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Question on Carcano & Type I Barrel Threads

6K views 13 replies 8 participants last post by  ireload2 
#1 ·
I posted this question on the Italian Firearms board a month ago, but received no answers. Let's try it here:

I know that the Japanese Type I rifles made in Italy in the late 1930s used Carcano actions. Did the Type I rifles have barrel/receiver threads like typical Carcanos? Did they have Arisaka threads? Or maybe some threading different from either?

(I've got a couple of Carcanos and a Type I in the safe, but I really don't feel like having my gunsmith take off the barrels just to answer this question.)

If you don't know the answer, but do know of a book or other source of reference material where I might find an answer, that will help too.

Thanks.
--Bob
 
#2 ·
I have no first hand experience, but would place a sizeable bet that the threads and size are Carcano type and not Japanese. It would have made no sense for the Italians to retool to cut a different size, JMHO.
 
#6 ·
Hello pitted bore:

Since I have a bunch of parts I just went and checked the thread premise. First of all I double checked to see if a 99 barrel could be installed on a 38 action, no way a the 99 has finer thread pitch.
I next took out a Type-I receiver and I can screw a 97 barrel onto it, the 97 and 38 are the same barrels by the way. The 97 barrel screws much more tightly into the 97 receiver I have and the final tightening to get the extractor notch to align with the right receiver passage will take a tool to do. But I was able to screw that same barrel onto the Type-I receiver all the way to the shoulder by hand, with a shim on the shoulder it would probably align correctly.
It is possible that the Italian threads may have a different degree on the thread cut, but the number of threads per inch is the same, otherwise they would not have come together so easily. I do not have the Italian barrel so I have no way of knowing how tight it fitted its action nor if it would screw onto the 97 receiver.
I hope that the above sheds some light on this question.
Vicasoto
 
#7 ·
Victor has answered the question on the general size and tread of the bbls; a major difference in the barrels is that the Carcano/Type I barrel will not have the large extractor cut out for the Mauser type extractor of the Arisaka.
 
#8 ·
I checked Frank de Haas book "BOLT ACTION RIFLES". It has a few pages of barrel shank drawings. It shows: ( all measurements in inches )

Carcano M91 shank .805 long including .050 unthreaded dia .968 at the rear, outside diameter of threads 1.065 with "approx 14 V threads per inch".

Type 38 & 44 shank .720 long including .70 unthreaded at the rear. No unthreaded diameter given. outside diameter of threads 1.020 with 14 V threads per inch.

Unfortunatly, the book does not list the type I, but perhaps the above information will help some.

Jim
 
#11 ·
I bought a Type I barreled receiver with a ruined barrel.
I turned the shoulder off and pulled the barrel. It and a Carcano barrel threads are identical in diameter and form. The barrel breech face is slightly different than the Carcano but not much.
 
#12 ·
Thank you for remembering this thread, and for taking the time to reply.

Would you be able to offer a description of the differences in the breech faces? I'll have to look to see whether there are differences between my Carcanos and my Type I. It's not clear why such differences should exist, because they are both Carcano actions shooting cartridges of about the same size and design.

Thanks again.
--Bob
 
#14 · (Edited)
Until I can take a decent photo of the two barrel types I will try to describe the differences.

1. thread major diameter = both 1.068"
2. ......................................shank thread
..........................................length length
1942 Carcano 24" barrel (M41) = .762 .615
.................................type I = .782 .685

3. Both have an un-threaded length Carcano = .958 dia
...................................................Type I = .948 dia
This un-threaded section is a thread relief that clears the termination of the receiver threads
4. Both barrels have a annular raised ring on the face of the barrel.
The ring is .058 tall on the Carcano
The ring is .034 tall in the Type I
.............Ring OD Ring ID
......Carcano .830 .707
........Type I .840 .703

There are no clearance cuts for the extractor on either barrel
It appears the raised ring might support the extractor a little if a case head lets go. The edge of the chamber of each barrel has an approx .015 edge break around 75% of the chamber edge
The lower edge 25% of the chamber edge has a slightly larger edge break.
 
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