I have always said that when it comes to AR-15s, if you can think of it someone else has already made it and most likely marketed whatever you are thinking. This overabundance of stuff and accessories for the most popular firearm in the US can lead to confusion when it comes to your home defense carbine.
Inspired by my “Bare Minimum” article, I want to explore the bare minimum needed for a home defense or duty rifle. Specifically the AR15, since it is the best choice in a home defense firearm. We will still hold this bare minimum rifle to a stringent reliability standard because our life depends on it. There will be no compromise on some of the principal components.
The barrel should be 4150 CMV steel per MIL-B-11595E with a chrome-lined bore and chamber. The chamber should be 5.56 NATO. The barrel and bolt should be subjected to a HPT (high-pressure test) load in accordance with MIL-C-46936 and then MPI (magnetic particle inspected) in accordance with MIL-STD-1949 or better.
Now that I outlined all that technical stuff, what should you buy? Just like I told you in my AR buyer’s guide you will be smart to stick with a name brand barrel and bolt. LMT, Colt, Daniel Defense, Bravo Company and Noveske all make products that are to specifications or better. A quick search of the interwebs revealed an FN barrel for $140, an entire Colt barrel assembly for $250 and a BCG (bolt carrier group) for $140.
If you know anything about BCGs you probably have heard about gas key screw staking. This is where you used to regularly see some pretty terrible staking from the “Alphabet” manufacturers. The entire industry has done very good job the last few years of addressing this issue, but make sure your gas key is properly staked on your carrier.
Another place you want to make sure you have a solid product is the receiver extension, buffer and action spring. You do not want a carbine that fails to feed or becomes useless when you bang it on something because you bent the buffer tube. A good receiver extension (buffer tube) will cost you $30-40, but you will definitely want to spend the money here. 7071 or 7075 aluminum and “Mil-Spec” size are the key to success when it comes to the receiver extension. Just be sure to buy from a reputable vendor and you should be fine. A quick look at Bravo Company (BCM) shows that a top-of-the line action spring and buffer are only about $15, so it makes zero sense to skimp on those critical parts.
There is room for compromise on some of the components. There is no real need for fancy pistol grips or muzzle devices for our bare minimum rifle. We don't need the newest, lightest freefloat, keymod, titanium bolt-carrier.
Any lower receiver parts kit (LPK) from a reputable dealer will do for our TGSP Bare Minimum rifle. (Catchy, isn't it?) There is absolutely nothing wrong with a standard trigger. If you cannot shoot a “mil-spec” standard AR-15 trigger well enough for home defense you need to practice more. As long as the lower receiver is within tolerances the name brand on the side does not matter. Yes you do have a slightly better chance of getting an out-of-spec lower with a cheaper brand, but even the lowest priced manufactures stand behind their brand. The upper receiver is another area where almost any brand will work, just stick with aluminum.
I like the original CAR stock. I also do not mind the M4 stock at all. The cheapest stock I can find for sale is a $16 BRB M4-style stock that will fit the bill very nicely as the bare minimum. Standard hand guards will do just fine too. Ditto for the pistol grip, the $3 A2 works perfectly. The A2 flash hider is probably the perfect muzzle device regardless of price and at $5 it is clearly the best value period.
D&H magazines, at the stupid cheap prices you can get them for nowadays, are the perfect bare minimum for our rifle when it comes to feeding our home defense blaster.
The MBUS sights from Magpul is easy to recommend as the best value in backup iron sights, and they would probably function well as a primary sight system, but are they the Bare Minimum? Honestly once the rear sight is zeroed you will not need to mess with it again in our home defense scenario. A $20 Chinese value-brand rear sight will work. I would rather see you spend a bit more for a $40 Troy fixed rear sight or even a $31 Ruger or $36 MFT rear sight, but I will call a cheap Chinese-made carry handle or carry handle-style sight the bare minimum.
A Light. Yes you will need a light. Every self defense gun should have a light. In this little project the best, bare minimum choice would be a SureFire G2X or a Streamlight Scorpion HL in an $30 Elzetta Mount. Another mounting option for those lights would be screwing the $18 Streamlight M-16 Rail Mount to our standard handguards and using a $4 1” Weaver ring to hold the light. Any of those choices will give us very sufficient lumens for home defense work.
So, what have we covered? Choose a good bolt, barrel, buffer tube, buffer and spring. The best magazines (D&H) work as a bare minimum. The standard sights, furniture and muzzle device are also the bare minimum. Just about any rear sight, upper, lower and small parts will do the job. And last but not least, don't forget the lumens.