M1 garand magnum conversion.

[matthias]

Has anyone seen, done ,or participated in converting an m1garand to a magnum cartridge?
Mccann industries made a 458 wm garand 5 shot. I am looking for any information, plans, or parts used in the conversions.

It seems like a complex conversion with quite a bit of fabrication. I would love to learn more , maybe enough to attempt my own at some point.

 

[Nick Caprinolo]

The Garand does not respond well to high pressure.

 

[Bill K]

That old Warhorse is not meant to be converted like that. Don't believe it would take the higher pressure and all.

 

[jackieschmidt]

Years ago, one of the national magazines did a conversion to 35 Whelen. They did make it all work.

As I remember, getting the gas operation functioning was a problem.

 

[matthias]

Just to have fun with all this 30 06 has a max pressure of 60 000 psi so does 458 wm.

What about the m1 garand loads at lower pressure? Yep make sure you don't use the wrong ammunition. I figure it would be a similar issue with the 458. Now I have not done the math but it has been done and it worked.

All that being said, I am more interested in how they did it. What exactly they did and why. Super interesting project. And way out in left field.

 

[mac86951]

Just to have fun with all this 30 06 has a max pressure of 60 000 psi so does 458 wm.

What about the m1 garand loads at lower pressure? Yep make sure you don't use the wrong ammunition. I figure it would be a similar issue with the 458. Now I have not done the math but it has been done and it worked.

All that being said, I am more interested in how they did it. What exactly they did and why. Super interesting project. And way out in left field.

It's all about pressure in the barrel, burn rate of the powder, gas port size, and mass/force of extraction. Well, and op rod strength.

 

[Minshooter]

35 Whelen is just 30-06 necked up to .35 caliber, so a that Garand conversion is very possible.
Same for necking down to .270.
So many reasons to not consider the .458 idea, they can easily be summed up with: No.
But, people have made a 50 BMG barrel for a Contender, so...

 

[Tommie]

Just to have fun with all this 30 06 has a max pressure of 60 000 psi so does 458 wm.

The current 30-06 or the one designed on 1906?

 

[Adam in WI]

Just to have fun with all this 30 06 has a max pressure of 60 000 psi so does 458 wm.

Just to be sure, run some numbers for bolt thrust between the two. I'm sure the WM is higher enough to warrant a look. Also, what happens to the Garand gas system when subjected to the increased gas volume/pressure from the increased charges and faster powders?

 

[Nick Caprinolo]

Handloading for the M1 Garand - Shooting Times

These handloading tips will help you avoid excess wear and tear and potential damage to your M1 Garand.

www.shootingtimes.com

 

[matthias]

Modern 3006 is max at 60000

50bmg contender? I can't find that at all. That would be something too see for sure. Maybe not shoot.....

Bolt thrust will be higher for sure on the 458wm.

Maybe its survivor bias but they seem to still work after 20 years, although I still want to see one and take it apart and really see what they did.

 

[three percent]

I've got two garands but I'd never dream doing anything to them.to valuable and perfect the way the are.i run mine pretty easy with starting powder charges of imr4064 and h4895 .I'm amazed everytime I shoot them how accurate they are.im sure they can handle more pressure than I run them but op rods are expensive and just don't care to hot rod them. 47gr of imr4064 and 150gr cheap speers seem to be magic in mine but I'm just plinking.

One has a lmr barrel made in Birmingham Alabama and those where highly sought after for national match builds from what I've been told.pretty cool
To me it's like seeing a 03 or 1917 converted to hunting rifles.it makes me cringe
You'll regret it one day just like my father building on Nazi marked 98k's.just my opinion

 

[three percent]

The CMP's are almost completely dry of garands.once the very last bottom of the barrel rifles they can salvage are sold which is pretty much right now they'll be starting at $1800+ on the street I'm sure for the non WW2 war time rifles.ww2 will be much higher .just something to think about

 

[akajun]

If you want a semi auto 458
Didn’t browning make one in 458?
I know they did in 7mag, 300wm, 338wm
Convert one of those

 

[Ggmac]

Okay , do it . Let me know how much time and money it takes . That is IF it works . Which I bet it doesn’t. The gauntlet has been thrown down .
Personally, my time is better suited to chase possibles not dangerous, expensive and ill perceived ideas.
Gas pressure, volume , pressure/ time , op rod weight , bolt thrust , bolt face - extractor , barrel tennon od , ...
The garand ammo isnt 60,000.

 

[matthias]

The BAR has been converted but I am not a huge fan of the magazines that ride the floor plate in a semi auto rifle. Why not make an easily detachable mag that falls away?

Okay , do it . Let me know how much time and money it takes . That is IF it works . Which I bet it doesn’t. The gauntlet has been thrown down .
Personally, my time is better suited to chase possibles not dangerous, expensive and ill perceived ideas.
Gas pressure, volume , pressure/ time , op rod weight , bolt thrust , bolt face - extractor , barrel tennon od , ...
The garand ammo isnt 60,000.

OOOD: McCann Industries .458 Win Mag Garand

Back in early 2000’s, McCann Industries (known for their M1 Garand Gas Trap Adjuster) manufactured an M1 Garand in .458 Winchester Magnum.Not made anymore after the passing of McCann’s primary gunsmith, the rifles are a fine example of ingenuity and practicality applied to big-game hunting.At...

www.thefirearmblog.com

They do seem to work. We all get way to comfortable and dont wonder too far from what works. If you read back to the beginning, I am looking for information and first hand experience. Is it a good idea? Is it a cheap idea? Is it a mainstream "this is what works" idea? Are their other rifles that would be better? Is it too much of a fabrication project ?

These are some of the questions that are involved.

 

[Pawnee Bill]

Sacrilege!

 

[Ggmac]

The BAR has been converted but I am not a huge fan of the magazines that ride the floor plate in a semi auto rifle. Why not make an easily detachable mag that falls away?

OOOD: McCann Industries .458 Win Mag Garand

Back in early 2000’s, McCann Industries (known for their M1 Garand Gas Trap Adjuster) manufactured an M1 Garand in .458 Winchester Magnum.Not made anymore after the passing of McCann’s primary gunsmith, the rifles are a fine example of ingenuity and practicality applied to big-game hunting.At...

www.thefirearmblog.com

They do seem to work. We all get way to comfortable and dont wonder too far from what works. If you read back to the beginning, I am looking for information and first hand experience. Is it a good idea? Is it a cheap idea? Is it a mainstream "this is what works" idea? Are their other rifles that would be better? Is it too much of a fabrication project ?

These are some of the questions that are involved.

You , in my opinion, have better challenges ahead . Something profitable or fun . I looked at the very early designs of semi auto military rifles. Britain had an interesting design based on the lee enfield, 1 m3 . It had an external op rod ( lack of a better word ) a guide for it a gas tap and a cam groove that opend the bolt and closed it . Very easy ,simple and robust . It had the strength of a bolt action and versatile enough for semi auto .
Personally I’d use a mauser or other bolt , not a lee enfield. Though I did convert a few to 45/70
If you were to download the 458 to garand op port pressure, you will no longer have a 458 win mag . You will have a 458 that may / may not shoot in a functional garand

 

[Ggmac]

I found a photo .

 

[three percent]

H&R was supposed to be coming out with a Garand.new current production.one of those might be fun to tear apart and hot rod.i agree 458 winny in a garand would be awesome but don't think I would try it on a surplus rifle.
Maybe if you bought a few barrels and played around gas port hole size and fabricated a more robust op rod.idk just thinking
There's probably some h&r surplus receivers floating around you could build one up from scratch.