Wow, BC, that's awesome!

I know 120's are adequate for marten, but think I would like to have a more uniform set of trapping equipment. I could also use 160's on raccoon, and like them for trail mink and bottom edge sets for rats. 120 isn't good for much except marten boxes. I won't even use 'em for rats.

Apparently you have never used a Belisle Super X 120.

Curious as to why you won't use 120s for rats. The 110 is generally considered the quintessential rat bodygrip and is just a single spring 120. Why don't you like the small bodygrips for rat and mink?

I am also confused. Seems to just want to use 160's? I could care less, though I have never heard of anyone preferring them for rats. But what do I know. Only been trapping 45 years, or so, and still learning.

The only problem I see with using 160's on marten is; higher cost, extra weight, the need for larger boxes, and probably a lot more misses on the incidental mink.

I can also see damage to the valuable middle of the back fur, with a larger trap. Marten, as we all know are small critters, and are eager to enter a set, usually. I spend more thought on where they are than how to catch them, once I know.

A 160 is a much better rat trap than a 110/120. A 220/210 is much better than a 110 as well. A swimming rat will never get through either, and the bigger opening will cause less misses/refusals/swim arounds. I have personally had very few mink get through 220/160 on dry land when set with a cross wire across the trigger. The point of my post is: I have a lot of 160's. They can be used on coons as well, so are a dual target trap. Is anyone using them with pans and having any problems. If they don't work well, it is no problem to use a 120. On my line, they would be used for only one animal- marten.

Thus ends another thread......

Not necessarily. On my line a 120 Super X Belisle was effectively used for weasel, rats, mink, marten and fisher for quick dispatch. No used for a 160 as a 220 or larger was required for humane dispatch of larger animals.

I agree 100%. We don't have rats here, to speak of, but growing up in Oregon in the 70's, I trapped many 100's of them with small footholds and 110's.
Here, mink , ermine and marten are the order of the day, and the Belisle 120 is my trap of choice. All outfitted with wood pans.
Boxes like yours, as well.
Fisher are a new arrival on my line, but the 120 certainly proves plenty adequate, as well.

Since we can't trap fisher here (may get a limited season soon) I would actually prefer if they did refuse 120s. I don't see a large problem with using 160s if you have them and agree versatility is always nice in traps. I just prefer the 120s for the reasons AV cited and would never buy 160s for marten. For that matter I wouldn't buy 150s or 155s for them, but since I've gotten a few free from MTP I use them and they work fine. They don't get used as much because again, you need different size boxes and that is a pain.
IF you are using supports and setting your traps on the outside of the box then it wouldn't be an issue. I do this some and am going to try using milk jugs this year, unfortunately I have multiple brands and ages/models, so that I have to have different supports for different traps, again a pain.