Ruger Mark IV 22/45 “Pygmy Shark” Suppressor-Ready Package: Threaded .22LR Performance with JK 105 VERSAX 22
Ruger Mark IV 22/45 “Pygmy Shark” Suppressor-Ready Package: Threaded .22LR Performance with JK 105 VERSAX 22
Introduction
A compact, suppressed .22 LR pistol is one of the most useful—and most enjoyable—tools you can add to a serious training or field kit. The Ruger Mark IV 22/45 “Pygmy Shark” .22LR Threaded Pistol Package (MPN 40190) is purpose-built around that idea: a Ruger Mark IV 22/45 host with a factory threaded muzzle and a rimfire suppressor included, giving you a ready-to-run setup for high-volume practice, new-shooter instruction, discreet pest control, and general range work.
One important note up front: the manufacturer spec sheet for Ruger MPN 40190 lists a 4.40" threaded bull barrel, not 3.1". If “Pygmy Shark” denotes a distributor/limited package variant, it may differ from the standard 40190 configuration—so the safest approach is to verify the actual barrel length on the box label and/or the firearm itself before purchasing holsters or setting expectations for handling. (ruger.com)
Key Features and Specifications
Below are the core specs and design elements that matter most for suppressor use, reliability, and practical shooting.
Pistol platform (Mark IV 22/45 architecture)
- Model / family: Ruger Mark IV 22/45 pattern (1911-style grip angle and controls)
- Caliber: .22 LR (ruger.com)
- Capacity: 10+1; includes two 10-round magazines (ruger.com)
- Barrel: Factory threaded bull barrel; Ruger lists 1/2"-28 threads with thread protector (ruger.com)
- Barrel length (Ruger spec for MPN 40190): 4.40" (ruger.com)
- Overall length (Ruger spec for MPN 40190): 8.50" (ruger.com)
- Weight (Ruger spec for MPN 40190): 33.3 oz (ruger.com)
- Sights: Fixed front, adjustable rear (per Ruger spec sheet) (ruger.com)
- Optics interface: Factory-installed Picatinny rail for easy dot mounting (ruger.com)
Suppressor readiness (what actually makes this setup work)
- Industry-standard thread pitch: The Ruger factory threading is the common 1/2"-28 used by most rimfire suppressors, which simplifies compatibility and minimizes the “adapter stack” that can cause alignment issues. (ruger.com)
- Thread protector: Protects muzzle threads when the can is off—critical on rimfire hosts because .22 LR guns get cleaned often and handled a lot. (ruger.com)
Included suppressor
This package includes the JK suppressor you listed:
Because JK’s site didn’t load cleanly in this session, the most dependable official reference I found quickly is JK Armament’s 105/155/195 series manual (covers safe-use considerations, constraints, and maintenance guidance). (jkarmament.com)
Ergonomics and maintenance advantages
- One-button takedown: The Mark IV’s defining improvement is fast field-stripping for cleaning—a real advantage for suppressed rimfire. Suppressors increase backpressure and blowback; that means more fouling, faster. Ruger’s one-button system makes it realistic to maintain the pistol at the interval it actually needs. (ruger.com)
- Cylindrical bolt design: Ruger notes this design maintains sight-to-barrel alignment and supports accuracy potential compared with moving-slide designs. (ruger.com)
Practical Applications
1) High-volume training without the fatigue
With .22 LR, you can run hundreds of reps—draws (where permitted), trigger press, dot tracking, target transitions—at a fraction of centerfire cost. Adding a rimfire suppressor typically reduces blast and perceived noise, which helps:
- New shooters focus on fundamentals instead of flinch
- Experienced shooters extend practice sessions without getting “beat up”
2) Rimfire suppressor host for range days
A Ruger Mark IV 22/45 is a proven host platform because it’s reliable, accurate, and easy to clean. Pairing it with a rimfire suppressor is especially practical when you want:
- A compact pistol for steel plates
- A “trainer analog” to 1911-style ergonomics
- A dedicated host that stays set up with the can and an optic
3) Small game / varmint and property chores (where legal)
A suppressed .22 pistol is commonly used for close-range pest work on a farm/ranch setting. The advantage isn’t “movie quiet”—it’s reduced disturbance and better communication with anyone nearby.
