I just got some of the new GT Cobra buckles
from ITW Nexus in the mail — exciting times! These are plastic versions of AustiAlpin's Cobra buckle
, which you're seeing more 'n' more in the bagmaking world.
If you're looking for a heavy-duty, smash-proof buckle, here ya go.
Spring-loaded sliding bar to keep slippery webbing in place.
Available in 1.5", 1.75" & 2" (shown), male parts will mate with all sizes of female buckles, so you could have a 2" strap reduce to a 1.5" one. Pretty cool.
Super-smooth action...with no chance of getting pinched...for those who worry about such a thing.
I believe the original Cobras are primarily used as harness buckles (though, like I said, you see them a lot on gun belts and expensive bags these days) and they're great for this because they won't open under load. If you intend to use them as the shoulder strap buckle on a messenger bag these may or may not be what you're looking for. If you have a loaded pack you might have to use two hands to release it. Not a big deal, but something to think about.
As of this posting, these aren't available yet for small-quantities buying, but I imagine they will be real soon. Keep checking Mil-Spec Monkey