Tom Leoni
AH fanatic
I handload for two Nitro for Black cartridges. I know the usual Seyfried conversion rate with the 4198 powders, but in this dystopic time of component scarcity I am running out of my last can of 4198. I'm also running out of RL15, so I am SOL with the other Seyfried conversion rate using the cordite load (x1.19). I was, however, able to score an ample supply of RL7, which now towers atop my reloading bench.
.450 Nitro for Black with 325-gr Bullet - My last load using the Seyfried conversions was 49gr of IMR 4198, which worked very well over a WLR primer and under a 325-gr lead bullet, with approximately 9gr of pillow stuffing in between.
Conv. from black: 40% of the original 120-gr load = 48gr.
The rifle's previous owner had great luck with the same exact charge of RL7 (which at the time I didn't have): 49gr of RL7 with the other components being the same. Velocity was comparable and both loads regulated very well in my P. Webley double.
.500 Nitro for Black with 440-gr Bullet - All other things being equal, 56gr of IMR 4198 should give me the smokeless equivalent of the original 140-gr black powder load. Interestingly, this same quantity of IMR 4198 pretty much duplicates the original NFB cordite load for the same bullet weight (55gr of cordite Vs. 56gr with the Seyfried conversion from the black powder load). A fluke exclusive of this cartridge?
Anyway, one of the infuriating things of handloading manuals--especially during this time--is that they only list a handful of powders for each caliber. The Woodleigh manual is a particular offender in this regard.
Does anyone have access to a handy conversion rate between IMR 4198 and RL7 with regard to use in these large British cases? The two powders are awfully near the same burning rate, with RL7 being a touch faster. Or between RL15 and RL7? I don't dare try the experiment of using the same charge without some helpful advice from someone who knows more than me.
NB: Luckily for me, in the case of the .500 NFB I don't have to worry about regulation because my rifle is a single shot.
Any help would be infinitely appreciated.
.450 Nitro for Black with 325-gr Bullet - My last load using the Seyfried conversions was 49gr of IMR 4198, which worked very well over a WLR primer and under a 325-gr lead bullet, with approximately 9gr of pillow stuffing in between.
Conv. from black: 40% of the original 120-gr load = 48gr.
The rifle's previous owner had great luck with the same exact charge of RL7 (which at the time I didn't have): 49gr of RL7 with the other components being the same. Velocity was comparable and both loads regulated very well in my P. Webley double.
.500 Nitro for Black with 440-gr Bullet - All other things being equal, 56gr of IMR 4198 should give me the smokeless equivalent of the original 140-gr black powder load. Interestingly, this same quantity of IMR 4198 pretty much duplicates the original NFB cordite load for the same bullet weight (55gr of cordite Vs. 56gr with the Seyfried conversion from the black powder load). A fluke exclusive of this cartridge?
Anyway, one of the infuriating things of handloading manuals--especially during this time--is that they only list a handful of powders for each caliber. The Woodleigh manual is a particular offender in this regard.
Does anyone have access to a handy conversion rate between IMR 4198 and RL7 with regard to use in these large British cases? The two powders are awfully near the same burning rate, with RL7 being a touch faster. Or between RL15 and RL7? I don't dare try the experiment of using the same charge without some helpful advice from someone who knows more than me.
NB: Luckily for me, in the case of the .500 NFB I don't have to worry about regulation because my rifle is a single shot.
Any help would be infinitely appreciated.
