I started out with springers, switched to PCPs out of frustration, then one day decided it was time to go back and revisit springers. I knew good accuracy was possible because I had seen springer shooters pound 1/2" spinners at 30 yards all day long when I flirted with FT, especially that guy with the Whiscombe. The gun I decided to work with was the TX200HC that I had purchased from Precision Air. Here is the history of that rifle.
Stock power plant, 15.5 FPE, JSB 7.87 pellets
Vortek PG-2 SHO, 14.0 FPE, JSB 7.87 pellets
Vortek PG-2 SHO, minimum lubrication,14.8 FPE, JSB 8.44/4.53 pellets
Vortek PG-3-12, minimum lubrication,11.8 FPE, JSB 8.44/4.53 pellets
Vortek PG-3-12, short stroke piston, minimum lubrication,10.8 FPE, JSB 8.44/4.53 pellets
Vortek PG-3-12, short stroke piston, minimum lubrication,10.8 FPE, AA 8.4/4.52 pellets
One thing to note through all of this is that the size of the smallest groups never changed! Maybe every couple sessions a MOA or smaller group would occur. Leading me to conclude that the size of the smallest group doesn't mean much. So I started tracking the average of 5 groups to try to figure out if I was making any progress. At the beginning, in the stock configuration, group variation was frustratingly huge. You would think you were on to something, and the next day it would all go to heck.
So step one was to perform a kit tune at the same power level. The gun was smoother cocking and quieter, but no real improvement in accuracy or group consistency.
After doing some velocity studies, I saw that extreme spread was excessive, around 30 FPS. I cleaned up the internals, applied minimum lubrication, and sure enough the ES and SD came way down. I hoped this might eliminate the fliers that caused the large variation in group size, and it probably helped some, but I was still plagued with a lot of group variation.
The next step was to drop power down to around 12 FPE. This did not automatically turn the rifle into a laser, but with lower recoil it was easier to see how the rifle was reacting to each shot and make corrections to technique.
The last major step was to install a short stroke piston and reduce power a little more. I really expected a lot from this change, but it took a lot of shooting to conclude that some improvement had been made. On the other hand, I love the cocking behavior. Very linear, light, and of course with a much shorter stroke.
The last change was a switch in pellets to the AA Field. Again no change in smallest group size, but improved consistency, which is what I like.
At the beginning of this journey I was struggling to keep groups under 3 MOA. Midway average group size was running just a bit over 2 MOA. Today I can stay under 2 MOA if the wind cooperates. The big contributors I would say were the use of minimum lubrication, the drop in power, and the change in pellets to the AA Field. The short stroke piston is icing on the cake, in that it makes the rifle that much more enjoyable to shoot.
Here are today's groups from a sighting in session. Wind was still variable, but the gusts were infrequent enough I could just wait them out.
I did note an error, but it is included in the group size. I apparently have a problem with throwing shots high. I hope at least some of you found this helpful, especially if you are thinking performing some kind of tune on your own springer.
Stock power plant, 15.5 FPE, JSB 7.87 pellets
Vortek PG-2 SHO, 14.0 FPE, JSB 7.87 pellets
Vortek PG-2 SHO, minimum lubrication,14.8 FPE, JSB 8.44/4.53 pellets
Vortek PG-3-12, minimum lubrication,11.8 FPE, JSB 8.44/4.53 pellets
Vortek PG-3-12, short stroke piston, minimum lubrication,10.8 FPE, JSB 8.44/4.53 pellets
Vortek PG-3-12, short stroke piston, minimum lubrication,10.8 FPE, AA 8.4/4.52 pellets
One thing to note through all of this is that the size of the smallest groups never changed! Maybe every couple sessions a MOA or smaller group would occur. Leading me to conclude that the size of the smallest group doesn't mean much. So I started tracking the average of 5 groups to try to figure out if I was making any progress. At the beginning, in the stock configuration, group variation was frustratingly huge. You would think you were on to something, and the next day it would all go to heck.
So step one was to perform a kit tune at the same power level. The gun was smoother cocking and quieter, but no real improvement in accuracy or group consistency.
After doing some velocity studies, I saw that extreme spread was excessive, around 30 FPS. I cleaned up the internals, applied minimum lubrication, and sure enough the ES and SD came way down. I hoped this might eliminate the fliers that caused the large variation in group size, and it probably helped some, but I was still plagued with a lot of group variation.
The next step was to drop power down to around 12 FPE. This did not automatically turn the rifle into a laser, but with lower recoil it was easier to see how the rifle was reacting to each shot and make corrections to technique.
The last major step was to install a short stroke piston and reduce power a little more. I really expected a lot from this change, but it took a lot of shooting to conclude that some improvement had been made. On the other hand, I love the cocking behavior. Very linear, light, and of course with a much shorter stroke.
The last change was a switch in pellets to the AA Field. Again no change in smallest group size, but improved consistency, which is what I like.
At the beginning of this journey I was struggling to keep groups under 3 MOA. Midway average group size was running just a bit over 2 MOA. Today I can stay under 2 MOA if the wind cooperates. The big contributors I would say were the use of minimum lubrication, the drop in power, and the change in pellets to the AA Field. The short stroke piston is icing on the cake, in that it makes the rifle that much more enjoyable to shoot.
Here are today's groups from a sighting in session. Wind was still variable, but the gusts were infrequent enough I could just wait them out.
I did note an error, but it is included in the group size. I apparently have a problem with throwing shots high. I hope at least some of you found this helpful, especially if you are thinking performing some kind of tune on your own springer.
