SI Enhanced AR-15 Complete Lower Parts Kits

In stock

The Strike Industries Enhanced AR-15 Complete Lower Parts Kits offers a convenient upgrade package for the AR15 and those looking for a complete Strike solution for new builds, or to update their plain jane AR. This kit includes all the essentials that you'll need to build out your AR (minus the pistol grip).

This complete kit includes our fire control group which offers a crisp 5.5-8.5 lb pull, with unmatched smoothness for mil-spec style AR15 triggers. Longitudinally ground and polished sear engagement surfaces coupled with precision cut sear angle equate a vastly improved trigger feel without sacrificing safety or reliability.

With our Strike Enhanced parts you're getting better aesthetics and performance than the average LPK.

COMPATIBILITY: AR-15 and AR-9 mil-spec lower receivers

NOT COMPATIBLE: AR-10: Bolt Catch, Bolt Catch Roll Pin, Pivot Pin and Takedown Pin are not compatible with AR-10 lower receivers.



- Enhanced Bolt Catch - features improved grip surfaces and angles
- Strike Magazine Catch
- Strike Magazine Catch Button
- Enhanced Pivot Pin - longer of the two large pins.
- Enhanced Takedown Pin - smaller of the two large pins.
- SI Selector Lever - 2 included in package
- SI Selector End Plate
- SI 60-90° 3-in-1 Selector Shaft - with screws

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

- Bolt Catch Plunger – mushroom shaped pin
- Bolt Catch Roll Pin - smaller of the two roll pins.
- Hammer Pin solid pin with machined grooves; can be inserted from either side.
- Pivot Detent - same as takedown detent; both sides usually rounded or semi-conical.
- Selector Detent - one end is flat, the other pointed/semi-conical.
- Takedown Detent - same as pivot detent; both sides usually rounded.
- Trigger Pin - same as hammer pin; can be inserted from either side.
- Buffer Retainer large hollow barrel with small pin protruding from the top

- Includes SI's signature Enhanced Lower Parts (AR-EBC, New improved SI-SMC, AR-EPTP, & AR-HS-60/90-3in1
- SI's Trigger Springs provide a consistent 5.5 ½ to 8 ½ lbs trigger pull with our fire control group
- Phosphate grigger and hammer are CNC machined investment cast, heat treated, precision ground.

WARNING: This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information: