onehole Posted December 27, 2010 Report Share Posted December 27, 2010 Up until now I have never had the opportunity to look at barrels in the raw and having just received some tubes for future rebuilds I thought I would share with you what they look like and the info stamped on the thick end of things.These are Bartlein HV gain twist tubes 30 , 6.5 and a 6mm which is a straight eight.Hope you find this interesting.onehole. Link to comment Share on other sites More sharing options...
1967spud Posted December 27, 2010 Report Share Posted December 27, 2010 very ibnteresting onehole as thats exactly the type im having for my new project but in 7mm Link to comment Share on other sites More sharing options...
andybrock Posted December 27, 2010 Report Share Posted December 27, 2010 That's interesting, take the one in the centre for example I'm guessing the number around the out side is it's serial number, SS is the type of metal in this case stainless steel, .256 and .264 tollerence range? but whats 9.35 and 5RT? Cheers Andy Link to comment Share on other sites More sharing options...
onehole Posted December 27, 2010 Author Report Share Posted December 27, 2010 Right,The gain twist barrels start their twist rate at a slow rate and then spin up to a slightly faster rate so the 6.5 barrel starts at the chamber end at 1 twist in 9.35 inches of barrel through to 8.4735 at the muzzle end.The 30 cal barrel starts at 12.5 through to 11.985. The 5R stamp is to denote that the tube has 5 groove radiused rifling instead of the more normal straight edged rifling ie the edges are radiused.Radiused rifling is thought to clean up better I believe or rather not to foul up so much??potentially.The bore dimensions ie say 256-264 denote bore to land measurements.Pretty sure I got that lot correct in general terms but a smithy may come on here and add a bit more professional explanation. Link to comment Share on other sites More sharing options...
Ronin Posted December 27, 2010 Report Share Posted December 27, 2010 Middle barrel 5r - canted rifling (5R) T - Transitional twist .256 - land nominal diameter .264 - groove nominal diameter 9.35 - start twist of rifling 8.4735 - end twist rifling SS - stainless steel. Outer number - not sure. Link to comment Share on other sites More sharing options...
andybrock Posted December 27, 2010 Report Share Posted December 27, 2010 Middle barrel 5r - canted rifling (5R) T - Transitional twist .256 - land nominal diameter .264 - groove nominal diameter 9.35 - start twist of rifling 8.4735 - end twist rifling SS - stainless steel. Outer number - not sure. Thank you Ronin, 1 out of 7 right, puts me at the bottom of the class.....must be why I'm a pest controller and not a gunsmith Cheers Andy Link to comment Share on other sites More sharing options...
Ronin Posted December 27, 2010 Report Share Posted December 27, 2010 Not gunsmith - maybe one day.. "Interested Amateur" is what I prefer Link to comment Share on other sites More sharing options...
foxing2night Posted December 27, 2010 Report Share Posted December 27, 2010 I would think that the outer number is the metal batch number ???? Darrel Link to comment Share on other sites More sharing options...
baldie Posted December 28, 2010 Report Share Posted December 28, 2010 It will be Bartlein's order number. Without some form of identification on a blank, you could get anyone,s. Link to comment Share on other sites More sharing options...
varmartin Posted December 28, 2010 Report Share Posted December 28, 2010 Can I have the one on the right please Dave ?? Link to comment Share on other sites More sharing options...
1967spud Posted December 28, 2010 Report Share Posted December 28, 2010 Can I have the one on the right please Dave ?? lol Link to comment Share on other sites More sharing options...
onehole Posted December 28, 2010 Author Report Share Posted December 28, 2010 Can I have the one on the right please Dave ?? Yeah might just be able to squeeze two out of that length mate!!!hehe Link to comment Share on other sites More sharing options...
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