Pistol powder to fireform 300 rum??

[azsugarbear]

Lots of info on this topic from previous posts. Any fast burning pistol/shotgun powder will work. I use cornmeal instead of cow. I plug the end of the case mouth with a little bit of TP. Works well - but do not use TP if you have a brake. Take the brake off, then fireform. I found that the cotton fibers from the TP caught in the gills of the brake and were going fast enough to bend the metal gills.

 

[Dean2]

Fireforming large brass like the RUM with no bullet in place is pretty much a waste of time. If you want a proper fireformed cases you need to be producing at least 55,000 psi or you will still only be partially formed. Accuracy of fireforming loads is usually every bit as good as full loads so they make good target practice ammo.

P.S. Just saw JE's response of the first page, I agree with him but hydraulic dies are too expensive for me. I prefer the mid range loads option.

 

[J E Custom]

I know many people use the COW method, But there is just something wrong with burning cornmeal or cream of wheat in a barrel that I go to so much trouble to keep clean. Besides, cornmeal is for cornbread.

I have found with a little planing I can load fire form loads that can be hunted with and normally keep them under 1 to 1.5 MOA. So I prefer to fire form with something I can do several task with at the same time. If a fire form load is not suitable for hunting, I use them for barrel break in and fouling shots and end up with cases that don't have to be shot several times before loading the final hunting/target load.

Several wildcats that I designed have increased the powder capacity by 20+grains and shot fire form loads very well (Less than 1 MOA) and still formed the cases to finished new chamber dimensions. In fact the same load data has been good range ammunition for practice for several of the guys In the new chamber, So no components are wasted and using a chronograph I can also see some load preferences at the same time based on SDs.

Changing from one chamber to another may require different ways to get good results, so planing and executing proper load Technics is very important if you want to save time, components, barrel life and above all be safe.

J E CUSTOM

 

[Bravo 4]

JE,
Do you think that smacking a die with a hammer could do any harm to your press? I have a hydro die and have to smack that dude hard with a decent sized hammer (multiple times) to get it to size the case anywhere close to final forming, then it still needs fireformed to take out the round shoulder.

 

[TLS]

I have tried COW with a pistol powder to form .35 Imp shells from new standard .35 Whelen cases. I never got good clean results. My preferred method is to neck-up to .378, partially resize leaving about a 0.10" long "fake" shoulder on the base of the neck.
Work-up your load development regimen, or use your favorite "lets-go-huntin'" load, and fire-form. The brass will fit the chamber before you reach the max chamber pressure - so even though they might look funny, go shoot! You'll be glad you did.

 

[J E Custom]

JE,
Do you think that smacking a die with a hammer could do any harm to your press? I have a hydro die and have to smack that dude hard with a decent sized hammer (multiple times) to get it to size the case anywhere close to final forming, then it still needs fireformed to take out the round shoulder.

Not sure, I have a friend that uses a Whidden Hydraulic Die and he says it works great. To be honest, I never used his because of the mess and did not want water on my press, (Like cornmeal in my barrel) so I fire form with a intermediate powder charge like explained on an earlier post. Maybe someone else with a hydraulic die setup will chime in.

I have not had any problems but some have with brass that Is to hard and the neck shoulder junction cracked/split, but with good brass the problem went away.

Never thought about hitting the die/press with a hammer because I never got that far.

J E CUSTOM

 

[wonderman4]

Most rifle brass will not expand with pressures less than 12k psi loads.

One thing I won't do is use COW or cornmeal in a good barrel.

My universal load for fire forming is 10-13 grains of Red Dot with a nominal weight cast bullet for 30 caliber and up. It exceeds the pressure requirement to expand the brass. I am not sure of a charge for less than 30 caliber since the only thing I have fire formed has been 30 or greater.

Another thing I do is to keep the cartridges bullet up to insure the powder stays close to the primer.

Sometimes depending on the cartridge you may have to create a false shoulder, or just jam the cast bullet into the lands to keep it against the bolt face for proper forming.

 

[azsugarbear]

Not to get cross-wise with anyone here...but go back and read the original post. He asked "can I", not "should I". Instead of just answering his question, we tend to digress and possibly give him much more than he ever wanted.

