Sub panel splice questions

[Pirate]

I want to put a sub panel near my main panel, and free up a pair of 50 amp breakers for my gen. Input.
The 2, 50 amp breakers have 6ga wire, that I need to splice to more 6ga, to feed sub panel.
What would be the best splice? Can't imaging using wire nuts.

[Splinter Puller]

I would use a couple power distribution blocks.  They are good to 175 amps and 600vac and will handle up to 2 gauge wires

https://www.zoro.com/square-d-pwr-dist-b.../G3506894/

[crokett™]

You want something like this:

https://www.mcmaster.com/set-screw-cable-splices/

Home Depot and Lowes carry them. I used several sets of these to extend several circuits some years ago. as recommended by the electrical inspector. I would put No-Alox on the wires before putting them in the splice. You'll need to heat shrink over the splices.