[PDI] Strong Recoil Spring / Tokyo Marui HI-CAPA & M1911A1

SUS303 unequal pitch springs hand-wound by artisans
Compatible with TM HI-CAPA4.3 & 5.1, M1911A1.
Unlike the "Recoil Spring HD," the soft version uses an uneven pitch, making it worthy of its name "Strong."

Tension level: HD < HD strong < genuine SP
The genuine SP is the stiffest and has the highest tension, but the higher the tension, the more energy is required to move it back when recoiled.
Especially in winter, when gas pressure drops, the gas pressure that retracts the slide decreases, and a stiff spring cannot retract it sufficiently, which can result in a decrease in the number of shots fired.To address this issue, the HD Strong has a slightly lower tension than the original, and compensates for the difference with the explosive force of the uneven pitch.
Experience the power of the unequal pitch (light pull and quick return characteristics) that produces the same powerful impact as the original.

Blowback efficiency improved! Improved by about 20% with the same magazine.
As a test to check the efficiency of the SP, we measured the number of times it could be retracted to the point where the slide stop engaged at 1 Mag.
While the stock SP's slide stop becomes ineffective after 50-55 rounds, the HD Strong lasts up to about 65 rounds! And yet the recoil shock is the same as the stock one.
This proves to be effective during seasons and conditions when gas pressure is low.
*The HI-CAPA was kept parallel during the test. The same magazine was also used. The test was conducted at an interval of one trigger per second. The HI-CAPA 5.1 used for the measurements was in 100% genuine condition, from distribution stock in the first half of 2009.

Ideal for metal outer barrels (SUS, steel)! Tension that overcomes weight increases
The metal outer barrel (SUS, steel) increases the weight, but this product has the same tension as the genuine SP to push back the load.
Please use this spring when using a metal outer barrel.

Specifications
■Compatible models:
#Tokyo Marui HI-CAPA4.3
#Tokyo Marui HI-CAPA5.1
#Tokyo Marui M1911A1
■Material: SUS304


※please note※
If you have customized your airsoft gun or replaced parts, be sure to measure the bullet speed using a bullet speed meter to ensure it is within the legal limit (possession of bullets over 0.98 J is prohibited). Also, be careful not to exceed the legal limit during the work.