Rechamber/Barrel Martini Henry

flipp121

flipp121

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Hey there: here's the scenario I have asked around PMing before but never got a response. I have a Martini henry Mk 2 currently in 577-450, but I would like to rebarrel/chamber it to 45-70 for obvious reasons. From what I have gathered i need:

1) A new barrel with the proper british threads
2) A new extractor modified for .303 (could have a machine shop make it?)

So my question is, how do I get this project started?

(please no comments about how its a collectible and I shouldnt touch it, I could always revert it back to its original condition)

Thanks
Mark
 
You want a .303 or a .45-70? It'd be a new, custom made, barrel for either and severely altering the bolt/breech face to accomodate the extractor.
"...could always revert it back to its original condition..." Not after changing the breech face.
 
1. Find a cheap Bubba'd martini action in .303 - one with no historical value. This tends to make them cheaper.

2. Find a barrel blank with no threads or chambering at all.

3. Get ahold of a decent gunsmith who does rebarrelling. Most will be able to cut the threads, do the chambering (you may have to pay for a reamer but 45-70 is common), and the extractor will only need to be opened up a little to work with the 45-70.

Biggest problem with the one that my father built this way doing most of it himself, was trying to get a tang site mounted on a rifle without a tang.
 
I agree. If you want to bubba a single shot, pick up one of TradeEx's Rolling Blocks. At least then it will be some semblance of correct.

You could always buy a chamber insert for the Martini, or just shoot 577-450 with BP loads the way God intended it.
 
Haven't priced out this sort of thing but I'll bet that you're looking at $600-$1000 depending on where you can find a barrel.

You would be way better off doing as BigUglyMan says and shoot it as it is if you already have a gun in good shape.

Everything you need can be found to load 577-450 at places like Buffalo Arms, Dixie Gun Works, or I've heard that Elwood Epps carries some parts for golden oldies.
 
Martini barrel threads

Just to get the old wheels turning, the barrel threads on a Martini are the same as those on a Lee Enfield.

In fact, the Lee Enfield New Zealand Carbine uses a Martini Artillery Carbine barrel. The difference is in the relief for the extractors.

So it is quite feasible to take a Lee Enfield barrel, set it back one thread, breech it up, recut the chamber and extractor slots. Seen it done. I used to have a Martini fitted with an SMLE barrel. Sweet gun, light and nicely balanced.
 
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Thanks for the replies, I have fired over 100 of my 577-450 hand loads. And yes you can return it to the original shape as it doesnt have a bolt, and a custom extractor can be made. Thanks for the info on the threads englishman. I have emailed pac-nor and they apparently make barrels for the lee enfield so I dont see why they couldnt thread & make a 45-70 barrel for my application. I am awaiting their reply. The reason I want to use my military one is that it is antique classed. None of the rolling blocks on tradeex seem to be in good shape, they all have broken extractors/etc...

englishman/vagrant:
I guess the trouble would be finding a gunsmith who could cut the extractor slots in the barrels and make an extractor. Do you figure this bill will start to run
in the $1000s? And is there someone in canada who could do it?

Edit:
I wonder if it would be cheaper in the long run to sell the martini and build up a rolling block 45-70 or something similar to 12.7mm? I know there was one on the EE in 45-70 recently but he said there was a little 'slop' in the action and that had me worried as i know little about rolling blocks...
 
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Cutting the extractor slots and fitting the barrel should not be too big a deal. The slots can be filed by hand. There should be places that have parts for martini's on the net too. Heres a place to start with...

ht tp://www.martinihenry.com/index.html (Goggle is your friend :) )


The rolling blocks at Tradeex are a mixed bag and you get what you pay for. I've got 5 in total from them now and paid less that $400 for each of them. 2 were shooters right out of the box and in great shape. 2 with blocked barrels should make good guns with new tubes and a bit of work. Both need the extractors built up and one needs a firing pin. The last was a 20ga for $99 and I'm still deciding if there will be any hope for it as a rebuild as its a bit loose. It could still probably take light blackpowder loads and the barrel is probably the best part on it.

Let us know if you go ahead with the conversion and what you find for gunsmiths and parts. Its always good to hear whats out there.
 
flipp121 said:
...I guess the trouble would be finding a gunsmith who could cut the extractor slots in the barrels and make an extractor...
Click to expand...

I had Ellwood Epps mount and cut the extractor slots in an SMLE NºIII barrel I got to replace the shot-out barrel in my Martini-Enfield .303. It was around $100, I think.

Your biggest problem may well be acquiring a suitable extractor. If you could find one for a .303 Martini it could probably be opened up for 45-70. Having one custom made would likely be very expensive.

You might also want check out this forum: britishmilitariaforums.yuku.com/forum/view/id/1.
There are folks there with tons of experience on these rifles.

I believe there is also a fellow named Jenkinson Sykes in Grand Forks, B.C. (?) who specialzes in M-H and other British military rifles.

:) Stuart
 
Sunray, I don't have a martini in front of me just at the moment but I am quite sure that the extractor can be modified for any rimmed shell that will fit in the action and not have to touch the block or any other part of the gun other than the barrel. The extractor sits infront of and below the breech block.

Some pics: http://www.martinihenry.com/apart.htm

http://www.martinihenry.com/actiondiagram.htm

The last 2 pics here show it about the best even thou the rest of the action is a bit different than a 577-450
http://members.cox.net/benchrest/EquipPicsMartini.html
 
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The only possible modification to the breechface would be bushing the firing pin hole, if a smaller diameter firing pin tip were needed. The MHs converted to MEs had a dovetailed piece installed across the breechface, and a new firing pin hole drilled. If a MH were to be used for .45-70, a smaller firing pin tip might not be needed.
I have never made the extractor cuts in a Martini barrel, but I have done them in Ruger No. 1s and in Mannilcher Schoenauer barrels, by hand, and it is certainly do-able.
I am sure a MH extractor could be built up and modified for .45-70.
 