4) Modular accessory setups
Because this configuration includes a top Picatinny rail, it’s straightforward to mount a pistol dot. That matters with suppressors because:
- A dot can be faster than irons when the suppressor partially obscures sight picture
- You can keep a target focus and still shoot accurately at realistic rimfire distances
Expert Analysis
The biggest technical win: factory 1/2x28 muzzle threads
For suppressed rimfire pistols, factory threads are more than convenience—they’re a quality control and alignment advantage. Ruger explicitly lists a 1/2"-28 threaded barrel on the 40190 spec sheet, and the Mark IV manual also discusses threaded-muzzle-cap use on some Mark IV variants. (ruger.com)
Expect more fouling (and plan for it)
Suppressed rimfire runs dirty. This is normal, not a defect. Your practical approach should be:
- Use quality, consistent ammo when possible
- Clean the pistol more frequently than you would unsuppressed
- Follow JK’s manual guidance for suppressor maintenance/service intervals and safe-use constraints (jkarmament.com)
Reality check on the “Pygmy Shark” description
Your provided description calls out a 3.1" barrel. The official Ruger listing for MPN 40190 calls out 4.40". (ruger.com)
If you’re writing product pages or selecting accessories, treat barrel length as a must-verify attribute for this package:
- Holsters: A 3.1" vs 4.4" barrel can change fit dramatically.
- Suppressor handling: Shorter barrels can feel “snappier” and balance differently once a suppressor is attached.
- Velocity: While .22 LR changes aren’t dramatic, barrel length still influences typical velocity and consistency.
NFA ownership note (U.S.)
Suppressors are regulated under the NFA and typically transfer on ATF Form 4. ATF’s Form 4 page notes a transfer tax of $5 or $200 depending on the NFA item type. (atf.gov)
(If you’re building a customer-facing listing, it’s smart to keep this general and encourage buyers to follow current ATF guidance and their local dealer’s process.)
Conclusion
If you want a suppressor-ready rimfire handgun that’s easy to maintain, highly shootable, and built around a proven platform, the Ruger Mark IV 22/45 “Pygmy Shark” .22LR Threaded Pistol Package (MPN 40190) stands out as a practical “do-it-all” choice. The factory 1/2x28 threaded muzzle and included JK 105 VERSAX 22 Suppressor make it a turnkey setup for training, plinking, and field use.
Before finalizing accessories or publishing specs, verify the actual barrel length for this “Pygmy Shark” package (your description states 3.1", Ruger’s 40190 spec sheet states 4.40"). Once confirmed, you’ll have a compact rimfire system that delivers maximum trigger time with minimum friction.
Sources
Ruger. "Ruger® Mark IV™ 22/45™ Rimfire Pistol Model 40190 (Spec Sheet)." Ruger. Accessed May 4, 2026. https://ruger.com/products/markIV2245/specSheets/40190.html
Sturm, Ruger & Co., Inc. "Instruction Manual for Ruger® Mark IV™" (PDF). Ruger. Accessed May 4, 2026. https://www.budsgunshop.com/prod_mans/42931-0415007367-002.pdf
JK Armament. "JK ARMAMENT™ 195, 155, & 105 SERIES" (Suppressor Manual PDF). JK Armament. Accessed May 4, 2026. https://jkarmament.com/wp-content/uploads/2024/09/JK-SUPPRESSOR-MANUAL-2023.pdf
Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). "Application for Tax Paid Transfer and Registration of Firearm—ATF Form 4 (5320.4)." ATF. Accessed May 4, 2026. https://www.atf.gov/rules-and-regulations/form-and-information-collection-notices/application-tax-paid-transfer-and-registration-firearm-atf-form-4-5320-4