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A great design once again by a great company! The Invert MINI bolt spring kits. Each kit includes 3 different force springs, from hard to soft. All springs have LESS force than your stock MINI bolt spring, its a tuners delight. This kit is optimized for use with our Delrin V2 bolt and allows for reduced input pressures, reduced firing signature, improved shot consistency, and reduced bolt wear while reducing mass.
Spring Kit Chart
Warning-May not work properly with stock or some other aftermarket bolts. We highly recommend using this with the NDZ Tru Flo V2 Bolt