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-   -   mk 2 international barrel (https://www.rimfirecentral.com/forums/showthread.php?t=996729)

loiner1965 09-16-2017 01:54 PM

mk 2 international barrel
 
what size thread is the barrel chamber please and will the .300 bsa sherwood barrel screw straight on.....many thanks

Yank 09-16-2017 03:54 PM

Making popcorn! :rolleyes:

loiner1965 09-17-2017 09:24 AM

ooops do i need to put a tin hat on here lol
not familiar with the small frame martinis only their larger brothers.
was looking over the mk 2 international and realisded how strong the action is and how well made they are.
always fancied a cadet but prefer the .300 round instead and thought if the 2 could be used together.....unlike you lot its a lot harder over in the uk to do these things so this is only in my head etc

Dave 101 09-17-2017 10:24 AM

I am in the UK also , my question would be why ? Finding a gunsmith to take this sort of work on would probably be impossible , why muck two rifles up to make a mongrel , why not just enjoy each as they are ? There are various rifles already out there in other calibres , just a case of finding one .

Dave

loiner1965 09-17-2017 12:07 PM

hi dave
i know a good gunsmith but was just wondering if they were the same thread size.
just curiosity thats all

Dickn52 09-17-2017 04:29 PM

Sorry, but will this gunsmith tackle the RF to CF issue as well?

DoubleD 09-17-2017 10:07 PM

Here is my opinion based having worked on one International in my shop 35 years ago, but I have worked on lots of other Martini's. ;)

I don't think the International could be modified for a .300 Sherwood. The Cartridge is to big.

I believe the International has been rechambered in .22 Hornet, so the conversion from Rimfire to center fire may be possible. But even then I can't point to a credible reference that says that has been done.

loiner1965 09-18-2017 01:00 AM

i thought you be able to adjust the breech height to alter the firing pin strike like on the large frame martini.
i read of centrefire conversions with the martini 12/15 models so i presumed the international series be the same....like i said gentlemen i know nothing about the small frame martinis even though i use to shoot a club gun 20 years or so ago,
all this started as a friend needed an extractor for his and when i saw it i thought they were very well engineered and extremely strong receivers

Dave 101 09-18-2017 04:54 AM

Another problem I could imagine might be the loading ramp angle as the .300 is a long cartridge at 2.02 " .

Dave

Yank 09-18-2017 02:34 PM

Quote from Bob Snapp re International action, "There's no room for anything." :cool:

MARTINI SHOOTER 09-18-2017 02:59 PM

Quote:

Originally Posted by loiner1965 (Post 9541009)
i thought you be able to adjust the breech height to alter the firing pin strike like on the large frame martini.
i read of centrefire conversions with the martini 12/15 models so i presumed the international series be the same....like i said gentlemen i know nothing about the small frame martinis even though i use to shoot a club gun 20 years or so ago,
all this started as a friend needed an extractor for his and when i saw it i thought they were very well engineered and extremely strong receivers

Would you have to have the modified rifle reproofed.???? Tony

loiner1965 09-19-2017 10:16 AM

i dont own either calibre and if i did i would choose a cadet or a .300 sherwood.
i was just thinking outside the box and wondered if it could be done like calibre changes on other small frame martinis.
i suppose you would have to have reproofed here in the uk, not sure about the usa.
i wouldnt know how to ask my feo about a variation for this hybrid martini if it could be done that is lol.
next time i see my rfd mate i will ask him as he is a small frame martini nut

DoubleD 09-19-2017 06:24 PM

I still think the problem is the action is not big enough.

The international is quite different than Francotte.

loiner1965 09-20-2017 10:41 AM

ahh right now i understand why i havent seen any international conversions douglas.....but i bet someone has done one.
would be a cracking rifle if it could be done

rick w. 09-21-2017 06:42 PM

I have a BSA International MKII LW that I rebarreled to 17HM2 using a Shilen barrel here in the states.

I hear you on the quality of these rifles, really shoot well. My particular one is a lefty.

When I did the work to convert to HM2, I was pretty hard over for a hornet. I studied the action and extractor, and with a touch to the extractor and lowering of the firing pin in the breechblock, I believed it would work. That way the action timing I felt would remain constant, kinda like doing a Ruger No.1 to rimfire; same basic concepts and machining operations.

However, extractors for the International at the time were really hard to come by. So I wimped out for a easier program of 17HM2 which I figured I could bump up to the 17HMR or even the real goal of 22 Khornet. But it remains a 17HM2. I see now that a fellow in OKC has international extractors made from scratch for sale, about 100 bucks per.

