M4A1/SCARv2/UMP45/MP5V2/hk416d/GEN8,9,10/V2 GEARBOX ETC
SILVER HQ 1.2mm UPGRADE SPRING
1.2mm is the sweet spot for distance and accuracy
We have done all the hard work and spent a lot of money in research for you and these parts that I am now selling are the best and will be the right type of upgrade that will give you the best benefits. These parts are limited so first in first served.