Martini 12 take-down action

[jholp]

Looking at my newly acquired Martini Model #12 take-down action - I am thinking about the relative merits of the take-down feature.

One could have the extractor altered to take the 357 family rim size. That way the 357 maximum, 357 magnum, 38 special, 256 magnum, 22 jet could serve as the parent case to build, as an example, 357 maximum for white-tail deer hunting and a 22 super jet for varmints.

Here is my concern relative to just how practical this would be.

I mount the scope on Martinis by using the weaver strap scope base mounted on the barrel. The Contender type strap works fine with a little step machined so the strap extends over the receiver - neat. So, one would have to purchase a strap mount for each barrel, then scope rings for each scope and last a scope for each barrel.

Even then when one removed the barrel retaining cross screw, then threaded the barrel out with hand strength, then thread in another barrel and replace the cross screw I would not be comfortable with shooting the weapon without a visit to the range to check zero. I am betting the zero would change between barrel switching. Has anyone done this and how did it work out?

I suppose one could use the weapon year around in varmint cartridge mode and swith to the hunting barrel during hunting season and accept the trip to the range each time to check zero.

Long ago the late John Appleton suggested one fit three barrels to such a take-down action in; 22 WMR, 5mm Magnum, and 17 HMR. Now you are set to have these cartridges, that share the same rim diameter, in one weapon.

I always get a kick out of the spy movies where the designated shooter takes a receiver out of a bag, fits the barrel, fits the silencer, fits the scope and then makes a 1000 meter head shot on a running human -- I don't think so.


John

[kenbro]

John,
Is not the 5mm mag a different rim dia? I think I've recently seen that info in another post.
Ken.

[ray h]

John at one time I had a bunch of barrels fitted to a Panda. Switching the barrels was kinda a pain. I needed a Davidson barrel vise to break mine loose though. If the front of the rec'r and the barrel shoulder are square then just a snap of the wrist will tighten them but I always needed the vise to break it loose. I had a vise mounted to a 6" drop hitch for my truck for the field/range. I would think if you can unscrew a barrel by hand then I'd be afraid of the accuracy repeatability. I'd look at quick release rings for a couple scopes and then get bases for each barrel. Changing calibers you'll probably need to rezero. Maybe using a bore sighter and recording the info for each combo would put you close so only a few shots would be needed to finalize the zero. How did they do a #12 to make it a sw barrel, like the Mks?

[jholp]

Ken,

It is my understanding they all use the same case and rim diameter, except for the part of the case that holds the bullet. There will be those that will come along and confirm or deny.

John

[Chuck Miller]

Well if your looking for opinions I think the switch barrel concept only has merit when replacing shot out barrels, ala Salvage. I also like the Weaver rail as it allows the scope to be mounted further back, in addition to the Contender rail that uses the Leupold STD ring setup for the same reason. Problem is that with these setups on a switchbarrel it requires not only removing the scope but also the base as you can't rotate the barrel with it mounted hanging over the front of the action. Throw in the fact that as a rule you will be switching to another chambering with different balistics, installing base, installing scope, you will be sighting in again. I tried it with a 22lr and 17m2, base mounted forward of the action barrel juncture so I could remove them in one piece. POI still moved, not sure if that was just the lack of a tight tolerance in the system or what. I sent the action up to Vic Samuel a few months ago with a couple others for his blueprinting and bushing work, had him fill all the extra holes, replace extractor with a new Hornet model and getting ready to make it a 17AH. He then surface ground it, it's the one on the right, it was originaly a 12/15 with the take down feature. Sign me....Not a fan of take downs

[jholp]

The barrel is threaded in just like the non-take-down models. Not a slip fit barrel.

There is a hole drilled through the action from one side to the other. That hole interrups the threaded hole that holds the barrel in the action. Down toward the bottom the cross hole actually breaks through the barrel threads in the action.

This is why you first screw in the barrel then the screw from side to side. Obviously there needs to be a fitted groove in the bottom of the barrel that takes the cross screw. I assume this groove is precisely matched to when the barrel is threaded home and the fit is tight when the cross screw is installed.

I believe this switch barrel technique is done on other actions so the solution should be well proven.

You are correct, if these parts do not fit precisely then accuracy would suffer.

I just assume the barrel could be removed with the strength of one's hands. If it needs a barrel vise then it is even less practical.

John

[ray h]

Chuck has the lower left action been knotched like the Mks, Vic did this?

[Chuck Miller]

No, the lower action had been modifyed by the previous owner for ease of loading. Vic would do it if you asked him, personally I wouldn't if had been mine at the time. The 2 actions with the straight levers are setup for centefire cases based off the 218bee case.

[jholp]

Nice to hear from you Chuck. I knew you would be able to contribute to my effort.

I had totally forgot about the strap scope base that hangs over the receiver not allowing barrel removal without removing the strap.

I am beginning to think the switch barrel feature is not such a hot idea. I will probably leave the cross screw hole in place and install the cross screw but fit the barrel like it is NOT a switch barrel weapon. Should one ever sell the action, not that I would, the switch feature is a big deal to some people but they probably have not thought through all that is involved.

I talked to Vic Samuel a day or two ago, he is getting over being ill but wants to do all of my conversion work to centerfire, extractor, etc., etc.

So you are building a 17 AH, neat idea, I think about that too from time to time.


John