I just made the new barrel shank like the original. The threads I cannot remember offhand but were English, probably in the 16-20 tpi range(never wrote it down). I have the loose International barrel and will actually measure if you wish for tpi and shank dimensions. The shank is about half threads and the other half is smooth(tight fit into the action). The barrel face receives the forked extractor with a projection over the boreline. I feel that the martini International shank is a bit more effort than the Cadet shank, but just my opinion from doing both.

I quickly compared the MKII International takeoff barrel to a Cadet take off barrel, the threading is no where close with the Cadet being much coarser in makeup, perhaps around a 14tpi?. I only have access to the International MKII and the Cadet, others I am unfamiliar with.

As I am sure you know, the centerfire updates to the International will be limited by the length/depth of the action. I feel quite sure that the hornet will slide in ok, but have not thought about other options as the international extractor ears are not that thick, but would do for the hornet head size. Not so confident that a larger like the 218 Bee would work without some study here............

I have heard that a International was done in 222 remington FWIW. He did his own floating extractor that slid to the side and then snapped into the rim recess.

FWIW,

loiner1965 09-22-2017 12:14 AM

many thanks rick and would be interested in the thread size....so it can be done with a little thought

Yank 09-22-2017 01:07 PM

Have any of you guys replaced a MK2 barrel with another take-off? Was wondering if the indexing is likely to be close, or way off.
Y

PS: Years ago, some guy tried to talk me into converting his Browning straight-pull .22 LR into a .25 rimfire. He wanted to do this because he once had a .25rf (probably an old Stevens falling block), and he liked it. Sometimes people get an idea in their heads, and they just can't shake it off. Oh well, it did work for Thomas Edison.

rick w. 09-22-2017 01:36 PM

My takeoff LW(light weight) BSA International barrel threads look like 16tpi to me with my gauges. When I rebarreled with the Shilen blank, I ground a piece of HSS to fit the original barrel's thread pretty closely, used magnification to help get as close as I could. The original threads are somewhat taller appearance(?), which might suggest a unique thread off the old basic 60 degree, but grinding to fit gets past that; at least for my needs. I ended up with something like a class 4 fit, and called it good.

The barrel shank is composed of three sections, the first section holds the recess for the case head, and two beveled cuts on each side of the bore for the extractor to reside in when breechblock is up.

The second section is the threading; about half of the shank length or thereabouts.

The third section is a smooth section(again about half) that fits into the front of the action with some snugness.

Then finally one has to do scope mount drill/tap if going that route. I used a Bentz reamer as it was all I had at the time, and allows most ammo to fit and shoot fine.

Kinda typical of an single shot action rebarrel, a bit more in labor than most because of all the extras setups/machining.

Once you pull your existing barrel from the rifle, the recipe to ponder is in front of you. Being across the big pond, I am sure your guys are quite familiar with the specific threading. I did not think the rebarrel was all that difficult, just have to pay attention to specifics.

I am pretty happy with my 17 HM2 rebarrel, but sometime the hornet will surface again, and onward and all of that stuff............:)

M14man 09-22-2017 06:03 PM

Reading what you wrote and trying to understand makes me realize I know nothing about gunsmithing.

tim slater 09-23-2017 02:16 AM

Quote:

Originally Posted by loiner1965 (Post 9565897)
many thanks rick and would be interested in the thread size....so it can be done with a little thought

Not as a straight swap, if one is a much coarser thread. You'd have to cut off the old tenon,thread and re-chamber. Throw in proof costs, and it will be expensive unless you can do the plumbing yourself.

epoletna 09-23-2017 09:03 PM

re-barreling a Martini
 
I believe you'll find they're Whitworth threads. Look it up and grind yourself a tool bit for that pitch and you'll be good to go.

loiner1965 09-24-2017 12:18 PM

idea is just in my head as i never seen or read of any international conversions,
i knew if any one can do it then it would be you chaps over the big pond.
you lot have the passion and ideas to do this where as us brits tend to stick to the boring calibres lol

oldtrobh 08-09-2019 10:18 PM

Quote:

Originally Posted by DoubleD (Post 9551401)
I still think the problem is the action is not big enough.

The international is quite different than Francotte.

HI All , I have converted one MK1 international to 32-20 chamber but .300 cal barrel and many 12/15's to .222 ,.223 and 6mm/223 and 32-20 with no problems what ever .. It has been said that the 12=15 can be rechambered to .30/30 but I would not consider that to be correct perhaps however the quote was meant to refer to the strength of the little action the rimless extractor is a head scratcher but it can be done several different ways just takes a lot of fiddling:) to get the extractor arm to clear the cartridge body


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