I have model 70 classic srainless and would like to convert it to 375 RUM , from 375 H&H. Is the magazine box large enough ? Would the follower need to be changed ?
Mark

Mark---

You'll need a *wider* action....and a magazine box.....and a follower.

The big question is WHY would you want to do such a thing?

Mark.
No problem!! The action is "wide" enough. The only consern I could think of must be the total lenght of the magazine.
I know, because I have mod 70 (pre'64), SS that I transformed from a 338 Win.Mag, and to 338 RUM. Works perfectly!!
But the 375 RUM (and 300 RUM). is slightly longer than the 338 I think??!
In my magazine I can have a C.O.L on max 92mm!!

It would be a real KICKER!! But I'll guess you already know?

Jack thanks for the advice again. It is the disease that leads me to wanting new toys that has me thinking about the conversion.
Arild thanks for your experience, my understanding about the differing lengths is the same as yours. As so often happens my "best ideas" need some more work.
Mark

Mark might be easier to get a cz .375 and convert it to the RUM.

Mark I have asked a question about your ordered 9.3 in my mounts thread mate.

Regards PC.

The .375 RUM and the .375 H & H are of the same length overall, so magazine length is not an issue. As Jack Belk said, it is the "width" of the magazine (and feed rails) that's the kicker. The .375 H & H magazine, unless the box is widened, will probably only hold 2 RUM cartridges. The feed rails will likely have to be milled (CAREFULLY) a bit wider in order to properly feed the fatter cartridge.

For dangerous game (or any game, for that matter), would you rather have a 3-shot gun with another 200 fps of muzzle velocity, or the 4-shot gun that you currently have? You pick.

I am pretty sure Daggaron or Jeffesso, I forget who has a really nice .375 RUM done up on a CZ 550 it looks unreal. If I were to opt for a hotter .375 I would use the extra power to drive the heavy 350 gr woodeligh's to the same speed the H&H would drive 270/300 gr bullets. I think you would have the penetrator of the century then.

They're trying to give away M70 classic stainless 300 ultramags now, I've seen them discounted over a hundred bucks. Why not get one of them and rebarrel it to 375 ultramag, the box and feeding work is already done.

My brother told me last night that Winchester isn't offering any of the Ultra Mag chamberings in the new catalogs they just got in so...

boltman--

There's a pretty good reason they've had to discount them......they don't feed or extract well and the word is getting around.

When the extractor cam on a M-70 galls you'll need another action.

PC,
It's Rab's wonderful 375 on a cz...

hey, this would be a good place to say "get a 404 barrel, and rebarrel it into a man's caliber"

jeffe

Why not just ream it out to .375 Ackley Improved? That's my newest project...just have to wait till after christmas to get my M70 classic stainless, and then it's going straight to the gunsmith...still have 4 shots, and circa .375RUM velocity! And, you wouldn't have to open the bolt face either...it's a win win situation.

Has anone had their paws on one of the 300 RUM Model 70's?

Just wondering what, if anything, Winchester did to the magazine to make the shells fit and feed.

Any windows and/or a wider box?

Joe.

Mark - a hunting buddy (Diesel Dude) had his mod 70 stainless 375 hnh converted to 375 rum by Dave Caboth, gunsmith at Chimo Guns in Wasilla, Alaska - restocked with a fiberglass stock and topped with Talley mounts and a 2.5x8 Leupold, DD gets some impressive groups from this rifle - total weight is about 9 lbs. I can't quote his velocity of his 300 grain loads but the rifle functions flawlessly - he has tinkered with 260 grain partitions, 270 grain and 300 grain of some other bullet - I think he selected North Fork bullets - don't know the load data either - it shoots nice, doesn't kick much - I don't know how much he spent to convert, however he is very pleased with the finished product - get what you want in your rifle selection - KMule

Thanks again for further replies. I thought of a 375 Weatherby a while back but plumped for 375 RUM as I think brass and dies would be much cheaper and easier, the catch obviously is converting the rifle. Brownells list a new magazine box to allow model 70's to handle the RUM's.
It is interesting Winchester is dropping the 300 RUM because they listed the 338 and 375 RUM in the custom shop but not currently. The reasons for dropping the RUM's would be interesting.
The problem in Australia is that we don't get those close out specials , sadly.
My writing may seem strange but I have a golden retriever chasing around my feet! In closing I must say real men shoot 416 Rigby not weedy little 404 Jeffreys !!

