I have both and prefer the 550 personally. Both are great traps I just feel the 550's are easier and quicker to set. Never had a problem holding a coyote in either.

Taximan, what is it about the 550 frame that you find advantageous over the 650 frame? Is it that you have a dogged rather than a dogless frame?

I always thought for as long as that trap is,hinge to hinge,that it could take more jaw spread.It also makes for a lot lighter trap that has a loose jaw,pit pan and is a little easier to set.

A few years ago,MT tried to pass a law,mandating 3/8" thick jaws.That is based on APHIS guidelines and could still happen one day.If it does,all my MB 550's and cast jaw 650's will be illegal.They may be advertised as 3/8" but the calipers say no.The IL 650 jaws easily make the cut.With the cost of shipping,I decided I'd rather modify what I have,to make a trap that would meet those specs and have more jaw spread,without adding one ounce of weight.I believe they probably have more square inches of space,inside the jaws,than the 650's,weigh 12 oz less than the 650 cast and are easier to set.Not knocking the 650.I like it too.

Both traps have their place, I took Taxi's idea with the hybrid MB600 and sent some to Tom Stalker. My old PC died or I would post pics. Jim Did you happen to save the pics I sent you? If you did please post. Stalker installed a #2 Bridger pan and dogless system and customized the spring pins. With 650 jaws bent to fit the 550 base. Jaw spread 6". Tom Stalker won't build more till I prove them and he is done with mod work for this year.

Before the snow hits I use more 550s, then after snows hit 650's get it done.. The 600 hybrid should do both..