What to inspect/replace on your AR

[cmshoot]

Good stuff!

I will add that I have a Colt AR15-A4 w/ 13,500 rounds through it. Exactly nothing has been replaced and it's still running fine. This is more of an experiment at this point to see what what point parts replacements become necessary. This is no longer my primary defensive long gun, and I do have a fill kit of replacement parts ready for if/when failure occurs.

Outstanding! That would make a great write-up with pics, as parts wear and have to be replaced.........if they wear and need replaced!

 

[PewPewChris]

2,500 rounds:
- Inspect the extractor spring and insert, and replace as necessary,

5,000 rounds:
- Replace extractor spring
- Replace extractor insert
- Replace Crane O-ring (if present)
- Replace gas rings
- Replace buffer spring

I use springs from Sprinco. https://sprinco.com/. They have a selection of AR-specific springs.

10,000 rounds:
- Replace bolt

15,000 rounds:
- Replace barrel

The “Replace” intervals are automatic. Even if the part looks decent, I replace it. Of course, I inspect all these parts anytime I clean or have the weapon apart; if a part needs replaced earlier, I do so.

During cleaning, check the following:
- Extractor, especially the groove, for wear or cracking, edge should be sharp
- Bolt lugs for peening and chips
- Gas key is straight and opening for the gas tube is round and smooth. It is tight and screws aren’t loose. If you have a reverse torque wrench, you can check the screws at 20 and then 30 inch/lbs, but no further.
- Check bolt carrier body for cracks, especially around the cam pin hole.
- Firing pin tip should be smooth and rounded; no dents, chips, or weirdness.
- Gas rings are whole and not broken. To test for wear, grab your assembled BCG. Pull the bolt out of the carrier as far as it will go. Stand the bolt and carrier up on a flat surface, with the bolt face down. If the carrier doesn’t start to slip down, you’re good to go. If it does, your gas rings are worn. Get some new ones. If you have a McFarland-style gas ring, this test won’t work.
- Look down in your lower and make sure that no debris, like metal shavings or primers, have fallen in there and gotten lodged.
- Inspect buffer for peening; it should be smooth. Wipe the crud out of your receiver extension tube (“buffer tube”), lots of folks don’t do that. If the “sproing” bothers you, wipe some grease in the tube and on the outside of the buffer spring.
- Check your magazines to make sure they aren’t full of sand, dirt, and general crud. If you use metal magazines, check the feed lips to see if they’re starting to spread. On all magazines, regardless of material, check the backs of the feed lips for cracking.
- Check to ensure that optics, lights, BUIS, muzzle devices, sling mounts, etc., are gut und tight. Can’t count how many times during a class that a student has had accessories fall of their weapon.

Being a new owner of my first AR, this will prove useful...as soon as I figure out what half the parts you mentioned actually are lol

 

[Leveraction44]

Brownell has a short video on YouTube with their recommendations.

Not very many parts are usually needed.

The buffer spring and a o-ring in the bolt were 2 items they listed. It is only about a 5 min. Video. You should check it out. They have the same video for 1911s, Glocks, etc.

 

[cmshoot]

Brownell has a short video on YouTube with their recommendations.

Not very many parts are usually needed.

The buffer spring and a o-ring in the bolt were 2 items they listed. It is only about a 5 min. Video. You should check it out. They have the same video for 1911s, Glocks, etc.

I don’t run O-rings. I recommend you run an O-ring, or an insert with the extractor spring, not both. Out of the two, I prefer the insert.

If your AR needs both the insert and the O-ring, it’s a symptom of a problem that is better solved at the source and not at the result.

If your AR is otherwise running fine and you run both, that can also cause problems. It places too much tension on the extractor, making it hard for the extractor to snap over the rim of the cartridge. More than once, I’ve seen the extractor smash right through the cartridge rim, removing a chunk, and preventing the case from being extracted after firing. You end up with a Failure To Extract that can only be fixed with a cleaning rod down the barrel.

Some companies ship their bolts/BCG’s with both an insert and an O-ring. Worth checking before your first range trip.

 

[cmshoot]

Regular use of steel case ammunition accelerate wear on such parts as the extractor. Important to check when performing maintenance.

A note on the bolt cam pin. It is now thought by many that it is better to install the cam pin in the same direction every time to reduce wear that can cause the pin to fail. Forward Controls Design now offers a cam pin that has an indicator mark on it to help orient the pin in the same direction every time. I took my existing cam pins and engraved a small arrow on them to help me with this. Best case, your cam pin will last longer and be less liable to crack/break/fail. Worst case scenario, you spent some time marking your cam pin. There is no downside to orienting your cam pin.

More information: https://www.theoutdoorstrader.com/threads/forward-controls-design-sotar-cam-pin.2098379/

 

[Leveraction44]

I don’t run O-rings. I recommend you run an O-ring, or an insert with the extractor spring, not both. Out of the two, I prefer the insert.

If your AR needs both the insert and the O-ring, it’s a symptom of a problem that is better solved at the source and not at the result.

If your AR is otherwise running fine and you run both, that can also cause problems. It places too much tension on the extractor, making it hard for the extractor to snap over the rim of the cartridge. More than once, I’ve seen the extractor smash right through the cartridge rim, removing a chunk, and preventing the case from being extracted after firing. You end up with a Failure To Extract that can only be fixed with a cleaning rod down the barrel.

Some companies ship their bolts/BCG’s with both an insert and an O-ring. Worth checking before your first range trip.

To say that I am no AR expert would be a gross understatement.

Here is a link to the Brownells' video - Quick Tip: Must-Have Spare Parts for Your AR-15

 

[cmshoot]

To say that I am no AR expert would be a gross understatement.

Here is a link to the Brownells' video - Quick Tip: Must-Have Spare Parts for Your AR-15

Is the video contradicting what I advised?

 

[Leveraction44]

Is the video contradicting what I advised?

If you want to know, check it out.

 

[Jack506]

cmshoot Thanks!!

 

[rhaney02]

If you want to know, check it out.

I guess you don't know what a rhetorical question is....