yes i have the reamer and 2 445 s. m. my 20 in barrel sends a 210 gr bullrt1970 fps...cant find my book with 44 mag speeds :evil: there is not really a 444 marlin bullet just 429...dia...the 445 is better than the 444because of recoil....you dont gain that much out of the 444 case <speed wise>because the 444 uses a slower powder. i can say this..445 is the only gun that kills deer faster than any others...only had 1 deer move from where they were shot , it only went 25 yds :-D i hunted with the 357 max four years but it will not take a big deer down 100% of the time so far tha 445 has .....i use imr 4227 powder, the barrel liked 200 gr. bullets,there are faster loads than mine so dont let my slow loads fool you....i shot a 444 marlin on a h&r action ONCE well maybe twice it does kick..just my 2 cents worth...JB