I guess my wording was not that great. Didn't mean to misconstrue a self tightening snare with one that would automatically tighten on its own.
Woodmaster: I looked at several snares that are for sale. Do all snares come with the stop? If the stop is not included with the snare then there could be the chance someone could use one that tightens to the point of strangulation.
We made our own snares, store bought snares cost too much. One can probably buy snares with stops premade but it would be a semi-custom order as the diameter at the stop would need to be specified. I'm guessing such an option would be found in the fine print somewhere.
The stop was merely a piece of conduit crimped onto the inside loop of the snare. A couple twists of wire often accomplished the same thing. We did that ourselves to prevent the loss of the snare if a deer or moose was caught as they could pull their foot out of the loop. I believe stops are now required in MN if using a snare for a dry set for precisely the reason mentioned.
Stops were not used on snares used for water sets as they were kill sets from the beginning. We used them mostly for beaver and beaver are strong enough to pull traps/snares up if not quickly killed. A loss of not just the snare but also a valuable pelt was not something one wanted to explain to Grandpa.
Wytex's video is a pretty good one regarding the various common snare mechanisms. They are actually fairly easy to open though if one is unfamiliar and in a hurry they could be tricky. Basically, they are like the inexpensive game hoists one can buy at the store used to hoist deer up to cool or skin. Add tension and it locks to keep the deer from falling, give it a little slack and the rope moves easily.
I haven't set a snare in decades, I moved from an area one could use them to one that they weren't allowed. Then the price of furs dropped, gas became more expensive, and I decided chasing a real job and girls was a better use of my time. I've set a few leg holds and a Conibear or two but most of my trapping these days are dog proofs for the raccoons that snoop around the chicken coop. And live traps for the occasional skunk that moves in under the outbuildings.