Guys,

Anyone developed loads for the 400 gr NEI cast projectile in the 416 Rigby?

What's the right way to fill the extra space in the case?

Given the recoil of the beast and its more than necessary power for most NA game, is this a viable route for extending the usage range of this caliber?

thanks,

What velocity level are you after? If you're looking for plinking loads in the 1200 fps range, Unique is an outstanding powder. Doesn't matter that the case has lots of air space, it'll burn efficiently even with a case 1/4 full of powder with no filler. I've used unique in my 500 Jeffrey with 470 gr cast bullets @ 1200 fps, and it is plenty accurate, and fun to shoot.

Even these plinker loads put the big bore rifles on par with the most powerful of handguns.

Any chance of a reasonable load at the 1500 to 1800 fps without leaving a major mess in the bore?

I am interested also, I have emailed Lyman, Sierra and RCBS for data, Lyman said they had no data, RCBS has not responded and Sierra suggested

350 grain cast - 28 grains - Alliant 2400 but no velocity
and
300 grain Lyman #412263 - 25 grains - SR4759 = 1400 fps

I found some data from Accurate arms that might work, check out the link.
accuratearms.com/data/guide/rifle/standard_data_(rifle)/416%20Rigby%20page%20329.pdf

Guys,

Still looking for additional data here.

Am particularly interested in the need/desireability of filler in the case. What are the best approaches for filler in a bolt rifle?

Thanks,

I have used xmp5744 with amazing uniformity, no fillers etc. This has to be the best powder I have tried in very large cases. I have a problem with my Ruger M77 in that my LBT bullets are full diameter and the Rigby has a very short throat, which requires excessive seating depth. One of these days I will get around to trying the RCBS bullets as they look like they are a 2 diameter design.
C.G.B.

Just an Idea, but maybe try a full case of Pyrodex FFG. I made up some loads with it in smaller calibers and in one word, FUN. As long as you don't mind a little dirtier cleanup. Not sure what it'll give ya for velocity, but I can assure you it wont be over preasured. Just load it so it's lightly compressed.