I'd been scratching my head about differences seen in maximum powder charges/velocity levels between data sources for the .300 Roy. We've seen notations in manuals and net postings concerning "non-freebored" .300 WBY chambers. OK, I can understand how this might have happened in the pre-Rem (proprietary) era with M-70 H&H conversions.

I couldn't see how anyone could sell a new .300 Roy these days lacking the requisite freebore.

I wondered about the brass. Speer data was shot with RP brass, and calls for the lowest powder charges. So I did some weighing:

RP primed avg 265 gr
WBY (early '70s) primed 228 gr


IMR 4350 needed to fill case:

RP 85 gr
WBY (early '70s) 93 gr

Frankly, this about bowled me over. Perhaps most here were aware of this. I was only vaguely aware, in a qualitative sense.

Sam

Sam,

My favorite Big Game cartridge (outa Blaser R93 w/Vias Muzzle Brake).

You're certainly light years ahead of me in brass cartridge analysis.

Ive seen some serious pushing the envelope with this cartridge and leave others to their own devices.

I've got older original Weatherby brass cases (Norma?) in original packaging that a friend gave me after firing the factory ammo. Primer pockets go first, 2-3 loadings max and I'm not "pushing" the envelope, either.

1 box of 50 Nosler Custom, great brass but, Whew! Expensive, but then again; the Best is almost good enough for my favorite.

Some Hornady (2nd load and already loose primer pockets) and my all time favorite R-P nickel plated which adds a real touch of class to an already Frist Class cartridge.

The R-P lasts the longest, never split necks and the primer pockets remain tight, some on loading #6. Do alot of on my hands & knees in the field to recover my prizes when the heat of battle is over.

Since I'm a "Batch" loader and tend to load 50's or 100's for an all-year long hunting season here in Europe I've done nothing more than eyeball the loads as I prepare them to observe that nothing untowards is occuring after the initial load testing.

I figure work-hardening, age, softness, primer pockets, thick, thin, capacity all have their place in The Grand-Scheme-of-Things but for me I concentrate on testing a Batch, going into major production and when that's according to Hoyle, leave well-enough alone; ditching the lot when their life expectancy is over.

Net, I always start well below maximums, develop the load for reliability & accuracy and let the velocity occur from it's own brass case/bullet/barrel combination.

Personally I prefer as close to 100% density loads and am using reference book max H-4831 loads, nothing spectacular when compared to some data floating around. Tried H-4831sc but didn't fill the case as desired, accuracy and POI were eactly the same with Barnes 130 & 180 grain TTSXs.

Gotta say I've never bothered myself with the most intricate inuendoes of bullet or brass weighing, run-out and other Units of measure other than keeping batches of bullets & brass together as they arrive and despite the Soothsayers Doomsday gloom have always managed 5 shots in <1" (usually much less with today's rifles, scopes & componets) or the rifle goes it's separate way.

There is a definite difference between brass that is available for the 300 Weatherby.

Brass sold as Weatherby or Norma is the same stuff made by Norma, has been forever.

Remington sells their own brass and as you have discovered, it is heavier than the Norma brass.

Both types are good brass. They are just different.

To get exactly the same velocity and point of impact when shooting 180 grain bullets I have to use 1.5 grains less RL 22 in the Remington brass versus Weatherby.

Thanks.

I sometimes load the .300 Roy "light". Occurs to me the RP brass would make more sense and save powder.

And if that Barnsness formula, an increase powder capacity (%) yields 1/4 the increase in velocity (%), is true I'd stick with the WBY/Norma stuff for top-end loads.

BTW, I just weighed my RP .300 Win brass and got 245 gr, w/IMR 4350 capacity of 83 grains - just two grains less than the RP .300 Roy.

Sam