With our recent shipment of Engage Armament Lowers, I have been doing a number of AR-15 builds. I wanted to take this time to give out my official recommended parts list. This list is not comprehensive, but it is a good place to start.
- Mil-Spec Engage Armament (ENG-15) lower (low shelf for accu-wedge and RDIAS)
- Spike's Tactical LRPK
- VLTOR Receiver Extension (mil-spec)
- Colt Castle Nut (staked)
- MAGPUL ASAP
- Buffer and spring type varies based on upper used, Colt H2 and Spike's ST-T2 usually work with everything
The reason we use the Spike's LRPK is the major parts (trigger, hammer, disconnector, etc.) appear to come from the same source as those used by Colt and Daniel Defense, at least with the kits I've seen in the past year. They use stainless spiral roll pins which are nice, they usually don't cause any of the anodizing to flake off on the corners of holes like split roll pins do. The Bolt catch fits our lowers very well, and makes for a solid mounting point for a BAD lever.
The VLTOR receiver extension is of high quality, and the anodizing is a nice dark black, matching our lowers. Spike's receiver extensions work fine but they have a grey-ish finish which doesn't match very well. A somewhat useless feature is VLTOR puts numbers on top of the tube that are visible through the hole on top of the Colt M4 buttstock, and its clones. It also has a good fit with most Magpul stocks.
The Colt castle nut is the only one I've seen with consistent quality, that threads tightly onto the VLTOR extension. You'd be surprised at some of the receiver extension/buffer tube kits people bring in... It's vital to spend a few dollars more in order to have a weapon that will not fall apart or unscrew itself when you least expect it. These castle nuts also do not deform or mar when torqued to proper spec, and have the proper relief to have the receiver end plate/ASAP staked correctly. I have yet to have one of these come loose, and many of my builds have been for people who use a single-point sling. A side note, if you bring an old-school CAR castle nut, I will crush it in my vise so no one will ever try such a silly thing ever again.
The ASAP is a great addition to SBRs and 16" carbines. We can always change this out for a standard receiver plate or another sling mount if you wish.
Obviously this is a starting point. Most people want to trash the A2 pistol grip, as there are much more ergonomic options out there that incorporate storage. My personal favorite is the TangoDown BG-17, as it fits my hand perfectly. Ambidextrous controls and aftermarket triggers are really the only place to go from here, but we feel the Spec-G lower has and will continue to fit the needs of our demanding customers!
Pictured below are a couple of SBRs that I've built. The black one is my personal rifle and the HK Mk23 was added as a size reference.
- Mil-Spec Engage Armament (ENG-15) lower (low shelf for accu-wedge and RDIAS)
- Spike's Tactical LRPK
- VLTOR Receiver Extension (mil-spec)
- Colt Castle Nut (staked)
- MAGPUL ASAP
- Buffer and spring type varies based on upper used, Colt H2 and Spike's ST-T2 usually work with everything
The reason we use the Spike's LRPK is the major parts (trigger, hammer, disconnector, etc.) appear to come from the same source as those used by Colt and Daniel Defense, at least with the kits I've seen in the past year. They use stainless spiral roll pins which are nice, they usually don't cause any of the anodizing to flake off on the corners of holes like split roll pins do. The Bolt catch fits our lowers very well, and makes for a solid mounting point for a BAD lever.
The VLTOR receiver extension is of high quality, and the anodizing is a nice dark black, matching our lowers. Spike's receiver extensions work fine but they have a grey-ish finish which doesn't match very well. A somewhat useless feature is VLTOR puts numbers on top of the tube that are visible through the hole on top of the Colt M4 buttstock, and its clones. It also has a good fit with most Magpul stocks.
The Colt castle nut is the only one I've seen with consistent quality, that threads tightly onto the VLTOR extension. You'd be surprised at some of the receiver extension/buffer tube kits people bring in... It's vital to spend a few dollars more in order to have a weapon that will not fall apart or unscrew itself when you least expect it. These castle nuts also do not deform or mar when torqued to proper spec, and have the proper relief to have the receiver end plate/ASAP staked correctly. I have yet to have one of these come loose, and many of my builds have been for people who use a single-point sling. A side note, if you bring an old-school CAR castle nut, I will crush it in my vise so no one will ever try such a silly thing ever again.
The ASAP is a great addition to SBRs and 16" carbines. We can always change this out for a standard receiver plate or another sling mount if you wish.
Obviously this is a starting point. Most people want to trash the A2 pistol grip, as there are much more ergonomic options out there that incorporate storage. My personal favorite is the TangoDown BG-17, as it fits my hand perfectly. Ambidextrous controls and aftermarket triggers are really the only place to go from here, but we feel the Spec-G lower has and will continue to fit the needs of our demanding customers!
Pictured below are a couple of SBRs that I've built. The black one is my personal rifle and the HK Mk23 was added as a size reference.
