Subject says it..

How do the case capacities compare 300 RCM vs 300WSM?

Basicly I am comsidering a 35 cal wildcat (350WSM, 350RCM)

350 WSM is the 350 Sambar, might want to look it up.

I considered re-chambering my Ruger 350 rem mag to a 350 WSM, but then I shot it pushing 225's 2700 fps. I just have no need to push 250's 2700 fps from a lightish rifle. Something to consider. And if you aren't building a light rifle, no real reason to use the WSM platform.

I don't know what the difference is, but the WSM case is .555 at the web, and the RCM case is .532. The WSM case is 2.1" long and the RCM case is 2.015".

So the WSM case appears to have a fair bit more capacity.


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I kind of like the idea of a short action 338 that would be between the 338-06 and the 338 win. Maybe the thinner cartridge will feed a little smoother than the WSM cartridges. Who knows.

Two or three years ago, an Australian hunting magazine named Guns and Game ran a very informative series of articles describing how they designed, built, and hunted with a rifle chambered in the 350 Sambar round. I was able to obtain back issues from them thru their website. Here's the link if you want to pursue it further:

Guns and Game magazine

Nothing wrong with a short action 338-06 +P. I am kind-of interested myself.

My guess is that feeding would be smoother than the WSM.

Per the reviews, in factory loaded form, it gives up nothing to the 338WM (though I am sure it does with heaviest bullets).

Hand-loads are likely to be a different proposition, with performance more like a 338-06 +P, since the propellants used in the factory ammo aren't available to the handloader.


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Here is some more 350WSM information:

350WSM or 35 Sambar


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If I were a betting man I'd say the case capacity of the 338 RCM would be very similar to the 350 Rem Mag. The 350 has a longer case which might make up for the slightly fatter but shorter RCM .

Agreed.

I'm struggling to understand how two less in the magazine and poorer feeding with minimal velocity gain makes this new case a worthy choice over an 06-based round...

OH NO!!! More practical, experience based opinion!!!!

This will NEVER do, how can we accept the antique rounds from long ago when ANY hip, trendy GenXer just KNOWS that wizzums, Ultragags and whatevers ARE the BEST, man!

The next thing we will be told is that there have been NO real improvements on the .45 Colt, .45ACP, .30-06, .375H&H and .450-3.25Nitro EVER.....the whole dang industry will collapse!!!!

Juat got my final Grizzly/packing rifle yesterday, a plain, old P-64 in .375H&H, 20"sts. tube, Recnagel irons, QD mts. 2.4xC Leupy, Micky stock and Decelerator...probably gonna get et in northern BC next summer as it is not a .375Ruger, Ultramag or a .416 Lazzemacaroni Blastum Super Mag...and wasn't "designed" by Col. Alphasoup! Horrors, what shall I ever do?

Geez Kute... I think I'm approaching Curmudgeonhood

Ya, I'm beginging to think so , Brad...(chuckle)

I'm just wondering how you fellas *know* these new RCM cartidges are not gonna feed well ?

As for magazine capacity , IMO 3 versus 5 is not gonna make a whit of difference for 99.9 % of hunting chores .

Did I SAY anything about feeding issues? NOBODY including YOU really KNOWS yet, OK. The Wizzums HAVE HAD feeding issues in various rifles as is well documented in threads here, check the archives.

As for magazine capacity, IF, you can get equal performance with more rounds in your mag., that is a benefit in Grizzly country and this is now becoming a problem in the western US as well as Canada, so, I think it IS a serious concern.

A .338RCM crf short-actioned rifle DOES interest me, but, I found Brad's comment quite appropriate as too much emphasis is placed upon new cartridge designs and nor enough on quality control of production rifles, IMHO.

Kute , maybe you did not mention feeding issues , but Brad did .

And your right , I don't know any more about feeding of an RCM cartridge than anyone else , but I do have some faith in Ruger producing a rifle that will feed and function.....IMO they have a good track record in that respect.

