Long-time shooter, first-time AR shooter here. I'm following some great advice and getting some spare parts for our new ARs before the ban in our state goes into effect. I've also been advised to upgrade our triggers. The moment I stuck my toes into the confusing world of lower parts kits, I realized some of them included triggers. So I'm thinking of buying a couple of kits that have triggers in them that are better than mine and then using my stock triggers for spares. Good idea? Bad idea? Thoughts?

Part 2, I need to move fast because the curtain is coming down any day or perhaps even any hour. I could use some specific recommendations for lower parts kits and any other specific parts and brands you think I should stockpile so my soon-to-be-grandfathered ARs don't end up non-functional in the back of the safe. My lowers are Alpha Foxtrot and Aero. My uppers are 2x 5.56, 2x 22 LR and 1x 6.5mm Grendel.

Thanks for the help!

BCM bolt rebuild kit

BCM enhanced lower parts kit

Firing pin

Gas rings

Gas tubes

Never had an issue with BCM.

Buy a spare BCG and a couple of these.

Regarding triggers, buy whatever you'd like.

https://www.aeroprecisionusa.com/ should ship local.

Larue MBT good trigger.

One of my rifles has an Aero upper and lower.

Thanks for the great tips, everybody. I'm on it and it should be on the way pretty quick. Y'all rock.

Are firing pins universal. please? Does a 6.5mm Grendel use the same firing pin as a 5.56?

I think it depends on the 6.5 bolt. From what I understand some do some don’t. But honestly I’m not 100% sure.

Yeah, pretty much, so long as we’re talking AR-15 rather than a large-frame gun like an AR-10

The only partial exception that I can think of is that some folks with an upper chambered in 7.62x39 will use an “enhanced” pin that gives a little extra protrusion. Supposedly helps with tough mil-spec primers, large-rifle size.

Grendel uses small-rifle size, so it should be fine with the standard pin.

ETA:  Scratch that — I forgot that most Grendel bolts have a deeper bolt face recess than regular 5.56. Brownell’s sells a special pin:

https://www.brownells.com/gun-parts/rifle-parts/rifle-bolt-parts/ar-15-6.5-grendel-firing-pin

https://www.ar15.com/forums/ar-15/High_round_count_AR_M4_s__over_100_000_rounds__and_how_they_have_handled_on_our_range/118-677135/?

It's a read, but this will give view to components lifespan/expectations.

Thank you. I have some on the way. :)

That was an interesting read, thanks! I don't know what half of those parts are yet but I made a list as I went through it.

if you haven’t already, you should research Type 1 vs Type 2 Grendel bolts and figure out which you have.  And if I were in your shoes, I’d get a spare.  Grendel and 7.62x39 bolts generally aren’t as strong as regular 5.56 bolts.

Thanks! I ran into that issue when I was researching the Grendel. I have a Type 2. When you say "bolt," are you referring to the entire bolt carrier group? I can get an identical bolt from BCA. If I can get a better BCG in the same price range ($80), I would rather do that. Any suggestions?

I was referring to the bolt itself. There’s nothing special about Grendel carriers — same as 5.56.

As for where to get a good Grendel bolt, maybe Toolcraft would be a better option than BCA.  Even if you couldn’t find a standalone bolt, the carrier itself would serve as a spare for all your calibers.

There’s an “AR Variants” forum here, mainly for folks shooting things other than 5.56. You might ask there about who’s making a good Grendel bolt.

ETA:  Grendel extractors are probably different from 5.56 because of the different rim diameter.  Might check into those too.

Good stuff! Thanks!

I would get a spare charging handle if parts were being restricted. Gun is close to useless without it.

Good heads-up. I'm ordering a couple of ambidextrous charging handles. I'll have the two stock handles leftover so into the spares locker they go. Thanks!

I just realized that the 20" Grendel upper uses a rifle-length gas tube, so I ordered a couple of those as spares. I had already ordered carbine-length spares for the 16" uppers. How often does a gas tube go? Given that it's another critical part, I thought it best to have a couple.

