Home Forums Hunting & Shooting Custom Rifles & Wildcats 7mm RCM????

Hey just day dreaming and wondering if anyone had taken the 300 RCM case and necked it down to 7mm. Looks like it would be a dandy little cartridge and should feed a might bit better than the WSM or SAUM. This is one 7mm I would buy or may build. Thoughts?? Anyone starting one???


Brno 284

Not yet but the day aint over...grin

Anything 7 has my attention. A while back I ran a couple rounds thru Rancho Loco's 7 Saum and the lil bugger kind of captivated me.

Dober

I like the Saums. In some ways I like them better than the WSM's. They're a true SA and I like the 30* shoulder better than the 35* of the WSM. Nit picking for sure though.

Can't really see the why of a 7rcm as it's a 280 that holds fewer down and doesn't feed quite as well.

Mac why you likey the 30 better than the 35?

Friend of mine bought a 77/300 RCM today. The stls and syn one, be interested to see how it shoots. I sure do like the feel of the lil gun.

Dober

Dunno Mark, guess it should feed a skoshe better, but that's likely nonsense. I suppose I just like the way it looks better, which is borderline stupid.

I saw Wards had some 300 RCM's on sale a while back.

Think he got a good price on it today?

How would a gun get those darn irons off anyway?

Dober

I have had wildcats, improved rounds etc. for awhile. I had to look up what a RCM is? I must have missed some article.

These days I look to the rifle. What I mean by that is I want a rifle that I like for its features, finish and finally caliber if you will. Many 'calibers' overlap. I hate to tell you that!

Do what you want. Thats the fun of guns. They don't cost all that much.

Since I can't get excited about another wildcat then I will talk about what I want to. I went into a gunshop and they had a MS half stock carbine. One of the old ones with the rotary magazine. This one was a 7-57 with a signed barrel by JD Darrow. On the postitive side it had the most interesting tiny pop up tang sight. The rifle was not that clean and its finish was gone. Must have been through a lot since Jud had it in his hands. They were asking $1300. Too much, too rough.

Thats what I do some of the time.

Dreaming about guns just like the rest of us.

Would a 7RCM be any different than a 284 in case capacity?

I believe a grain or two... likely it's a 284 +P

Yes, I am starting one. I have a new Broughton 5C barrel ordered, a Pacific Gauge & Tool reamer, and a Redding FL die for necking down. I will have my 7mm-08 competition seater and neck dies reamed out for the new caliber, so only need a new FL one. I plan to shoot Barnes TXT-tipped 150 grain bullets and will initially try the new Hodgdon Hybrid 100V powder. FYI, Dave Kiff at Pacific Gauge & Tool says that many people are using the 7mm/.300 RCM due to smooth feeding and efficiency compared to the SAUM and WSM versions.

It would be good to see a comparison pic of the four cartridges, that is the 7mm in wsm, saum, 284 and the RCM

Von Gruff.

Von Gruff,

Reference your sig, I have read a similar saying.

The contemporary saying was there was nothing a man could not do with a .303 and a .404...jim

Terry B.,

I would be interested in hearing the results when you complete your 7 RCM.

I just got my reamer from Dave to make a 35/338 RCM. Redding is going to make the two pc die set. Have to wait approx 12 weeks for the dies! I chose the 338 RCM because it is a bit shorter for bullet fit and will be easier to neck up. It turns out am the first to do it. There are 35/30 RCMs but no necked up 338s. A dummy fits and feeds like a dream from my old tang safety short action Ruger. Looking forward having a + P 35 whelen in a short action.

Be sure to update us when your rifle is complete.

Not taking issue, but how would a 7RCM be all that much different than a 7SAUM other than hold a few grains less and feed better? Personally, I would rather the Ruger version over the Rem or Win versions...just based on case design and nothing else. It's unfortunate that Ruger is a day late and a dollar short, because they did design the better case in the Short/Fat competition.

Azshooter - been thinking about that one myself. Liked the 2.015" case length for long bullets. Got a request out on a forum up here in Canada for a few spent 300RCM and 338RCM cases to neck up to 35 and compare case capacity. Too few RCM guns up here yet I guess.