As for the magazine capacity , my take would be that if one or three shots do not sort out an unexpected grizz problem , a fella would be in deeper dodo than a couple more shots is gonna help........but I'll defer to your experience when it come to extracting one's-self from grizz dodo......

The 338 RCM looks cool, and probably will sell simply beause it is a short fat 338. Ruger ain't dumb, ya know.

But . . . . .I thnk I'll just shoot my 308.

BMT

What am I missing here. The "new" RCM's are basically the same as the WSM's as far as capacity, design, etc. so why are they even coming out with them?

This whole cartridge of the month thing has to stop sometime!

Here's one more small thought. My 7mm-08 Model 7 was a somewhat "balky" feeder. When I rebarreled it to .358, it cleared that up. Feeds great now. It must be because the .35 cal bullet leaves such a small shoulder on the case, right? So maybe the same thing would happen with the WSM's necked up to .35 cal.

-jeff

There is an old man who lives at Hagensborg, BC, in the mid-coast region of BC, his name is Jack Turner and he is the husband of Trudy Turner, daughter of Ralph Edwards,OC., the "Crusoe of Lonesome Lake, this man shot the then world-record Grizzly near their home in May, 1965.

He is, among serious, esperienced BC bush people, a living legend and at my best, I am an infant in the wilderness beside him. I knew his/Trudy's elder brother Stan at Ocean Falls nealry 40 years ago and these are simply amazing people, I say that as a member of one of the founding, pre-Confederation families in BC.

This TRUE EXPERT was attacked two years ago, in the evening, just outside his front door by FOUR yearling Grizzlies and mauled a bit. He escaped and survived, but, this is only one incident that makes me feel better with more rounds on tap.

I also MUCH prefer shallow-angled rounds for my hunting rifles, .338WM, 9.3x62 and .375H&H are my usual choices. I own a lot of Rugers, have examined a Hawkeye African and was VERY impressed, although I wishthat they had put a Rigby-style floorplate on to hold one more round and a larger button on that safety...still, one of the better factory rifles in years, IMO.

As to Brad, well, he IS a curmudgeon, a Viking AND getting on toward geezer status....what can ya do, eh?! MORE Moose Drool!!!!

I think you're probably right (though I do like short actions).

Per my new issue of Rifleshooter, the 338RCM has the same case capacity as the 30-06, and the 300RCM being slightly longer sits half way between the 30-06 and 300WSM (ala 300 SAUM).

The article tries to make a case for improved short-barrel performance, and that may be the case with the tailored pressure curves Hornady ammo is providing, but of course handloaders are likely to be disappointed.

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i guess i didnt know people are having trouble feeding the wsm cases. my model 70 feeds them like a champ and never had one feed wrong. and i dont think anyone needs 5 rounds verses 3 rounds for hunting and if you do you might want to pratice more or get some shooting sticks.

You really haven't been paying attention, have you?

There have been many reports of poor feeding, though I have owned at least 10 of them and have also seen no problem.

It is true, however, that they don't feed as smoothly as a 30-06 or other slimmer rounds with more generous body taper and less acute shoulder angle.

As far as magazine capacity, I don't place much value beyond the third round myself, but a lot of guys on this forum do.

Either way though, it appears that performance of the RCM rounds will be very close to the 30-06 and 338-06 in handloaded form due to limited case capacity.

With no performance advantage, you really have to LOVE short actions to jump in.

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.... just buy a .325 WSM. It's a proven round... as much as a WSM can be anyway... and it'll do the same dang thing!

-jeff

I'm not an old sourdough, but the time I was charged by a griz on Kodiak, I recall thinking that more rounds would be better than less rounds.

I never ever want to be afield with a rifle that does not feed perfect every time.

The RCM has potential to be a smooth feeder. Belted mags--gun scribe rantings aside, typically feed very smoothly. Crud, my M-70 375 H&H will feed and chamber empty cases. A belted mag is nominally .532 at the rim and the belt.

The WSMs have had their share of feeding issues. They have a nominal .550 head diameter.

