Past, kick killer, kick eaze, limb saver...they all make good pads, either shoulder pads or butt-stock mounted pads.

Running 40rnds through it wasn' t really wise since you' re unfamiliar with high powers, especially since it hurt so badly, you' re probably going to flinch now when you go back out, causing really bad accuracy.

Since it beat you that badly, you might also look into recoil reducers, either have a gunsmith add lead to your stock in the proper places and amounts, or add a spring-mass or mercury recoil reducer, there' s nothing fun about shooting a rifle that beats the hell out of you.

Also remember to keep the rifle snug up to your body and keep your shoulder taut/firm, not totally relaxed or totally tense, just ready. Also, check out where you' re shouldering at, it kind of sounds like you might be too far away from yourself, your buttstock should fit right in the pocket b/w the shoulder head and pectoral head, too far out makes it hit more bone than muscle and joint.

What I think is curious, why do you shoot better at 200yrds than at 100yrds? You got 2" groups at 100yrds= 2MOA, when 3.5" groups at 200yrds is 1.75MOA, sure it' s a small improvement, but there' s no reason that 1.75MOA at 200yrds should come out of the same rifle you shot 2MOA at 100yrds with, your 100yrds should be equally good or better than your 200yrds, might look into that further, maybe the 3.5" groups were luck, or maybe you' ve got some other strange problem?