... I'd like to hear about it as well. Are some complicated ways, but with a specific power goal you only need to do it once, so if the mod fro external adjustment is a lot of work, it's easier to just keep taking the rifle apart and adjusting to that goal.
Ways to adjust power (but none lend them selves to external adjustment without a good bit of work).
I'm going to assume CO2 power (think I remember the pic. you published...this is a co2 tanker, right?)
#1. Smack the valve harder or lighter.
A. Striker spring tension can do this, but with the cock on closing system, can't just tap the end cap for an power adjuster.
B. Striker weight. No easy adjustment here.
C. Striker stroke. Your trigger moving system can give you a small adjustment in this area, but getting the trigger unit to stay put is a pain.
#2. Strangle off the transfer port.
A. Making different sized port seals is the easy way, but no external adjustment.
B. Not enough room for a variable restrictor screw in a standard QB breech... a one-piece riser breech does have the room to add a restrictor screw.
#3. Limit the valve travel.
A. Can limit the amount of valve stem that sticks out of the valve to be smacked by the striker.
(that gets complicated. Changing the valve stem length also changes the striker's stroke).
B. Changing the valve return spring tension.
C. Making a positive stop for the valve stem's travel.
Personally, I'd just take the gun apart a few times, fiddle with whatever seemes easiest to fiddle with, and test it along the way until you get where you want to be. but with co2, temperature plays a big part in energy, and if you tune it up on a 70F day, but "they" test it on an 85F day, you might be faster than you planned on.
took me awhile, but for some on-going tests, got a .177, 20, and 22 QB (these are HPA tankers) all running at about 12 foot pounds. No power limit here, so i just stopped fiddling around when they were between 11.8 and 12.4 foot pounds. So I know the ping-pong game it is to hit a goal..a little fast...a little slow...little fast...etc.
For my tests, I just increase the range a bit for the 12.4 foot pound versions to get impacts to work out very close to equal.
This message has been edited by gubb33ps on Oct 11, 2010 5:19 PM
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