Martini Henry barrel thread
A friend of mine has a Henry Martini rifle and wants to rebarrel it. He need to cut threads on the new barrel to fit the action. From what he told me (I havent seen the action) it has a 14V thread. Does anyone know this thread? Is this a British thread (like the 55 degree Whitworth)? Where can I find information on it. Im not familiar with it ..thanks
perhaps measuring the old barrel thread would help? perhaps get your friend to take the barrel to a licensed gunsmith to measure it to be sure.
Should be a whitworth thread given the age of the rifle, and the O.D is 1.00 inch, thread length is 0.700 inch long, 14 TPI V thread which most likely is 55 degrees, assuming he has the full size martini and not the cadet rifle.
Personally I would avoid rechambering to its original caliber as the 577/450 cartridge is a bit tough to come by.
Hickstick, you can save me a few minutes head scratching---what's the shank and thread on the Cadet? I have two coming up later to rebarrel. Thanks, Mike
The Cadet thread is .655" long, major dia. is .750", pitch is 14 TPI(V type, probably 55°)
First you need to be sure its a Martini Henry and not a Greener Martini. They are different.
A real Martini Henry/Martini Enfield will be .700 x 1.00 14 V-TPI. I have never been able to clearly tell if the thread on these rifles are Whitworth or not. I do not feel from the ones I have done that they are Whitworth---the pattern antidates standardization. 60 degree works just fine. Although it predates standardization, the MH-ME tenons and threads are very uniform and cutting to the dimension will fit most actions.
Warning however they are a great number of counterfeit Martini's and they should be avoided. There have been failure reported, mainly in the knuckle seat. If you have a question about the authenticity of one of these rifles, visit the Martini forum on www.Gunboards.com or the Martini forum at www.martiniforum.org.
The Greener action has a larger barrel tenon. The one I have here is .710 x 1.090 x 14 V-tpi This tenon is always very uniform except in form. Early ones are clearly 55 degree Whitworth, later appear to be 60 degree.
The Cadet actions are supposed to be .690 x .750 14 V-tpi. Don't believe it. I have found a good deal of variance in the length of receiver ring and some diameter differences. If the action is a Francotte the barrel trenon wil be even smaller. I suspect the Francotte Tenon might be metric, but is close to a inch pattern and I have always been able to fit using inch dimensions.
In dealing with Martini's I find it a lot less "stressful" to measure the receiver ring and fit the barrel to that.
hot damn hes right, a v thread is 60 degrees, sorry for the misinformation
I don't believe the Martin Henry/Martini Enfield thread is standard 55 degree whitworth or 60 degree v. I believe it is it's own standard. 60 degree does work. This applies to only the MH/ME action, not any of the others.
Originally Posted by hickstick_10
577/450 is not tough to come by. Ammo, dies, brass and proper .468 diameter bullet moulds are all readily available. Okay maybe tough is correct, they are not cheap.
anyone ever rebarel one of these to a 45 70, 45-90 or a similar cartridge?
Yes, I have rebarreled a few of these to 45/70, but prefer cartridges like 450 Musket and 375 2 1/2 Flanged NE.
They can handle most any of the rimmed cartridges that will feed. I have 577 2 3/4 NE on a Greener Martini action. That same Cartridge will not feed in the Martini Henry action.
The way to check this is make a barrel stub and dummy chamber and see if the cartridge will feed.
When this barrel from a 45 70 or 45-90 thread had no standards not found in the new Machinery Hand Book. Even in my older books do not go back to show threads
The shop back befor 1900 shops made own taps in the shop.
Gun threads are not often seen in Machinery's. True standardization in the English gun trade didn't realy take place until about 1904, especially in chambers.
Im pretty sure the Cadet rifle I finally got a look at is a Whitworth thread. ( Its Australian marked) It was cleary radiused at the root. A 60 degree thread may very well work although it looks to me that it would be a crush fit. I couldnt get it in my mind how they radiused the peak during production. This link shows the chaser they used to do it. Simple after you see it. I dont understand why they kept this labor intensive threading system until the 1970s. I guess they had the tooling and the skilled labor and didnt change until they had to.
Never had a problem with 60 degree and crush fit of the threads in these guns.
Originally Posted by TNMIKE
It is probably a 55 degree thread. It is just as easy to grind a 55 as it is a 60. If you use the correct thread and do not crush fit the thread then you are not as apt to have galled threads and a ruined action if you or someone else decides to rebarrel it again.
If I discovered a ruined thread on the barrel or action, I would badmouth the a__hole responsible to any and all that might listen.