Everyone,
Thanks for the info. I have installed a Sims pad on it, but will not put a mzl brake on it. He is just getting enough size on him to really hold a "real" gun. His weight is sufficient to deal with light recoil, but it just seems that kids arms are just not long enough to wrap themselves around a rifle. I really don't want to buy him a youth gun, as every youth gun I have ever shot has kicked way harder than the adult version of the same gun.
My son has shot a 223, a 9mm carbine a and 410 shotgun. He has done real well with them. He can really shoot my 22-250 from a bipod (I dig the heel of the butt into the dirt to absorb recoil), but it is that jump to the 243 WSSM that I fear is just that much more than any of the above (the 410 is the hardest kicking gun of the above).
I have an outstanding email in to Lyman, so will await thier reply. If they don't send me something, I will probably try the advice for the 33 grns and 75 grain bullet.
Thanks to all who wrote.
Jim