Mark

Or they simply shoot 460 Weatherby, without muzzlebrakes!!
I'm with you, KMuleinAK!!
There is a lot of people here saying "this and that", but I actually HAVE a 338 RUM. buildt on a Mod 70 (pre'64), stainless steel, that also works flawlessly. And the magazine holds 3 rounds. Its the nicest feeding rifle I actually have!!
(and there is nothing wrong with my other ones, except a mauser 98 in 416 Taylor, though)

[ 12-17-2002, 22:27: Message edited by: 460wby ]

Mark, you might call Dave Caboth and ask him what he had to do to get it to feed. The Brownell box for converting the Remington to feed the WSM cases didn't work with my brothers because the lips controlled the rounds and were too soft, they gradually bent up and let the rounds pop out. My brother and Dave have been working the kinks out with a Winchester box I think, like my dad had to do to his Rem. My brother is over there trying to get his model 70 470 capstick to feed now too. I don't think the 375 Ultra would be too bad in the right hands.

Thanks Brent, you are right there is no need to re-invent the wheel.
Mark

Mark Smith,
I liked the "weedy little 404 Jeffery" comment, and the headsup on the Brownells magazine box for M70 to RUM.

Here is the picture, AGAIN , of my CZ 550 375 RUM. I had been toying with the idea of a 375 RUM on a Winchester M70 Classic Stainless ...

I should have clarified a little better about the mag box of Brownells. It was designed to feed from the center so the boltface had a good bite, it worked great but when the cases shoulder hit and ramped up it worked the lips open in short order. Just a tad too soft or thin.

Thanks Brent, it sounds like the 375 Weatherby may be easier if the magazine box for ultramags has problems. Hopefully the problems will be solved in the future, a factory rifle would be easier.
Mark

Daggaron

I wouldnt be seen dead with such an ugly, ill looking rifle like that. You should not either.

Give ya $50.00 for it today? Act quickly or the offer goes........

Truthfully, I think it is georgous, clean lines, well proportioned and the visual impact is great.

Jim B.

Having owned a .378 Weatherby and fired a .375 RUM (700) I don't see how good shooting, on an consistant basis, can be done with either.

When my .375 Improved project was tied up at the smith's I came across a .378 Weatherby MK5 (Sauer) and loaded for it. To be honest I never got over 105 grs of 4831 even though the max load is 115 grs for the 270 gr bullet. This rifle was accuarate group wise but I could not imagine any application for the rifle or cartridge. At short range on dangerous game I think the .375 H&H may be more reliable.

This .378 kicked so freaking hard that I was afraid of it.

Then a like new pre64 M70 came my way at a low price yet in .375 H&H. This happened before the .375 Improved was finished. The M70 is so superior in every way to the Mark 5 or the Sako L61 that the Improved is on that I sold the .378 as fast as I could. I was not the money. None of these rifles cost me much.

In summary if I still had that .378 I would not shoot it nor would I let my son shoot it.

John Wooters shooting is over folks. The cornea detached in his eye!

As Elmer said "What's it good for?"

Jim B,
Thanks for the comments on my "po' man's 375/404."

I cannot let you have it that cheaply, however.

Y'all remember that it can be loaded down too. Triple Magnum recoil pads from Pachmayr will make them more gentle too.

The CZ 550 Magnum magazine holds 4 in the box and 1 up the spout makes 5 total, in 375 RUM. It weighs 10.25 # unloaded and scope sighted as above, 9.25 # iron sighted. Loaded, scoped, and slung, it weighs about 11 pounds. It is not a light gun and is very tolerable in recoil.

