Convert .35 Remington to .350 Rem. Mag

R

roadhunter

Inactive
A couple of years ago, I bought a Marlin 336 CS in .35 Remington as a "brush gun" for deer hunting. Ever since, when it comes time to head to the woods, I grab my trusty Rem. 788 Carbine in .243, and it has never failed to drop a deer in its tracks, so the 336 sits in the safe.
My gunsmith has been after me since the beginning to let him turn this .35 into a .350 Remington Mag. I'm not worried about recoil, nor do I have need to hunt bears, moose, or bigfoot. The idea just sounds like fun, and he'd do it at cost just so he could take it to the range himself and show it at guns shows as an example of his work.
Does anyone out there have any thoughts on the viability of this? Are there liable to be any pitfalls (other than recoil)? Will the conversion require anything more than re-chambering? Will the fact that the .350 is belted be an issue?
Lastly, would any of you suggest an alternative magnum caliber for this conversion?
 
I am not a gunsmith but even so, I can think of some things you and your gunsmith must know before you jump in.
With or without modifications:
Will the bolt face and extractor handle the larger head diameter?
Will the bolt travel and cartridge lifter handle the longer OAL?
Will the belted case diameter go down the magazine tube?
Will the bolt lockup and (reduced) chamber wall thickness handle 53,000 CUP pressures instead of 33,500?

From my reading, the answers are probably yes, maybe, no, and no.
 
35 Remington operates at 38,000 CUP, 350 Rem Mag operates at 55,000 CUP. The Marlin 336 is designed for 42,000 CUP.
35 Rem head diameter is .460", 350 Rem Mag is .532".
35 Rem COAL is 2.52", 350 Rem Mag is 2.80". The 336 ejection port will handle cartridges up to 2.6" in length.

If your gunsmith can figure out how to overcome these obstacles and make it work safely, my hat is off to him. I can't.
 
SELL him the gun at a nice price and let him do whatever he wants, but don't let him mess up your gun.

And let us know his name so none of us allow him anywhere near our guns. I don't think the .350 Rem Mag will even fit in the magazine tube, let alone in the action.

Jim
 
I cannot believe any gunsmith would suggest such a conversion. There are a few that convert 35's to the 356 win. that was around briefly in the 80's.
 
If he was serious about converting the 336 to 350 mag I can't think he is much of a gunsmith. Are you sure he did not mean .358 Winchester? I have heard of converting .35 Remington 336s to .358 Winchester. It is supposed to be a workable conversion with the .358 cases loaded with the equivalent of356 Winchester loads.
 
I'm sure I'm mistaken

Thanks for the FIRM replies, guys. I could have SWORN he said Winchester at one point, but it's been a LONG time since I talked to him about this. I am sure it is my mistake.
This guy is a gifted smith who has done his share of conversions. I happened to mention this to someone else, and he said "surely he's thinking of going to .350 Rem. Mag". That guy was NOT a gunsmith.
So, is there any consensus on converting it to .356 or .358? I am not new to guns. I have been shooting them the last 25 years, have quite a collection, and am an avid hunter. However, I am very new to the idea of converting guns, so your advice is truly appreciated.
As I mentioned, the only reason behind doing this would be for the "fun" of creating something unique, and allowing a long time gunsmith and friend of mine to have an opportunity to show off his work at gun shows.
I'm glad I didn't mention his name when posting my mistake, as I'd never want to hurt his reputation as a gifted machinist. Once we figure out what the gun will be converted to, and it's been tested and proven, I'll be happy to do that.
 
The 358 is basically the 308 necked up to .358. Unfortunately, your Marlin won't handle the pressure at 52,000. The SAMMI limits on the 356 is 52,000. None of these cartridges should be in a Marlin. Just too much pop when you pull the trigger......literally. There has been a few of the 35's turned into Ackley Improved. While the folks that have done the conversion rave about it, there is only the small part of the shoulder that changes. And that will never produce enough to rave about.
 
This conversion(35 remington to .358 or .356 winchester) is done often by certain gunsmiths. They claim it is perfectly safe. The .356 Winchester has been factory chambered in the Marlin 336 in the past. The exterior dimensions of the .358 and .356 Winchester cases are the same with the exception being the rim on the .356. With 336s converted to the .358, .356 data and overall length should be used. The advantage to rechambering to .358 are more common brass, can even use necked up .308 brass. I am posting a couple links.

http://www.gunweek.com/2003/feature0301.html

http://www.associatedcontent.com/article/1182274/rechambering_the_35_remington_marlin.html?cat=11

I do not have one of these conversions, but have seriously considered it.
 
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