Spare Parts for AR-15

I’m a new AR-15 owner. I’m working to become as familiar with the platform as I can. What spare parts should I keep around just in case?

I am partial to having a LPK or five laying around, the other option is an “Oops Kit” which contains all those detents and springs that will launch themselves int the darkest corner of any room. In general I watch the sale section of my most common parts dealers. When bolt carriers went on sale for $39 I bought a couple, when barrels went on sale for $75 I bought a couple, blemished M-4 uppers were going for $35 I bought a couple. blemished M4E1 Aero lowers went on sale for $45 I bought a couple. Extended charging handles for $12 I bought a couple. Spare parts are good to have, when you have enough spare parts to build an extra rifle or pistol or two sitting in a can unassembled, you might have enough.



  • QTips and pipe cleaners for cleaning

Pretty much everything lol
Buy as you can afford to, when you have enough parts to build an entire AR, do so and start over :grin:

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Complete BCG, and everything else that I might need to change in the field. Charging handles, triggers etc. I don’t have or carry an extra barrel.
Now I think, between Covid-19 and riots just have an extra AR or 2 at hand. Your not going to have time to change an o-ring or bolt gas rings or extractor o-ring. All great to have on hand.


The easy answer is have another AR15 :rofl: if one goes down pick up the other one, or scavenge it for parts.

The longer answer is pretty much everything. With the exception of a BCG, which I would buy “soon” if i were you, most of the other bits you can keep your existing when you upgrade your current equipment.

I would start with a complete Bolt & Bolt Carrier Group (BCG). Toolcraft BCG on sale are as low as $75 (just keep an eye out, especially for Black Friday), common good brands are in the $100-$150 range, and premium coated ones are a bit more. The main thing you want to ensure is that the bolt is Carpenter 158 steel, and the keys on the BCG are properly staked. Any reputable brand will have that and ensure they are tested HPT (High Pressure Tested) and MPI (Magnetic Particle? Inspection). Colt, Bravo Company, Toolcraft, Sons of Liberty, I know I’m forgetting a few more brands that are good. Even PSA has their own branded BCG that is really good as well. The coatings dont really matter for durability (phosphate vs nickel) but the premium nickel coatings are easier to clean off. If you get a premium one, then use that one in your rifle and keep your current one as a spare. (Dont buy one of the lightweight ones because then you will set yourself off on an adventure playing with buffer weights…)

A LPK (lower parts kit) (or two or three) is ~$50 each. You may as well buy this and an oops kit just because its cheap and they take up no room at all.

A spare plain charging handle is cheap, or buy an upgraded one and keep your current as a spare. I really like the Radian LT and the Geissele Airborne charging handles (~$60-80).

Buffer and spring assembly (not sure how much this cost by itself).

A trigger (or two or three) is between $50-300 depending on quality, but my advice here is to buy an upgrade for your AR at some point in the future and keep your existing as a spare.

After that, you will need tools to change a barrel (barrels wear out maybe 5k-30k depending on construction and your usage). So having a spare barrel means also keeping tools to remove the handguard and properly torque the barrel plus a vice to keep it all steady… so its not for the faint at heart.

Way down at the bottom of the list is stuff like spare pistol grips, stocks, rails. But seriously, by the time you get to this point you already have 3 other rifles you can canabilize :wink:


Oh no, what have I got myself into :man_facepalming:t2::rofl:


I just bought a BCG from Odin. It is simply terrific. Runs great, nice finish, and seems very well built.


Y’all think a lot like this is worth while?

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That looks pretty decent. The trigger springs aren’t really needed if you have a spare trigger instead, but it doesn’t hurt.

There are kits like this (literally called “oops kits”) that have all the detents and springs that typically go flying when you assemble/disassemble your rifle

And then you have lower parts kits like this one

All of the kits have some degree of overlap. The kit you listed has firing pin and gas-rings which aren’t in the others i listed (usually sold by themselves)


@Scoutbob you can find more for less. CMMG makes great parts, though. Cabelas can be pricey. As goofy as this sounds, JoeBobs is a good getting place. They are very competitive and ship really fast. If you are MIL/LE you can get a 5% discount to boot.

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