P320/ P250 MAGAZINE SPRING, ISMI +10%, X5, M17, M18 17RD & 21RD MAGS

ISMI Plus 10% Extra Power Magazine Springs are ideal when using extended capacity base plates or replacement worn out springs in high-capacity mags such as in the Sig Sauer P320, P250 as well as P365 & like models. This extra power aids in the travel distance and power needed for reliable feeding and function.

When using new magazines and / or plus power magazine springs it may be difficult initially to load magazine to full capacity, especially for low cap magazines or magazines without extension plates. Springs may require a break in period before being able to fully load.

ISMI Premium Springs are manufactured exclusively with certified aerospace specification alloys; chrome silicon. Then their springs are heat treated, shot-peened and stress relieved after winding to enhance performance and durability. Chrome silicon springs have 10x the life of traditional music wire springs, and they hold much better tolerances during compression and cycling.

These springs utilize the same design and manufacturing technology as used in IndyCar and Formula One racing. In a typical 500 mile race, a valve spring in an IndyCar will go through more than 2,500,000 compression cycles. Consideration of factors such as modulus, wire diameter, mean diameter, active coils, total deflection, spring relaxation, maximum service temperature, and operating environment, results in you having modern spring technology available for your pistol.