Casing Burn Marks

[jayhitek]

I've been tweaking a Glock 17 custom slide build that I've been working on for the past bunch of months.
Finally starting shooting properly after lowering the recoil spring to 11 lbs and striker pin spring to 3 lbs, but one thing I noticed that was odd though.. Look at the ejected casings.. One is heavily burned.
What would cause that?

The barrel is inexpensive and I did upgrade it last night to a better one. So I haven't tested it in it's newest configuration. But cheap barrel and the pics.. kind of curious.

 

[greencobra]

i'm no expert...looks like the chamber is a bit oversize and gas is flowing back. factory or reloaded ammo?

 

[Mountain]

I'm assuming you are not reloading 9mm: Bad chamber or rounds are firing out of battery. Either way, that's some bad mojo. Scuffs on case might indicate something 'off' with the chamber dimensions.

What's a cheap barrel? Bought used and screwed up by someone else or bought new from a questionable source?

 

[mac1911]

Me thinks weak load and just did not seal well?

 

[Dennis in MA]

scuffs could just be contact with teh ground and other brass.

I've had plenty of blow-by brass in my day. A little has never been a concern for me. That "seems" like a lot.

 

[jayhitek]

i'm no expert...looks like the chamber is a bit oversize and gas is flowing back. factory or reloaded ammo?

Brand new factory ammo.

 

[jayhitek]

I'm assuming you are not reloading 9mm: Bad chamber or rounds are firing out of battery. Either way, that's some bad mojo. Scuffs on case might indicate something 'off' with the chamber dimensions.

What's a cheap barrel? Bought used and screwed up by someone else or bought new from a questionable source?

It was just inexpensive. And to quote Tim at Gartman who originally worked the kinks out for me, "using a cheap barrel in a Zev slide.. no wonder you're having problems.."
https://www.sgmtactical.com/products/glock-compatible-match-grade-barrels/

And the Silencerco barrel I put in last night does fit better in there. Almost no slop. And the recoil spring has much less play.

 

[bill o]

Weak ammo not obturating the chamber.

 

[SJan]

Me thinks weak load and just did not seal well?

this

Weak ammo not obturating the chamber.

this again but with an expanded vocabulary

 

[jayhitek]

this

this again but with an expanded vocabulary

haha I actually had to google it to understand what was being said..

 

[SJan]

What sort of factory ammo?
Some factory 9mm is weak or inconsistent

 

[jayhitek]

What sort of factory ammo?
Some factory 9mm is weak or inconsistent

Sellier & Bellot 9mm Luger Ammo 115 Grain Full Metal Jacket

 

[Dennis in MA]

this

this again but with an expanded vocabulary

And expanding vocabulary about case expansion. LOL

EDIT

I haven't bought S&B in almost 20 years but it was HOT ammo back then. I don't think it's the ammo. Got another 9mm to be sure?

 

[Fixxah]

.380 by accident?

 

[Mountain]

Me thinks weak load and just did not seal well?

Agreed, if reloads.

 

[bauer]

.380 by accident?

Or possibly 9x18 makarov?

 

[bauer]

I wouldn’t think there would be lacquer on brass correct?

 

[jayhitek]

Just came back from the range and shot it with the new barrel. I think it was an anomaly.

The spent casings didn't have the same over-burn marks.

 

[mac1911]

Agreed, if reloads.

You have not shot enough UMC

 

[mac1911]

I wouldn’t think there would be lacquer on brass correct?

Why not? It would keep it from tarnishing. Not that the manufactures would do it.

 

[Mountain]

You have not shot enough UMC

Not planning to shoot enough either!

 

[DW357]

Sellier & Bellot 9mm Luger Ammo 115 Grain Full Metal Jacket

That stuff is loaded pretty damn warm. Lots of guys I know, use it to make power factor in IDPA with shoter barreled guns.