In the sub $1k AR thread, someone mentioned the parts kit makes a difference, and it got me thinking.

 

What makes a parts kit good or bad?

 

I haven't built a high-end AR yet. My first build probably ran around $500-600 using decent, but not great, components, and has a PSA lpk. I used a PSA lpk on my second build as well. Both have the PSA enhanced polished milspec trigger group. My current build is using many of the same components but looking for a better upper.

 

What would make a $$$ lpk worth it over the cheaper options? Are the springs going to last longer, or have a better heat treat, or are the pins going to be a better material? Or is the beauty of buying a PSA lpk over a $$$ one is that I can buy a second PSA one and have a full set of spare parts should the worst happen?

Personally I think most of the "mil-spec" trigger components in LPK's are kinda garbage. You can get the various "enhanced" stuff but to my mind the ALG trigger should be the minimum quality anyone puts in their guns.  At that point, it isn't worth buying the LPK's anymore, just buy the few remaining parts from brownells or midway and select one of the better names. 

 

In short, I don't buy LPK's, not worth it. 

 

edited to add: or buy something like JP LPK minus trigger and add your choice of decent trigger: https://www.rainierarms.com/jp-lower-parts-kit-minus-trigger-assembly

I mentioned that. The biggest difference you will see is with the larger metal parts. The bolt catch. The mag release lever. The takedown and pivot pins. Etc.

 

I had a spikes lower I was installing a PSA LPK that front takedown pin wouldn't "click" when taking down the rifle. A colt part fixed it. From smaller parts, the detents seem to vary in finish but they seem to function the same.

 

There are an abundance of great LPK offerings now. BCM, ALG, colt triggerless from g&r tactical. Even the Midwest Px lower parts kits are nice. I tend to just buy the parts individually from brownells since I go with geissele trigger and battle arms safety and BCM grip and battle arms takedown and pivot pin there isn't much left to buy in a "kit"