.458 (45-70) minimum barrel thickness

[dnegative]

Hey guys, looking to rebarrel a martini enfield to 45-70;
Rifle is in really nice external shape unfortunately you can drop a 303 bullet down the muzzle.
Plan is to re barrel it, keeping all the woodwork, bands and original sights etc
Had a chat to a local barrel manufacturer here about getting a barrel made in the factory contour except in .458 for 45-70.
He was open to making a barrel but stressed that its on the thinner side of thin.

At the muzzle its .650" OD
My martini henry in 577-450 is .695"
Chamber end looks fine meat wise.

Not looking to make a target gun out of it, will be shooting black power and nothing smokeless over 28k psi through it.

Anyone been here and done that with pencil thin 45 cal barrels.

[john.k]

A Martini Enfield has a liner glued and screwed into the forend to accomodate the smaller OD 303 barrel......remove this ,and the forend is 450 size..............The Martini Henry carbine barrel is a lot smaller dia at the muzzle than a rifle........I think a 303 barrel could be rebored to 45 without problems.

[dnegative]

A Martini Enfield has a liner glued and screwed into the forend to accomodate the smaller OD 303 barrel......remove this ,and the forend is 450 size..............The Martini Henry carbine barrel is a lot smaller dia at the muzzle than a rifle........I think a 303 barrel could be rebored to 45 without problems.

You are correct;
But the odds of 120yr old glued bits of timber coming apart are slimmer than the barrel I want and I'll still need a set of bands which are literally worth more than gold in good condition.

[RustyReel]

I don't know squat about these rifles, but when I first read your post indicating a .695 muzzle, rebore is what I thought also. Rebore keeps everything on the outside as is and no need to change/refit anything. But apparently I'm wrong (again)!

[swheeler]

Sounds too thin walled to me at .650", that only leaves .096" thick wall at muzzle. You are getting into shotgun barrel weight there.

I measured my hipoint 4595 45 acp barrel, .110" at the muzzle and it looks thin with .452 groove

[John Taylor]

The 45-70 is a low pressure cartridge ( 28,000 psi). Most of the pressure is at the chamber end. At the muzzle end the pressure is much lower.

[john.k]

The Martini Henry carbine (450) is exactly the same diameter at the muzzle as a Martini Enfield barrel......yes ,its thin,but the Artillery carbine takes a sword bayonet with a 24" blade,so if its strong enough to have a short sword attached ,it would be OK for a rebore.

[swheeler]

The 45-70 is a low pressure cartridge ( 28,000 psi). Most of the pressure is at the chamber end. At the muzzle end the pressure is much lower.

That may be, plus it should be real easy to straighten when bent!

[dnegative]

Sounds too thin walled to me at .650", that only leaves .096" thick wall at muzzle. You are getting into shotgun barrel weight there.

Lothar do a pre fit Mauser 98 barrel in .458 win mag with a muzzle OD of 16.5mm (0.650") so it must be feasible enough.
https://www.lothar-walther.de/drop-i...stainless?c=19

Beyond that, not finding any first hand information.

[Cap'n Morgan]

What Taylor said.

A 2,800 psi load in a 45/70 will be reduced to 50% after 8". At the muzzle, the pressure will be 10% or less.

[john.k]

Some might think the thin muzzle easily bent.....however I have a carbine barrel (.650 muzzle),thats been squashed ,and trying to make it round again might sound quite easy...its not,the 1878 made barrel is some kind of tough steel,and has to be overbent considerably ,as it springs back.

[GregLaROCHE]

Why not rebarrel it in it’s original caliber ?

[dtknowles]

If it is true that the barrel you have already has a liner installed drilling it out could leave you with a mess.

Tim

[swheeler]

Lothar do a pre fit Mauser 98 barrel in .458 win mag with a muzzle OD of 16.5mm (0.650") so it must be feasible enough.
https://www.lothar-walther.de/drop-i...stainless?c=19

Beyond that, not finding any first hand information.

Contact John Taylor on here, I'm sure he'll be glad to re-barrel or re-line, probably has the liner laying on the bench.

[john.k]

Slight correction here.....its the wooden forend that has the liner ,not the barrel.......A Martini Enfield has been converted to 303 from 450,and a lighter profile barrel fitted .....the space in the forend filled by a wooden liner glued and screwed in.....The work done between 1895 and 1902.......1900 was the big year for conversions due to the South African War.

[John Taylor]

When the old Martinis were converted to 303 for the home guard the ammo was loaded with black powder or cordite, a little lower pressure than the service round. Firing modern 303 ammo may get some pierced primers from the large firing pin. A 45-70 will not have these problems.

[beshears]

Shilen 458 #5 contour is .700 at the muzzle.

[dnegative]

I'll send it off in the new year and see how things go.

[john.k]

Here a did ja know?.....the blackpowder ammo for the 303 actually had a higher chamber pressure than the cordite round that replaced it.......I would also add the conversion of the Martini Henrys to 303 was for service use,the rifles used the same issue ammo as for the Lee Enfields of the day......The conversions were mainly to arm colonial troops with the 303 at a cheaper rate than buying new rifles ...the army was run as cheaply as possible ,the bulk of the defence budget (90%) went to the arms race in navy ships and ever improving guns and consequent improvement in armour. Warships were obsolete in five years.

[GregLaROCHE]

Just to state my opinion again. It’s a shame not to keep a classic arm as close to original as possible. Even if it went through conversations, why not ré-barrel it in the original or one of the conversation model calibers?