Sig Sauer P320 Lower Parts Kit


(30 customer reviews)

122 in stock

Categories: , , SKU: RB-Frame-P320


Sig Sauer P320 Lower Parts Kit

This parts kit has all of the pieces necessary to complete your Sig Fire Control Unit or 80% MUP unit
This is an upgraded kit with new drop-safe components. These Sig P320 Parts are compatible with any upgraded Sig p320 slide in 9mm, 40 S&W and 357 Sig.

Parts Included:

  • Trigger stop pin
  • Slide catch lever pin
  • Safety lever pin
  • Sear pivot pin
  • Split coil pin
  • Slide catch lever spring post
  • Take down safety lever
  • Safety lever
  • Slide catch
  • Sear
  • Oring
  • Take down lever
  • Slide catch assembly
  • Spring, slide catch lever
  • Spring, sear (2)
  • Trigger bar spring
  • Spring, takedown lever
  • Flat Faced Trigger
  • Trigger bar
  • Sear housing
  • Manual disconnector

30 reviews for Sig Sauer P320 Lower Parts Kit

  1. Frederick ledger (verified owner)

    Everything you need for none safety 320

  2. Jack Green (verified owner)

    Great quality parts and at a reasonable price. Will be shopping again.
    Thanks Jack

  3. D Owens (verified owner)

    Great Parts kit…great company…Rockey Brass hasn’t let me down yet. And they support veterans.

  4. AC

    Not OEM Sig parts. These are Taiwanese parts manufactured for JSD Supply and their MUP 80% frame. The parts are correctly sized, of high quality, and function perfectly. 4 stars, not for any defect in the physical parts, but for lack of that transparency as to the authenticity of manufacture as listed in the product description.

  5. Erik

    Parts made in Taiwan, still seem good but I love parts made in the good ol USA which would be similarly priced on other websites

  6. Joe Gardner

    Well i have ordered a couple times now and the only thing i am disappointed in i wasn’t using them sooner. i am not sure how i came across them but i sure am glad, the other places i was using were out of stock and more expensive. inexpensive doesn’t have to be cheap, i think they have as good a product as anybody. the service and price is much better.

  7. Dakota

    Awesome parts kit. Feels better than my factory m17 parts

  8. Eric Sadler

    They didn’t feel the need to include a spring that controls the safety mechanism of the gun. Safety third screwing over the customer first. Zero stars if I could thanks for screwing up the holidays.

  9. Dan

    Parts are of very good quality- Everything fit together perfectly- Actual trigger pull ended up at 3.5# right out of the package. Very Pleased! Will definitely be shopping here again.

  10. Tim St.John

    Great kit, better pricing. quick enough shipping. parts are all here and appropriately shaped.


    First as always it way a pleasure doing business with Rockey Brass, In stock and out the door in a matter of a couple days EXCELLENT service. About this product like everything else they sell it fit perfect, cost less then any others and with the upgraded trigger too. Don’t think of shopping elsewhere not when you can get the best deals here

  12. Kirk

    All the parts I needed to finish my MUP-1

  13. Kurt

    I have assembled several FCU’s now and this has been the best pricing I have found for the complete parts kit. AND it’s in stock! I would have liked to have the option to upgrade to an APEX Trigger & Trigger Bar as I currently have multiple SIG triggers & trigger bars that I don’t need. I have saved ROCKEY Brass to my favorites and will start here for my next parts & accessories purchase.

  14. Rob

    First time ordering form Rocky Brass and couldn’t have been happier with the service, price and shipping. Everything came with the kit, individually bagged parts, and they all fit perfectly. Definitely recommended and will be ordering form again!

  15. Mac McLaughlan

    Fits well, works well. Have to say I don’t think it is quite as smooth as the original Sig Sauer P320 trigger, but it is hella better than ANY Glock trigger I have used. That is at the expense of additional and more complicated parts. Haven’t used this for long term yet but I suspect it will have the same durability as the OE parts.

  16. Bennet Milloy

    Came fast and exactly like it showed on line. No hassle. Need Rockeybrass to start adding to the things they sell so I can buy more!

  17. Matthew Jahn

    I’ve purchased several different fcu parts kits from around the web, and this is my favorite non-oem by far. The price is almost $100 less than some other brands, but this one seems to be higher quality in my opinion. It went together much easier than other well known brands, the fitment seemed more precise, and operation is super smooth.

  18. Raymond Malone

    Fast shipping, priced right, parts were nice one exception was the trigger I think it’s bent I have another one coming the link won’t stay on , we shall see

  19. David Brunz

    I have purchased multiple times from rocky brass and it never disappoints. Always a good deal and fast shipping.

  20. David

    Great parts kit. Every part fit and the surface finish are coated correctly. Updated kit with flat trigger fells good.

  21. Justin

    Put these small parts on my mup-1 and they fit. Every part is included in order to complete the FCU. Very impressed with the quality and finishing on all of the parts. Not sure if RB makes these or sources them but they’re the best deal in town. Gonna order a few more.

  22. Bill

    Best price and very good quality, fit and function is perfect.

  23. Graham Neall

    Excellent quality parts. Highly recommend finding a good YouTube video to take you through the Assembly process. After drilling the frame, take the time to thoroughly clean out the holes, remove all the burrs and clean-up all the sharp edges on Frame. Test fit all the Pins to insure a good fit…de-burr the holes prior to final assembly. Invest in a good quality set of Swiss Files., the Frame material is of high quality steel.

  24. Rich

    Ordered this lower parts kit and the order process and deliver was great. Unfortunately the trigger and trigger bar were a little out of spec. The bar was bent to where when installed it rubbed on the grip frame. I tried it on another FCU and it did the same thing. Also the upper pin for the trigger was off center and caused trouble installing it and added to the rubbing. All other parts were perfect. I give the company a 5 star but the parts a 3

  25. Scott Feller

    Every part is there and work great it’s even the upgraded drop safe kit excellent quality and super fast shipping

  26. Peter J. Bertini

    Nice kit. Happy I made the purchase

  27. Michael D Mai

    I haven’t assembled the parts in my 80% FCU yet, but I have inspected them. everything seems to be top quality. I’m sure I will be happy with this kit.

  28. Scott

    I purchased this kit and I was very pleased with the shipping and fast service from Rockey Brass. I have ordered numerous times from here and have never been disappointed. This particular kit was everything I need to finish my SIG p320 build, and I am not very happy with the quality. After assembling the build, I have been having serious trigger reset issues. The trigger bar doesn’t clear the P80 grip module I have and it allows the trigger to get stuck after firing and it will not reset unless I manually push the trigger back forward. I wish the kit came with an APEX trigger instead of this one. The quality is lacking on the trigger and this kit missed the mark. I will have to find another trigger that works correctly.

  29. Kalen J Underwood

    I’ve been buying a bunch of stuff from Rockey Brass lately and I’ve yet to be disappointed. JSD had done an awesome job on the MUP Sig insert, but it takes 4+ weeks to get it from them. I bought an insert and FCU parts kit for cheaper, equal quality, and it arrived in less than a week. I’ve been buying 80% parts from them for more than 6 months now and they beat everyone hands down. I’ve told my brother and much of my friends now and will continue to buy from them until they give me a reason not to. Awesome value, excellent customer service, 10/10 supplier. 100% satisfied, you won’t regret it.

  30. Jp

    I was looking at the all the products basically everything is good either product you want is there

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