Swiss Herman P Dettwyler in Basel 7.5 cal

[hawkeyeMASH]

hi I just bought single shoot swiss rifle. I know its in 7.5 swiss but wether it gp90 or gp11 I dont know. All I know is its a Swiss Herman P Dettwyler in Basel 7.5 cal.
here are the pics of the proof marks.; any help would be great.

 

[SHELL SHUCKER]

I would reckon that the circled 11 in the second photo would indicate the cartridge load. Could be amiss though.

 

[diopter]

^^ Correct. Rifling would be likely be three groove, if for the earlier GP90(1890) round

 

[sail32]

This might help;

http://www.swissrifles.com/proofs/

https://www.tapatalk.com/groups/britishmilitariaforums/swiss-martini-t3767.html

Off subject but interestingly Swiss.

http://www.littlegun.info/arme suisse/arme ordonnance/a arme ordonnance gb.htm