...If you plan on installing an SSG, they work much better with a longer, lighter spring, with about 3-5 lbs. of preload on the spring guide, and about 1/8" of free flight for the hammer.... That requires enough length behind the valve, and often a longer rear cap is required to do that.... However, it spreads out the cocking force, harder to start with (to overcome the preload) and less when fully cocked.... Overall, a properly designed SSG makes the gun FEEL much smoother to cock, as the force does not suddenly peak at the back of the pull-back.... Sorry I could not give you an easy solution to your question....Bob