Extractor's

**Disciple** · 04-02-23, 21:36

I expect to replace gas rings and cam pins, but not hammers. I should rethink that. Any practical way to check for those "metallurgical issues" before it becomes a problem?

**prepare** · 04-03-23, 02:50

Originally Posted by lysander

Your mileage may vary . . .

Barrel
Bolt
Hammer Spring
Ejector Spring
Burst Disconnect
Extractor
Extractor Spring
Gas Tube
Hammer
Cam Pin
Gas Rings
Sear (Full Auto)
Semi Disconnect
Trigger
Ejector
Magazine Catch
Magazine Catch Spring
Burst Cam
Burst Cam Spring
Action Spring
Ejector Pin
Extractor Pin
Firing Pin Retaining Pin
Gas Tube Pin
Hammer Retainer
Buffer
Sear Spring (Full Auto)
Upper Receiver

5 of those failure items are specifically related to full auto.

**rpoL98** · 04-03-23, 06:13

https://www.kakindustry.com/5-56-replacement-extractor

**lysander** · 04-03-23, 07:51

Originally Posted by Disciple

I expect to replace gas rings and cam pins, but not hammers. I should rethink that. Any practical way to check for those "metallurgical issues" before it becomes a problem?

This is one of the unfortunate consequences of giving out reliability data . . .

40 weapons, 150,000 rounds of ammunition, at least eight weapons shooting over 18,000 rounds, half of it full auto, and somewhere in all that 4 or 5 hammers break, and of those half of them had an unknown number of round on them before the test started.

The same goes for all the other parts, really. If you plan on shooting twenty-thousand rounds this year through your one-and-only AR-15, keep a spare hammer at home, otherwise don't get all excited about it.

As you spotting trouble, yes, you can x-ray them for casting flaws, do a superficial hardness test to see if the carburization was done right and then cut them in half and do a core hardness test to see of the through hardness id correct. Or, you can do what I do, after a few hundred rounds, give the hammer a close examination, if there is no peening, cracking, or other damage, I don't think about it again.

**lysander** · 04-03-23, 07:52

Originally Posted by prepare

5 of those failure items are specifically related to full auto.

And, a fair number of those parts probably failed due to full auto . . .

**Disciple** · 04-03-23, 13:47

Originally Posted by lysander

Or, you can do what I do, after a few hundred rounds, give the hammer a close examination, if there is no peening, cracking, or other damage, I don't think about it again.

Thank you.