At Shot Show 2011, Gemtech released their new 42 grain subsonic ammunition to the general public.  The ammunition was designed to be harder hitting, cleaner burning, and more consistent (thus more accurate).  It was rumored that the ammunition is made for Gemtech by CCI/ATK as the packaging was very similar.  Regardless of where it was made and by who, the proof is always in the pudding.  We wanted to compare this new ammunition to the gold standard in silencer testing, CCI Standard Velocity.  CCI Standard Velocity is published to fly at 1,070 feet per second.  The Gemtech ammo is designed to fly at 1,020 feet per second.  Silencer enthusiasts have one big concern when it comes to bullet flight speed; the speed of sound.  What a lot of people don’t know is the speed of sound changes with temperature and elevation.  What is subsonic in Florida at 100 degrees might go supersonic at 30 degrees in Wisconsin.  Therefore we need a consistently subsonic round in the majority of operating environments.  Anyone who has discharged a silenced 22LR only to hear the loud ballistic crack of the bullet tearing downrange can tell you how disappointing supersonic 22LR ammunition can be.  Just a word of caution about published velocities.  SAAMI specs on 22LR velocities are from a 24″ barrel.  Silencer people seldom use such excessive barrel lengths anymore.  Research has shown that bullets in these longer barrels can actually allow a bullet begin its forced exit from a long barrel, reach a velocity beyond the published number on the box and actually slow down before exiting the crown.  That means when a gunsmith cuts off a 22LR barrel to 16.5″ the bullet may actually exceed the published numbers.  Since we flirt with supersonic in an effort to extract maximum hitting power from our suppressed shots, we can get a loud trans/supersonic shot.  Chamber dimensions also play a role in actual bullet speeds.  Very tight match grade chambers can increase velocities as opposed to loose sporting chambers in semi-autos.  Finding a good quality 22LR ammo for silencer affectionados that works reliably in across many platforms has been somewhat difficult in the past.  Does the Gemtech ammo fit the bill??…read on.

In order to find out how the new Gemtech Silencer Subsonic performs, we did several tests.  First we tested noise reduction at the MIL STD 1474D Reference Location and at the left ear (another MIL STD 1474D location) using two calibrated Bruel and Kjaer 2209s equipped with B&K 4136 transducers and calibrated with the 4220 piston phone.  This is one of two systems acceptable for testing silencers to the military standards set forth in MIL STD 1474D.  The other is a Larson Davis 800B.  Next we tested velocities with a chronograph from Shooting Chrony for each weapon and ammo type.  Finally we tested for accuracy.  The test was conducted using the Walther P22, the Ruger MKIII with Tactical Solutions Pac Lite 4.5″ barreled upper, the Ruger 10/22, and the CZ 452 American.  Accuracy tests were done with the rifles.

Remember that it takes one dB of difference for a well trained human ear to detect a discernible difference  in sound pressure levels.  In most cases, these results show no real  differences between these two ammo types.  In other words, the Gemtech Silencer Subsonic ammunition isn’t louder or quieter than CCI Standard Velocity.  Ear testing is very subjective and in my opinion, not very reliable since silencer impulse noise is VERY directional.  The CZ 452 American was also tested with Aguila Super Extra 38 Grain ammunition, as its typically subsonic in that particular host.  The numbers it generated were 118dBA at the reference and 115dBA at the ear.  Since the sound testing didn’t detect any significant differences, we moved on to chronograph results.

Here we revert back to our concerns with velocities out of rifles.  We simply cannot have transsonic shots from a suppressed 22 rifle as it very nearly defeats the purpose of using the silencer.  The Ruger 10/22 performed quite well with both CCI Standard Velocity and the Gemtech ammo.  In fact the Gemtech ammo from the 16.5″ threaded 10/22 barrel was spot on at the published 1,020 feet per second with the ten shot average.  The extreme spread (the difference between the fastest bullet and the slowest bullet in the shot string) was smaller with the Gemtech ammo.  The CZ 452 using CCI had one shot at 1094 feet per second as the fastest shot, whereas the Gemtech ammo had its fastest shot at 1,075 with this host.  Either way, neither ammo type can be counted on to remain subsonic in all temperatures.  That is why we typically use the Aguila in this host, as it’s always subsonic.  The fastest shot using the Aguila Super Extra SE Subsonic ammo was 1,060 feet per second…which is subsonic in most reasonable temperatures and altitudes.  The extreme spread and the standard deviation numbers on the Gemtech ammo seem to give it an edge.  So we tested accuracy at my preferred 22LR sighting in distance of 40 yards.  I hunt squirrels in the Ouachita Mountains with my suppressed 22 rifles, and that range gives me the best possibility of hitting my quarry in the head at the distances I typically encounter them.  Keep in mind the accuracy tests were conducted using only a simple range bag, I don’t have ready access to a machine rest so the accuracy tests are subjective to the shooter.

The silencer used for these tests was the XCaliber Genesis.  It has proven itself as one of the quietest, most affordable silencers available today.  It is available in aluminum or all stainless and offers tremendous sound reduction on any platform.  With virtually no first round pop on a pistol, testing with this silencer removes many of the testing variables that are prevalent in other designs.

We create videos so that you can hear what these silencer tests sound like.  While video is not the best representation of what a silencer will sound like when you shoot it at your location, it’s better than not having any video at all.  These videos are all available at YouTube.


So does the Gemtech Silencer Subsonic 42 grain ammo live up to its reputation?  It does hit slightly harder, it IS more consistent statistically speaking and as for cleaner burning..we will test that claim on another day.  22LR ammo is traditionally pretty filthy so that will be a fun test.  The only concerns I have with the Gemtech Silencer Subsonic ammo is that the cost is $ 4.95 per box of 50 and CCI is $6.33 per box of 100 at Cheaper Than Dirt.  The packaging is not up to the cost, as I typically use empty CCI plastic boxes to hold the ammunition for easy loading.  This ammunition was not marketed and produced to provide cheap, bulk pack Wal-Mart plinking and the testing shows that it’s better than CCI Standard Velocity when tested for consistency shot to shot.  Is it worth the extra price??  I am glad that a major silencer manufacturer is finally offering ammunition like this, as this was an industry first, but the price is not commensurate with the performance.