Ya know, sometimes it's entirely too easy to tell the guys that use their guns from those that build a model. The same ones that have every bell and whistle imaginable yet not even so much as a port door mark on the rib of takedown pin. The same ones that have a $1200 ACOG that's not even sighted in. The same ones that look aghast when a rifle has been painted to blend in with its background. The same ones that believe malfunctions never occur because they put 500
rounds thru their rifle a year if they're lucky and the wife lets them.
There's a reason that the ribbed M4 stock and older CAR stocks are on pretty much every "high speed" fighting rifle you see out there.
The Magpul is nice, but its meant more for comfort that functionality. The aluminum bar is a stopgap solution for a problem that shouldn't exist in the first place. The stock is too heavy for what it is and obviously too weak by design. I was on deck when a bud was shooting and blew apart an M93A when clearing a malfunction at a match. Never had I seen or had it happen to me with a 4 or 6pos M4 or CAR stock. Backtracking a moment, Magpul did indeed stand behind their product and replace it. After that however, I promptly sold it.
For most shooters that run their rifle a few times a year and dig comfort, the M93 is great. But for people that use their rifle like a rifle, get something else.
And as for shearing your bolt, sounds like a defective part to me. Do you know what brand stock you had?