the new chamber and the pressure will be less because of volume changes during firing.

J E CUSTOM

 

[rewiltshire]

I agree with J E CUSTOM. Either use a reduced load of your normal powder (best option IMHO), or get one of the hydraulic dies. I fire form 7-30 Waters from 30-30 cases and that seems to work the best.
Hornady will make a hydraulic die for you. Send them a couple formed cases and a drawing/dimensions of the reamer, but they "ain't cheap".