What should I do with this pre-64?

[Vern Humphrey]

The belted magnum was an early 20th century means of getting express rifle performance in a Mauser bolt action, it was not meant for double rifles. It was to give headspace control with the long tapered, shallow shouldered Cordite cartridges. When you see a double rifle made in a belted magnum calibre because of the decline of the superior rimmed cartridge, it will have the same trick extractors as for a rimless cartridge.

Your late Packard era advertisement and photo are interesting. By that time, a Packard was just a "badge engineered" Studebaker. The fins are right off the Hawk series of Studebakers.

Holland and Holland wanted a cartridge compatible with Mauser actions. But they also wanted a rimmed cartridge because they felt boring the chamber deeper was best in tropical conditions -- crud could be pushed forward as you chambered a round and wound up between the shoulder of the chamber and the shoulder of the cartridge. That required a rimmed case. But in Mauser magazines, rims can interlock, causing bad jams.

So Holland and Holland made the rim VERY thick -- too thick to allow one cartridge to get back far enough to interlock with the cartridge below it. Then to accommodate the Mauser claw extractor, they cut an extraction groove in the edge of the rim -- resulting in the belted appearance.

 

[someguy2800]

I cannot think of anything more inconsequential as whether a cartridge has a belt or not.

 

[Vern Humphrey]

I cannot think of anything more inconsequential as whether a cartridge has a belt or not.

In general, no. The original British idea is long shown to be inconsequential. But for cartridges that have no shoulder, and must feed through a magazine, such as the .458 Win Mag, and the .458 Lott, the belt is necessary.

 

[Slamfire]

But in Mauser magazines, rims can interlock, causing bad jams.

I would say, rims in general cause rim lock in magazines. I staggered my 303 Brit rounds as you are supposed to, and can't remember a rim lock in a 303 Brit, but my Mosin Nagants, I had rim lock. The Nagant has an interrupter, it keeps the 2nd round down so the rim does not rim lock with the top round feeding into the chamber. However, different lots of Chinese ball, something was a little different about the rims, and even though the interrupter functioned, I would get rim lock.

I have never handled a Bren magazine or any of the Russian magazines what use 303 Brit or 7.62 X 54R, but pictures of the things show them to have the curvature of a banana. They must be spacing the cartridge bases out so the rims don't inter fer with each other.

I do have a 458 Win Mag, I lubed my expensive cases up, fired them with cast loads that would not group on an eight foot square target at 100 yards, then tried to figure out how to size the cases without pushing the shoulders back excessively. I think ice sickles have more of a shoulder than a 458 Win Mag.

 

[Offfhand]

Previous mention of the .458 Win Mag, again points out the tremendous range of calibers the Pre-64 M-70 adapts to. Another example is this M-70 action that was fitted with an octangular barrel with integral quarter rib for express sights. The addition of "drop box" bottom metal added another round magazine capacity. Which, along with restyling the bolt handle and styling the stock along Pre-WWII British express rifle lines, it the flavor of the bolt rifles built by Holland & Holland back during the golden era of African hunting.

 

[Bbear]

I own and shoot a modern production Model 70 264 Win Mag. I'm loading Reloader 33 behind the Nosler 142 Long Range Accubond. It is one of my favorite range guns. I 'down-sized' from 300 and 338 WM due to shoulder problems and the 264 is amazing. One shot dropped my elk in 2016 and I've taken a couple of whitetail doe and an axis doe with it.
Range time, I'll usually shoot 20-30 rounds through it while letting other rifles cool off. Usually 3 shots at a whack.
If you don't pile the shots down range one after the other, you should get 2000 or more rounds before accuracy drops off.
Mine is consistently under an inch and has 400 rounds through it. I've had it for 2.5 years now. It should last as long as I do unless I decide to start shooting long strings of shots and burning it up.

The Reloader 33 is one of the newer powders in the H870 burn rate and seems to be a bit 'cooler' burning powder. Fairly temp stable but not the most stable of powders. Better than what I saw with H870 though.

Clean the bore of your rifle well. Take it down to it's bare metal. As stated earlier, bronze brushes and several different cleaning solutions should help remove any powder and/or copper in the barrel. Then, in 3 shot groups, fire 6-9 rounds to foul your bore. Don't worry too much where the foulers go. Then see what the rifle will do with different factory fodder. Or, if you reload for it, work up a load for the riflle and enjoy shooting it. As for finding bullets, Shooters Pro Shop has blemished and over-runs available quite often for not much $$$