I see trappers posting about chain length and swivels and shock springs
I found my chain setup through trial and error. I run an 18" chain with 3 swivels and a 3/16" quick link in the last jhook.
Swivel at the baseplate, 3 links of #3 chain, another swivel, 3 more links of chain and another swivel and a quick link.
I anchor my trap on the loose jaw side so the first and second swivel form the stake are placed under the loose jaw. With a tap of the hammer I have a solid resting place for the loose jaw. That's for my k-9 traps

I run a longer chain with more swivels if I'm trapping in tall weeds. But that's not very often

What's your setup and why

I run the exact same chain setup as you, with the exception that I run a welded j hook to a chained super stake off the last swivel. I've found this setup to work almost perfectly for my area. Plenty of sniveling in areas with longer grass, not too long to let them get a good hard run on the chain, but not too short either. I do the same thing with staking and bedding the loose jaw on the 2 swivels.

One my coyote traps I use a swivel at the base, 15” of chain, a second swivel then 15” of chain and a super stake. I weld all my J hooks. That system is a carry over from years ago when I used the Iowa disposable stakes and 1/8” inch cable. Back then I used the same 15” of chain and two swivels, one at the base plate and one at the earth anchor cable. I caught several hundred coyotes on that system before Washington lost trapping and never had a coyote jack one out.

When we moved back from Alaska I started using the super stakes with chain and kept the same system except with all chain.

My wolf traps that have super stakes have 36” of chain with swivels at the base, 18”, again at 36” and then 18” of chain on the super stake. The longer chain is to reduce the wolf’s ability to get an upward pull on the super stake. Don’t know that it’s necessary as my coyote system held well enough for two wolves to power out of four coiled, laminated #3 Victor RJs.

it really doesn't matter the length of chain but all traps designed for live holding any critter should have minimum two swivels one on either end of the chain (pretty standard factory chain) i also add one or two in between because coyotes and grass will have that chain balled up and the swivels stopped we are legally only allowed 12 inches above ground on anchored trap

Age old argument, length of chain.

I’m a short chain guy with lots of swivels (one at the trap, one mid chain, one on end). Mine are all center mounted.

I’m no scientist but I had much better luck this way. Smaller catch circle. No long run lunges before they hit the end of chain. Less crap and weight to carry. You name it lots of reasons.

Probably will just as many arguments why longer is better too.

Anyway, mine are all shorter length maybe a foot total with swivels included. Some are less length than that in my stuff, too.

Jim

Short chain, 3 swivels. Just easy for me. Some coyotes but mainly fox and the rest of the zoo that comes with land sets here. Watch them fox and yotes bounce around and don't pull out. Also less weight with short chain and cable earth anchors

Swivel, one or two links of chain, swivel, one or two links of chain, swivel, earth anchor is what I use

It makes no difference to me as long as it's long enough to set the trap over my knee while it's staked down. I like them at least 24" so that is easy. I don't think a long chain gives any advantage to the critters in fact it helps avoid stake jacking and after the first lunge they don't fight as hard as short chained traps, for obvious reasons.