Dustin,
I’ve never replaced a striker, either. But, I had a spare for the BSS, and I’ve got ‘em for the Uggy. If the design allows for making a repair easier, why wouldn’t you take the few extra steps to line up the tools and parts, put ‘em in the case, and check to see if the discs could be removed before you had to find that out? Probably explains why the 700 came with a less serviceable design, people maybe didn’t do it anyway. ‘Kinda like the new automatic transmissions, that have no provision for maintenance, and get new fluid and filter, at rebuild.
Tim, there are GREAT gunsmiths who live in Canada. I’m not up on who is working and who isn’t, but, Canvasback, a poster who is here regularly, can put you onto some of the best. You wouldn’t regret either gun, but, whoever described the 700 as more “workmanlike” nailed it. They built a lot of them, the 400 not so much. I have but one 2 1/2” gun, a 12, and if ammunition is tough to find, I slip some of the lighter AA loads in it, 1 Oz or 1 1/8th Oz, the 1150fps loads, and don’t worry too much about it.
Good luck.

Best,
Ted