I have about 10 pounds of RL15 hence my search for loads that I can use RL15 for.

I am now on a search for a .416 Rigby load for RL15 with 400 grain bullets. I can find loads listed for .416 Rem at 82 grains of RL15 but of course the Rigby case is much larger. I can also find loads for the Rigby with RL19 at 96 grains. I know that a filler will be required but would like to find a load with RL15 yielding approximately 2400 fps. If any one has any actual experience or QL data that would be great. Thanks.

For what it is worth, my own extrapolation would suggest something between 84 and 88 grains, but that is little more than an informed guess.

Nothing in my Barnes book, sorry.

Close, Mike. It says 83.0 will give you 46,831 psi and 2354 fps. It also says it's 80% of useable case volume.

Thanks, I have been through all the reloading books I have (Nosler, Barnes, Hornady, Speer and Swift) and nothing in those since I think RL15 is a little fast for the Rigby and other better powder choices exist. If (i) I did not have 10 pounds of RL15, and (ii) powder was not such a bitch to find these days, I would probably try another too.

Thanks Harry, if I recall pressure max is just over 47,130 psi.

Yes, in that neighborhood. It's not a convenient powder but I bet it shoots accurately.

Mike I checked Ammoguide.com and reloadersnest.com and neither have anything with RL15. I like it as well, but use it only in 375 H&H 300gr. loads.

David

Mike, if only you had a .500 A-Square and a .416 Remington Magnum instead of your .505 Gibbs and .416 Rigby . . .

You have too much in the way of case for RL-15!

H-4831 or H-4350 would be right up your street.

FYI

Good Luck Brad

Looks like I am in a failing search for a round hole to stick my square peg. Sounds like time to abandon RL15 for the Rigby and explore other options. Thanks for all the help though.

Interesting variation. I used the Woodleigh 400 gr Weldcore and got 46,824 and Brad got 47,784 psi with the Hornady 400 gr bullet (as do I when I change bullets). I would guess the real world difference is much less than the 900 psi that the mathmatics would have us believe.

FWIW...LD5 doesn't give RL15 in the list of powders...basically, because it is outside the burning range predicted for this case volume.

But it does give a good starting load for RL19...98 gr RL19, 3.72" COAL, 2295fs/41875CUP...109.6 gr RL19 at 3.72" COAL, 400 gr Woodleigh, 2567fs/51912CUP for a high pressure load and tops out a 115.3 gr, 2701fs/56843CUP.

I like RL19...it gave me the highest velocities I ever obtained in a 30-06 with 180 gr Hornady SP bullets, but the pressure was maxed out also...the cases only lasted 3-4 reloads before the primer pockets were too loose to hold a primer. Never any problems with sticky extraction in my Savage 110 or a Rem 700, but I don't recommend doing this...the few fs difference in ballistics isn't worth the possiblilty of a FU at the wrong time.

You always have to keep in mind that dropping the pressure by 10% only looses 5% velocity...and usually results in a 100% increase in accuracy and case life.

You can go to the Alliant website and compare the burning rates of RL15 and RL19, calculate a ratio and use a lessor amount of RL15 for a beginning load then work up...or ask for a recommendation...a much better solution than the iffy proposition of asking questions on the net...which...as you probably have seen just on this thread alone...is a questionable alternative at best, notwithstanding the very expert people providing information here.

Or...you could use a ratio between the 416 Rem volume, 102 gr H2O and the 416 Rigby, 132 gr H2O, the Rigby being about 27% larger then extrapolate the same information as above. That difference in case volume should be a cogent clue as to why RL15 ISN'T a good choice.

I doesn't necessariy follow that having a large amount of a specific powder makes it OK to use in the wrong application.

I would be more inclined to save the RL15 for use in the correct applications and go with what is conventionally accepted in this case.

There are many roads leading to Nirvana...some are filled with potholes that will swallow you and the 18 wheeler plus triples you are driving...whole...like a frog swallowing a fly and you will never be seen again.

H380 is the "fastest" slow powder listed by LD5 which is just below RL-15 on the burn rate charts, but it also has a faster pressure rise than I like to work with, which means a lower case volume and I WON'T use fillers except in very specific applications...there are usually much better ways to get where you want to go in this sport.

Luck on your project.

Mike, looking at my 1926 repro Manton catalog, which seems to show 416 Rigby loaded with 69 grains of Cordite. I'd sure want to confirm a second source but it seems right as other NE cartridges such as the 450-400 are listed consistent with cordite loads. One approach could be to use the rl-15 multiplier of 1.19 to give 82 grains, packed in with a big wad of dacron. This is really no different than any of the other large NE cases, RL-15, and dacron filler. As long as the dacron holds the powder to the primer and you test on a chrony, don't see the downside of giving it a try. I'll see if I can find a second verification of the 416 cordite load. Bob

Bob I am proud to have you use your 1000th post on me.

I was able to locate an 8lb container of IMR 4350 today and so I am going to use that for my .416 Rigby load development. In the end, that is probably a better powder choice.