FWIW, here's a pic of the breech of my .303 Martini, with the SMLE barrel installed by Ellwood Epps. (The original extractor cut is clearly visible in the bottom pic). The breech block was not altered.

Martini breech.JPG


:) Stuart
 
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Lots of good info, still awating word from pac-nor. It seems the hard part will be finding a spare extractor to modify for 45-70. I assume the extractor is not a load bearing piece so the part built up just needs to be strong enough to extract the shell right? So in theory a guy could weld up a 577-450 extractor and cut it with a dremel to fit a 45-70 case? I suppose this would also change the headspace...

Vagrant:
I dont see why anyone would have to modify the falling block breechface as it is a seperate piece from the extractor.

Tiriaq:
The reformed CBC cases I am shooting are large pistol primers and the firing pin doesnt seem too large. So im not sure why I would need to make the firing pin smaller.

I'll take apart my martini and take some pictures, maybe it will shed some light.
Edit:
Here we go:

MartiniBreechs.jpg

Martinibreech2.jpg


And one just for fun:
Martini1.jpg
 
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If you are not loading to higher pressure, the firing pin should work as well in .45-70 as in .450. Alterations to the extractor will have to be done very well. There can be a lot of stress applied.
Forget the Dremel. Do the final finishing of the extractor with the chambering reamer, with the extractor in place in its cuts in the barrel. The rim cutting portion of the reamer will cut the rim recess in the extractor. Then the extractor and its rim cut will fit perfectly. The .45-70 is a lot smaller at the rim, so the extractor will have to be built up quite a bit. The extractor has nothing to do with headspace.
 
...I assume the extractor is not a load bearing piece so the part built up just needs to be strong enough to extract the shell right?...
Click to expand...

Yes, but there could still be a fair bit of stress if you had a sticky case. However, most of the strain is taken by the pivot and arms so a good weld should be OK. Headspace shouldn't be a problem as the only difference will be the opening in the extractor. [edit: I see tiriaq has just addressed this - much better than I - while I was typing!]

I dont see why anyone would have to modify the falling block breechface as it is a seperate piece from the extractor.
Click to expand...

Apparently there is a risk of a ruptured or set-back primer when used with modern high-pressure cartridges, although the 45-70 doesn't really fall into this class, unless perhaps "Ruger Nº1" loads are used. I have a Martini Cadet I'm thinking of getting Ron Smith to rebore and rechamber to .357 Mag. and I'll probably have to bush the firing pin. The man who "wrote the book" on this is Frank de Haas. A Google search for "de Haas bushing method" should turn up some info.

Here's a post I just found at assra.com/cgi-bin/yabb/YaBB.pl?num=1135876375. The author "David" is a gunsmith at Brownell's, I think. He uses an alternate method, it seems, although I'm a bit surprised at his comment about compression of the bushing as these are usually made from set screws, which are very hard, as apparently is the breech block itself.

...I've used the threaded firing pin bushing a lot over the years, but I've gotten away from it recently. I had one compress over time, on a Martini 12/15 that had been converted to centerfire, using the .357 Max. case and breech seated bullets. Primers started backing out and locking up the action, this with a load that had performed well for years. I cut a transverse dovetail into the breech face and fitted a spring stock "bushing" similar to the British .303 Martini conversion. No more threaded bushing compression! I've done this with all my centerfire small Martini rifles that get used much, and have not had any problem with primer setback. BTW, I use a pin tip diameter of about .062", with a protrusion of about .045" to .050", using a slightly flattened hemisphere shape for the tip.

David
Montezuma, IA
Click to expand...

Darn...now I'll have to take my Martini apart and see if the breech-block face has been altered but I don't think so. The block on mine might have been made for the early smokeless version of the .303 cartridge rather than adapted from a previous model. The pin certainly has quite a broad tip.

:) Stuart
 
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If there is concern about a threaded bushing setting back, this could be avoided by making it with a shoulder - the breech face having a shallow counterbore larger in diameter than the threaded hole into which the bushing screws. I believe this system was used when High Wall Winchesters were fitted with safety firing pins, for use with high intensity cartridges.
 
Ahh I know very little about gunsmithing, and will need to hire out for this work. I didnt know that the chamber reamer would cut the rim so nicely. I'd like to clarify that I would only be shooting black powder/mild smokeless loads. So I think the stock breechblock will be fine. I have heard the Martini action is very strong, that's part of the reason that I have chose it to do this conversion.
 
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flipp121 said:
...I have heard the Martini action is very strong, that's part of the reason that I have chose it to do this conversion.
Click to expand...

Somewhere on the Martini-Henry Forum a year or so ago there was a thread on a fellow who had one chambered for a seriously "thumpy" .500 smokeless cartridge. He refinished the action completely and made a new stock, so it wasn't a trivial exercise. I must check if he ever got it done. It looked pretty impressive- likely at both ends!

:) Stuart
 
Lots of good info and good pics from everyone.

The existing firing pin setup should be fine for low pressure 45-70 if its working as it is. The extractor build up would need to be pretty strong. Theres a lot of leverage putting pressure on the tips if a case sticks. A part from a 303 would need little taken off and have structural integrity. Either way will work.

They are a very srtong action but I did see one that had 2 cracks that went up from the block pin to the top of the action. I have no idea how they did it. The barrel that was on it was only hand tight and not fitted. Looked like someone had grabbed an old SMLE barrel that was lying around to make it look like a gun so it would sell.
 
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