Logun's Sweet 16 on CO2 - Part 2
The other S-16s!
by B.B. Pelletier
Today, we'll look at performance. I filled the 20-oz. CO2 tank at a local paintball shop and coated the O-ring with silicone diver's grease before connecting it to the gun. The fill was $5, by the way, for well over 1,000 shots.
The S-16s has no open sights, so a scope or red dot sight is required. To get the full accuracy potential, a scope is the wiser choice. Since the rifle has no recoil and a long, unbroken dovetail base, you can choose just about any scope you want, because it's easy to get the correct eye relief.
What it's NOT easy to do is get the correct scope height! The straight line of the tank/stock, coupled with Logun's rather low scope rail, means a high mount is needed - an ultra-high mount is even better! The scope I chose has a 30mm tube, so I mounted it with a B-Square one-piece AA adjustable mount with ultra-high risers. That combination brings the eyepiece to the correct height for me if I hold the butt/tank high on my shoulder. Shooters who own AirForce rifles will not find this strange, but shooters who have no experience with a straight stock may need to get used to it.
The S-16s magazine has two captive 8-shot clips. Like many PCP circular clips, each has an O-ring around its circumference that also intrudes on the individual pellet chambers. It's supposed to hold the pellets in their chambers by fitting into the waist of each pellet; of course, all pellets are not made the same. I found that it held .22 Crosman Premiers and JSB Exacts a little loose. Unless I was careful, they would fall out of the magazine until it was loaded into the rifle. Then, the tolerances of the rifle held them in check. Since every pellet is different, this is something you have to experiment with.
Here's a closeup of the S-16s magazine. Looking through the chamber, you see the O-ring that holds each pellet's skirt. That's a Crosman Premier pellet in the loaded chamber.
The rifle is cocked by pulling straight back on the bolt handle, then pushing it forward until it locks with a click. When the bolt is pushed forward, the bolt probe pushes the pellet out of the chamber and into the breech. For that reason, the bolt must be cocked to remove the magazine, or the bolt probe passing through a chamber will hold it in place.
The first test was velocity. I used 14.3-grain Crosman Premiers. At 70 degrees F, the test rifle ranged from 593 to 609 f.p.s., averaging 601 f.p.s. That works out to 11.47 foot-pounds, on average. The rifle is rated to 30 foot-pounds with air, so I'm guessing it gets about 25 foot-pounds with Premiers (887 f.p.s.). So there is the comparison between CO2 and air. CO2 obviously changes the nature of the airgun, which is a pretty good deal when you just want to shoot targets indoors.
I started at 10 feet, and on the first shot the pellet was lined up with the center of the bull and about three inches low. Since that was the approximate height of the scope over the bore, I was finished at that range and could move the target out. At 15 yards, I shot several groups, making fine scope adjustments to hit the aim point. The groups I got, however, ranged from 1/4" to 1/2", which is far larger than expected. Having noticed the very small exit hole in the muzzle cap of the barrel shroud, I held it up to the light to see if there were any silver streaks on the side of the hole; and, of course, there were.
Some of the pellets were brushing the side of the muzzle cap and destabilizing. To get better accuracy, I needed to drill out the hole in the cap. This gun is on loan from Pyramyd Air, so there won't be any drilling. Instead, I removed the shroud, and the groups tightened right up! I knew what to look for because I've had this problem with other British PCPs that used a shroud. They drill the exit hole a little too small and sometimes the pellets nick the edge on their way out. Enlarging the hole just a little makes all the difference.
I'm still getting used to the 10-lb. trigger. Shooting from a bench, I can keep the gun steady, but it feels strange to have to pull that hard to make it go.
I will test this rifle at long range for you next. The 3-12x Leapers scope I'm using is a good compliment to the accuracy potential of the rifle, so we will see just how good it can be!