The .338 RPM hasn’t yet appeared on the market by Weatherby, but is simply the 6.5 RPM (which has been in production for a while) that has already been “necked up” by wildcatters as well as by Weatherby. But recently Weatherby has made it official along with specs adopted at Saami, so the PSI at 65K and resultant ballistics of a 225gr at 2820 fps is no longer a mystery. That is proposed from a Weatherby Mk V “Backcountry” with a 20″ barrel and weight of 6.2 lbs ready with scope, ammo, etc. The case (a necked up 6.5 RPM) is said to hold 83.4 grains of water – a bit less than a .338 Win Mag. Generally, the idea (having been reviewed by a sufficient number of potential buyers) has a positive rating. The goal by Weatherby is a rifle weighing less than the typical .338 Win Mag by a couple of pounds with near identical ballistics for hunters who want power with reach in typical mountainous regions. That’s attained from a 20″ tube at 65K psi whereas in the .338 Win Mag it’s standard ballistics are reached from a 24″ barrel at 64K psi. “But the same or similar ballistics is from a much lighter and handier package”, says Weatherby and hopefuls.
So one is tempted to ask: What does this achieve that is not already achievable in the Win Mag that’s been around since 1958? And the Weatherby Mk V isn’t a “cheap” rifle, as well as Weatherby’s ammo and components – when you can find them. My Sako FS in .338 Win Mag with a 20″ barrel came very close to those results from the powders of the day at less than 65K psi.
And then the “kick” from such a beast will be on the order of 60 ft-lbs (if the total package is 6.2 lbs) compared to about 40 ft-lbs for a typical .338 Win. Granted the Win will weigh 8.5 lbs (or should). Is 2 lbs going to make or break a hunt in the mountains?
<Odaray Mountain in the background of Lake O’Hara, located in SE British Columbia in the Canadian Rockies. This is a famous hiking area.
But this comparison is between the .338 RPM and the .35 Whelen firing the same weight bullet. As stated, the RPM is made to fire a 225gr at +2800 fps for any range, shooting in mountainous terrain – according to Weatherby’s promotional material. Depending on what brand and model of a 225gr will, of course, determine the outcome at both near and far distances. Since the avowed purpose of the cartridge is mountain game (wherever hunted globally) that could include some wildlife that attains 800 lbs or more.
My question then would be: What is the best short-range to long-range bullet that makes at least 2000 ft-lbs at up to 500 yards from a 225gr in .338-caliber? Since mountain hunting doesn’t always imply “long range”, the hunted animal may be no more than 65 yards from the muzzle when the trigger is squeezed. So whatever be the brand, it must be well constructed for high impact into a shoulder bone at close range of, say, 40 yards (impact velocity around 2750 fps) out to ~500 yards where the velocity has dropped to ~2000 fps/2000 ft-lbs at an elevation of 5000 ft in the mountains. At about 1200 ft elevation the retained velocity will be around 1870 fps/1748 ft-lbs. So atmospheric conditions (temps, elevation and wind) ALL will influence the story to be later told – not even to mention the hunter’s condition and abilities.
There is a Barnes MRX BT in 225gr with a .433 BC. Then there is a 225gr Nosler AccuBond with a much higher .550 BC giving it a distinct advantage in range. And the 225gr Partition at .454 BC. Since I’d choose the Partition, we’ll pit that against the 225gr, .358″ from my rifle in .35 Whelen.
<Those are three 225gr Partitions loaded in the lower right corner for my .35 Whelen, with the 225gr AccuBonds in the background. The Partitions will be kept for backup if needed. Only two more remain in the original box. Being unable to locate more, I’ve settled on the 225gr AccuBonds at about 2850 fps.
The .338-cal, 225gr Barnes at 2820 fps grants 1987 ft-lbs at 500 yds
The .338-cal, 225gr Nosler Partition at 2820 fps gives 2056 ft-lbs at 500 yds
Which would be your choice, and why?
Some would choose the Barnes, others the Partition and still others would favor the AB, all for their own reasons.
Mine would likely be the 225 Partition for no other reason than I have more experience with Partitions.
But whichever is chosen, any of them should give the desired results for mountain game at typical ranges if the bullet is placed into the heart-lung region.
Any of those two should be more than adequate for a 300 to 800 lb animal at up to 500 yards.
The knowledge that a minimal impact velocity of ~1800 fps is deemed necessary for some bullet expansion, limits the range to about 500 yards.
But the bigger issue for me, and likely for many others, would be the recoil without a brake. Therefore, I expect that Weatherby will include a brake on such a light rifle. That should bring recoil down to around 48 ft-lbs. Other than that issue, they’ll likely be snatched up by some adventurers with thick wallets and thick skins.
