Originally Posted by mattybock
Can you define heavy? And would at what point, or at what chambering, would a lug be necessary?
most all rifle have a recoil lug. some it just prevents any movement fore or aft. but on some rifles, it does help to arrest recoil and transfer it to the stock. the chambering is irrelevent, since even my 17 HMR has a recoil lug. even my 204 Ruger has a recoil lug.
there are many different things that can cause a stock to split or crack and recoil, or heavy recoil is only one of them. poor wood to metal fit as JTJ mentioned is one. defects within the wood itself is another cause. age of the wood can cause it to split or crack.