Building Your EP-80 Ar15 Rifle Lower at Home With Common Hand Tools

EP Lowers EP-80 Polymer LowerAmmoLand – by John Freeman

Bakersfield, Ca –-( The EP-80 Polymer 80% lower receiver is a fiber reinforced composite polymer rifle lower available in several colors from

Our 80% lowers can be ordered online and shipped direct to your home, without the hassle of serial numbers, registration or background checks, then finished with common hand tools.  

The lowers are easy to make usable as the following photo essay with show. These 80% receivers typically require at least a drill press and jig or vise to complete.

For those who do not have a drill press or jig the following photos show how the EP-80 can be completed without either and with a minimum of tools many already have on hand. See our handy tool list at the article end.

Tool Required

1. For this method the tools required are a Dremel rotary tool or equivalent of another brand, Dremel flex shaft (optional),Dremel EZ drum, 115 and 562 bits, a Hand Drill, 1/16″ bit for pilot holes, a 5/32″ bit, and 3/8″ Brad Point Bit, Mallet, Chisel, Canned Air or compressor (optional), vise grips, allen wrench, vise, rubber face pads for vise (optional), Mag well vise block (optional)

Clamp The Lower Securely

2. First clamp the lower securely in the vise at the trigger guard using rubber in between to not mar the surface. Cardboard or some other material would also work fine. This is a bit more secure then mounting with the magwell block. Then drill 1/16″ pilot holes for the hammer, trigger pin and selector switch just penetrating through the walls of the lower and stopping after the core material becomes visible on the drill. Repeat this on both sides.

Remove The Raised Pins

3. Remove the raised pins for a flat surface with pilot holes to guide the larger bits.

follow up with 532 bit

4. Then follow up with 5/32″ bit for the hammer and trigger pins and the 3/8″ brad point for the selector switch. Make sure you eye ball from the top and side to make sure the bit is perpendicular and not canted. Again you are only drilling through the wall. Repeat on the other side as well.

Dremel And Begin Milling

5. Then install the 115 bit on the Dremel and begin milling.

Patches Of Ribbing

6. Beyond a certain point there is patches of ribbing that are the same color as the lower. As you mill deeper the ribbing will fade out to solid black again. That will tell you you are close to the bottom.

Switch To The 562 Bit

7. Once you have taken enough material out with the 115 bit switch to the 562 bit for the finish work and removing the black portion from the corners where the other bit can’t reach.

Chisel To Remove The Last Of The Core

8. You can use the mallet and chisel to remove the last of the core from the sides of the lower and to shave down the ribbing for a smoother finish.

All The Core Material Is Removed

9. Even after all the core material is removed the side walls are too thick for installation of parts and a small amount must be reduced and smoothed to allow fitting; that’s where the drum sanding bit comes in. Its a matter of builder discretion but the interior finish of the pocket doesn’t have to be perfect and won’t be using this method. Don’t worry about it so long as the parts can fit and function correctly.

Pop The Square Out For The Trigger Hole

10. Once enough of the material was removed you can pop the square out for the trigger hole and begin sizing the hole for the trigger. This has to be done free hand with the 562 bit. You may want to measure and mark with the help of a caliper transfering sizes from your trigger to the lower. I really didnt have a problem opening it up to the right size just by eye. The best way is to shave small amounts and continue to fit the trigger until it fits through well. Then you are ready to begin fitting your parts.

Threads On The Buffer Tube

11. The threads on the buffer tube can be tighter than aluminum lowers. The use of Teflon plumbers tape can aid in threading the buffer tube into the receiver.

Hole For The Pistol Grip Screw

12. The hole for the pistol grip screw is not threaded. It is designed to be wide enough to allow the builder to thread the hole using the screw itself for a tight fit since the material is conducive to threading. For this use an allen key with vise grips to carefully crank down the screw and seat the pistol grip

Front Pivot Pin And Rear Take Down Pin

13. front pivot pin and rear take down pin detent holes can sometimes have polymer burs left from manufacturing which may impede the function of the detent and spring. It’s not a bad idea to run a drill bit of the same size to make sure the holes are clear. This can be done by hand by just holding the bit.

14. After the fitting work is completed you can assemble your new rifle! 

Parts & Tools Check List:

Our product is offered online at Also we invite folks to check us out on facebook for daily updates at Our product will be available at dealer locations as well and we have plans to market at gun shows very soon. Thank you so much

Kind Regards, Chris Cook, founder EP Lowers EP Arms LLC

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4 thoughts on “Building Your EP-80 Ar15 Rifle Lower at Home With Common Hand Tools

  1. Eh,prefer the aluminum/steel ones.I am a bit sad that the lack of a better word 80%’s getting so much media attention but was bound to happen.I know folks who have done 15&10 receivers with excellent results,they also make em for the 1022/1911/mossy 500.The state of Ct./NY must love that,really is a easy process.

  2. I would be interested to know how well these hold up. The only problem I see is ware in the mag well. Should make the weapon lighter.

  3. Red,seen em on slick gun with jig and a lower partially finished receiver for about 80 bucks.That said,prefer the aluminum ones as when done right match up perfectly to upper of your choice.Defense distributors(believe right name)has done quite a bit with poly recivers for AR’s,probably some u tube videos if interested.Is my understanding some of these have kevlar built in to critical spots.

  4. I recommend a group out of Redmond OR called Redmond Black Rifle or‎ . This guy is legit. He was California based until he was basically forced to shut down by their state laws so he came to Oregon. For the price of a finished gun you can get a half dozen or two 80%lowers and finish them your self. What a great gift for each person in your family. They can make their own and it is theirs for ever. I like the .308 version better but lots more .223 laying around when SHTF happens.

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