But… I wanted to know how my “cheap” .35 Whelen would fare (single-shot G3, at 7.75 lbs loaded with a 225gr AccuBond in the chamber and 3 in a buttstock shell holder) against this new .338 RPM in a fair fight under the same conditions proposed above – not that I might be climbing the Rockies anytime soon.
< This blind was for a bear hunt over bait at 55 yards out front. My partner shot a 400 lb black bear from here at 65 yards as it came to the pond for a drink, slightly off to the right. I was alone at this site for one afternoon/evening while he was absent and prior to him killing the bear an evening later. My intent was not to shoot a bear, as I did that the previous day at another site one mile away. I used a .45-70 for that 6-foot bear. On the day I was attending this site for observation purposes, I toted my CZ 550 in .458 Win Mag. It weighed (ready to shoot) about 10.5 lbs. Resting as it was, it was no burden to me – no more than my NEF .45-70 I’d killed the bear with on the previous evening. That rifle ready weighed 8 lbs. Both rifles were equally suitable for the purpose at hand.
The point of this is: a rifle’s weight and ballistics can usually be adapted to a great variety of situations. There’s little need to own a particular rifle dedicated to a single task… especially a powerful “Mountain Rifle” that could easily kill grizzly that when purchased barely weighs 5 pounds! In my mind, there’s something definately bizzare about that concept when considering the exchange of two pounds weight for 50% more recoil! OK, that’s 32 ft-lbs from the .338 Win (with brake) vs 48 ft-lbs recoil from the proposed .338 RPM (with brake). Just do the math! It’s quite apparent that Weatherby’s ploy is more sales… and who could blame them? Well… I could on the issue of complete honesty! Any rifle from any manufacturer could be made the same to do the exact same thing… if chambered in .338 Win Mag!
Here’s the complete story: At my last trip to the range this past Monday, August 1st, 2022, I loaded one grain more (70) of CFE-223 under the 225gr AB. Conditions were not perfect (sort of hunting conditions), but 3 went into MOA at a corrected average MV of 2865 fps without drama from cases that had already been used five times in the same rifle working up loads for the .35 Whelen.
Here’s the dope on that (if we are to believe Nosler):
MV = 2865/ 4101 ft-lbs
BC = .430 (Yes, I know that .421 was printed in their manual and .430 for the 225gr Partition – but some have said it’s much higher than that from their rifles – so on Nosler’s wedsite they give the same as for the 225 Partition – .430 BC. And it may be higher or lower from any particular rifle. My choice would have been the 225gr Partition but none were available in this area. (Zero is for 275 yards)
100 = 2684 fps/ 3598 ft-lbs/ +3.3″
200 = 2509 fps/ 3146 ft-lbs/ +3.5″
300 = 2342 fps/ 2740 ft-lbs/ -1.9″
400 = 2180 fps/ 2376 ft-lbs/ -13.6″
500 = 2026 fps/ 2050 ft-lbs/ -32.6″
*** All that from a “cheap” single-shot that shoots MOA and can basically do what the “new” .338 RPM from Weatherby is proposed to do! (The conditions for both rifles were 5000 ft elevation at 50*F and 50% RH)
In addition: It’s as light as I want with less recoil, and less than 40″ OL. And 1-shot is all the Weatherby can fire at a time – same as mine! Ha!
But this particular view commenced when reading about the .338 RPM, and I began to make mental comparisons with the results from the same weight bullet in my .35 Whelen, well knowing that a comparible 225gr in .338 would have a better BC and SD, but the .35-cal has a larger cross-sectional area by 12.6%. That means that the .35-cal would make a bigger wound cavity (all else more or less equal) and the .33-cal would give better penetration (all else more or less equal). Things don’t always work out that way but those are sort of rules of thumb. Whatever we believe, there’s not a lot of difference between the two except the .358-cal will be more efficient in the use of powder than the .338-cal assuming the best powder for each at the same or similar psi. Yeah, I know the SAAMI standard for the 35 W is 62,000 psi, but who is going to be present to test the PSI of “their loads” or mine?
However, the .338 RPM will use considerable more powder than the .35 Whelen for the same or similar results – meaning more recoil and, in the long haul, more expensive to feed. It will have a big appetite!
So go get yourself a .35 Whelen and pretend it’s a .338 RPM on a diet… that’s what I’d do, or doin’.
<Dieting?, this ain’t! This was FD Roosevelt’s favorite dish (the menu said so!) when living at their estate on Campobello Island, New Brunswick, Canada – within 300 yards of the Maine coast. In 2017 my wife and I visited Campobello where we grew up and graduated from high school together in 1954. 2017 was our 60th anniversary and, among other activities, we had a meal at the former Roosevelt guest house (for American friends and politicians) – now an elite restaurant on the Roosevelt International Park — it’s a haddock chower (lots of haddock in creme and butter) with biscuits, and it was yummy!
A look out the window of the restaurant toward the main Roosevelt residence, now a museum.
See ya next time…