My Pre-64 actioned M-70 375 H&H will hold a total of 5 rounds too, 4 in the box and 1 up the spout. It weighs 6.75 # empty and iron sighted, barely under 8 # with scope, and 8.5 # when loaded, scoped and slung. It is a light gun and very tolerable in recoil.

Hey, I like them both.

I also had to have a 378 Wby to know the fearsome bite of this, that so many complain of.

That is due to the hot factory ammo and a light barreled Mark V. Easily avoided.

I have a 378 Wby built on a CZ 550 Magnum 375 H&H simply rechambered to 378 WBY, and placed in an ArmTec synthetic stock (thanks to Nickudu). A triple Magnum Pachmayr pad of 1.5" thickness brought the stock up to my preferred 14" pull. This gun weighs 9.5 # empty and iron sighted. 10.75 # scoped with a 3x-9x Sightron mildot scope in CZ rings. It only holds 3 in the box and one up the spout for a total of 4 fully loaded. Fully loaded, scoped, and slung it is approaching 11.5 #. About my limit for portability.

111.0 grains of IMR 7828 with a 300 grain Sierra GameKing gave sub MOA and 2860 fps from the 25" CZ barrel.

Recoil is far from fearsome.

This is an excellent long range big game load.

Replacing the bullets with Swifts, Barnes X's, or GSC FN's or HV's of 250 to 300 grains would make it do good both near and far, on anything that walks the planet. Just use the right bullet.

Mark, I don't think you'll have much of a problem because it will feed from the rails which can be massaged to work.

I had a Ruger #1 in 378wby and shooting 300gr X bullets at 3000 fps was just plain fun, at the bench no less, not a young kids rifle at all, but not unmanageable by any means. Mine was not heavy either. Recoil was faster than my Ruger 416wby but neither are as bad as most everyone thinks they are.

Problem I see with 90% of shooters is they don't pull the rifle into their shoulder, they just simply put it up against their shoulder and fire, resulting in beatings from everything they shoot. Most shooters are a custom to lower recoiling rifles and never bother, or see the need to really get the rifle tight into their shoulder so when the touch off the beasties they get bit instead of rolling with it. Quite a new concept to many, but most catch on quick, or just give it up quick.

DoggaRon, that is a sweeeeet little rifle, makes me want to run down and get the CZ 416 Rigby the shop down the road has for $600. Is that the original stock, I've only seen a few light color ones like that in them this last year or so?

Brent,

Don't let a 416 Rigby CZ 550 Safari Magnum for $600 get by you or you will be sorry!

Thanks for taking note of the "Po' man's 375/404.".

That is a custom walnut stock, lightly stained. The barrel is a Winchester Super Express take-off, chopped down to 23" rethreaded and rechambered to 375 RUM.

Actually, the stock came from Boondock Sporting Goods, Eagle River, Alaska. Somebody traded it in along with a BRNO(CZ) ZKK 602 in the original stock. I swapped for the gun with the original stock plus the custom wood back in '92. The 602 became the 510 JAB.

The custom stock lay fallow for 10 years and just now got bedded, finished, and checkered to fit the CZ 550 Magnum action. It is pillar and glass bedded with three hidden crossbolts and one visible.

This action was an AHR action I found at Great Northern Guns a couple of years ago.

If you have made the rounds at the shops up there over the last 10 years, you may have seen the parts.

Parts is parts.

The 510 JAB is itching to go along as a backup gun with a buddy who is itching for a brown bear.

Here is the action that the stock was originally meant for:



I hunted brown bear twice as a resident, but KING KONG OF KODIAK caught wind and ran off with me running after him clutching a 375 WBY, down at Kaguyak Bay. The other time, everybody and his brother was over at Bruin Bay, on the Peninsula, and the bears had long since hightailed it.

[ 12-25-2002, 02:54: Message edited by: DaggaRon ]

Jbelk why all the negativity regarding winchesters? I have a 375 RUM on model70CRF,feeds flawlesly,shoots wonderfully.