Magazine. Gun is useless with 10 round magazines.

I ordered three complete BCGs from Aero Precision. Two in 5.56 and one in 6.5 Grendel. I know the 6.5 will be an upgrade over the stock BCA BCG in there, so I'll swap them out and use the BCA for the spare. I'm also going to order some spare bolts and extractors. And some spare M-LOK hardware. I should closing in on a pretty complete spares locker, thanks to all of the great help. I've learned more about my rifles along the way too, which is a good thing.

Our main goal is livestock protection and 10-round magazines are fine for that. I'm upgrading from five-round internal magazines.

That having been said, I intend to have plenty of them. Thanks!

If you don't go around and do abuse testing of machine gun AR's or constant mag dumps, a steel gas tube will last more than a lifetime. Just get some long pipe cleaners to swab out the tube once a blue-moon (and this probably won't even be needed) and you'll be ok. Unless you start to see jamming or difficulty of the bolt in picking up a round when it worked before, then most gas tubes are basically maintenance free of problems. This is if nothing else was changed or has broken like a bolt gas ring(s) or weak charged ammo used.

When I got into AR's I got lots of spares of little parts (springs/LPK/UPK/bolt rebuild/etc) that come as kits or separate. I must of got 5-6 of them over years to have on-hand.

Also, get a couple "good" AR armorer's wrenches and a complete set of AR15 builder's punches in the needed sizes. You might not use them to build a new AR, but guaranteed, one time or another you use a punch or two to help disassemble to replace a part. A jeweler's hammer with different screw on tips is helpful also. I got such a hammer from Harbor Freight for about $10 long time ago that I've assemblied a few AR's with and it worked great as a lot of force isn't needed to drive in the roll pins.

 Like others have said pick up a couple 2-3 bolts to match the AR calibers you're using and at least a couple 2-3 pins extra. Find a good sale and pick up the complete BCG if want.

Something I've dedicated with my AR spare kits, build/repair tools and larger AR items like handguards and such is getting a few GOOD poly tool boxes that have a rubber seal around the lid. I have some Stanley tool boxes I got at Walmart as they had what I wanted and they're sturdy. They keep out moisture and help protect the steel products from getting rust. Also keeping small spare parts in a separate box for easy finding when needed, instead of jamming everything together. I also throw in some of those moisture absorbsion packets to also help and I wrap up barrels and BCG's in oily rags to keep even more rust and such at bay. Living here in Missouri, we do see lots of humidity, so anything I can do to keep rust away, I'll do it.

Spare parts become spare AR's pretty quickly.  Just a fact of life.

Good advice! Thanks!

Good to know.

So true.

I was running into that last night while I was cataloging all my spares. All I need to build a couple of rifles is stripped lowers. But then, I wouldn't have any spares. Seems like  vicious circle.

Just rationalize it this way. Spare rifles = spare parts

or..
Spare rifles are just pre-installed spare parts.

That’s even better!

Works for me.

I've been shooting AR15s since 1984.  I've had my share of bad experiences with them.  If your guns do not work properly sort them out before buying spare parts.  Assuming they all work, here are somethings I would have on hand:

+ Action springs (measure new and replace when it loses 1" of length)
+ Bolts (7-12,000 round replacement)
+ Bolt rings (wear out)
+ Firing pin retainers (easy to lose)
+ FCG (trigger with spring, disco "sear" with spring, hammer with spring, both pins)
+ KNS pin set (in case you end up with walking FCG pins)
+ Buffer retainer with spring
+ LPK

However, the best solution is to just buy a couple of $129 complete PSA lowers.

The best spare parts kit is another gun.

Interesting gear. Thanks.

Great information, thanks. I came to the game late, about ten days before the ban went into effect. I was in a panic to make sure I had all the parts I might need even though I didn't even have my rifles yet. Fortunately, based on the advice I got here, I was able to get most of what you listed before the curtain came down.