I don't have a lead sled myself, but my brother-in-law does. I've never seen a benefit from one, so I only had one for a short time...

BUT... Loaded with a couple hundred pounds of sand, it'd sure be a good stress test for a stock. I even still have a couple remote firing devices from my R&D days. Definitely more pressure than 200lbs of me behind it would have. BUT... definitely more likely to crush a stock, which might not be representative of what 200lbs of me would do.

I can usually get through 20-30rnds of 458wm before I give up, plus my wife is generally more recoil tolerant (or at least rolls better with heavy recoil) than I am, so she'll be able to stack up some rounds too.

I'll be bedding with a healthy layer of Devcon Steel (considering Titanium), and considering adding a solid steel block to the stock behind the recoil lug, supported screws and bedding. Kicking back and forth using steel tubing instead of the aluminum pillars that I have as well, at least for the front pillar. I've ran that idea by a couple smiths that are versed in building/rebuilding big bores, and they've all agreed that a good thick layer epoxy bedding job would be sufficient, let alone my plan(s), citing that factory rifles with extra lugs are designed to survive firing without bedding at all - just raw stock, which are generally poorly fit, so bedding offers more action support than it had from factory.

Hopefully I'm worried about nothing, but since the only down-side is having a pressure/contact point on my 300wm barrel, instead of fully free floating, otherwise I'd just dovetail a lug into the forend, drop a block of steel behind it in the wood, and be done with it.