Keeping clean is key to 742 accuracy, reliability, and durability
Had a 742 I bought used. All those locking "ribs", looked to skinny to call lugs, showed no wear - unlike most I'd seen for sale. Seller explained that was result of clean/proper lubrication. Having seen so many where "ribs" looked unsafe, I listened to him. Was very accurate, with everything from 110g to 220 g in 30-06. Never could figure how it could fire such a wide variance in load, with never any problem, but it did. I would use some decent 6mm loads and check accuracy and functioning. In a clean and lubed condition. Use 87g , compatible with insufficient Remington twist. The 6mm was/is a better cartridge than .243, but Remingtons twist couldn't stabilize heavier bullets. I loved my 742, but was stolen. Haven't seen a decent used one since, and I am still looking. Pat