My Husky 5000 has a Canjar,but not a set trigger.
Given that receiver has a "X by 57" length and style mag box not quite full 30-06 length,and its an alloy box,
I myself would not consider anything but Mauser or 06 derived cartridge brass. I say that because I have played that game with the .308 and 7-08 in a Mauser action. I'm not saying it can't be done. I am saying the different case taper has an effect on the cartridge stack in the mag,and can result in headaches. Same with the 6.5 -284. I'm not knocking the cartridge,but why go to exotic ,over diameter,rebated 308 length brass for a near 30-06 length Mauser box? Same with 6.5 Creedmore.
Myself,I'd look at what cartridges are based an brass that the Mauser was designed to run on,rather than cartridges that other folks have been dreaming of building their own rifle for.
At this point,you have eliminated 7 mm and 8 mm. You have 25's,and 25 bullets are limited. So,that leaves 6mm. A 6mm Rem or 6mm Rem AI are possible.
There seems to be some 6.5 interest,with a length rejection of 6.5-06.
OK.I'm listening. The Warren Page 6.5 version of a .257 Ackley Improved,or 7x57 Improved, is the .260 AAR,I suggested already .His "One rifle that will do it all" IMO,this is the straight line answer to the 6.5 dia.You can long seat heavy bulles,and case capacity is about optimal.
You could do the same in a .270 version of a 7x57 AI.
And then there is 8mm brass. .270? .30 ? .338? Might make fine cartridges. .I'm not sure why a person would do all that.You CAN short chamber with a 30-06 reamer and use 8x57 brass necked down.Grind the bottom off 30-06 dies. I think its called the 30 Dunlop.
130 gr .270 cartridges would work in that box,I think.
9 by 57? or .358 or 9.3?? If you think you need one.
You have a push feed bolt,I would not mess with the bolt face/extractor.