But maybe you could advise me as to the grs. of water to the case mouth of your 35/338RCM as compared to 35/300RCM flavour - if you mocked one up for comparison?

Also interested in your donor gun for your project?

I built a 350WSM a few years ago and feel the need to go down that wildcat road again for some reason. Dave Kiff also supplied my reamer too for that project - which turned out to be a great rifle BTW.

Thanks - and sorry for the sideways hijack.

Whelen B PM sent

Before the .300 WSM hit the market Heavy Express was selling two .358 cartridges on cases of the same size as the WSM (developed from .348 brass converted to rimless and using 40 degree shoulders).

The .350 Heavy Express was a 2.25" case and their data for a 24" barrel showed 200 gr/3,050 fps; 225 gr/2,950 fps; and 250 gr/2,860 fps.

The .350 Heavy Express Short Action Magnum was a 2.060" case and their data again for a 24" barrel showed 200 gr/3,000 fps; 225 ge/2,910 fps; and 250 gr/2,785 fps.

I asked Ruger/Hornady to consider a 6.5 RCM, so I will have to check at SHOT to see if there is any glimmer.

jim

Yeah...What ever happened to "Heavy Express?"

I remember reading about that cartridge back in the mid 90's, then a couple years ago, I was looking for anything on them, and I couldn't find a thing.

The guys name was Jim Busha..or something like that wasn't it..?



Sincerely,
Scott

Brno,

I may be assuming here, but here goes:

I have been told that the RCM brass has the same basic case head as the .376 Steyr. IMO, that is the biggest detraction. Why would one want to build a wildcat with a bastard case? Especially so, since we already have the 7mm SAUM. The SAUM will easily outperform the RCM, thus building one accomplishes exactly nothing except having something different. Now having something different is nothing which I havn't done... When I built my 1st 9.3x62, few shooters had even heard of it!

Now, I am quite aware that some folks just HAVE to pee on the electric fence for themselves... Thus, if the shoe fits... Que pasa?

Now if I am wrong about the brass dimensions, that makes my logic fairly flawed. However, If one builds a wildcat on the SAUM case, the .284 Win. case or the WSM case, at least one is using a standard bolt face... If one uses the .495 case head, and tires of his 'cat, there is not much one can do with the bolt... And the other downside, is that it adds extra machining to the custom process... Unless one starts with a standard Ruger RCM, and then one is stuck with owning a Ruger. (Which means one is STUCK with a hokey safety... )

Just random thoughts from a mostly idle mind....

Grasshopper

addendum: Besides, it would be a fair stretch to come up with an idea for a custom cartridge that hasn't been thought of already, or can possibly fill a logical void...

Even before Jim Busha (sp?) prounounced: Bu-Shay, There was Fred Wade and Roy Gradle who both made short magnums on the .348 Win case with the rim removed. Just goes to prove you have to go back a ways to find something truly original...

GH

RCM cases are the same head size as belted cases, but the case itself is the diameter of the belt, rather than the smaller belted (H&H-style) cases. So building a 6.5 or 7 mm RCM would be dead simple in any short action set up for a .350 Rem, et al.

Just one of the multiple reasons I'd like to build a 6.5 RCM one of these days... .

Dennis

Dennis,

Well, I guess that blows my theory... Evidently, the gunsmith who told me that was wrong....

That being said, What is the difference between the RCM case and the SAUM case?

GH

Jim shut down HE when his sales dropped to almost zero after the .300 WSM was introduced. I was sorry to see it, but that is how it goes.

The Hornady RCM brass that I have goes .530" on the head and the Hornady .376 Steyr measures .500" so there is considerable difference. The .376 Steyr case is derived from the 9X64 case, and the Ruger and Ruger Compacct Magnum is not.

The .348 Win itself was descended from a black powder case, .50-110 IIRC...jim

GH - The RCMs are not rebated rims so better in regards to potential bolt over ride feeding problems. RCMs are significantly less case capacity than the SAUMs (roughly in the 70grs versus closer to 80grs range water to the mouth I believe).




