New full power kit for both older and the later high velocity guns. Can be used in any HW77-97-60-61.

Includes hardened and polished rear flange washer.
 

 Two spring guides and spring. Supplied with black tar.

If your getting high 700's or very low 800's in a new gun in .177 and sub 700 fps with lwt pellets in .20- Than your new gun has issues that higher power kits will not fix. Putting in a higher power kit will not get more power and often lower power. Sealing and barrel issues are the cause.