• 1x Bolt Catch Spring - easily confused with the disconnector spring; disconnector spring is tapered though.
  • 1x Buffer Retainer Spring - second largest coil type spring in the kit.
  • 1x Disconnector Spring – slightly larger than bolt-catch spring, identifiable because one end is a little bit wide than the other.
  • 1x Hammer Spring - largest of all the springs.
  • 1x Magazine Catch Spring - this is the largest coil spring in the kit.
  • 1x Pivot Detent Spring - same as the takedown detent spring, so there are two in a kit.
  • 1x Selector Spring - similar to the takedown and pivot detent springs, but larger diameter; there will only be one of these.
  • 2x Takedown Detent Spring - same as the pivot detent spring, so there are two in a kit.
  • 1x Trigger Spring - the smaller of the two largest springs.

Pins and Parts:

  • 1x Strike Industries Enhanced Bolt Catch - features improved grip surfaces and angles
  • 1x Strike Industries Enhanced Magazine Catch
  • 1x Strike Industries Enhanced Magazine Catch Button - features improved grip surface
  • 1x Strike Industries Enhanced Pivot Pin - longer of the two large pins.
  • 1x Strike Industries Enhanced Takedown Pin - smaller of the two large pins.
  • 1x Strike Industries Selector Lever - 2 included in package
  • 1x Strike Industries Selector End Plate
  • 1x Strike Industries 60-90° 3-in-1 Selector Shaft - with screws
  • 1x Bolt Catch Plunger – mushroom shaped pin
  • 1x Bolt Catch Roll Pin - smaller of the two roll pins.
  • 1x Hammer Pin – solid pin with machined grooves; can be inserted from either side.
  • 1x Pivot Detent - same as takedown detent; both sides usually rounded or semi-conical.
  • 1x Selector Detent - one end is flat, the other pointed/semi-conical.
  • 1x Takedown Detent - same as pivot detent; both sides usually rounded.
  • 1x Trigger Pin - same as hammer pin; can be inserted from either side.
  • 1x Buffer Retainerlarge hollow barrel with small pin protruding from the top

This Strike Industries Enhanced Lower Receiver Parts Kit does not come with the trigger, hammer, disconnector, pistol grip assembly, and trigger Guard.


  • AR-15 lower receiver

*Magazine Catch thread is metric and will not work with California Compliant Bullet Button or other third party mag release buttons.


Whether you start out to do a major upgrade on an existing rifle or plan on building that perfect system from the ground up, the sheer number of small parts that need to be added to the purchase list can be overwhelming. Of course, the performance of each tiny spring and pin is also important to the functionality of the rifle as a whole. For many armorers, the best way to handle the upgrade of an AR-15 lower is to use a pre-packaged lower parts kit like one of the Strike Industries AR Build kits.

If you’re upgrading a lower receiver, there’s no need to wade through a sea of inferior parts. A Strike Industries Enhanced AR-15 Builder’s Lower Parts Kit includes high-quality versions of everything on that laundry list of small but important lower parts and leaves you the freedom to use the large trigger parts that fit your shooting style. No guilt over wasting money on duplicate parts, and no compromise with a trigger you didn’t want.

The Strike Industries Enhanced Lower Kit features many of the same reliable parts as Strike’s other AR build kits, but offers some premium upgrades for those of us who want the whipped cream and cherry on top. The improved gripping surfaces on Strike’s Enhanced Bolt Catch and Magazine Catch Button are just two of those little extras included in this Enhanced Lower Parts Kit. Upgraded Pivot and Takedown Pins, as well as Strike Industries best selector parts, will push the performance of your upgraded rifle beyond the realm of simple expectations. If you want to build your dream rifle, use the Strike Industries Enhanced AR-15 Builder’s Lower Parts Kit.

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