Recommended AR Parts to Keep On Hand

[Navy87Guy]

I want to keep my AR’S (.223 and .308) running as reliably as possible. What parts would the Collective recommend keeping on hand, based on failure frequency?

For reference, my AR-15 is a Sig (M400 TREAD) and the AR-10 is a build on DPMS lower with mostly Mil-Spec parts.

Thanks!

 

[mcb]

For bare bones spares: a complete spare bolt, spare firing pin, spare hammer spring. More is always better but those three items will encompass the largest majority of your parts failures.

 

[BigAlShooter]

Firing pin, extractor, extractor spring. If you tinker with your guns, have a spare of all of the little parts, as they are cheap and you might lose them or damage them when you take your gun a part for some other problem.

I hear a lot of advice to have a spare bolt or whole bolt carrier group. But, that ain't cheap to have a spare of, especially now. And I have never heard of a bolt needing replaced, but I don't know, maybe it is more common than I know of. Maybe something to consider. I'd like to hear some stories. Plus, I think I would want my bolt headspaced to my barrel, but in an AR it may not be that important. If you're going to have $500 of replacement parts, you might as well buy a spare rifle. But, $100 worth of spare parts is probably being responsible.

 

[Bcwitt]

Charging handle. If the factory one gets the slightest bend, you are 100% out of action.

 

[Bcwitt]

Or you could just get an AK & never worry about spare parts again.

 

[Navy87Guy]

Or you could just get an AK & never worry about spare parts again.

I have one...you notice I didn’t ask about parts for it.

 

[DustyGmt]

Gas rings, spare cam pin or two, firing pin, basically any kind of bolt rebuild kit is appropriate. I have had to replace my gas rings before, they are cheap enough.

 

[gotboostvr]

I find it's easiest to keep spare AR parts in the form of an entire extra rifle. That way, no matter what the part, you have one!

 

[CapnMac]

Buffer retention pin & spring.

 

[Corpral_Agarn]

I keep at least a baggy of lower parts around then spare bolt carrier groups.

if stuff goes south, its probably has something to do with bolt carrier group.

 

[aaronu]

A few places sell "spare parts kits". A few detent springs, buffer retainer, firing pin retainer key, ejector spring and o-ring.

To that I added some gas rings, a few fire control springs and a firing pin.

If I had more spare $$$ for this I would stock a spare bolt carrier group.

FWIW the only part failure I've had to date was a broken firing pin.

 

[Tortuga]

In the army we called the firing pin retaining pin the "Jesus pin."

Because if you lost it, oh Jesus.....

That said, I actually recommend people keep several on hand. It's a part not a lot of people think to keep extra of because it will basically never malfunction, but the likelihood of losing it when disassembling the rifle is greater than any other part because it's so small. They're also cheap.

 

[taliv]

And I have never heard of a bolt needing replaced, but I don't know, maybe it is more common than I know of. Maybe something to consider. I'd like to hear some stories. Plus, I think I would want my bolt headspaced to my barrel, but in an AR it may not be that important.

bolts have been known to break in two particular ways. It’s prob a little less common now than ten years ago because quality seems to be somewhat improved.

first, lugs can shear.
Second, they can break in half at the cam pin hole

usually that won’t happen early on with a bolt that’s been peened and MPI tested but even the best bolts have a service life and there were some mil docs suggesting that for some of the army’s guns that number was in the 5000 rounds area. The knights bolt was designed for 25k rounds and made the lugs rounded and has a smaller cam pin to address those specific issues.

headspace is very important but by some magic of specifications, most bolts will headspace. Get a set of go no go and field gages and check it yourself to be sure.

to the OP
I like the bcm bolt rebuild kits. It contains everything you need to replace most common wear parts except an action spring. It’s a good idea if you actually shoot your rifle.

Check your action spring and extractor and gas rings and ejector spring every 1-2k rounds. Replace if necessary.

