So does the 25yd sight = to 100yd work for all calibers, or just .223.

I used the 25yd to get on target, and dialed in at 100yd with my AR, will this same approach work for say, 8mm mauser?

I have learned to take any 25 yd paper sight and move it to 50 then 100. I don't trust a 25 yd sight by itself for any caliber. Seems whenever I try to adjust a 25 yd sight to equal a 100 yd zero it never works out and I still have to adjust at 100. Probably something I am overthinking or something. I always go 25 to get close, make big adjustments at 50, then fine tune at 100.

A 25 yard sight-in is only designed to get you on paper at 100. It actually works best when your scope or sights are very close to your bore say within 1.5 inches. AR platform with scope puts your sight and bore 2.5 inches apart. I quit using this method 20 years ago as it wastes ammo IMO. Better to just use a large target at 100 and you should never need more than 3 shots for a good zero. I normally use a 3ft X3ft target.

^^THIS^^