aga man Posted July 21, 2012 Report Share Posted July 21, 2012 hi people, just recently bought a sxs and cannot workout the proof marks on the flat of the barrels. i have looked through previous post and cannot find any marks relating to the guns chamber length. is it as simple to measure with a tape or is there another way of telling. the gun is a english made midland gun co in 12 gauge. any help appreciated. aga man Quote Link to comment Share on other sites More sharing options...
aga man Posted July 21, 2012 Author Report Share Posted July 21, 2012 i know its not ideal but here's what is stamped on the flats of the barrels Quote Link to comment Share on other sites More sharing options...
clayman Posted July 21, 2012 Report Share Posted July 21, 2012 Are you sure its English? Midland Gun Co imported most of their guns, although Birmingham proofed, they were still mainly of European origin made for Midland Gun Co. Unless its a very old gun ( in which case it could be British made in their Demon works ) it will be 70mm chambered, but the pre-war ones may be 65mm Midland still exist, so why not ask them about your specific gun sales@midlandguncompany.co.uk Quote Link to comment Share on other sites More sharing options...
aga man Posted July 21, 2012 Author Report Share Posted July 21, 2012 Are you sure its English? Midland Gun Co imported most of their guns, although Birmingham proofed, they were still mainly of European origin made for Midland Gun Co. Unless its a very old gun ( in which case it could be British made in their Demon works ) it will be 70mm chambered, but the pre-war ones may be 65mm Midland still exist, so why not ask them about your specific gun sales@midlandguncompany.co.uk thanks for the info matey. to be honest i presumed the gun was english made as is has midland gun co birmingham and london stamped on the barrel rib. i will try to contact midland. thanks very much Quote Link to comment Share on other sites More sharing options...
HDAV Posted July 21, 2012 Report Share Posted July 21, 2012 (edited) Midlands name was bought by Mid Wales Shooting Centre iirc so chances are the older records may not be present. There should be a chamber length in the proof marks but on the safe side 2" 1/2 Edited July 22, 2012 by HDAV Quote Link to comment Share on other sites More sharing options...
matone Posted July 22, 2012 Report Share Posted July 22, 2012 (edited) A photo of the proof marks would be handy. From what you`ve posted it was proofed in Birmingham betweem 1904 and 1925 with a bore size of .719" and was made in England. If its marked 1 1/8 it`s 2 1/2 " 1 1/4 it`s 2 3/4" Edited July 22, 2012 by matone Quote Link to comment Share on other sites More sharing options...
cockercas Posted July 22, 2012 Report Share Posted July 22, 2012 slowly stick a pen down the barrel touching the side you will feel it, then get a tape and measure it. Quote Link to comment Share on other sites More sharing options...
fo5ter Posted July 22, 2012 Report Share Posted July 22, 2012 (edited) slowly stick a pen down the barrel touching the side you will feel it, then get a tape and measure it. But don't forget that this is the size of the fired cartridge, if the chamber actually measures 3" it won't take 3" cartridges The problem with shooting a 3" shell in one of the shorter chambers is that there is no space for the crimp to open up into. Since they are longer than the chamber, the crimp actually opens up into the bore, which is significantly smaller than the chamber diameter. So when a 3" shell is fired in the short chamber, the crimp opens into a constriction if you will, and presents a bottle neck to the shot charge and wad. This raises chamber pressure, which means you feel more recoil. It can and usually does also alter the pattern to some degree. But more importantly it also stresses the barrel in the area just ahead of the chamber. Edited July 22, 2012 by fo5ter Quote Link to comment Share on other sites More sharing options...
HDAV Posted July 22, 2012 Report Share Posted July 22, 2012 (edited) Here is a picture of my SBS flats you can clearly see the 2 3/4" mark next to the 12 in the diamond Edited July 22, 2012 by HDAV Quote Link to comment Share on other sites More sharing options...
chrispti Posted July 22, 2012 Report Share Posted July 22, 2012 But don't forget that this is the size of the fired cartridge, if the chamber actually measures 3" it won't take 3" cartridges The problem with shooting a 3" shell in one of the shorter chambers is that there is no space for the crimp to open up into. Since they are longer than the chamber, the crimp actually opens up into the bore, which is significantly smaller than the chamber diameter. So when a 3" shell is fired in the short chamber, the crimp opens into a constriction if you will, and presents a bottle neck to the shot charge and wad. This raises chamber pressure, which means you feel more recoil. It can and usually does also alter the pattern to some degree. But more importantly it also stresses the barrel in the area just ahead of the chamber. I know of someone else who frequents this forum that would benefit from reading this and then implement it :yp: Quote Link to comment Share on other sites More sharing options...
aga man Posted July 22, 2012 Author Report Share Posted July 22, 2012 try as may i cannot get a clear photo as the barrel flats are black. so i have drawn the proof marks as the are on the barrels. i'm no rolf harris but hopefully you get the jist i think from what matone says this makes it 70mm chambers. Quote Link to comment Share on other sites More sharing options...
Graham M Posted July 22, 2012 Report Share Posted July 22, 2012 The 13 over 1 means that it's actually halfway twix a 12g and a 13g and as matone has already stated will have a proofed bore of a maximum of .719. It would be interesting to see what the actual bore size is, and if it's still in proof G.M. Quote Link to comment Share on other sites More sharing options...
aga man Posted July 22, 2012 Author Report Share Posted July 22, 2012 The 13 over 1 means that it's actually halfway twix a 12g and a 13g and as matone has already stated will have a proofed bore of a maximum of .719. It would be interesting to see what the actual bore size is, and if it's still in proof G.M. thanks for the input graham. i bought the gun from a r.f.d so hopefully it's still in proof. i intend to try an contact midland this week but the input here is great and very helpful. Quote Link to comment Share on other sites More sharing options...
mpk Posted July 22, 2012 Report Share Posted July 22, 2012 I know of someone else who frequents this forum that would benefit from reading this and then implement it :yp: Pa ha ha ha h a .....scary if it wasnt true though Quote Link to comment Share on other sites More sharing options...
welshwarrior Posted July 22, 2012 Report Share Posted July 22, 2012 try as may i cannot get a clear photo as the barrel flats are black. so i have drawn the proof marks as the are on the barrels. i'm no rolf harris but hopefully you get the jist i think from what matone says this makes it 70mm chambers. Try grinding some chalk over the flats and brush it into the marks the flats will clean up and the proof marks will have chalk in them and will let you get a picture easier Quote Link to comment Share on other sites More sharing options...
matone Posted July 22, 2012 Report Share Posted July 22, 2012 (edited) The 1 1/4 indicates 2 3/4" chambers. i.e.1 1/4 oz shot load in old money ! Edited July 22, 2012 by matone Quote Link to comment Share on other sites More sharing options...
Katash Posted July 22, 2012 Report Share Posted July 22, 2012 To be sure I'd get a vernier and use that to determine distance to start of forcing cone, you should be able to see or feel this. Someone here will be able to tell you OAL of a fired 2 3/4" shell case which should not exceed distance measured as stated above, crimp needs to fully open. Quote Link to comment Share on other sites More sharing options...
cockercas Posted July 22, 2012 Report Share Posted July 22, 2012 But don't forget that this is the size of the fired cartridge, if the chamber actually measures 3" it won't take 3" cartridges yes i know, sorry but i thought it was common knowledge that the cartridge had to open in the chamber. sorry for any confusion people. Quote Link to comment Share on other sites More sharing options...
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