Remington 760/7600 conversion

A

Andy1

New member
This is my first post here, so I'm hoping to get some help. I'm into guns and shooting, but not reloading or gunsmithing. I shoot factory guns and ammo.

I'm looking into a custom Remington pump project. I have two .35 Remington's. One is an older 760 and the other is a 7600 from the 2005 limited run. I'm a fan of the pumps and of big bore .458 cartridges, but the pumps weren't available in this caliber.

The .35 Remington has a rim diameter of .460 and a .458 base diameter. Is it possible to blow out the shoulder of .35 Remington brass and make a rimless straight walled .458 cartridge? Then have my pump rechambered and rebored to match. I don't think port ejection clearance would be an issue and the bolt face wouldn't change. I would just need a custom cartridge company to make my ammo.

Does this sound possible or am I missing something? Thanks for any help.
 
Beyond the obvious, you can't fit a 0.458 bullet in a 0.458 OD case unless you had a "heeled" bullet like a .22 RF (or my .41 Long Colt). My drawing says the 35 Rem case has an OD of 0.457 and a slight taper to the neck. If you could straighten it out to a right cylinder, you could chamber 0.430 or 0.429 bullets, such as are used in 44 Rem Mag and 444 Marlin.

The 35 Rem is a 40 ksi cartridge, so performance would be pretty mild.

You could talk to a smith about doing a complete rebarrel to 45-70; I don't know if it's feasible.

Now, the obvious: You will spend a lot more than the price of a new rifle in any case. Plenty of lever guns out there in 444 or 450 Marlin or 45-70.
 
You are neglecting the brass thickness at the neck. If you were to go with a straight-walled cartridge you could run .429" bullets (44 Mag neck diameter is .457"). You are essentially talking about a rimless .44 Magnum or 445 Super Mag (35 Remington is 1.920", 44 Mag is 1.285", 445 Supermag is 1.620"), only longer, so you could use 44 Mag dies for sizing. But as a gunsmith, it all sounds doable.

If you really want a pump rifle in .458" caliber, find a 7600 in 30-06 and rebarrel to 450 Bushmaster.
 
Oh right! .458 would be the case OD. I wasn't even thinking that. I was just looking at the numerical dimension.

How about if I got a .308/.243 donor gun. My dad has a 7600 .243 I could get my hands on. I'd rather use a short action if possible. This case has (according to Wikipedia) a .473 rim, .471 base, .454 shoulder.

I contacted the guy at .35caliber.com about a .450 Marlin conversion and he replied that it wasn't possible. That's why I'm looking at converting an existing factory chambering case to .458.

Is it easier to cut down .30-06 brass than neck up .308 brass? I don't know what's involved in the process of either situation.
 
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All 760-7600 actions are long enough for 30/06 length cartridges. At one time, there was a wildcat called the ".400 Whelen" which didn't work all that well due to nearly no shoulder to hold cartridges against the bolt face snugly.
With enough $$, you could have a 760 redone into a 458 SOCOM or 450 BM. For far less $$, you can buy an AR in either caliber.
 
All 760/7600s are the same length, so action length is a non-issue. Not sure why you are pondering 450 Marlin, it uses a magnum bolt face, so the standard bolt and barrel extension would be iffy. A 450 Bushmaster is a lower-pressure cartridge but has pretty respectable energy numbers (close to 444 Marlin), it uses a rebated rim to stay with the standard bolt face (.473").
 
I appreciate the help. It doesn't look like a big bore pump is gonna happen. Not at a reasonable expense anyway. In the mean time I'm gonna try to learn more about gun and cartridge combinations work together.
 
While it doesn't meet the true definition of "big bore", if I wanted something unique and potent in a pump action I'd look hard at a 9.3X62 conversion. Not much bigger than 35 Whelen, which was offered in factory rifles. I'd think the standard 30-06 magazines would still work. While expensive, factory ammo is available and it meets the legal requirements for elephant in many African countries.

I know next to nothing about it, but a 400 Whelen is a possibility. This gets you into big bore territory and since it is based on 30-06 brass it creates fewer obstacles.
 
With modern bullet technology, the 338/06 or 35 Whelen will do anything a .45 caliber capable of fitting the 760 action will do. If the "use parameters" require a bigger bore, the shooter probably isn't well advised using the pump action anyway.
 
I'd say a 375 Whelen is probably the limit. The 7600 bolt face doesn't have enough meat to really open it up. I'd say the 375 Whelen might be a rebore job but I don't know if the barrel is large enough in diameter for that.
 
Pump action isn’t the strongest type of action to be making a true big bore out of. Maybe a lower pressure hybrid would suffice but there is a reason the mfg didn’t chamber that action in .458 caliber to begin with...
 
The .450 Marlin is a rimless, straight walled, .458 cartridge. However, as mentioned, it's more about the strength and to some extent the length of the action that'll cause grief.
A 760 Remington weighs 7 pounds. A .450 Marlin using a 350 grain bullet at 2000 FPS out of a 7.0 pound rifle has 37.2 ft-lbs of recoil energy. It'd hurt to shoot.
"...but not reloading..." You will be. Makes a lot of stuff possible that isn't using expensive factory ammo.
 
I might end up buying a big bore lever gun. I don't know much about them other than Marlin has gone down hill since Remington bought them. Either Henry or Winchester I guess. I'm not looking for a semi auto cause we can't hunt with them in PA. Plus I'm not into the MSSA guns. The only cartridge that interests me in that platform is the .500 Auto Max. I might get a inexpensive single shot.45-70 just to do something for now.
 
I think others have made it clear a big bore pump isn't going to work out. Too bad, it was a good idea.

If I were in the market for another big bore (had a 45/70) this is what I would buy. And Marlin quality has reportedly gone up in the last few years. A 444 Marlin. The American answer to the old British express rifle of 44 caliber with a 300gr bullet going 2,000fps. And with the new 1/20 twist a 300gr bullet should do just fine.

https://www.marlinfirearms.com/lever-action/model-1895-big-bore/444-marlin

You might check over at marlinowners.com and see if there is any feedback on these guns yet.
 
If you want a large caliber pump, get a 20 gauge slug gun with a rifled bore. The better end of accuracy will put you at about the same effective range as a 450 BM or 458 SOCOM.
 
JES does reasonably priced rebores.
He doesn't show anything larger than .35 Whelen as a "common application" for 760, but he goes larger in other actions. Maybe he would make a pump .400 as an uncommon application.
http://www.35caliber.com/2.html
Click to expand...

Yep, his prices appear reasonable.

A .35 Whelen was always regarded as the 'poor man's magnum.' If you're looking to upgrade in ballistic power from the .30.06, the .35W would be the way to go. I'm considering having a donor M1 re-barreled to .35W. :eek:
 
Just get a 7600 in .35 Whelan. With full pressure factory loads, it will hurt a grizzly bear just as bad as it does your shoulder. Nothing larger needed.

I would put the 7600 in the safe as an investment and hunt with the 760. In the hands of an experienced hunter, there is not much you cant kill with a .35 Rem. You won't be sniping at elk across a canyon, but if you are a good stalker and hunter, it will do for just about anything but big bears.
 
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