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Thursday, October 01, 2020

Quick Tip: Must-Have Spare Parts for Your AR-15

We asked Brownells Gun Techs Steve and Caleb bring their unbeatable combination of wisdom and good looks to answer an important question: What spare parts should I keep on hand for my AR-15? Gas rings and buffer spring wear out through normal use, says Caleb. And he has a handy rule of thumb for telling when that buffer spring needs to be replaced. Most likely to fail on the bolt / carrier group are the extractor spring and pin. The cotter pin and cam pin can break, but more often they get lost when the BCG is disassembled for cleaning. Steve says he's tried but has never succeeded in getting an AR-15 firing pin to break. 

26 comments:

  1. Another thing to consider. Make sure your AR replacement parts will fit your manufacturers type of rifle. I have an older Colt (early 90's) made A2 model that has different size pins than some of the newer makes.
    Granted a firing pin is a firing pin..But some other parts don't interchange.

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    1. My Colt(tm) came with an M-16 firing pin. Kept having failures to feed. Turned out the larger flange on an M-16 pin (as opposed to a semi-auto pin) was hanging up on the hammer. This was from the factory! Your point is well taken - parts ain't parts.

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  2. Spare parts for my AR-15...is a spare AR-15.

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  3. The heavy duty Bravo Company extractor the way to go,Bushmaster sells small parts kit that has double all the little springs/pesky detents ect.I would also have a full spare bolt for the AR along with gas rings ect.I have in spare kits one piece gas ring,have as of yet not needed but there when needed and perhaps easier in field/on the road ect. to replace then all 3 rings.

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  4. I did a quick check to see if Brownells has an AR spare parts kit based on the vid's recommended spares. Nope. They have upper and lower build kits, (none of which are in stock at the moment), but no kit specifically named AR 15 Spare parts kit that I could find in 5 or so minutes of looking at the couple of pages returned from an "AR 15 spare parts kit" search query.

    Nemo

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  5. Properly made springs will never "wear out" and should never need replacing. Unless its Elastic Modulus is exceeded or they suffer some mechanical injury they will last forever. Period. If your spring looses its properties then it wasn't manufactured correctly and you should be sure to buy a proper one next time from a better vendor.

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    1. never underestimate the power of private snuffy to tear shit up.

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    2. So spring fatigue doesn't apply to firearms? Yeah, no.

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    3. Actually you mean the yield point not modulus of elasticity. Carbon steels have a modulus of elasticity (Young’s modulus) of about 30,000,000 psi, and stainless steels about 28,000,000 psi. The yield strength of spring steels is well over 150,000 psi.

      The spring will never “wear out” and fatigue will never happen because the endurance for fatigue is probably in the range of 10,000,000 cycles, something that will NEVER be achieved firing a firearm. You probably couldn’t afford that many rounds, and barrels wear out in the

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  6. Oops. Missed this, sorry

    https://www.brownells.com/rifle-parts/receiver-parts/parts-kits/repair-parts-kits/ar-15-m16-replacement-parts-kit-prod73626.aspx

    Nemo

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  7. I have a couple spare BCGs.

    .mil tends to transport weapons without BCGs.

    Coincidence?

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  8. Gee Stuart, it's been a long time since my Mark I eyeball was last calibrated to judge tensile strength and other properties of a well made part. Why don't you give us a short class on it. Meanwhile, I'll just accumulate some spares.

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    1. Simply buy from reputable vendors. Spring fabrication isn't magic. My point is - they do not wear out. When did YOU ever have a spring "take a set"? If you want to spend your money buying multiple sets of recoil springs that will never be needed, be my guest.

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    2. I buy from reputable vendors *after* the factory spring wears out.

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  9. I picked up an anderson whoops kit that has many of the detents, springs, and a few pins that tend to take off across the room when you get careless on disassembly/ reassembly. The price tag on it is $11.50 when I got it at the show last year. I bet there's more essentials I still need to get.

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    1. I bought one of those kits to round up for free shipping. Damn if I haven't gotten every penny out of it! On my next order, I need to grab another one.

      Plus there's a gun show in Chantilly this weekend!

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  10. The best spare parts kit for an AR15 is another complete AR15. I have decided, like the title of the old TV show, that eight is enough.

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  11. Try Damage Industries (http://damageindustriesllc.com) for spare parts. Usually good deals on parts kits and cheap shipping.

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  12. Only had -one- firing pin break on me in 30+ years of dot mil experience, dot PMC experience (private mil contractor) AND in two years of being THE Army Reserve's MAster Armoroer for the AmSA shop for the ENTIRE state. And it was MY personal AR that had the tip break off. No idea -where- I had bought the bolt/bcg group from./ The very tip of the FP had sheared off. Shot three or four rounds, then bupkiss. Went thru all the SPORTS shit, then went further when it wouldn't fire. Found the pin tip broken the fuck off.
    NEVER in over (no bullshit) 50,000 +rifles I inspected at depot level did I -ever- find that sort of deadline. Burned out barrels, bad gas keys, bolts with missing gas rings or worn lugs... some of the rifles I inspected literally dated to the GM Hydromatic Days (look it up) and they were still running strong. Total oddball, BUT, one = none, two is good, 1/2 dozen = perfect.

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  13. After about 10,K rounds the extractor on one of mine wore so smooth that it couldn't grab a casing. Had a spare BCG that saved the day, but the range meister pointed out that extractors do wear out more than most folks think. So I got a Rubber City Armory rebuild kit and had it back in fighting form in no time. But, yeah; keep a complete spare BCG in your range bag.

    Also, running a pistol length with that O-ring around the extractor spring tends to shave a lot of brass on to the bolt face and will require frequent cleaning on a long day. I pulled the O-ring off on my .300 AAC shorty and it really cut down on the brass getting into the bolt.

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  14. I wish that I had as much money as you people obviously have.

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  15. Interesting. I had a broken trigger spring in Basic. Almost half of the time, click, no bang.

    Spare parts are a wise move. Get gas rings and a spare extractor. If you're not so mechanical you can accomplish the same by swapping in a new bolt carrier group.

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  16. Spare parts are useless without the tools to install them. If you're gonna have all those little springs and detents and roll pins (AND YOU SHOULD) you're gonna need a set of roll pin punches and roll pin starter punches of the proper size and a little hammer to hammer with. None of that is terribly expensive so there's no excuse not to have them. The little bolt disassembly tool is also relatively cheap and you ought to have one of those too.

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