Originally Posted by
BruceB
Herb;
My .416 Rigby is only a humble #1 Ruger, but I reckon my load data doesn't much care what rifle it gets used in.
My ONLY mould for the cartridge is the RCBS 416-350, and it has worked splendidly for me. In my wheelweight alloy it casts at 365 grains, and is BARELY touched by a .417" RCBS sizing die. I do sorta wish it was a thousandth or two larger, but it's hard to argue with the results. For the vast majority of my .416 shooting, I water-drop the WW boolits from the mould, and they shoot without visible leading. For some special purposes, I've also run PURE LEAD versions at 2000 fps without leading, and also I have created dual-alloy bullets for hunting, with pure-lead noses and WW-metal shanks (from the crimp groove back).
I have fired this RCBS boolit with everything from small charges of Unique to full-case loads of IMR 4831, with good success in all cases after some experimenting. Any charge which leaves much appreciable airspace in the capacious case gets a dacron tuft to keep the powder back against the flash hole. Note that this is a LOOSE tuft, just big enough to comfortably fill the airspace without being tightly compacted.
So....all of the following loads use the RCBS 365-grain bullet, fired from Norma brass. and using standard Large Rifle primers in most loads. None of the loads were really tweaked intensively, as I was mostly looking for safe levels from which to work in further research. All listed cast-boolit loads were perfectly safe in my rifle, with no signs of excessive pressure. ALL, except the 4831 loads, use dacron fill!
-IMR 4198, from 40.0 grains to 48.0 grains. The 40.0 charge yielded 1588 fps average, Extreme Spread of 30 fps. I raised this charge in 2-grain increments up to 48.0 grains, where the average speed was 1865 and ES was 58 fps. This 48.0 load put ten rounds in one inch at fifty yards. This charge could still be increased.
-44.0 IMR 4064 gave 1373 fps, ES 41.
-XMP 5744 has been my most-used powder to date, including the hunting soft-point cast-boolit loads I took to Alberta back in October '05. 55.0 XMP 5744 gives 2088 fps with an extreme spread of 4.9 fps, that is FOUR decimal NINE ES for a five-round sample. Remember now, these loads are all using dacron fill. 40.0 5744 gives speeds in the 1800-fps area. The 55.0/5744 charge is not maximum, and I've never (yet) bothered to work up to maximum with any of the listed powders. The .416 is awesomely effective even at these reduced levels, believe me.
-With IMR 4831, 100.0 grains (easy to remember, that load, a nice 'round' figure) the 365 departs from my rifle at 2540 fps average, ES 48 fps. NO DACRON in this one. For foot-pounds of energy, this one's a bit above the ancient 1912 factory load of 410 @ 2370....and yes, the recoil pad is highly desireable. I have used as much as 120/IMR4831 with a 300-grain Barnes X-bullet, but got slightly-sticky extraction and velocity right at 3000 fps....what an elk load THAT would be, with a trajectory about like that of a 165/.300 H&H!
-Using 2400 powder, I got hangfires until the charge was raised to about the 26.0 -grain level, where the speed was 1350 with 37 fps ES. Five rounds grouped in 0.55" at fifty yards with the 26.0 load. At 34.0/2400, speed was 1602 and ES was 34 fps.
-At the request of another poster, I did a series with Unique powder as well. At 22.0 grains, velocity ran 1353 and ES was only 15 fps. Raising the charge ONE grain at a time, I eventually stopped at 28.0 grains, where the speed was averaging 1530 and ES was pretty high, at 115 fps. Five rounds of the 28.0 load grouped in 1.4"/50 yards. He wanted plinking loads, and I reckon these would serve.
That should give you some places from which to start. Again, remember that dacron was used in almost every load listed. The RCBS bullet is a dandy in my book, and I recommend it highly. The Rigby is a very interesting and entertaining round to work with, and you won't find one on the next-bench-over very often. I have a lot more loading to do for test purposes with this cartridge, and I'm looking forward to it. Of course, I ALSO plan to build a standing benchrest for Der Schuetzenwagen, to minimize the "discomfort" sometimes encountered with the more ambitious loads.