Andy RV Posted February 9, 2014 Report Share Posted February 9, 2014 I've got a Martini action Greener GP which has only got a 2 1/2" chamber, this is ok for most purposes but is restrictive if you want to fire any heavy loads as most are 2 3/4 or 3". So the question is has anyone ever had a chamber machined out to increase the length? I presume a re-proof would be recommended as well? Andy. Quote Link to comment Share on other sites More sharing options...
kent Posted February 9, 2014 Report Share Posted February 9, 2014 I've got a Martini action Greener GP which has only got a 2 1/2" chamber, this is ok for most purposes but is restrictive if you want to fire any heavy loads as most are 2 3/4 or 3". So the question is has anyone ever had a chamber machined out to increase the length? I presume a re-proof would be recommended as well? Andy. Expensive on such a gun question the worth Quote Link to comment Share on other sites More sharing options...
Andy RV Posted February 9, 2014 Author Report Share Posted February 9, 2014 Yes I think you're right! Quote Link to comment Share on other sites More sharing options...
JohnfromUK Posted February 9, 2014 Report Share Posted February 9, 2014 Re-proof would be needed, because if you wanted to sell, extended chambers without re-proof would be 'out of proof' and it is illegal to sell an out of proof gun. Quote Link to comment Share on other sites More sharing options...
theshootist Posted February 9, 2014 Report Share Posted February 9, 2014 The greener GP is built like a tank so it will be possible but as mentioned above the cost of the work and a reproof will mean you spending more than simply buying another. Mine is 2.75" and proofed to 1.25oz, which is what, 36g? I've never seen a 3" GP. It would be interesting to see whether the GP could actually eject 3" shells without fouling the ramp. Quote Link to comment Share on other sites More sharing options...
malkiserow Posted February 9, 2014 Report Share Posted February 9, 2014 (edited) If you want another greener GP.... Try a PM to PH5172 on here as he was talking about selling his...... That has a bigger chamber than yours and a nice gun. Edited February 9, 2014 by malkiserow Quote Link to comment Share on other sites More sharing options...
welshwarrior Posted February 9, 2014 Report Share Posted February 9, 2014 Yes did it on a 410 that was bp proof OU so lengthened the chambers then re proofed at 3" nitro. Quote Link to comment Share on other sites More sharing options...
ozalid Posted February 9, 2014 Report Share Posted February 9, 2014 Try Nigel Teague, he seems to be able to machine most things. Quote Link to comment Share on other sites More sharing options...
HDAV Posted February 10, 2014 Report Share Posted February 10, 2014 Possible and worthwhile are quite different... Quote Link to comment Share on other sites More sharing options...
welshwarrior Posted February 10, 2014 Report Share Posted February 10, 2014 Cost of proof I recall being the biggest cost. Quote Link to comment Share on other sites More sharing options...
Bobba Posted February 10, 2014 Report Share Posted February 10, 2014 Try Nigel Teague, he seems to be able to machine most things. +1 Quote Link to comment Share on other sites More sharing options...
Andy RV Posted February 11, 2014 Author Report Share Posted February 11, 2014 Thanks for the feedback guys, I've seen a video and the actual process of increasing the length looks very simple by using a purpose made reamer, i'm not surprised the proof is the largest proportion of the cost. Quote Link to comment Share on other sites More sharing options...
Gunman Posted February 11, 2014 Report Share Posted February 11, 2014 Lengthening the chamber is not a problem ,proof should be OK provided the barrels are in good nick .Later GP's were 2&3/4" but if memory serves me correctly the length of the breech block is not long enough for a 3" case .Not so much the loading but the extraction after firing . Quote Link to comment Share on other sites More sharing options...
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