Between 5-10k rounds replace your bolt.

that should keep you running a long long time. Yes, lots of guns like filthy 14 run 50k rounds but that doesn’t mean you want to push your luck.

 

[taliv]

And don’t forget to check your mags

 

[taliv]

Buffer retention pin & spring.

I have to say that’s not something I’ve ever seen worn out.

 

[Armored farmer]

Probably not what you want to hear, but i keep an entire spare gun.

 

[taliv]

FWIW the only part failure I've had to date was a broken firing pin.

I haven’t seen one like break in two. But I have seen many where the tip is eroded to a sharp point. A hot round will pop the primer and gas will jet back into the hole and cut the firing pin tip. After that the sharp fp makes piercing primers more likely which in turn keeps sharpening the tip etc.

 

[aaronu]

I have a spent case with the tip of a firing pin embedded in the primer.

Steel cased, lacquered ammunition fired out of a Colt HBAR II. The Colt was still new and probably had a few hundred rounds through it at that point. Firing pin punctured the primer and when the case tried to eject the firing pin was held and broke off. At the breaking point the firing pin was bent slightly but could be removed without damaging the bolt. The neck of the case is damaged. I am not 100% sure what happened but am thankful there was no other damage to the gun.

And now I carry a spare firing pin in my gun box and avoid the cheap milsurp ammo like I was using then.

 

[jmorris]

If I have 99.9% of all the parts that make up a mechanical device, the part I always seem to need is the .1%.

Why mechanical things that are important for me to not be without, I always have at least two.

 

[shoobe01]

+1 on a spare gun. If you really need it to work, like for classes when downtime is serious loss of value, bring another similar-enough gun. Only time I didn't do that I had like 30 people who knew me attending, who lived closer so brought their spare carbines so would (pre-arranged) borrow one. Similar issues for things like upgrading, deep cleaning, etc. You can take one apart, still have a running gun.

+1000 on magazines. You will have mag failures (broken, bad followers, worn springs) much faster than a broken gun if they aren't on your maintenance schedule.

I keep no explicit spare parts, just keep all (good) spares I have taken off for updating, etc.

I do keep a handful of spare recoil springs, so if I suspect that or notice it's too short on a cleaning, I just toss it, get a new one.

If worried still, I'd not over-think the specifics and get a "spare parts kit" (as mentioned already) from any reasonably reputable maker. One of those that comes bagged like an LPK, ready to use. Make sure it has all the tedious pins: a replacement extractor with no pin is begging for the pin to be lost during install.

• This is a good minimalist one, of pins and springs that are most likely to break or be lost https://www.midwayusa.com/product/1019428041
• This is a fuller assortment, but DPMS is right on the edge of acceptable to me. I'd look harder if I was buying for myself https://www.cheaperthandirt.com/ar-...tor-gas-rings-firing-pin/FC-884451000891.html

There are pistol grip storage inserts with spare parts storage, like a bolt. I never got that. It's a fair bit of effort to take apart the whole gun, unlikely to be done with only my gun on me, so even if I was on some save-the-world expedition I'd carry spares in the pack or just assume casualties and pick up a spare gun

 

[mjsdwash]

complete bolt, thats about it. Even the springs are good for longer than a barrel. A barrel isn't really a spare part. Anything more than a bolt, may as set aside parts for an overhaul. Barrel, all springs, handguards.
A complete "lower parts kit" and a bolt should get you to the 50K range if you can accept the accuracy loss that comes with it. I see a lot of people saying an AR bolt is good for 14-20K, but I have about 25K on an old M&A bolt and its doing fine. Supposedly the lugs crack, and when they do you can assume the barrel is about done too.

 

[Gordon]

a lower parts kit , a carbine heavy buffer and spring , a BCG and a bolt rebuild set or two , a buffer tube and cheap .750 Low pro clamp on gas block. a milspec charge handle you took out to put in the trick one a carbine stock and tube.