Tossing "Rocks" - Shooting Subsonic .22s
Andy Moe - JHO ProStaff - San Diego, CA
December 20, 2004
At a time when American shooters crane their collective necks to get a glimpse of the newest and particularly the fastest cartridges on the market I find myself suddenly taken by the idea of s-l-o-w. I’m referring to sub-sonic 22LR rounds and for the past few months they have positively fascinated me. For the longest time they seemed to me to be the ballistic equivalent of a slingshot, and why they seem to work so well was a mystery.
This mania started in Scotland this past fall when I was introduced to shooting rabbits with 22LR sub-sonic rounds. These Eley rounds would thump into those 4-pound rabbits and knock them over with never a lost rabbit. Even out to 60 yards these slow moving bits of lead would bowl the bunnies with authority. “Click! (pause) Whump!” was all a blind man would have heard during a successful shot. The farther the shot, the greater the pause. Returning home I decided that I needed to investigate the possibility of sub-sonics for my own general field use.
The first thing I found out is that these sub-sonic 22LR rounds aren’t very common. They’re definitely not a K-Mart item. With a bit of scrounging I managed to come up with four different makes with loadings of three different bullet configurations. In order of their appearance, they were as follows:
Aguila “Sniper Sub Sonic” 60 grain Round Nose
PMC “Moderator” 38 grain Hollow Point
Remington Sub Sonic 38 grain Hollow point
Aguila “SE” Super Extra 40 grain Round Nose
All of these rounds were purchased from local gun-shops, and while I’d have liked some Eley 38 grain HP in the mix, I feel that these cartridges are a fair representation of the options available to US hunters and .22 enthusiasts.
Finding a rifle was the next order of business. I wanted to find a rifle in my .22 rack that could be dedicated solely to subsonics. As it turned out I had two rifles that weren’t labeled for any specific use: My Marlin 880 SQ and my Chinese JW-15, a copy of a Brno #1 Sporter. The Marlin was quickly eliminated. Accuracy through the Micro Groove barrel was less than par with groups running close to an inch at 25 meters. With the 60 grain Aguila “SSS” bullets the groups were close to two inches with some key holing evident.
This left me to cross my fingers and put my faith in the JW-15. It so happened that it shot the majority of the ammo as well as I could hold the rifle, including the under-revved 60-grain Aguila bullet. A Parker Hale 6X scope helped deliver the goods on target.
After an initial zeroing-in I ran all varieties of ammo over the chronograph. These are the results of the 10 shot strings I fired.
Aguila “SSS” 60 grain 956 ft/sec. High = 997, Low = 941
PMC “Moderator” 38 Grain 1012 ft/sec. High = 1049, Low = 996
Remington 38 Grain 1018 ft/ sec. High = 1090, Low = 933
Aguila 40 grain Solid 1019 ft/sec. High = 1045, Low = 998
At 100 yards, the Moderator is listed as having a remaining velocity of 873 ft/ sec with a remaining energy of 88 ft/lbs. The Aguila 40 grain’s numbers are roughly identical to those of the PMC. The Aguila 60 grain “SSS” round is listed as retaining 120 ft/lbs of energy at 830 ft per second. All of the cartridges tested came within a few feet per second of their advertised velocities.
At the bench I found that the sub-sonic rounds took a bit more care and follow through to make shoot well. If I neglected to pay attention to my grip and the amount of pressure I placed against the butt-stock, I found myself tossing rounds out of the group. These were easy to spot as my error, vs. ammo failure, as the reticule would end up exactly over the bullet hole after recoil had occurred. The bag sensitivity caused me to adopt a style of holding on to the forearm while resting my hand across the front shooting bag. This improved grouping from this light barreled sporter.
And the groups were generally good. The oddest thing is that the 60 grain Aguila load –the one that by all rights shouldn’t have stabilized in that 1-16” twist barrel -delivered the best over-all grouping. Right in behind the Aguila “SSS” was the Moderator H.P. and the Aguila 40 grain solids in about a dead-heat tie.
In far last place was the Remington Sub Sonic. This ammo gave erratic grouping and a look at the chronograph data would suggest the cause. While the other varieties kept their velocities within 50 or so feet-per-second, the Remington spread its shots over 137 feet-per-second. The groups were still minute of rabbit, but not on the same level as those produced by the other three test samples. How good were the other groups? I didn’t measure them but all had most of the holes cutting each other when I did my part.
My experiences in Scotland had already shown me what these rounds would do afield so I decided to see what would happen if I shot some form of ballistic medium with them. For my “medium” I chose 5-pound blocks of commercially prepared pottery clay; one shot per block at 25 meters using the two Aguila offerings, and the PMC 38 grain HP. The clay blocks were left in their thin cardboard boxes. All the rounds entered on the left and exited on the right. The photos tell it all.
The 60-grain “SSS” loading blew a straight channel of about 1.5” in diameter clean through the 6-inch long block. Obviously, this is the load to use when penetration is an issue. The 40-grain Aguila round seemed to expend a goodly bit of its energy as it was leaving, punching out the backside of the container and generating a hollow at the rear end of the wound channel. The 38-grain PMC round unloaded its energy on impact, as shown by the 2.5” wide cavity just inside the impact end. It was notable that this round barely left a tear in the cardboard carton when exiting, unlike the other two, which tore a large hole in the box when leaving the scene.
The performance of the PMC “Moderator” 38 grain HP on that clay block may have revealed why those Highland rabbits fell over when hit in the brisket with the very similar Eley 38 grain HP round. A measurement of the hollow point showed that unlike most hi-speed “hollow point” cartridges that only bear a dimple in the bullet nose to differentiate them from their solid nose counterparts, both the PMC and the Remington had deep hollows in their projectiles. The PMC was the deepest with the hollow extending back through the nose to the leading edge of the driving band. The Remington had approximately 2/3 that depth. Obviously, both rounds were engineered for rapid expansion at low velocities. Another factor in the performance I witnessed abroad.
I now have a rifle specifically set up for my sub-sonic rounds and plan to do some serious rabbit hunting with them during the coming winter months. I’ve started by doing some 50-yard off-hand practice on my steel “swinger” target. Crack! Clank! Crack… Clank!
Still sounds like somebody tossing rocks to me!