1) Have you cleaned the guts of the bolt assembly?? (meaning remove the firing pin, etc from the boltto clean the spring assembly and insides?)

This must be done faithfully or you'll have problems.

2) Possibly the spring needs replacing

3) Have you tried different #11's. Brand wise

4) #11 nipple is worn down and needs replacing

Those would be my guess, I have owned a ml700 since they hit the market and probably at least 20 others who haveor still shoot the ml700. Usually the lack of cleaning the bolt assembly results in ignition problems with the #11 set up and potentially causing damage where cleaningalone won'tfix the problem (replacement parts maybe be required).

Hope it helps..good luck.