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Unknown Caliber

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09 February 2019, 21:04
Clemson
Unknown Caliber
This rifle is somewhat of a mystery. The owner does not know the caliber. It cycles and chambers 7.65 Argentine cartridges just fine. I understand that the 7.65 cartridges used in Europe had very slightly different dimensions. Regardless, I have not run into a "cigarette" rifle in this caliber before.
The photos show the barrel markings. The rib is marked "Remo". Various caliber markings underneath are no particular help to me, but they may mean something to one of you. Any help in determining what cartridge this gun is intended to fire is greatly appreciated.

Bill Jacobs

IMG_0307 by William Jacobs, on Flickr
IMG_0306 by William Jacobs, on Flickr
IMG_0305 by William Jacobs, on Flickr
IMG_0304 by William Jacobs, on Flickr


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09 February 2019, 21:37
nopride2
I'd be inclined to shoot the Argentine and compare the brass with the unfired.

Dave
09 February 2019, 21:43
rgg_7
Can you post a picture of the bolt face and extractor. 7.7 could be 303 British. 7.65 uses same bullet diameter however O/L a little shorter. See top of barrel is marked "Cal 3.?" Chamber cast to tell for sure. Ron
09 February 2019, 21:47
Luckyducker
I would tend to agree with nopride2 if you are certain that the groove diameter is somewhere near .308-.312". If it is a smaller bore you wouldn't want to do this as it would be unsafe. The only other recourse I can see is to do a chamber cast and measure the results, then compare them to known cartridge dimensions.


Dennis
Life member NRA
09 February 2019, 22:55
Clemson
The bolt face is the standard .473 bolt face. The extractor holds a 7.65 cartridge just fine. The magazine is made for rimless cartridges and is full length. I can actually seat 8x57 cartridges in it, but the bore is smaller than 8mm. I can cast the chamber if I need to -- I was just hoping to save the customer the cost of doing that.

Bill Jacobs


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09 February 2019, 23:00
dpcd
How much does a chamber cast cost? It is not that hard.... Slug the bore too. Then no more guessing by AR members, even though it is fun.
09 February 2019, 23:27
dpcd
Ok, do this; (suggested by a very wise person);
Take a 30 caliber bullet; see if it will go though the bore. If it will, then see if an 8x57 will chamber. If it will, fire it. Even if it is an 8x60, the extractor will hold it and then you will know.
If a 30 cal bullet will not go into the bore, see if a 7x57 cartridge will chamber. Repeat.
10 February 2019, 00:16
Clemson
OK. 7mm drops down the bore.

This is a 7.65 Argentine from Norma. Bullet measures .312.
IMG_0309 by William Jacobs, on Flickr

This is a .308 round from Federal with a .308 bullet
IMG_0310 by William Jacobs, on Flickr

Fun, huh?


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10 February 2019, 00:53
WoodHunter
Chamber cast is the only way. Anything else is flirting with disaster.

An action full of blown back gas will wreck the action and likely put an eye out.

Cerrosafe is cheap and easy to use. Get it from Brownells.
10 February 2019, 02:30
bpesteve
If, as you say, you can seat 8x57 in it (and by that I'm assuming you mean chamber a round and close the bolt) it is certainly not a 7,65 Argentine.

I can't tell from your photo if the "CAL" mark is a 3 or an 8.

The 7,7 mm mark would be typical of an 8mm "J" bore; 7,7mm being the bore, not groove diameter before it was rifled.

It is most probably an 8x57J, but could be any of several others.

Please, please don't fire random cartridges in it! Take the time to do a chamber cast and slug the bore; it's easy and the only sure way to find out!
10 February 2019, 02:50
craigster
A chamber cast can be done in what, 15 minutes ? Maybe 1/2 hour if you're really slow. Would eliminate a lot of mental masturbation.
10 February 2019, 04:03
Clemson
I'll cast the chamber on Monday. That won't give me the length, but it will give me the shape of the chamber.

