Ruger has been listening to the suggestions from Steel Challenge shooters, as well as other aficionados regarding its 22/45 and is producing the pistol with factory installed rails and a threaded barrel. 
The 22/45 comes with a 10-slot rail on top and a 6-slot rail under the barrel to allow for easy installation of a holographic sight on top and a laser, flashlight, or other accessory on the under-barrel mount. The barrel is also factory threaded 1/2×28 to accept a suppressor or other .22 caliber muzzle device and includes a thread protector.
From their press release: Ruger announced two new 22/45 rimfire pistol models with threaded barrels. These new models allow owners to attach an assortment of muzzle accessories to one of America’s favorite rimfire handguns, the popular Ruger 22/45RP rimfire pistol.
Both models feature a 4.5 inch, factory ½-28 thread barrel, which accepts many popular muzzle accessories. When not using a special application attachment, the threaded barrel and barrel crown are protected by a muzzle cap.
The 22/45PRRP model (10149) comes without sights and features a Picatinny rail on top of the receiver for mounting optics. A shorter Picatinny rail is mounted on the bottom of the barrel for attaching lights, lasers and other accessories.
The second model (10150) features a fixed rear sight and Partridge-style front sight. The receiver is drilled and tapped to accept a Weaver-style scope adapter so shooters can mount a variety of optics on the pistol.
Like all pistols in the 22/45RP lineup, the new Ruger 22/45 Threaded Barrel pistols have replaceable 1911-style grip panels on the polymer frame that features the grip angle of the classic 1911. Similarly, the locations of the magazine button, manual safety, and bolt stop are virtually identical to the classic 1911 pistol. The slim polymer-grip frame has a serrated front strap and a checkered back strap.” Click here to purchase a Ruger 22/45 with Picatinny rail and threaded barrel.
I love my Ruger 22/45 silenced. Took it to the next level with an upper from oregon precision arms. I dont think there is much more I can do to it.
Just got mine – very nice – good balance – lots of fun! Even my wife will shoot this one – raises your “cool” factor at the range
Ruger Mk III’s, with or without a suppressor, will not function reliability with ammunition marked Subsonic. But use of those shells is unnecessary because most bulk packed 22’s are subsonic in barrels shorter than 8″.
Take care and shoot straight
Ruger recommends you fire a couple hundred rounds of high velocity ammunition first to break in the gun. After that is should cycle with decent quality sub sonic rounds.
This gun has a threaded barrel to accept a suppressor. Will it cycle with subsonics?
Can the rail on the barrel be removed?
I want one.
“second model (10150) features a fixed rear sight and Partridge-style front sight.” read the article next time.
What-no irons? Besides that, I’m sold.
I want this exact upper on the standard Ruger Mark III handle design. Hopefully Ruger decides the other grip design is worth their time.
Very nice. I’m buying one, that’s for sure.