Small Hole on Outside of Barrel Chamber

[Captains1911]

While cleaning my Springfield XDs 9mm after its first 120 rounds, I noticed this tiny pit on the outer left side of the chamber. I did not not notice it when I performed the initial field strip and cleaning prior to shooting it for the first time, but it's possible I just missed it. Although probably nothing to worry about, I've never seen anything like it. What do you folks think?

 

[Technosavant]

No clue. I might try calling Springfield Armory's customer service about it. If it's a flaw they will likely want to replace the barrel.

 

[geetarman]

I don't know for sure but it looks a lot like a Rockwell indentation. I wonder if there are a certain number of barrels from a particular heat lot that are checked for Rockwell hardness. Seems like an odd location but I have certainly seen stranger things.

 

[Kevin_d77]

I just checked my XD and XDm and they both had that identical mark. I wouldn't worry about it. Same mark in essentially the same place.

XDm9

 

[Vireye]

I'd still see what SA says about it.

1.) For your peace of mind.
2.) I'm REALLY curious...

 

[Yung.gunr]

My XD9 has it too. That's funny, I've had it for almost 10 years and I've never noticed it.

 

[Kevin_d77]

Never noticed it on both of mine either until I just checked!

 

[NYPD13]

I just had to grab my XDM40 out of the vault and check. Yup same indent, same spot. I agree with it being a Rockwell hardness check indent.

 

[dayman]

I've never checked the hardness of steel with a rockwell gauge, but I have checked the hardness of concrete. I can't imagine the needle hits the barrel hard enough to leave a pit in the steel. The gauges we used on concrete didn't leave much of anything of a mark. For it do do that it would be very likely that if would deform the barrel.

However, I could be wrong. And, based on the number of people who are seeing it, I imagine it's something intentional.

 

[geetarman]

I can't imagine the needle hits the barrel hard enough to leave a pit in the steel.

All Rockwell machines leave an indentation where the load was applied. It is the nature of the test. A Rockwell Superficial will leave a smaller mark, but it will be there. Normally on machined surfaces, the test is conducted and the results recorded and then the surface around the indentation is stoned smooth to reduce the surface that has been displaced by the test.

If not done correctly, Rockwell tests can lead to stress risers in critical surfaces.

On parts and materials for flight use, the location for a Rockwell test will be defined in the engineering drawing. Any deviations from the correct location will scrap a part or require some sort of Material Review Board corrective action.

They are serious tests and improper tests or evaluation of results can have very negative consequences.

 

[Mystro]

Does the hole go all the way through?? If it did, it would be a over pressure relief hole. Its not in the typical place but that's my guess.

 

[dayman]

I should have said "a pit like that"
It looks like a pretty deep hole with defined sides rather than a dent. But again, I'm really just familiar with concrete. Also, it could just be the picture. Either way, I'm interested to find out what SA says.... I forgot to check my XDS this morning to see if it had the same thing.

 

[UtopiaTexasG19]

In anticipation of a bullet and smokeless powder shortage the XD is outfitted with a "pre-made" hole for a fuse. Just add some black powder and a match.

 

[BillM]

As others have said, it's the result of a Rockwell hardness test.

Hardened steel ball, known pressure, how far it indents indicates
hardness.

Nothing new---every model 1897 Winchester shotgun I've seen has
a little indent like that on the receiver.

 

[James K]

Since the hardness test is done on the barrels after the barrel is made, the mark would be left so the assembler can be sure the test was done before installing the barrel in a pistol.

Jim

 

[2ndsojourn]

From Bill:
"Nothing new---every model 1897 Winchester shotgun I've seen has
a little indent like that on the receiver."

Tsk....now I gotta go check when I get home tonight.

 

[Captains1911]

Response from Springfield:

"I had my technician look at your picture and that is a normal mark on the barrel. That mark is from heat treat and is on every XDs pistol.

Hope you continue to enjoy your pistol and if you have any further please feel free to ask."

 

[TheNev]

It also depends on which hardness scale they go by. One scale is for a 1/8" diameter ball, another uses a cone or diamond, etc.

 

[g.willikers]

I was going to suggest it was from a woodpecker.
But the black powder fuse explanation is better.