I would like to fireform the rest of my 300 Norma brass w IMR4831 (l have way too much of this and too little of my other powders). How much should I use to safely shoot 150 gr Speer cheapos?
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Help with safe fire form load Please
- Thread starter DIY Mtn Hunter
- Start date
Well, if case capacity is similar to 300WM I would "guess" that something on the order of 75 grains (IMR4831) with a 150 grain bullet should be a reasonable fire forming load?
My question is; why bother fireforming? Just to get cases that have been fired in your chamber? I would be more concerned with round count and doing something more productive, aimed towards your eventual load development. After you are finished with your "cheepos" basically you have not accomplished a lot. Maybe I'm missing something, but fire forming is needed when dealing with non standard chamberings such as the Ackleys "Improved" with a blown out shoulder. I will go out on a limb and say that what you want to do is unnecessary. BB
edit: actually, I don't know what a 300Norma is? I assumed 308Norma Magnum, but thinking about it, maybe you mean 300Win Mag with Norma cases? Or, maybe Norma actually has a proprietary chambering called 300Norma? If so disregard whatever I said above, you may know a lot more about it than I do? BB
My question is; why bother fireforming? Just to get cases that have been fired in your chamber? I would be more concerned with round count and doing something more productive, aimed towards your eventual load development. After you are finished with your "cheepos" basically you have not accomplished a lot. Maybe I'm missing something, but fire forming is needed when dealing with non standard chamberings such as the Ackleys "Improved" with a blown out shoulder. I will go out on a limb and say that what you want to do is unnecessary. BB
edit: actually, I don't know what a 300Norma is? I assumed 308Norma Magnum, but thinking about it, maybe you mean 300Win Mag with Norma cases? Or, maybe Norma actually has a proprietary chambering called 300Norma? If so disregard whatever I said above, you may know a lot more about it than I do? BB
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Why don't you just work up a load in new brass and then adjust it once all your cases are fireformed.
The biggest reason is because I don't have the components at this time. I have a huge excess of IMR 4831 powder and some 150 grain speers that I don't plan on ever hunting with or even developing a load for that matter. I'm running thin on H1000, Retumbo & have no premium hunting bullets at this time.
I was hoping to run a light load that will not create much barrell wear with what I already have (don't have quickload or similar). This way, whenever I do get enough bullets in I won't have to worry about the noise of unformed brass when making load development decisions or the additional time required (I actually have some time to reload now, just not the components - damn liberals).
The 300 Norma is based off of the 338 Norma Mag and much large than the old 308 Norma.
Using a light load will not fill out the case to the chamber and the load could end up headspacing on the primer. Meaning the pressure generated would not force the rear of the case against the bolt face.
You need real load data and the capacity of the case in grains of H2O, I just loaded data into Quickload from the Speer manual for the 300 Norma Mag and a max load with a 150 grain bullet with 75 grains of IMR4831. The chamber pressure was only 45,602 psi with a velocity of 2839 fps. Something is off here and Quickload data are just guesstimates without chronograph velocity input to Quickload.
Rather than fire form I would check to see how much head clearance your new cases have and see how much they will stretch when fired.
On a rimed or belted case shoulder location on a new case can be pretty far off as you can see with the Remington .303 British case below.
You need enough chamber pressure so the rear of the case ends up touching the bolt face and fills out the shoulder. There after you let the case headspace on the shoulder and not the belt.
You can use your new cases and a fired spent primer and just using your fingers seat the used primer in the primer pocket and then chamber the test cartridge letting the bolt face seat the primer to get your head clearance.
1. Measure the length of the new cartridge and write it down.
2. Chamber the test cartridge and seat the primer with the bolt face.
3. Remeasure the case again from the primer to the case mouth and write it down.
4 Now subtract the first case measurement from the second and this will be your head clearance.
I have had new cases that were .011 shorter than chamber headspace length and cases like this can stretch on the first firing. If your cases have .008 or less head clearance I would not bother worrying about fire forming the cases.
Also at approximately 43,000 cup or 49,000 psi the peak flame temperature is just starting to reach the melting point of modern barrel steels. Meaning your chamber pressure levels would have to be between a 30-30 and a .222 to not cause wear on your bore.
If your rifle has good headspace with minimum head clearance with your cases your better off just working up a normal pressure load and then fine tune your load with your fired cases.
Or order a Hornady hydraulic case forming die.
Hornady?s Hydraulic Case-Forming Dies within AccurateShooter.com
You need real load data and the capacity of the case in grains of H2O, I just loaded data into Quickload from the Speer manual for the 300 Norma Mag and a max load with a 150 grain bullet with 75 grains of IMR4831. The chamber pressure was only 45,602 psi with a velocity of 2839 fps. Something is off here and Quickload data are just guesstimates without chronograph velocity input to Quickload.
Rather than fire form I would check to see how much head clearance your new cases have and see how much they will stretch when fired.
On a rimed or belted case shoulder location on a new case can be pretty far off as you can see with the Remington .303 British case below.
You need enough chamber pressure so the rear of the case ends up touching the bolt face and fills out the shoulder. There after you let the case headspace on the shoulder and not the belt.
You can use your new cases and a fired spent primer and just using your fingers seat the used primer in the primer pocket and then chamber the test cartridge letting the bolt face seat the primer to get your head clearance.
1. Measure the length of the new cartridge and write it down.
2. Chamber the test cartridge and seat the primer with the bolt face.
3. Remeasure the case again from the primer to the case mouth and write it down.
4 Now subtract the first case measurement from the second and this will be your head clearance.
I have had new cases that were .011 shorter than chamber headspace length and cases like this can stretch on the first firing. If your cases have .008 or less head clearance I would not bother worrying about fire forming the cases.
Also at approximately 43,000 cup or 49,000 psi the peak flame temperature is just starting to reach the melting point of modern barrel steels. Meaning your chamber pressure levels would have to be between a 30-30 and a .222 to not cause wear on your bore.
If your rifle has good headspace with minimum head clearance with your cases your better off just working up a normal pressure load and then fine tune your load with your fired cases.
Or order a Hornady hydraulic case forming die.
Hornady?s Hydraulic Case-Forming Dies within AccurateShooter.com
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