Martini Receivers and such

[knight0334]

Anyone have any experience building a custom Martini or Martini Henry with a more modern cartridge/barrel?

What limitations are pressure are there using an original type receiver?

I'm not looking to build a 70K PSI barrel burner, just a custom smokeless cartridge on a custom rifle. .....something like a .320 Preston Express(my lastname) with a 26-30" barrel, in the 2000-3000fps range depending on bullet weight.

I have access to a machine shop, and a highly skilled machinist for what I personally cannot do. ...so that isn't a problem. And I'll be ordering a custom barrel, which will contain more of the pressures than what the receiver and breech block will hold via bolt thrust.

I do know the oldest of the old of the Martini platform was built around black powder and cordite, but I'm hoping to score a later production that might be more friendly to smokeless.

[Delkal]

The Martini Henry rifles were later converted to the 303 British so pressure should not be a problem if you use a British made receiver in good condition. Indian made receivers might be OK but make sure you don't use a Khyber pass copy. Cordite is smokeless powder and I believe the pressure was the same as modern loads.

Tell us more about your wildcat idea.

[knight0334]

The Martini Henry rifles were later converted to the 303 British so pressure should not be a problem if you use a British made receiver in good condition. Indian made receivers might be OK but make sure you don't use a Khyber pass copy. Cordite is smokeless powder and I believe the pressure was the same as modern loads.

Tell us more about your wildcat idea.

Thank you!


About the wildcat - I haven't finalized anything on it. I just want something .321"(.32WinSpl bullet dia) or larger, but equal to or less than .377"(.375Win or .38-55 bullet diameter). A straight or tapered wall, more likely straight walled because we can make our own cases(lathe turned) and reloading dies easier. Who knows, maybe even a new custom bullet caliber requiring having to make my own bullet mold, like .329, .333, .344, etc.. Bullet profiles will likely be spire tip ogives, with likely a couple bullet lengths for differing purposes(long range target, woodchuck vaporizing, tack driving, etc - although I'm really not into killing any critters anymore). Probably jacket them myself as well, with at minimum of cast bullets being gas-checked.

Case length will probably be on the longer end of the spectrum, 2.75" to 3.25"+ - depending on loading limitations of the breech.

I'm already fully expecting to have a custom barrel made. Once I narrow down the bullet diameter, range of bullet lengths, and range of velocities I can then figure out the needed twist rate to give to the manufacturer. I'm definitely going with an octagon barrel, I'll possibly will then flute the flats once I receive it.

It will likely have iron sights only, unless my vision gets worse as I get older. lol

[Delkal]

Designing a new wildcat would be fun but for me anything requiring a custom lathe turned case would be a show stopper. Just find a commercial rimmed case with the correct rim / body diameter then neck it up / down, shorten it and play with the shoulder angle. With a martini henry I would make it even easier and start with a 303 British case since the extractor dimension have already been worked out. Older cartridges usually have a shallow shoulder, tapered body and a long neck which is not that efficient so consider something like the Ackley improved type. Look up pics of a 30-30 vs. a 30-30 AI to see what I mean.

I think a custom caliber would also be out because even if you could find someone to make it the cost would be outrageous. Custom reamers and rifling is not going to be cheap (especially for just one barrel).

If you are planning to use cast bullets forget about 3000 fps. For rifles the most accurate load is usually around 1700-1900 fps and while people claim they can load to 2500 fps that is the exception and usually not repeatable by others. If you are designing your own case you would want to make it shorter to reduce the case capacity since the biggest problem with cast rifle loads is the excess capacity with a reduced loads. Look at this site for everything you need to know about cast "boolits".

https://castboolits.gunloads.com/

You might not even need a custom mold since Ideal / Lyman have been making them for over 100 years and there are many bullet designs that are haven't been made in the last 50 years. With patience you might be able to find one and shooting it would be far from being common. Here is a good page on the mold types and numbers.

http://ps-2.kev009.com/ohland/Cast_B...criptions.html

[knight0334]

I'm not apposed to punching jackets from copper sheets and swaging lead into them, or even turning a smaller brass case(like a .32H&R mag case with rim turned off) into a jacket to swage some lead into it..

