38T
Crosman 38T.

Part 1
Part 2
Part 3
Grips & tips
Part 4
Resealing the Crosman 38T revolver: Part 5
Part 6
Part 7

History of airguns

This report covers:

  • Pellet test
  • The test
  • Rotate the barrel
  • Next group
  • Discussion
  • The rear sight
  • Rotate the barrel some more
  • What has been learned? Summary

In this report we will learn a lot more about the workings of the Crosman 38T revolver. I tested the .22-caliber 38T that wasn’t shooting very accurately in the Part 7 test. This is the revolver that was resealed by reader 45Bravo, who is Ian McKee. He suggested turning the barrel to see if that would affect accuracy. Today we will see if it did.

Pellet test

This particular 38 T in .22 caliber didn’t really have a favorite pellet. RWS Superdomes were the most accurate, but I decided to something entirely different — based on your answers to my question, “How to test pellets?“. I used a pellet that I didn’t test for accuracy previously in this air pistol — the RWS Hobby wadcutter. In other words, I tested this concept with a pellet whose accuracy I knew nothing about in this air pistol. It was the only pellet I used for the entire test. Doing that helped me a lot with the how I test pellets question — because the question always has to include a test gun, as well.

The test

I shot 5-shot groups from a bench rest at 10 meters. The pistol was hand-held and my hands were rested on the sandbag. I’ll explain why 5 shots and not 6 in a bit. The first target was to establish where the pistol is at the start of the test.

The first 5 pellets landed in a vertical group a little to the right of the centerline. The group measures 2.068-inches between centers. This is approximately how good this pellet is in this gun when shot by me on this day.

38T first group
On the first target five Hobby pellets landed in a group measuring 2.068-inches between centers.

Rotate the barrel

For the first test I disassembled the pistol and rotated the barrel about 30 degrees clockwise as seen while holding the pistol in your shooting hand. Before I rotated the barrel I made a mark on the outside of the barrel to index it.

38T disassembled
One slotted screw and the barrel shroud comes off. One more Allen screw on top of the receiver and the barrel is loose to rotate. It’s a two-minute job, start to finish.

I had thought I would leave the shroud off the barrel after turning it until it dawned on me that the front sight is on the barrel shroud. A front sight is fairly necessary when you want acuracy! So back on it went.

Next group

My next group was interesting. I saw the first shot land low and hit the edge of the bull between 4 and 5 o’clock. The other four pellets went higher on the target with three of them in a nice tight group. That gave me confidence that I was on the right track by rotating the barrel.

The group measures 1.948-inches between centers. The upper 4 shots measure 0.847-inches between centers.

38T first turn
The first turn of the barrel produced this group. It looks as large as the first one, but the last 4 shots are all above the first one. Five pellets in 1.948-inches with the top four in 0.847-inches.

I found it easier to load the pellets this time, after rotating the barrel. They seemed to go into the cylinder much better and without hitting anything. Maybe what Ian said about aligning the cylinder with the barrel is also true.

I shot a second group without changing anything. I wanted to confirm that the previous group was a good one. This time the first shot hit the edge of the bull at 6 o’clock and the other 4 went to 2:30 on the bull. Five shots are in 1.97-inches at 10 meters with the last 4 in 0.541-inches. This is the accuracy I expected to see from this airgun. And it gave me a great idea.

38T first turn group 2
First shot at the bottom and the other 4 are in 0.541-inches. The first shot opens the group to 1.97-inches.

Discussion

I had noticed that twice the first shot had hit low on the target. It may have done it on the first group as well, but I didn’t see it that time. What if I loaded five pellets but fired 6 times? The first shot would be a blank that might serve to settle the revolver for the next five shots. Would that tighten them?

I adjusted the rear sight to the left, I thought, and shot a third group with the same barrel rotation. This time all five pellets stayed together, going into a group that measures 1.067-inches between centers. The group didn’t move over to the left as I had thought and I discovered why on the next try.

38T first turn group 3
This is the third group fired since the barrel was turned 30 degrees. This time the rear sight was adjusted to the left, but it didn’t take. These five shots measure 1.067-inches between centers.

The rear sight

Apparently the rear sight was adjusted as far to the left as it wants to go. Turning the screw both ways moves the notch to the right, and the adjustment screw is starting to back out of its hole.

I adjusted it to the left as far as it would go and then I pressed the notch to the left and the notch moved a small amount more. This is as far left as I can get it.

38T first turn group 4
The group didn’t go to the left like I hoped, but five Hobbys are in 1.466-inches, which with this revolver isn’t that bad.

Rotate the barrel some more

I decided to rotate the barrel further in the same direction (clockwise) to see what that would do. So off came the shroud and I rotated the barrel to a total of 180 degrees from the point where it started. Then I put the shroud back on and shot what would be my last group. This one was an eye-opener!

The final five pellets went into 1.338-inches at 10 meters. But look where they hit. They went up and to the left. That tells me the barrel is bored off center or it is bent, and turning the barrel has a noticable effect on accuracy and also the point of impact. At least it does on this one. Ian was right!

38T second turn group
After the barrel was rotated 180 degrees the pellets landed up and to the left. Five Hobbys are in 1.338-inches center-to-center.

What has been learned?

I have learned that rotating the barrel of a Crosman 38T is not just a way to tighten the group. It’s also the way to move the impact point, just as Ian told us.

I have also learned that the .22 caliber version of the 38T is indeed accurate. You just have to be willing to work with it.

Summary

We aren’t done with this series yet. There is still the adjustable mainspring tension to explore. So stay tuned and we will get to it