I am planning to build a big bore singleshot rifle and wondered what would be the best caliber something in the big 500 up class any Ideas would be appreciated

Quisto56

What action will this be based on, Ruger #1, Farky, Dakota? Rimmed, Rimless? A few more details please.

a clark action Looks a great deal like a winchester highwall but the sides are a bit higher and the hammer is more covered. Big falling block action Can hold I believe up to 577 or 600 nitro I'll have to check to be sure but I believe this to be right Rimmed case I was told it will handle a 12 guage brass shotgun shell and easily handle 50,000psi BIG action Thanks for helping

Damn, why not a 700 Nitro??

For biggie-sized single shots, look here:

http://www.searcyent.com/farq.htm

Thats what I was thinking 500, If your gonna do it better do it right.

Quisto56--This Clark action you mention.Do you have the specs,the cost, where made, barrel thread diameter, etc.
A bunch of us looking for actions to buid 12 Ga From Hell.And a few other big calibers.Searcy's
falling blocks are nice, but out of my budget
range...Ed.

Take a look at the 577 Tyrannosaur, by Lazzeroni. 10,000 FPE at 30-30 pressures. Neck to .510 and still get 8500 FPE, or run the pressure back up for as much as you can take!