I'm hoping this is the right place to post this. Basically I want a 50 caliber, but I am not made of money so I've been looking at the Safety Harbor 50 cal uppers, and for about 2k I can have a fifty caliber and I don't have to go through an FFL, which isn't a problem except the transfer fee and the general pain in the butt it just seems easier to direct order it. My main question s does anyone have experience with these bad boys? I imagine their will be some play between the upper and lower and how will this affect such a heavy caliber? Will this present any risk to the made for 556 lower?

You might want to ask this in the 50 cal forum under Armory.

But the answer to you question is there is no concern for damage to the lower.   Your shoulder has a much lower yield strength.

Yes I have one and yes its awesome do not worry about stressing the lower it will be fine but be prepared to buy a real scope with a lifetime warranty as they will break on the 50 bolt action!

I own one. The first firing pin that showed up was soft and peened over, as did the replacement. I had a new pin made locally and it works fine.

only other issue I had was magazine flipping out under recoil - they need to have the stop located differently so that under recoil it doesn't move.

other than that, no issues, enjoy.

Thanks guys I really wasn't sure if the 50 cal page was right or this one. Looks I'm going to make the plunge. I found some Lake City 50 cal ammo for 2.50 a round, only 20 rounds though this weekend and picked it up figuring if anything I could resell it and break even. Sucks is the only place I will be able to shoot is at my Uncles about an hour away, he gave me the big bore bug.