Here's a look at how to increase or decrease the power of the BSA R10. Always make sure that you use a chronograph regularly to make sure that you stay within any legal limits. This is an easy job to do. All you will need is a 4mm Alan wrench to undo the stock and if the end cap doesn't come off by hand you will need to heat it with a blow torch or similar to melt the glue or Loctite that holds it in place. Be careful with any heat source. You will also need a wide blade screw driver or chisel to make the adjustments, or something to turn the adjuster for the hammer spring.