I am trying to load 104 grains of H 4831 with a Barnes 400 grain X bullet. This load data is listed in the Barnes No. 3 reloading manual as a maximum load. I believe it was a favourite load of Jack O'Conners. I am using Federal nickel plated brass, and try as I may, I can't seat the bullet to the cannelure without compressing the powder about 1/8". Is this supposed to be a compressed load? Unlike other reloading manuals, the Barnes manual doesn't mention if a particular load is a compressed one.

Don't know about your load but don't worry about compressing the powder a bit, certainly not 1/8" in a case the size of the Rigby.

After checking the reloading masnuals ... A-Square in particular ... I'd back off the charge some as they show a range of 97.0 to 101.0. The Barnes #1 manual shows a range of 98.0 to 104.0 with the latter yielding a velocity of 2553 fps.

I'd work up to the place I had 2400 fps and bag it. I'm bettin' that will probably be about 101 grains of H-4831.

I tend to be conservative, but I REALLY don't feel the need to hot rod the .416 Rigby.

I agree with mstarling. I use 100 grs. H-4831 and get 2440 fps. This is a very accurate load in my Ruger RSM and it really hammers buffalo. The original load was 400 gr. bullet at 2370 fps and that load has been laying waste to big game since 1912 !

Geronimo

Here is another load for you to try - it is what I shoot in my 416 Rigby.

416 Rigby
400 grain Barnes X
96.0grs H-4350
Norma Brass
Federal #215 primers
OAL=3.643 (top of cannelure)
velocity = 2483fps (chronographed)
<1"@100 yards

Sounds like you need to pour the powder in s-l-o-w-l-y with a drop-tube... that'll help you pick up the needed space for the "longer-than-normal" barnes bullets.

That mono-metal barnes has no lead core (as I'm sure you know) and is longer than a traditional lead cored bullet... If Jack knew you were using those with his recipe, he would give you the same advice.

Since the Barnes bullet may be a bit longer than most others, you might try 4831SC. It's the same powder with shorter-cut grains.