Joe Bob Outfitters’ Spartan-15 Enhanced Billet Lower Receiver is one of the most affordable billet lowers on the market but is it worth even a smaller premium over a forged lower? That is the kind of question that everyone has to answer for themselves but for me, it is. Here’s why…
As you can probably surmise from the name, the Spartan-15 starts life as a solid billet of 7075-T6 aluminum, not a forging. It has a black hard anodized finish and a Spartan helmet/Molon Labe roll mark. The trigger guard is integrated and oversized. Other custom touches include a threaded bolt catch pin, a captured rear take-down pin detent, and an upper receiver tensioning screw.
The Spartan-15 is also marked and notched to work with Battle Arms Development’s short throw selectors.
Observations from Use
The Spartan-15 accepted the White Oak Armament parts kit that I installed without issue. Magazines drop free easily without excess wobble. It appears to be dimensionally correct.
The fit and finish are excellent. The quality of the machining is quite good and the finish is a very nice, dark, even black. The finish appears different than other hard anodized finishes likely due to a different surface preparation. It has a sort of frosted (hopefully that makes sense) appearance that is very attractive. The Spartan helmet marking and Molon Labe roll mark both look nice without being over the top. The pictogram selector markings look great too.
I probably won’t use the upper receiver tensioning screw. I just prefer to avoid them and I don’t mind a little play between the upper and lower. The captured rear take-down pin detent is just neat. It makes installing the castle nut and end plate a breeze. The thread in bolt catch pin is VERY convenient. Installing the bolt catch roll pin is probably the worst part of building a normal lower but this couldn’t be easier. This is a great feature. Remember to use a bit of thread locking compound to ensure it doesn’t back out. I didn’t have an issue with the screw backing out but applying thread locker would be cheap insurance.
You can tell that care was taken to round many of the edges and remove sharp corners. However, the corners around the trigger guard are left fairly intact which is a little disappointing. They aren’t going to cut you but if there is one place that a chamfered edge makes sense, it is there.
The magazine well is also a little disappointing. It is very good dimensionally and it is well finished inside but it has very little flaring at the opening. A flared magazine well is often one of the hallmarks of a billet lower but the Spartan-15 is only flared about as much as a forged lower. Yes, it works but there was room for improvement here.
I saved the best part for last. The lower is designed to accept Battle Arms Development’s Short Throw selectors without modification. There is a small notch on the selection hole to allow the pin to slip in without having to grind it down and the selector markings are designed to work with 45 and 90 degree selectors. At $129 retail, this is the most affordable lower available that accepts these excellent selectors without modification and that is a huge plus for me.
The Spartan-15 Lower is very attractive, dimensionally correct, and offers some very convenient features. It is likely the most affordable lower on the market that will accept the Battle Arms Development Short Throw Selectors. The magazine well is flared enough but could have been flared more and I wish the edges around the trigger guard were broken just a bit more.
Obviously, the Spartan-15 Lower costs more than a forged lower but it also offers more functionality. As with anything, you will have to decide if the features are worth it to you. I find it to be a good value based almost on the short throw selector compatibility alone. Throw in solid quality, convenience features, with some good looks and I think you have a winner.
Disclosure: I received this product from the manufacturer, free of charge, for review.