Air Rifle Question
I have an older Slavia 630 break barrel air rifle in .177 caliber. For the Canadian market this gun was derated to less 500fps muzzle velocity. What I would like to know is if the muzzle velocity can be increased by sourcing a higher rate spring (if so where?) or machining a spring shim to increase the preload. Also, much the same question for a Beeman air rifle. If I have a Canadian market version with the lower muzzle velocity is there a means to increase it?
Can't say for sure
There are a few blogs around for airguns, even a few Canadian ones.
From what I understand... some of the airguns are derated by drilling holes in the pressure tube and others by reducing the strength of the spring.
I don't have my list of links here but there is a forum... Airgun Machinist Workshop... I think. You might ask over there.
Please try to find the link,Google search did not turn up any results.
Originally Posted by huntinguy
Google Chinese airgun forum, I was active in this forum years ago when hi
power Chinese airguns hit the market. It was common practice to replace the
stock spring with a Maccari spring, you can also find info on better seals.
There are alot of tips on how to increase FPS for any brand of airgun.
Give these a try
Lot of good people and info at airgunone.com
When the piston comes to a stop the air has been compressed into a given space. If that space is reduced the pressure will go up and the velocity increased. Redesign the piston to accomplish this. A longer barrel will increase the performance also. With a precharged pneumatic the space after the regulator is increased to accomplish an increase in velocity.
With the pneumatic using a longer barrel will tend to make it much quieter.
The forums there are a great source of information.
Stronger spring, increased swept volume and reduced (if any) headspace will all increase power.
If the trigger mechanism latches on a rod which extends from the piston head out the back of the spring then this is often lengthened to reduce power, if you have spare length & the spring & cocking mechanism will deal with it, shortening this is one way to increase swept volume.
Barrel length is a funny one on a springer, on high end guns like the Beeman R1 shortening the barrel can increase power, on PCP & CO2 lengthening gives more up to a point,
Last edited by NickH; 07-25-2009 at 06:10 AM.