SR4759 in 8mm Lebel rifle ctg.

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Pete04

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The paper instructions that come with the Lee dies say starting gns for SR4759 are 18.4 for 170 grain jacketed bullet (never exceed 20.5 gns) and 19.3 gns for 150 grain jacketed bullet (never exceed 21.5 gns).

So, can I reason that for a 125 grain jacketed bullet my starting load would be 20.1 gns of SR4759 (never exceed 22.4 gns)?

I can only find load data in my Richard Lee manual (and only for the 150 grain jacketed bullet), none of the others have anything for 8mm Lebel.

Thanks in advance
 
i just loaded some today. book says with a spitzter 198 IMR 3031 use 44 grains for factory ball duplicate. i loaded some with 40 to start with, but havent shot any over the crony yet
 
I'm trying to load three differrent weight( 170grn, 150grn and 125grn) bullets with the same SR4759 powder. I have the start loads for the 170 and 150 but not the 125.

The question is what is the start load for the 125 grain bullet using this powder?
 
Beater said:
i just loaded some today. book says with a spitzter 198 IMR 3031 use 44 grains for factory ball duplicate. i loaded some with 40 to start with, but havent shot any over the crony yet
Click to expand...

You're on the right track. I found 42 was about right in my 07/15's. I worked up to 45, no pressure signs, but I settled on 42. No need to hammer a 100 year old rifle! :)
 
LOL, quite high jackin' my thread you guys! LOL

I'd like to get on with loading the 125 grain bullets.

As a secondery question, is it safe, as a general rule, to extrapolate loads from known/published loads?
If (for example) a 100 grain bullet starting load is listed at 20 grains of x powder and we also know that a 150 grain bullet starting load is listed at 15 grains of x powder can we be safe predicting that a 200 grain bullet will have a safe starting load of 10 grains of x powder?
 
The first thing you need to understand is that the bore will likely slug in the 0.328" range, so a 125gr 8mm bullet will almost rattle down the bore (an undersized bullet with very little bearing surface). Your best best with these is usually cast, and Lee makes a mold for the 8x56R Hungarian that works well. It casts a 205gr bullet which is close to the original loading (198gr at 2400 fps).

You certainly can extrapolate, and a good cartridge for comparison is the 8x57 (8mm Mauser) which is about 5% smaller than the 8x50R. Loads for it will produce lower pressure in the 8x50R. You can also be sure that the same load with a lighter bullet will produce lower pressure.

SR-4759 is an excellent all round low pressure powder (burns well at cast bullet pressures without the need for a filler and is not position sensitive), and with a 125gr bullet I'd work in the 20.0 to 25.0 gr range (stop at 2500 fps). Lee is conservative - a 198gr bullet at 2400 fps is right in 8x57 territory, so a 125gr at 2500 fps is a light load, but since SR-4759 is a fast powder, you'll need to stop there. If you want to push it closer to 3000 fps you'll need to go with something like IMR3031 for as much as 48.0 grs.
 
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