Everything, other than the receiver and working parts(breech, fire control, etc), will be custom.

[Delkal]

Nice! You are definitely in the very deep end of the pool and I would love to hear how this turns out. When the preliminaries are worked out could you start a separate thread and keep everyone up to date on how it is going?

[MD66948]

I saw one converted to a shotgun. I don't remember the gauge.

[knight0334]

I saw one converted to a shotgun. I don't remember the gauge.

Same, .310, .410, 9mm bores and 12, 16, 20, 24, 28, and 32 gauge shotguns. Shotguns don't have the pressures or bolt thrust that rifle cartridges have.

I'll probably be in the 45K to 55K PSI range on a breech face area of about the same as a .303Brit or less.

I'm going to try to find a later production rifle/receiver that was built when the .303Brit cordite loads were in fashion, rather than an earlier production that was converted.

My pattern of build will likely be a Schuetzen style. I intend it to be my magnum opus to pass down. Fancy wood, high cheek riser, silver wire inlay, possibly engraving on the metal(I have to learn that yet, may send off to have that done).

It won't be far removed from what you see below.

[Delkal]

Same, .310, .410, 9mm bores and 12, 16, 20, 24, 28, and 32 gauge shotguns. Shotguns don't have the pressures or bolt thrust that rifle cartridges have.

I'll probably be in the 45K to 55K PSI range on a breech face area of about the same as a .303Brit or less.

I'm going to try to find a later production rifle/receiver that was built when the .303Brit cordite loads were in fashion, rather than an earlier production that was converted.

My pattern of build will likely be a Schuetzen style. I intend it to be my magnum opus to pass down. Fancy wood, high cheek riser, silver wire inlay, possibly engraving on the metal(I have to learn that yet, may send off to have that done).

It won't be far removed from what you see below.

That is a sweet looking rifle! As far as bolt face pressures go cases with less body and shoulder taper can give lower bolt thrust at the same internal pressure. A lot of work has been done, and countless wildcats have been developed, for the contender pistols since the action has limited strength. If you are worried about the actions strength you might want to incorporate some of this in your cartridge design.

[knight0334]

That is a sweet looking rifle! As far as bolt face pressures go cases with less body and shoulder taper can give lower bolt thrust at the same internal pressure. A lot of work has been done, and countless wildcats have been developed, for the contender pistols since the action has limited strength. If you are worried about the actions strength you might want to incorporate some of this in your cartridge design.

Since I started this thread, I've been thinking about starting off with either a .38-55, .303, or 9.3x74mmR case as a basis. ...but making a longer version of it if .38-55 or .303. Then maybe doing a taper or neck down to whichever bullet caliber. If neck down, it'd probably be on the 30 to 40 degrees at Ackley did. Case length may be determined by what can be fed into the gun given the Martini's "ski slope" breech. I'm really digging the 9.3x74mmR case, maybe blowing it straight, then necking down to my caliber.

If I do get to the point that I have to have a certain length cartridge that a Martini cannot feed, I may just switch to a falling block platform. ...like a Ruger #1, Browning/Win Highwall, etc, etc.

I do have a really big itch for a custom bullet caliber. ...or least a caliber that is rarely used or hasn't been used for a long time. Making my own bullets and bullet mold isn't an issue. I'll have plenty of barrel length to get something up to speed and I have experience with making duplex and triplex smokeless loads to take advantage of longer barrels and fill high capacity cases(my .45-120 "Express" loads in my H&R Buff. Classic -upto 3000fps 300gr JHP groundhog exploders).

Heck, I'm not apposed to keep velocities down and using really long super high BC bullets either.