M4 / AR-15 80% Lower Finishing Part II



Finishing an 80% lower with a mill is a cake walk, but we wanted to see how it would be with a drill press only. Surprisingly it was very easy and can be done in under 2 hours. We broke this video into 3 parts. The first part covers the rough in work, the second part covers final machining, and the third covers finishing the receiver in a teflon coating. All in all you can do this process on a drill press, but it is a huge pain. You can get all of the bits seen in this video here: http://bit.ly/1yA84ph
For more information you can check http://bigborear.com. If you find this video helpful please comment and like.

32 thoughts on “M4 / AR-15 80% Lower Finishing Part II”

  1. I plan on getting a mill for this I know a drill press with hack it out but I could use a mill for many other things so might as well get one

  2. So when you're milling you're putting it in an actual hole before you start passing it or do you pass it above and around the holes?

  3. Hi How much do you think cost? to Sende to Canada,
    Please, I would like to order the following item.
    thank you

  4. Hello,     I wanted to try and convince you all of the dangers of the selling of 80% receivers online. I am pro 2nd amendment and strongly disagree with any measure to limit purchases of ammunition or guns to american citizens. I do however approve of measures to limit or outright deny these rights to those persons who have proven they have no regard for the general well being of our society. Let us not forget the point of the 2nd amendment is to keep an armed population and militia to eliminate the threat of a tyrannical government and to protect life, liberty and property. With that being said we live in different times with a much higher rate of crime. These criminals should not be able to order gun parts like this with no background check online. I support laws for criminal background checks on all people who wish to own guns. Some say there should be second chances, I say these people have proven they do not deserve the right to own a firearm and therefore should not be able to buy these parts online. So let me ask do you feel safe knowing these people are allowed a loophole in obtaining a firearm? Please reply and tell me your honest opinion on this topic it is for my english final I’d be very greatful for some replies.

  5. I am having trouble with my drill press and the mill. I am running the drill press at 2340rpms and the chuck is coming loose and slowly lowering the carbide mill. Less than ideal drill press, but will going closer to 1000rpms, as in the video, help with that problem? Or do I need a better drill press?

  6. Did mine in under 2 hours with a drill press and I DID consider it a cake walk. I didn't even use a x y vise. I drilled out the receiver with 1/8 then 3/8 and then used a 3/8 end mill with my hands guiding the jig around the end mill with someone else controlling the depth

  7. I hate doing these with a drill press but the manufacture wanted us to do the video that way. I mill out a few hundredths under and then sand finish before hucking it in the polisher prior to finishing. Finish and tolerances between drill press and mill are pretty much the same if you know what you are doing. Big difference is time. On the CNC I can finish one of these in under 30 minutes. Drill press and sanding plan on several hours. Also if you use Dura-bake an gouges that are under a hundredth or so get covered. http://bigborear.com/forums/uploads/gallery/album_4/gallery_1_4_93042.jpg

  8. You could simply edge find or touch off and use the dimensions specified in the prints that can be found all over the internet.  This process seems a bit imprecise.

  9. I know this is an old video but I just found it. I have finishesd my upper receiver which is comprised of a DPMS LR308 (The original SR25 pattern) reciever, a Ranier Arms 20 inch barrel and a JP brake. I have an 80 percent lower and a lower parts kit in my safe awaiting the funds to buy a Hi Torque solid collomn X2 mill and the required tooling.
    Knowing that tooling cost will ulitmatly cost more than the mill, what would be the minimum tolling I would need to finish an 80 Percent reciever?  

  10. What a pain.  Lol.  No substitute for the right equipment.  Easy to knock out an 80% lower using no jigs whatsoever on a full size knee mill, takes about 40 minutes from unboxing to installing the LPK.

  11. Question:
    concern with the tolerance exceeding the size. My lower is bare metal.

    What is the experience using duracoat shall I apply first then install the lower parts kit or install the kit trigger hammer FCG, bolt catch and then paint them.

    how about the the threads on buffer tube!

  12. From what I could see and at the beginning looked like the mill chattered all over the place; inside looks all chewed up??

  13. where is part 3 video? Do you sell the jig used in the video? If not, where can one be purchased? Kinda screwed without the jig! A complete list of the size of bits and mills would be nice. Can you help us out?

  14. can you make a list of what size drill bits i need for everything…i think its better to buy them on my own vs buying some 100$ kit

  15. Wouldnt it be easier to buy a stripped lower? I mean seriously, ya you have to register it but who cares!

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