Over-sized bores were notorious in very early Marlins, 1880's to 1930's. Anything made after that , provided it isn't shot out should be okay. The notion that all old marlins are "loose' is not a hard & fast rule neither, I have shot with a fellow that regularly cleaned our clock with an all original second year production model 1889 in 38 WCF.
Actually for lever gun sillywet, because of the less importance on "time restraints" I would recommend guns that I wouldn't for Cowboy main match rifles. My go-to gun for sillywett is a second year produced model 1892 in 32 WCF, the wife's is a Marlin 94 short rifle in .357 mag. Both guns shoot good every day...its us that have the good or bad days.
In this sport a good shooter can make a mediocre rifle look good but very seldom will a good rifle make a mediocre shooter look good.
The .44 mag is an excellent round for pistol cal silhouette shooting but won't do the job on rams consistently if you are planning on using it in rifle cal. shooting. The bullets aren't heavy enough to consistently knock the heavier ram targets over at 200yds.