Ruger doesn’t come to mind when one thinks of silencers, but since 2017, the company has offered two rimfire suppressors of its own design and build: the Silent-SR detachable can, and the Silent-SR ISB, an integrally suppressed barrel that fits the receivers of Ruger’s 10/22 takedown rifles and takedown 22 Charger pistols. “SR ISB” is shorthand for Sturm, Ruger Integrally Suppressed Barrel.
The SR ISB is 16.18 inches long and attaches/detaches to the host firearm in the same manner as the native barrel assembly with no modifications or added parts required. Though Ruger makes more than a dozen takedown versions of the 10/22 and 22 Charger, the ISB is best paired with the 10/22 model 21133 which has a similar barrel length, finish and fore-end.
Internally, the ISB consists of a narrow-diameter, 10.6-inch-long, cold-hammer-forged barrel made of 416 stainless steel followed by a spacer, six pushed-cone baffles and an end cap. The spacer and baffles are about 6 inches long when stacked together and are made of investment cast, hardened 17-4 stainless steel. They are held together inside a barrel sleeve made of 6061 aluminum by an Allen screw that extends through the end cap, the bottom sections of each baffle and the spacer.
The barrel sleeve is finished in black Cerakote and is permanently attached to the barrel with the assemblage being at least 16 inches long to avoid a 10/22 with attached ISB being legally classified as a short-barreled rifle, which would trigger an additional $200 transfer tax beyond the tax required for the suppressor alone.
Though the barrel sleeve lends the rifle the look of a miniature over/under shotgun, the design isn’t intended for cosmetic reasons. Rather, the added volume of the under situated “barrel” is a key component of this suppressor’s effectiveness in reducing muzzle report from an average unsuppressed level of 139 dB to 113.2 dB using standard-velocity ammo, according to Ruger. There was no first-round pop on any load tested, and though the barrel shroud conveys a false sense of weight, the ISB equipped 10/22 weighs slightly less than the model 21133—and surprisingly, it isn’t muzzle heavy.
Cleaning rimfire suppressors is necessary to remove carbon fouling and condensed lead from the baffles, which would otherwise accumulate to a point where sound reduction is compromised. Moreover, even a moderate amount of shooting can cause baffles on many rimfire suppressors to stick to the inside of the tube, making disassembly difficult and increasing the potential for parts damage while attempting it. Ruger’s design avoids this risk by using baffle shells that fit together tightly to contain combustion gas inside the baffle core, largely preventing gas from cementing the baffles to the suppressor tube as with most mono-core designs.
Disassembling the ISB for cleaning is simple, because the baffle stack is held together by the 5/32 Allen screw. Loosen this screw slightly, withdraw the stack as a unit from the barrel sleeve, then disconnect the baffles from each other and clean.
Ruger advises cleaning after firing no more than 1,000 rounds, or any time dirty baffles are disassembled. I’d advise a 700-round interval if unplated bullets are used, as the chore is much reduced. The company also cautions against shooting shot-shells or loads with heavy bullets like the Aguila SSS 60-grain load, which may not be stabilized and may potentially cause baffle strikes.
The ISB was tested for reliability, ammo preference and velocity differences between it and the 16.1-inch barrel of the model 21133. Because the ISB is intended for field use and plinking, the three loads I selected, though not target grade, are realistic choices to pair with this type of rifle. To minimize shooter error on the accuracy testing, the rifle was shot from a Caldwell Precision Turret Rest. Average five-shot, 50-yard groups measured 1.4 to 2.4 inches, with the best coming in at 1 inch. Velocity loss between the ISB and the standard model proved negligible, from 11 fps for the Remington 22 Target load to 39 fps for Federal High Velocity.
Out of the box, the ISB exhibited feeding problems, so I called a Ruger customer service representative who immediately e-mailed a prepaid shipping label to return both the ISB and the host 10/22 rifle. The day the package arrived at Ruger’s NH factory, I was notified that the receiver of the host rifle was defective and needed to be replaced; two days later a replacement was on its way back. Though I requested rush service on this repair, Ruger’s responsiveness was nonetheless impressive and the corrected rifle functions perfectly.
Buying a suppressor is still not quite as simple as buying a firearm, but, the indeterminably long wait times for ATF approval seem to be a thing of the past. According to Silencer Central and Silencer Shop, average wait times in days for ATF approvals of electronically submitted Form 4 transfers for individual purchasers of silencers is now down to single digits from the 10-month wait times of recent years, though ATF claims an average 60-day wait. Yes, there’s still an outrageous $200 transfer tax on each suppressor and, more ominously, registration of the buyer with the ATF. However, for those who aren’t so deterred, Ruger’s ISB is an easy-to-clean and durably made suppressor for one of America’s most popular rimfire rifles. It does this while fitting the same footprint as an unsuppressed 10/22 without the muzzle-heavy feel and added length of using a detachable can and with practically no loss of velocity. It levels up your 10/22 game.
