You are absolutely correct to point out that the .270 Win has a bullet diameter of .277. BUT the .270 is considered to be included in the cartridges acceptable for use in those counties where the maximum "calibre" is .275. I have heard the argument that the measurement is taken between the lands, not the grooves, but I doubt very much that this is true. I think the correct answer is the idiots who devised this stupid regulation just did not know that the .270 shoots bullets bigger than .275"
So let's not tell them, eh?????
I am never sure why people choose three cartridges at random, like .270, 7 mm and .300 WSM, but exclude hundreds of other choices. Like in the 7 mm CALIBRE, you have the 7 mm Rem Mag (which I assume is the cartridge referred to here), and the 7 mm Wby Mag (awesome cartridge), the .280 Rem (even more awesome cartridge), the 7X57 that was used by Kilimanjaro Harry or whatever his name was to shoot a bunch of elephants, the .284 Win, and so on and so forth. All excellent cartridges, all perfectly fine for deer and moose. If you are not a reloader, well..........you can buy 7 mm Rem Mag most anyplace, and .280 Rem sometimes, but the others are not carried by every gun shop!
And we have left out discussion of the quarter bores, of which there are quite a number, not to mention the 6.5/.264s which are also excellent cartridges. Hell, there are literally HUNDREDS of good choices out there when you count up possible cartridge and rifle combinations...........
My go-to rifle happens to be a BLR model 81 in .308. It fits me, I have great confidence in it, it is accurate and I love this rifle. But I would not suggest that this is the right gun for everybody!!!
If I were in cityhunter's shoes, and thought I would hunt in the southern Ontario counties with the "calibre" restrictions, I would be looking at a bolt gun in .25-06, .257 Roberts, .260 Rem, 6.5 Swede, or .270 Win.
Doug