I first wrote about James Madison Tactical nearly two years ago when I was able to help introduce their new 80% AR-15 lower receiver. Since then I have had countless friends build AR-15 rifles off of JMT 80% polymer lowers with great success and zero issues. Once people started to see how easy it was to machine the JMT lower they started pretty much demanding that JMT offer a .308 (AR-10) lower. James Madison Tactical listened to their customer base and decided to move forward with developing a .308 lower. A few days ago I received a package from James Madison Tactical. On the outside it had their logo with the title “308 Equalizer”.
All James Madison Tactical lowers come with their own machining jig so of course inside the box I found…you guessed, a machining jig. The JMT machining jig has a 3-piece construction and is made of a rigid plastic that could probably be used more than once but all JMT lowers come with a new jig so you’ll probably never have to use it again.
What I was more interested in seeing was the lower itself. I have handled a few JMT AR-15 80% lowers before and they are nice so I was curious to see if the fit and finish on the .308 receiver was as nice. Maybe its just me but I think the finish on the .308 is the best they’ve produced yet which is pretty impressive. The webbing on the mag well looks great and the flare on the mag well is not just a sharp line but is actually curved out.
A couple of feature that I was happy to see carried over from the AR-15 lower are the aggressive texture on the front of the mag well which can be used as a support hand grip and they also used the threaded brass insert for the pistol grip screw so you can really tighten the grip screw down without stripping the threads. They also reinforced key areas of the lower so you don’t have to worry about them breaking like other less desirable poly lowers do.
Basically, as you can see, the 80% lower just needs to have the Fire Control Pocket machined as well as drill holes for the Safety Selector, Trigger Pin and Hammer Pin. That is where the supplied jig comes in handy. It has all of the holes in specific places to make sure you don’t screw it up. JMT has great machining instructions showing exactly how to machine their 80% lowers which is a great tool. It also shows you all of the tools you’ll need as well.
Over the next few weeks I plan on machining this James Madison Tactical .308 80% lower receiver, assembling it and getting it out to the range. I already have a few nicely running .308 uppers that I built so I will be able to quickly see how well the JMT .308 80% lower does with them and report back to you guys with more info after some range time.
This could be a great start to a new .308 build for you and a nice way to reduce some of the added weight these big bore rifles bring with them. The James Madison Tactical .308 80% Polymer Lower Receivers are now available for purchase at www.RainierArms.com for an intro price of just $124.95 including the machining jig.