BSA Power adjustment

[Kingston73]

Question about adjusting power on a BSA (r10 specifically but I think they all are the same basic adjustment?) - to reduce power you turn the hammer spring counter clockwise, correct? 

Without a chronograph can anybody give me an approximate amount of change per full 360 deg turn?  Is there any way I can get even a rough idea of my power without using a chrono?

[Gipper]

You are correct, counter clockwise reduces power. As far as how much a 1/2 turn would effect your speed is nearly impossible without a chronograph.  If you had the spring nearly maxed for preload a 1/2 turn may make only a slight difference.  If you had very light preload adding a 1/2  turn could make a significant difference.  A chrony is definitely a plus (must) when tuning pcps.  Only thing I can think of is if you have another rifle you know the fps on with a given pellet you could compare penetration between the 2 rifles with the same pellet.  May also look into a chrono app for your smart phone if you have one,  won't be as accurate of course but could get you in the ball park and at least let you know if you are seeing any increase in velocities versus just using more air.

[toddbrat]

I've used ChronoConnect on my Android with decent success. Another option is a PITA but it somewhat works:

Using ChairGun and a flat shooting range, 50-75 yards if possible, place targets at 5 yard intervals starting at 10 yards. Zero you rifle first for 25. Then, check the path for as far as you can to measure the arc. You'll need to start plugging numbers into ChairGun to get them to match up, but it will get you pretty close. Take 3-5 shots per target and use the average drop. I don't have a chrono or a flat range, but this is the method I use. "Close enough" is all I personally need but a chronograph is on top of my short list of things to buy.

[solder]

One full turn is about 10 fps.