The Merc wasn't as bad as the Meteors as the forend stock lugs were at the end of the yoke (On the Meteors), If the stock was tightened at the forend tightly it could open the jaws of the yoke and the barrel gets side to side slop!!
Also, What made the Meteor easy to bend was the fact that the yoke wasn't machined from billet but was actually a type of brazed tinplate construction, If the axis pin and the latch pins are removed they can be seen to be hollow, It makes it a very weak setup!
The stock screw lugs on the Mercury were further back so it tended to resist the outward pull from the stock screws
John..