An interesting question for those with great experience of dangerous game hunting ,
is how often have you got off more than 3 shots ? I just wonder if the posts pushing large magazine capacity are really pushing a realistic line. My very limited experience with big game (non-dangerous )suggests 3 shots in rapid succession is optimistic.
The big reason I like the idea of the 375 RUM is I have 3 375's H&H, so it is not a replacement. While there is a lot of criticism of the new cartridges , the RUM's and short magnums , I would
ask some of the critics if you were starting from scratch would you put a belt on the cases you designed.
Mark

One shot ... Meat!
Two shot ... Maybe?
Three shot ... Heap big shit!

Of course dangerous game is a different matter.

Of course the 375 H&H could not function reliably without the belt, but if H&H were doing it all again with what we know today, they would probably have designed the 375/404, or a 375 Dakota, or a 375/338 Lapua.

[ 01-03-2003, 08:54: Message edited by: DaggaRon ]

DaggaRon,
I can't get that 416 right now, but what do they usually go for? I never really gave it that much thought but figured that was the going price. I've heard about them being the bargin way to go and but assumed it was about right I guess.

Them bears are something too aint they. I know what you mean about the hightailing it, sounds like my moose hunting story this year too.

Question, what is the 510 JAB, can you describe it for me I mean?

Thanks

Brent,
$599.95 is the lowest price I have seen on a new CZ 550 in 416 Rigby. I have never seen any used ones for sale, as no one who owns one will want to get rid of it. Shops in other places may ask as high as $799.95 for one of these. That is the max retail I have ever seen on a price tag. Might have been some room for dickering.

My 510 JAB is my "big schtick." It is a 500 A-Square with a different throat and a shoulder of 30 degrees instead of 35 degrees per side. It allows me to have a one-of-a-kind cartridge and rifle, all my own, for fun.

510 JAB = ".510/460 Weatherby Improved Jenkins And Berry"

Jenkins is the gunsmith.
Berry is yours truly.
Dave Manson made the reamer.

Actually the shoulder angle is a trivial and insignificant thing in this cartridge. I just use 500 A-Square dies from RCBS, and the cartridge headspaces on the belt. The Weatherby brass is made by Norma and is as good a case as can be found, IMHO.

Hey thanks alot. My brother wanted to build the 50 Peacekeeper or something like that for .510s in a #1 action and I was telling him about your .510 JAB, just wasn't sure what it was.

How fast with a 750 A-Max in what length barrel, for comparison sake if you've shot them?

Thanks again.

Brent,
An excuse to post the pic of my Ruger Number One in 500 A-Square (with .587" throat cut specifically for the 750 grain Hornady A-Max and COL of 4.760"), again :



This rifle has a 27" barrel without the brake.
My most accurate load is 2150 fps with the 750 grain A-Max, using 110 grains of IMR 4350. Though 2300 fps is obtainable, I don't like to go there with this rifle. This rig, as shown with the 4x-16x Schmidt&Bender PM mil dot reticle scope, weighs 14 pounds.

With BC = 1.050 the A-Max stays supersonic and accurate past 1000 yards, even when started out at 2150 fps at the muzzle. IIRC, a 3" high zero at 100 yards, puts the bullet on target at 945 yards with a 5 mil holdover.

The 705 grain Harlow bullet by AAA Ammo is even more accurate, at 2125 fps with the same charge, 110 grains of IMR 4350.

The barrel is a McGowen stainless 1 in 10" twist that is 1.000" at the muzzle. The screw on brake makes the overall barrel length 29". This is the same length rifle as a bolt action with a 25" barrel, due to the Number One action being so compact.

Very Nice!

Thanks for the info there too.

I had a #1 in 378wby that also had a heavy 28" Duglas bbl and it was real nice because of the short action like you say. It had a muzzle brake on it too. Sold it to my smith and now it's a 450 Nitro 3 1/4" I think, not sure though.

I had just bought my Ruger Mag 416 and was wrapped up in it when I finally let it go.