M305 in 45-70 stage 2 is....getting there....

[Levon12345]

This is a brilliant idea.

Reference your concern about the barrel thickness from the gas system forward, you should be able to ream out the gas block a bit to give you a bit more meat if you think it's going to be a concern. They're pretty chunky if I recall correctly.

 

[D3vin]

So does this project intend on staying a semi auto or straight pull?

 

[NewGunner7.62]

So does this project intend on staying a semi auto or straight pull?

I want it to be semi and with any luck i will find somebody to copy the contouring of a m14 barrel to a .458 barrel and if not it will be a heavy barrel with a gas system bolted and or welded on some how.

 

[m14medic.ca]

I want it to be semi and with any luck i will find somebody to copy the contouring of a m14 barrel to a .458 barrel and if not it will be a heavy barrel with a gas system bolted and or welded on some how.

It would be pretty tough to copy a ‘14 barrel profile with a .458 bore..... you would wind up with a barrel wall thickness of .065”-ish in front of the gas cylinder....

I had a Chinese barrel bored to .338 and the fella who did the work told me .358 was a no-go as there wasn’t enough meat in the bbl to accommodade to wider projectile....

You’ll be needing a custom gas cylinder, IMHO. Do-able, but expensive if you can’t do the machining yourself.

John

 

[NewGunner7.62]

It would be pretty tough to copy a ‘14 barrel profile with a .458 bore..... you would wind up with a barrel wall thickness of .065”-ish in front of the gas cylinder....

I had a Chinese barrel bored to .338 and the fella who did the work told me .358 was a no-go as there wasn’t enough meat in the bbl to accommodade to wider projectile....

You’ll be needing a custom gas cylinder, IMHO. Do-able, but expensive if you can’t do the machining yourself.

John

#### our calculations were off then, we got .109 for wall thickness which is still lower then the recommended .120 but .065 is unknown territory in 45-70 in 308 we got that but it burst with a hot load(bolt gun).

 

[Claven2]

It would be pretty tough to copy a ‘14 barrel profile with a .458 bore..... you would wind up with a barrel wall thickness of .065”-ish in front of the gas cylinder....

I had a Chinese barrel bored to .338 and the fella who did the work told me .358 was a no-go as there wasn’t enough meat in the bbl to accommodade to wider projectile....

You’ll be needing a custom gas cylinder, IMHO. Do-able, but expensive if you can’t do the machining yourself.

John

Norinco gas cylinders are just plain carbon steel (GI and LRB are blackened stainless). In theory you could cut a norinco unit and weld on new, larger rings. Broaching key cuts would be difficult, so pinning it in place would be an easier approach. All doable, provided enough money is applied to the project.

 

[Claven2]

As for barrel contouring, etc. any licensed master gunsmith with a real shop (read: lathe and mill) can do this work. The only question is whether you can find one who will take it on. Make sure you use a reputable guy, timing barrels on the M14 is an advanced machining job as no gunsmith around here is going to have an interchangeable parts jig like, say, Criterion would have.

If you find one, I almost guarantee they will be charging you an hourly rate, not a fixed price, and won't guarantee your project will actually work at the end - they'll just do what you ask for and you'll be on your own. Such is the way of things when breaking new ground.

 

[m14medic.ca]

#### our calculations were off then, we got .109 for wall thickness which is still lower then the recommended .120 but .065 is unknown territory in 45-70 in 308 we got that but it burst with a hot load(bolt gun).

Well you were almost there.... ya forgot that you need that thickness on both sides, so you have to divide .109 by 2....

 

[m14medic.ca]

Norinco gas cylinders are just plain carbon steel (GI and LRB are blackened stainless). In theory you could cut a norinco unit and weld on new, larger rings. Broaching key cuts would be difficult, so pinning it in place would be an easier approach. All doable, provided enough money is applied to the project.

I believe SAI gas cylinders are steel as well....

 

[Jon.]

Any updates on this? I'm figuratively dying of curiosity.

 

[cr5]

Very neat project, I would have never even thought to try to get the 45-70 to work in an M-14.
My Marlin was starting to get uncomfortable with 405gr over 1800fps, the extra weight of the M-14 and the gas system should reduce the felt recoil quite a bit, if you get it working it should end up being a very nice shooting rifle.

Good luck, I hope you get it going safely and that it turns out to be reliable.