The RCM has a head diameter of a belted mag. Since the belted mags feed well, an RCM would seem to have a good chance of feeding well too.

I think it has more to do with quantity and angle of the shoulder. WSM's, at least, have a steep, long shoulder... but I don't know fer sure that that's the reason they can be balky, just a guess. FWIW they AREN'T balky feeders in the two WSM's I have- they are fine.

-jeff

My 7mm Rem Mags and 300 Winnys and 340 Wby all fed very well too, as did my 375 Ack with it's 40 degree shoulder. There is some relationship between the diameter of the case, it's taper, and the shoulder angle. I am not sure where the break points are, but a fat case is not a help.

The most recent Rifle Shooter states the water capacity for the RCM's is 68-72 grains, while the 300 WSM holds 79 grains, if it helps your thesis.

Will the brass be made by anyone other than Hornady? Kinda pricey compared to Remmy and Winchester. Not an issue for some I guess.

I would like to interject the size and shape of the .416 Rigby case into the argument: .589" head size, 2.90" length overall and a 45 degree shoulder angle.

I have not seen one that did not feed well (of course I am not the warranty repair point for same).

I resisted the .300 WSM and .300 SAUM , but I intend to give the .300 RCM a test drive. It has some virtues for me.

jim

I just remembered that the Barnes #2 manual lists the case capacity of each cartridge using water. They list the following:

• 350 Rem Mag - 73.74 gr
• 35 Whelen - 72.63 gr
• 338/06 - 73.17 gr
• 30/06 - 68.01 gr

With the 350 Rem Mag available in my opinion there is no good reason to do a wildcat on the RCM case. Using the WSM case would get some what more velocity and may be the way to go. I wonder what would happen if Hornady used their "special" powders in the cartridges listed above. An interesting thought.

Thanks for that information. Now I can rank them and just a 30-06 case capacity is not a new invention. There is very tough competition at that capacity level. The 30-06 Springfield for instance.

Unless a cartridge will fit in a true Featherweight contour barrel I would just as soon have a WSM and get a standard barrel contour.

The Kimber Montana goes only 6.1 lbs with a 24" barrel.

I am listening but so far I see no real use for this new round. I have already forgotten its name! LOL

It's called "Apprentice Curmudgeon". I just entered the program a few years aog


Casey

Do I even want to know at what age I should expect the letter from the Apprentice Curmudgeon folks? Jeez... one more group to join... do I at least get some free ibuprofen or something?

-jeff

after firing a 5 1/2# 350.. 225's @ 2700 will knock your socks off... fun but mostly entertaining to bystanders... the 350 mag rocks.... whatever turns the wheels though..... that is what this is all about....

enjoy

woofer

OK, I gotta ask this - what does this new Ruger cartridge do that is different from the 284 Win cartridge? Capacity about the same as an '06 in a short action cartridge. Is there something else here that I am missing, besides the proprietary powder/loading of Hornady?

cant re-sell the 284

woofer

Got it, that's what it sounds like to me. Wildcat a 338-284 or a 308-284 and I'll bet you'd have the same capacity as these new ones within a couple of grains.

I beleive the case capacity listed by Rifle Shooter magazine is going to turn out to be a bit low .

Otherwise , these new cartridges are not going to come anywhere near their published speeds , special powders and loading techniques not withstanding . Particularly out of a 20 inch barrel .

The RCM case will be fatter than a 350 Rem. mag , so it just about has to hold more powder than that case........

The 350 RM's shoulder is farther ahead compared to the RCM, might make up for the slightly fatter case.

1) A non-rebated rim (if you care about that kind of thing).
2) This isn't in reply to your post, but compared to the WSM's, potentially one more round of mag capacity and smoother feeding.

From early appearances, it looks like the 300 RCM would allow for a 30-06 +P out of a short action with a relatively short barrel - that'd be a good thing. It's too early to tell, though, so I'd at least give the round a chance to prove (or disprove) itself.