Bob58 Posted March 15, 2009 Report Share Posted March 15, 2009 Can someone help me with some characteristics / dimensions that might help me identify (w/o chamber casting) whether the attached picture is possibly a 7.7 Arisaka barrel? From earlier posts elsewhere on this forum I suspect, with tinkerfive's help, that it could possibly be a Japanese barrel. I've been able to determine the following: Dimensions @ shank - 1.075" wide and .75" long in "bulbous" area, A .308 bullet hangs in crown (upside down, it hangs prior to the cannelure) A spent 308Win case can be chambered, 4 grooves / 4 lands with grooves approximate 3x land width Attached to a FN commercial mauser action (is it a Japanese barrel that has been cut and shank and rethreaded?) Any ideas? What would you evaluate next? (Other than chamber cast which I'll likely do). Quote Link to comment Share on other sites More sharing options...
CTI Posted March 16, 2009 Report Share Posted March 16, 2009 If it was a jap barrel they have cut some off the back,and could possibly rechamber'd it for 308. only way to know bore is to have it checked.could be done with set of calipers would be close enough to tell you. Interested to know myself. Quote Link to comment Share on other sites More sharing options...
Bob58 Posted March 16, 2009 Author Report Share Posted March 16, 2009 If it was a jap barrel they have cut some off the back,and could possibly rechamber'd it for 308. only way to know bore is to have it checked.could be done with set of calipers would be close enough to tell you. Interested to know myself. I'm thinking it is 308 Win. but still don't know the origin. Bore diameter at crown measured with my dial caliper is the exact same ID as a spent 308Win neck - I measured both. My dial calipers said .307 (?). A .308 bullet rests upside down in the crown .192" from cannelure. I measured the distance from the chamber opening (front edge of extractor groove) to the base of the neck at the shoulder to be 1.602". If it were 7.7 Arisaka I think that measurement would approach 1.874" and bore diameter would be .311". I also chambered a spent 308Win case and it chambered to the extractor groove. If there is anyone out there who has a 308Win cartridge or spent case and a 7.7 Arisaka rifle, I'm wondering if a 308 Win would chamber? I believe the 308Win's wider body would prevent it from fully chambering in 7.7 Arisaka - its taper is more severe than the 30-06 in which a 308Win will not chamber. That would be very helpful and give me additonal confidence that it is 308 Win. Quote Link to comment Share on other sites More sharing options...
bkranch Posted March 17, 2009 Report Share Posted March 17, 2009 I'm thinking it is 308 Win. but still don't know the origin. Bore diameter at crown measured with my dial caliper is the exact same ID as a spent 308Win neck - I measured both. My dial calipers said .307 (?). A .308 bullet rests upside down in the crown .192" from cannelure. I measured the distance from the chamber opening (front edge of extractor groove) to the base of the neck at the shoulder to be 1.602". If it were 7.7 Arisaka I think that measurement would approach 1.874" and bore diameter would be .311". I also chambered a spent 308Win case and it chambered to the extractor groove. If there is anyone out there who has a 308Win cartridge or spent case and a 7.7 Arisaka rifle, I'm wondering if a 308 Win would chamber? I believe the 308Win's wider body would prevent it from fully chambering in 7.7 Arisaka - its taper is more severe than the 30-06 in which a 308Win will not chamber. That would be very helpful and give me additonal confidence that it is 308 Win. Hey Bob I've got some .308 cartridges and I will try to chamber them in my 7.7 tommorrow and will let you know Quote Link to comment Share on other sites More sharing options...
bkranch Posted March 17, 2009 Report Share Posted March 17, 2009 Hey Bob.the .308 would not chamber in the 7.7 Hope that helps Quote Link to comment Share on other sites More sharing options...
Bob58 Posted March 17, 2009 Author Report Share Posted March 17, 2009 Hey Bob.the .308 would not chamber in the 7.7 Hope that helps Thanks, that helps a lot. That eliminates the 7.7 Arisaka. A 308 Win go-no go gauge will be available in the next few days and I'll try it. Quote Link to comment Share on other sites More sharing options...
bkranch Posted March 18, 2009 Report Share Posted March 18, 2009 good luck to ya Quote Link to comment Share on other sites More sharing options...
riceone Posted May 2, 2009 Report Share Posted May 2, 2009 You can make a quick chamber cast using a melted candle or beeswax. Put a patch on a cleaning rod and push it down the barrel close to where the bullet in the cartridge would stop. Melt wax and pour into the chamber of the barrel till full. Wait a few minutes and push the cast out with the cleaning rod. Now you have something you can get rough measurements off to tell what it is. Don't look like a Japanese Barrel to me. riceone Quote Link to comment Share on other sites More sharing options...
Bob58 Posted May 3, 2009 Author Report Share Posted May 3, 2009 Thanks, I determined it was 308 win with go-no go guages. Quote Link to comment Share on other sites More sharing options...
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