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Discussion Starter · #1 ·
The last few times at the range, I noticed when using two different types of factory ammo (Blazer Brass and Fiocchi), that the brass empties had a V-shaped scorching (black scorch/carbon) with the wide part of the V at the mouth and narrowing to more of a point about halfway down the side of the brass case.
The size was only about 1/4th of the circumference of the case - so just one 'side' of the case.
I didn't take any pics and I don't recall if I had the same issues with other factory ammo. (It had been a while since going to the range.)

Does this imply that the mouth of the case is not sealing well in the chamber and I'm getting 'blow-by' from the mouth back into the chamber?

Is this common with various Sig pistols?
(I did see a bit of that years ago when I owned a Beretta PX4 Storm)
Is it anything to be concerned about?

Thanks!
 

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The last few times at the range, I noticed when using two different types of factory ammo (Blazer Brass and Fiocchi), that the brass empties had a V-shaped scorching (black scorch/carbon) with the wide part of the V at the mouth and narrowing to more of a point about halfway down the side of the brass case.
The size was only about 1/4th of the circumference of the case - so just one 'side' of the case.
I didn't take any pics and I don't recall if I had the same issues with other factory ammo. (It had been a while since going to the range.)

Does this imply that the mouth of the case is not sealing well in the chamber and I'm getting 'blow-by' from the mouth back into the chamber?

Is this common with various Sig pistols?
(I did see a bit of that years ago when I owned a Beretta PX4 Storm)
Is it anything to be concerned about?

Thanks!
It isn't "common", and concern would be dependent on the reason.

Photos are almost necessary, besides the scorching, was there any denting of the brass? The chamber needs to be concentric, or round, and not oddly shaped.

Of course, you never mentioned the model, or if it has a loaded chamber indicator, or not.

More information needed, if we are expected to diagnose problems from afar!
 
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I don't think that it is common. Worst case concern: bullet in bore, maybe?? Probably not....

What I would do: The next time it happens (look at your cases after each mag full during your next range shoot), put that box of remaining ammo aside. Shoot the rest of that box in a different pistol - a friend's if you don't have another pistol. You might be able to rule out your SP2022 as the cause.
 

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Sounds to me like the brass didnt fully expand to make a good seal and you had some gas escape there.
Pictures would be helpful.

Could be harder brass or more likely a lighter load will often do that as well blazer and fiocchi aernt known to be the hottest stuff
 

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Discussion Starter · #6 ·
The model (as noted in the thread title) is my SP2022. Does not have a LCI.
There were no denting of the brass nor any bulged primers or primer flow.
Just the smoky looking carbon on the brass as I had originally described. It did seem like it was not sealing in the chamber that well. The brass cases do look quite thick, so maybe that is part of the issue.
My friend has a P320 and does not have that issue with similar make/model of ammo.

Next time I go to the range, I'll save the brass and take some pics.
The pistol is very accurate and has always been 100% reliable, so I'm not too-too concerned. The Blazer Brass and Fiocchi are rather soft-shooting target FMJ ammo, so maybe that does have something to do with it...
Just thought it was a bit odd, but will try other brand factory ammo next time to see if it does the same with others.

Thanks!
 

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I just started shooting a new (purchased last fall) case of Sig Elite Ball 115g 9mm in my 365 and have noticed the same 'scorching' on the casings.
The loads seem normal in every other respect. I've not noticed it before on any of the other brands of ammo I've run thru the gun.

Going to try some Norma I just bought on the next trip to see if it shows the same blow-by. Betting it's not the gun, but something related to the ammo casing not expanding as it should for some reason or another.
 

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Yes, just shot and picked them up..
normally I don't keep them after range but my wife wants to keep some :)
Brass from blazer FMJ and
Steel from Sierra HPJ
defense rounds.
 
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