Regarding cornmeal vs. cow: I know it is heresy to use cornmeal for anything other than its God-intended purpose - but it works well. I suspect that burning cornmeal (largely carbon-based) is no different than burning powder (carbon & nitrogen based) in your barrel. If you pack the case well, you get a 99% fire-formed case first time around. I did this for years making 277 Allen Mag brass from 338 Lapua brass. I still use this method to make 6.5-06 AI brass from 270 Win brass. I first heard of this method from Kirby Allen, who made both of the above-mention rifles. It may not be the best, sexiest way of fire-forming, but it flat out works. So yes, Mram10us, you can use any fast-burning powder with cow.

 

[J E Custom]

I would also ad this bit of information and let the shooter decide what or if he wants to do.

Squib loads can be very dangerous for many reasons and using powder with burn rates not in the cartridge range can be tricky and unforgiving.

Case density is very important because ANY space not taken by powder has added oxygen and this oxygen changes the burn rate of that powder. Any fillers. Cornmeal, Dacron wool, Tissue, ETC are porous and have a certain amount of oxygen that is added to the powder (It already has it's own oxygen producing compounds). This is also the reason that 80 to 85% case density is minimum for safe operation.

When you use a faster burning powder the whole process is accelerated and can be even more dangerous. If you place powder is a controlled environment it is relatively safe, But if you alter the proportions of all these factors. you create as explosion instead of a controlled burn. and what seems like a safe operation can turn ugly.
If you accidentally double charge a 80 to a 100 % case density load all you get is a mess where it runs over and spills out on your bench. But when you make the same mistake with a fast burning powder that could take several charges without filling the case. You will not enjoy the results.

Time was, that duplex loading was use by some (Like me) and the problems were many and just not worth the risk. now that we have so many choices in powder burn rates, this practice has gone the way of the dodo bird.

Just because something is done buy many, doesn't make it safe.

J E CUSTOM

 

[azsugarbear]

You are absolutely right regarding the possibility of a squib..... if you are planning to top off the powder/cow case with a bullet. But if there is no bullet, then there can be no 'squib'. Neither I nor the OP suggested a bullet with the cow method. Perhaps you were addressing another poster that suggested such?

Doubling-charging a rifle case with a rifle powder is difficult to do. But double-charging a rifle case with a pistol/shotgun powder is very easy to do - and as you suggest, quite dangerous. But I submit it is no more likely than the possibility of double-charging a pistol case with a pistol powder. Both rifle and pistol cases have the extra capacity to take a double charge of a pistol powder. Either way, precautions must be taken. A good rule for reloading in general.

You could be right with TP and additional oxygen, but I can't see how the burning powder even gets close to the TP. To be clear, we are talking about 10 to 15 grains of a fast burning powder. This fills up the bottom 10% to 20% of the rifle case such as the 30-06 or 338 Lapua (smaller cases require less powder). Then the balance of the case is packed with cow - all the way up into the neck. The cow plus the pressure from the burning powder is used to blow out the walls and move the shoulder forward. TP is just used to keep the cow/cornmeal in place. I estimate I have fire-formed over a thousand cases this way between my various wildcats. If you move forward several yards from the barrel after doing a hundred cases, you will begin to see some of the unburnt cow or cornmeal on the ground. A guy at the rifle range brought this to my attention.

Again, lots of good ideas and alternatives on this thread. But to the OP's original question: yes, any fast-burning powder will work fine and give you a nicely formed case - provided you load the case safely as described in previous threads posted over the years on LRH.

 

[LongBomber]

I run 17gr of green dot and cow packed to the base of the neck to form my edge ai brass. Forms them almost perfectly, the shoulder has the slightest bit of roundness to it right at the shoulder/body junction.
When you are forming 100 brass to do it with light loads and a bullet I would be somewhere around $150. (Snow mexican so things are pricey up here). A pound of green dot will do 400-450 cases, and $5 worth of cow goes a long ways. Cleanup really is noext to nothing, a couple patches and the bore is clean.