Thanks for the info. I just looked at the marking on my 1894 .44 mag I bought in 2009. It has the JM mark on left side of barrel. YES! Shoots very well. Does have a jam from time to time, but I think it is the way the lip of the ammo shell. Only using Hornady Leverlution ammo 240grain, shooting lonely deer.
My problem is 2 fold.
1. The fit on the bolt when seated, where it flushes against the receiver, protrudes a little, maybe 1/32 inch. It is the same on all Marlins with that same 39a type action (which is different from the 336 action). I have pointed this out to the Remington rep at the Dallas Safari Club convention as well as the Marlin "Custom Shop" rep at the same following year convention. Still no change that I can see.
2. My first round each year or after cleaning is a flyer. At 50 yds, seems to want go high 3-6". Takes about 6 rounds then settles to about a 2" group, open sights. I always shoot a magazine full and don't clean until I am ready to put it away. Also, I shoot into a woods before going to my deer stand. Always a little wary of shooting a deer when I do not know for sure where the bullet is going, especially when I s do not know what effect the fluctuating temp or humidity is doing to it. Anyone else have an issue with this? Love the rifle and Marlins. Totally disappointed with their quality problems. Hope they return to the cult following we all love.