I am relatively certain that it is a 7.65. The reference to 8x57 meant that I could seat 8x57 cartridges in the magazine. They won't come close to chambering.

This has been a fun exercise for a Saturday. Still, no one has seen a 7.65 Mauser in a cigarette rifle. I think Belgium and Turkey both used the round.

Bill Jacobs


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US Army Veteran
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Gunsmith
10 February 2019, 04:44
craigster
AKA 7.65x53 Belgian, adopted by them 1889. Used by the Turks and others over the years.

Winchester, I believe , at one time offered the Model 70 so chambered.
10 February 2019, 05:45
NONAGONAGIN
FWIW...I would fireform an Argentine case with a stiff load of grits/polenta/cornmeal and Bullseye or one of the other fast burning powders and also slug the barrel...you only need an inch or so at the muzzle, not the full length. Neither of which would harm anything but would give you something concrete to measure INCLUDING all the chamber shoulder and neck lengths and the OD's...then compare numbers to SAMMI drawings if visual/mic won't do. Much quicker than Cerrosafe and just as good unless you want numbers to do a reamer.

Dropping a 7.65 bullet down the chamber should give you a rough COAL...or use slugged bore size bullet...again giving you some numbers to think about without actually firing a bullet.

Good Hunting tu2 beer
10 February 2019, 07:24
dpcd
All Argentine Mausers are 7.65 as well. I used to take my 1909 Carbine to the MG range (we had lots of extra ammo) and shoot 7.62 Nato out of it.
No, it didn't blow up; just get a very short neck.
10 February 2019, 13:10
Nakihunter
Fire forming case with 20 gr of shotgun powder and tissue will solve the mystery


"When the wind stops....start rowing. When the wind starts, get the sail up quick."
10 February 2019, 20:18
dpcd
But really, do a chamber cast; the stuff melts in boiling water and you put a cleaning rod with a patch on it in front of the chamber. Very easy. Might heat up the metal a bit first so you don't get wrinkles, which don't hurt anything. Or do it twice.
11 February 2019, 03:52
NONAGONAGIN
HAHAHAHAHAH...just like firing a 308 in a '06 chamber...causes a bit of head scratching for those few.

Always several ways to get to the same cow pasture.

Good Hunting tu2 beer
11 February 2019, 05:14
dpcd
I also took my Rock Island 03 to the M60 range sometimes; fired hundreds of 7.62s in it. Made lots of long 45 brass.....
Later I bought a 308 Ruger 77 from Sumner's Hardware in Louisville.
Flat bolt.
Some useless history for sure.
11 February 2019, 07:50
craigster
quote:
Originally posted by NONAGONAGIN:
HAHAHAHAHAH...just like firing a 308 in a '06 chamber...causes a bit of head scratching for those few.


Ran across a couple bozos doing that with a Garand, and yup, they were scratchin' all right.
12 February 2019, 05:02
NONAGONAGIN
Yeah...that too...Don't EVEN try to explain. Cranks some up and others get the joke...hahahahahahah...still kills deer very well.

Good Hunting tu2 beer
12 February 2019, 20:29
bpesteve
Bill, don't keep us all in suspenders; what did the chamber cast show?!!
12 February 2019, 21:15
p dog shooter
Years ago one could buy a insert to turn a 06 chamber into a 308.
13 February 2019, 01:23
Clemson
OK, casting complete. See the new topic labeled "Chamber Casting".

Bill Jacobs


NRA Endowment Member
US Army Veteran
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Gunsmith
13 February 2019, 02:50
dpcd
Good job.
A comment on what P dog said about the 06 chamber sleeves; the US Navy converted a few thousand M1 rifles to 7.62, from 30-06 by inserting one of the sleeves.
I have one for sale; it has a nice 1944 dated barrel, and is marked 7.62. H&R did the work. Later they went to new barrels because sometimes the sleeves came out.