300SAUM

Hi Jim -

While you're putting bees in their bonnets, ask about a .25 RCM. Probably with .25 WSSM essentially come 'n' gone I doubt winchester will gives us a .25 WSM, but Hornady and Ruger might tackle that gap.

Tom

Whelen,

Thanks for posting those diagrams. Now all this has me wondering where the RCM fits in the grand scheme of things.

Supposedly the SAUM is dead, because the WSM out-performs it, And yet the RCM is even less than the SAUM...

That being said, I have rifles in the .270 WSM, 7mm WSM, .325 WSM, 7mm SAUM, and .300 SAUM. And I had a .300 WSM, but sold it. Of them all, my favorites are the 7mm SAUM and the I expect the .325 to become a favored one.

In all honesty, I fail to see what perceived gap the RCM fills...

However the above notwithstanding, I can see a #1-S in .338 RCM coming to roost in my gun safe. (Us rifle looneys seem to be a bit irrational, at times...)

Grasshopper

Ahhhhhhh....., Grasshopper...Sometimes "Less is More.."

"Wax on.., wax off........"


...and for the RCM, less IS more...


less case diameter, more magazine capacity, and bolt pick up...

Less shoulder angle, more slippery feeding....

less bullet intrusion into powder space, more inclined for a 2.800" C.O.L mag. length.

Less powder, more like a 338-06/35 Whelen(respectable big game cartridges in their own right)


If the 350/6.5 Rem Mag and the 284 Win got together and had a baby..., it would grow up to be a RCM.

Good one.

The 6.5-300 or 6.5-338 RCM is on my list of things to do... as soon as I dump the cash for the reamer and dies, Ruger will come out with the other as a factory offering, so you guys should all be good to go... LOL.

The RCM, WSM, or RSAUM mag box for the M77 can go four down when stuffed with RCM cases, with a little massaging of the follower.

As far as case capacity, Hornady claims 68 grains for the 338 and 72 for the 300...

Mattman,

Are you talking about the newer Mark II M77 allowing four to fit the magazine? I just tried placing some 338 RCMs in the tang safety M77 and only three will fit the magazine.

I had a gunsmith who knows Rugers and has figured out how to lengthen the Ruger M77 safety do one for me for my M77 Hawkeye African .375 Ruger. So far I don't see the need for my .300 RCM, but I may decide to have it "fixed" too with use.

jim

Only with the correct mag box and follower. Ruger designed a new mag box and follower to fit 3 WSMs down, instead of just 2 like everyone else. So with the RCM diameter, you can get 4 down in the short fat mag box, if you know what to do where...

On a tang model, I'd think you should be able to get 4 down by using a 350 or 6.5 mag box and follower. Don't know, never had one, nor have I tried. But a 243 tang model holds 5 down, and I thought the belted models held 4. The tang mag boxes and stocks were deeper than the MKIIs and Hawkeyes.

The safety hasn't proven to be an issue yet on any MKII or Hawkeye I've been around... much less hokey... I don't trust nor to I rely on safeties, but the Ruger design is about as idiot proof as I've seen.

I looked for a sako a7 338 federal in stainless to modify into 338 rcm but haven't found one yet. I am curious to see if the rcm will feed out of the sako a7 magazine. Bolt face has enough meat to be opened and a 338 federal or 7mm-08 could be rechambered easily, I would think.
Should give 338-06 or 280 performance in light handy rifle.
K

I can't figure out why we need yet another case shape necked to .284, but "need" stopped being a relevant criteria about 1965.

Hey! I resemble that remark!

I fail to see the issue of how many rounds in the "belly". I never load more that 3 rounds in my rifles... And have never needed more than two.

I do readily admit that is excluding Alaska and Africa... (But if you're hunting dangerous game, one is likely to use more than a 7mm anyway...)

Grasshopper

You can stick two or three down in a mag that holds four, but you can't stick four in the one that only holds two.

That's the advantage...

I'm an Optimist not a Pessimist, therefore I dont need all that ammo...


