How To Determine Regulator/HST Setting via Velocity Testing

Here is how I figured out where the fps were for my chosen pellet at the stock regulator setting on my EdGun…

I loosened the spring at least one full turn from where the fps were that I wanted (it may take more depending on how the reg is set) and began shooting ten shot strings.

At first I turned the HST screw in 1/2 a turn but decided that 1/4 turn would be a better indicator. As I shot I recorded each HST adjustment and each pellet velocity.

If you turn in the HST and your velocity doesn’t rise, turn the HST out one full turn or more and start again. At the end I show how to analyze the strings to determine the regulator setting based on the HST tension.

String #1
848.8
859.4
848.5
860.1 (max)
849.9
852.2
846.1
847.8
855.3
843.1 (min)

Max spread 17fps, avg velocity 851.6fps.

1/2 turn in on the HST.

String #2
898.0
897.1
901.2
903.6 (max)
894.6
899.2
901.4
903.3
895.8
892.9 (min)

Max spread 10.7fps, avg velocity 898.25fps. About a 50fps jump from string #1.

1/2 turn in on the HST.

String #3
951.2
952.2
949.1
950.4
951.5
955.2
956.5 (max)
948.6
946.7 (min)
951.4

Max spread 9.8fps, avg velocity 952.1fps. About a 50fps jump from string #2.

1/4 turn in on the HST (decided that a 1/4 turn at this point to the end was probably more accurate).

String #4
971.8 (max)
971.1
965.0 (min)
967.3
965.9
965.6
968.7
971.5
967.2
966.3

Max spread 6.8fps, avg velocity 968.4fps. About a 15fps jump from string #3.

1/4 turn in on the HST.

String #5
981.7
982.4
985.7
975.7 (min)
985.1
984.5
987.2 (max)
987.1
986.8
983.5

Max spread 11.5fps, avg velocity 981.5fps. About a 15fps jump from string #4.

1/4 turn in on the HST.

String #6
992.9 (max)
985.5
990.9
990.0
985.1 (min)
992.5
992.1
992.8
992.8
989.2

Max spread 7.8fps, avg velocity 989.0fps. About a 10 fps jump from string #5.

1/4 turn in on the HST.

String #7
994.5 (min)
999.1
996.8
996.5
998.8
994.9
997.1
999.3 (max)
997.0
997.2

Max spread 4.8 fps, avg velocity 996.9fps. About a 10 fps jump from string #6.

1/4 turn in on the HST.

String #8
1003 (max)
996.6
999.5
1000
1001
999.9
993.6 (min)
1000
1000
997

Max spread 9.4 fps, avg velocity 998.3fps. About a 2 fps jump from string #7.

Notice how at the end of string #7 the spread is the smallest and when I did the 1/4 HST turn in and shot string #8 the velocity only went up by 2fps? This is a good indicator that the reg is shooting at it’s most efficient in string #7.

From this test I figured my reg was set to shoot my pellet of choice at around 996fps. I wanted somewhere around 880fps, with the ability to go from about 850 to 900 for tuning.

So 3/4 of a turn in on the reg got me where I wanted. From my testing so far, 1/4 turn on the regulator screw is about 50fps.

When I get some time this weekend i’ll post some before and after setting the reg shot strings (i’m getting over 150 shots per fill from a 177 R3 standard). This will show the drop in the standard deviation as well as the overall spread (high and low velocities) and what I call the max jump (the difference in velocity from shot to shot).

It’s so easy to disassemble this rifle and adjust the regulator it’s not even funny. I spent more time worrying that it would be hard I could have done it ten times over.

So while it is easy, don’t do it unless you absolutely need to or feel that you can see it all the way through.

Ed would say don’t do it at all. 😉

But IF you decide to do it, I hope I have given you insight into the first step in figuring out where the regulator is set without opening up the rifle.