Size matters?

[ButteMT61]

Been meaning to ask, and I did a quick search and didn't see this discussed...
I wore my favorite "off the rack" jacket out last night - a USWings Centennial G-1. It's a sweet jacket, and I got 'er on sale for under $175 this spring.
I love the #10 zipper on G-1's. It made me wonder - why do G-1 (and other) jackets use the bigger zip and the A-2's use the smaller #5? There's something reassuring about the #10, and since they're both military, I wondered why the A-2 uses the smaller zips? Or I guess, why does the G-1 sport the #10?

 

[JanSolo]

It must have something to do with the A2 having a small windflap whereas the G1 uses a wider but hidden windflap. If you would use a size 10 paperclip zipper on an A2 the slider would be too beefy and the zipper would be too wide to be fully covered by the flap and/or the flap would not be able to lie flat due to the thick slider.

Edit: Also the G1 has full leather facings on the inside which well support a strong zipper. On traditional i.e wartime replica or mil spec A2s the lining goes all the way to the zipper which makes it feel kind of wobbly. A motorcycle gauge zipper would probably accidentally shred the lining on contact.... Just my 2 cents...

 

[ButteMT61]

It must have something to do with the A2 having a small windflap whereas the G1 uses a wider but hidden windflap. If you would use a size 10 paperclip zipper on an A2 the slider would be too beefy and the zipper would be too wide to be fully covered by the flap and/or the flap would not be able to lie flat due to the thick slider.

Hmm, good point! It really had me thinking about getting an M-422 like the one 767 got. It really is a sweet jacket and very versatile. I just love that beefier zip lol