Which reminds me of a story (true): My buddy took his 17 yr old son out hunting. When they came in, he didn't see him unload his rifle. When he queried the kid, the kid said he already did. So he asked him how many rounds he had... And the kid reached in his pocket and took out two rounds. He said: "That all you got?" The kid answered: "I only need one, but I brought two in case I made a bad shot and need a follow up."

Now that's Optimism!

Grasshopper

I like the whole RCM package.. Plenty of power for B.C. hunting in a nice little package..
If Ruger came out with a 7RCM I would buy one..
Another one that appeals to me is the .358-30RCM which I understand has been done..

That's a classic.

I can remember another true story about a guy (real genuine dipshit) on a trophy rut muzzleloader elk hunt that didn't even bring a possibles bag, so he had to stuff everything in his pockets. He lost his extra caps whilst dropping dukie in the woods... which remained undiscovered until he needed a second shot to finish a huge 7x7 bull. I'm too ashamed to tell the story of the rodeo that ensued... but it lasted nearly 8 hours and involved at least one trip all the way back to civilization and a near heart attack for the hunter. I wasn't there, I would have knocked him cold with the butt of his rifle and left him lost in the woods...

Matt,

Nice story...

The kid graduated from HS last spring, I gave him a M-700 SS Mtn rifle in .280 Rem for his graduation. He took his deer with it this year. (ONe shot!) (Last Nov.)

Last Monday, he left to be inducted into military service. I never had any sons... Thus he and his brother are like my God-sons...

Grasshopper

I had a spare 300 rcm under the bed that I considered trying a 6.5 rcm on but I just sent it to a new home in Texas. When I think of 7mm's I still dream of one on the full size 375 ruger case. You could seat long heavies out to 3.6 and still run em through the mag of a remmy. Think of a shorter beltless stw with more room to chase the lands.

I carried my 338 rcm this fall in eastern Idaho and it sure is easy to like in the brush. Mine wears a vx3 2.5-8 and shoots well. I'm currently running 225 g IB's at 2650 over rl15 out of a 20" tube.

Bb

Burleyboy - do you happen to know if the case taper and shoulder angle/position is identical on the 300RCM and 338RCM? I notice the 300RCM is longer over all (2.100) than the 338RCM (2.015". But is that just a longer neck without any other case dimension differences? In other words could the same headspace gauges be used for either flavour?

I can't tell from my pics and info. Also perhaps others may know this and could enlighten me with the facts on this.

They definately need different gauges. The shoulder on the 338 is back further and the case capacity is less by about 4 grains. They probably did it because of the long ogive on most 338 bullets. I did a dummy round where I necked up a 300 rcm to 375 and those bullets seated at the canlure still fit in a short action. I think the 300 is the one to wildcat unles you want more room to seat a bullet out the the 338 is better. 338 bullets just tend to have longer ogives leaving more bullet length out past the neck.

You could probably find diagrams at pacific tool and gauge.

Bb

Curious if Hornady mentioned anything about the 7mm RCM at Shot Show or if anyone has some news. Mostly just tracking the post to see if anyone has gotten a reamer or any new information.
K

I asked the reamer makers at SHOT about requests for a 6.5mm wildcat on the .300 RCM and got blank looks. One volunteered to check the file and get back, but no email yet.

jim

300 and 338 capacities are supposed to be 72 and 68 grains, respectively.

This got my attention. I think 7mm saum is too much power and 284 too long for SA so why not a 7mm RCM and make it 2.0 overall case length.

I think that at this point it would be too hard to locate cases to be worth it. Those other cartridges are excellent company though, you might use .300 saum brass necked down, that gives you a longer neck and reduced capacity closer to the 7mm rcm.

Only problem i have with saum and wsm is they rebated, gotta friend with a wsm and bolt run over sometimes. To bad the rcm died. Imagine a true short action case with 284 winchester performance. A long neck for long bullets and not so darn overbore and killing barrels.

huskyswede,

The RCMs are not dead.

The RCM brass is still available:

300 RCM
http://www.midwayusa.com/product/17...s-300-ruger-compact-magnum-rcm-box-of-50

338 RCM
https://www.grafs.com/retail/catalog/product/productId/7082

As for rifles Ruger still offers both chamberings in the guide gun.