Anderson Manufacturing AR-15 Lower Parts Kit - Stainless Hammer and Trigger

Manufactured by Anderson Manufacturing
MPN: G2-K421-A000-0P
Manufactured by Anderson Manufacturing
82 Reviews

Out of Stock

NOTE: Limit 1 per household. Quantities exceeding 1 will not allow checkout.



Anderson Manufacturing builds rifles, pistols, and parts utilizing the latest in computerized manufacturing. By keeping manufacturing in house, Anderson can offer quality, American-made products at an affordable price, backed by a limited lifetime warranty.

The Anderson Manufacturing Lower Parts Kit contains almost everything you need to assemble a stripped lower receiver. Just add your favorite stock kit for a complete lower receiver!

This MIL-SPEC parts kit is precision machined for a drop-in fit with nearly all lower receivers on the market. Features the Anderson Manufacturing stainless steel hammer and trigger set with a lightened speed hammer for improved lock time!

Kit includes:

  • (1) Stainless steel hammer
  • (1) Hammer spring
  • (1) Stainless steel trigger
  • (1) Trigger spring
  • (2) Hammer/trigger pins
  • (1) Disconnector
  • (1) Disconnector spring

  • (1) Bolt catch
  • (1) Bolt catch plunger
  • (1) Bolt catch roll pin
  • (1) Bolt catch spring

  • (1) Buffer retainer
  • (1) Buffer retainer spring

  • (1) Magazine catch
  • (1) Magazine catch button
  • (1) Magazine catch spring

  • (1) A2 pistol grip
  • (1) Pistol grip screw
  • (1) Pistol grip lock washer

  • (1) Standard safety selector
  • (1) Safety selector detent spring
  • (1) Safety selector detent

  • (1) Takedown pin
  • (1) Pivot pin
  • (2) Takedown/pivot pin detents
  • (2) Takedown/pivot pin springs

  • (1) Trigger guard
  • (1) Trigger guard roll pin

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BrandAnderson Manufacturing
ManufacturerAnderson Manufacturing
Weight8 Oz

WARNING: This Product can expose you to chemicals which is known to state of California to cause Cancer and Reproductive Harm. For more information, see

First time AR build


Added this LPK to the budget Anderson stripped lower. Everything fit as expected. I just followed a YouTube how to video. Bought a DT stock kit as well. Now I just need an upper and I'm in business! Primary Arms is great. I just wish they were open a few hours on Saturday for the working man.

Everything l buy @ Primary Arms


As l expected, on time and exactly what I ordered. I've been doing business with them for two years now and they are a 5 star company.

Good fit, good finish


As with everything I have ordered from Primary, top quality and fast shipping.

Parts kit


Awesome service and shipping. Although i don't need it, I would have thought a parts list and instructions would have been included. No biggy.

good product at great price


best bet for basic builds.

Great Price, great service


Bought this and as always, have never been disappointed by any purchases made from primary arms. I recommend PA to all my friends

Great Parts


Came fast, fit well. Everything seems to work fine.

Lower parts kit


Everything is there and the workmanship looks to be very good.

TC Group


Exceptional quality at a value price. Would buy again!

Anderson lower parts kit


Fast shipper and received product as ordered. Will be doing buisness in the future.Thank You.

Lower receiver parts kit


Fast shipping, best price and as advertised. Doesn't get any better than that!



Fit just like its suppose to! I like better than some more expensive kits work great.

Solid overall. Good value.


Great kit but would be better if the triggers were not so gritty.

Great product for the price.


Have already purchased a few of these lower parts kits and have used on all my lower recievers I have on hand.

Good kit


I bought 5 of these LPK's for some builds. Overall I feel these kits are top notch. All parts for lowers are included. trigger weights : 1 @ 5.5 #, 3 @ 6.5 -6.75# and 1 @ 7#.with just a little break in the triggers were smooth, had little or no creep or over travel. I deducted 1 star due to 2 of the triggers not resetting initially... but with break in they functioned normally. I had to manually push trigger forward to get sear to release and the trigger to reset. One took just a few cycles to get right and the other took about 3 minutes of manipulating trigger to reach reliable reset. Overall I find these to have the best mil-spec trigger I have used yet (after break in). I added a JP lightweight trigger spring kit ($12) to one of the LPK's that had a trigger weight of 6.75# and that brought the trigger to 4.5#. Making it just about perfect.

I can't say enough.


I can all ways trust products from Primary arms. And their prices and customer service are the best around.

great product


I had been looking for a decent parts kit for several weeks for less than $60.00. I found them on sale here for $40.00 and grabbed four. At that price is was cheaper to buy a complete kit instead of buying the "oops" kit. I now have extra parts and am able to complete a few builds. Well built mil spec. Would recommend even at full price.

quick and excellent service!


I had my order in and picked it up almost immediately.

Anderson LPK


I have not installed the kit yet, but it is complete and appears to be good quality. However, Stainless Steel hammer, trigger groups like the one included are not polished, so the pull is very poor. I had this experience with another brand too. Buy ALG ACT. Primary Arms service excellent.

Anderson Manufacturing Lower Receiver Parts Kit -


I like it for a decent build the trigger pull could lighter but its fine all the parts line up and seem fine

Great Customer Service !


I ordered this kit on sale but it sold out before they received my order. The professional service rep assisted me when a new shipment arrived and honored the original sale price and I was very happy. The parts kit is very good for the normal price but even better on sale

Great parts better service!


I ordered this lower parts kit and the post office lost it so after getting a case number from the post office I emailed PA and they shipped a new one out immediately without any trouble or hesitation! I am extremely happy with my parts but am thrilled about how well I was treated by customers service! I WILL be shopping with PA in the future!

Great price and quality products


I received my lower parts kits in just 2 days and I am very happy with the price and it is a great quality parts kit I have ordered in the past and will continue to ordering the future primary arms has quality products at affordable prices and also have a great customer service team. Thank you for your professional team

Decent LPK, great price.


If your on a budget, this is a great kit. It works. I bought two of these and one was missing the bolt catch. Emailed Primary Arms and they simply said sorry swing by and pick one up at no charge. fantastic customer service everytime. Trigger is probably the roughest I've used out of all LPK's but for the money the parts fit and function as they should.

Not Bad


Just finished the first build with the lower receiver parts kit. Fit and finish on the parts was very good, no problems.