Factory test fire x??

[RWB]

I just bought a new 22" 930 Pro Tactical and have read many posts advising a thorough cleaning before any use.
That may have been the best tip I could've gotten.
After breaking it down, I found the gas piston fouled beyond anything I would have expected after only a round or 2 from the factory, not terrible, but it did take an effort to get completely clean.
It may be normal since this is my 1st semi auto scattergun, I'm only used to seeing a very light film from one factory test round on my handguns.
The big concern tho is, in side the barrel, directly behind the engraved model & barrel discription, there is a "patch" of dissimilar texture, almost like very light surface rust, but not pitted, which I have soaked in Hoppes 9, and scrubbed with a brass barrel brush over and over, with little change.
I havnt gotten a totally clean swab yet tho so i may be making a little progress.
At this point, I don't believe any normal effort will remove this entirely, so before I take it back to my gs, thought I'd ask if it is, by chance, possibly a normal result of how the model inscription is created, and could be from temp change in that spot?
I wouldn't think so, but, again, this is somewhat new territory for me.
It's not a huge thing, but, if it's not normal, as I suspect, then the ocd in me is never going to let me get passed it and besides, I paid retail for a new gun, so I just want it right, ya know.
O yea, also, where the barrel goes in the reciever, there is a hole formed into the end of the barrel, that I would expect to match a "lug" inside the reciever to lock them together, but nothing there to mate with it?
Sorry for all the questions, I'm just too concerned now, to even try the gun out, before I resolve this situation, so any thoughts will be appreciated.
Thanks,
Roger

 

[John A.]

Unsure what shell they test fired it with.

Some powders are a lot cleaner burning than others. And to be honest, I rarely ever clean any of my pistons. And when I do, it's with nothing but hit it with a scouring pad to get the caked on stuff off, then I put it back. Especially don't oil or use clp on it. That's just going to gunk it up faster.

The square lug is normal. That's what the bolt itself locks into when its' in battery. If you look at the top of the bolt in the front, you'll probably see what I'm talking about.

As for the discoloration, I'm going to say normal. Especially if they're laser engraving these days. (speculation: I don't know how they're doing their engraving)

If you scrubbed the spot in the barrel with hoppes and a brass brush and you have a clean patch, there's not going to be much trouble from it I don't believe.

 

[RWB]

Thanks JohnA, I wasn't thinking about the barrel locking in in only in battery, duh.

The rough patch is still bugging me tho.
The barrel engraving wasn't done via laser, it looks as if it could've possibly been stamped, maybe before boring, or possibly carved by a cnc.
I imagine it's only a coincidence as to the location anyway.
I still havnt gotten a very clean swab.
I'm going to soak more and put the brass brush in a drill to see if I can eliminate it, if not, im afraid, since that +- 2-1/2" × 1" spot is not slick and shiny as the rest of the barrel, it will be prone to catching crud or easily oxidizing.
I was hoping to hear this may be common, but perty sure it's from residue being left to set up after testing.

 

[CaddmannQ]

Residue plus humidity plus zero lube = rust and pits.

I've seen this in a few of my new guns, but was lucky & got it all cleaned out before pitting.

Those guns were all leftovers and had been in long storage.

 

[Lefty9]

I believe in Jerry M. ; he sez to keep the piston REAL clean , so thats what I do . It takes some time to soak and scrub all the caked on crap off of it -but it's worth it .

 

[RWB]

CaddmannQ, the situation you describe is exactly what i suspect, that there was definitely an extended period of time between test firing and the 1st cleaning it received once I purchased the gun.

When you say "These guns were leftovers and had been in long storage", what exactly does this mean?
As far as I've been able to determine, the 85119 model has been, and still is production and readily available for new purchase, so this statement really confuses me.
I purchased the gun from my local gs, who I trust when he sells me a new gun, that said, the gun was fired multiple rounds without cleaning, and left considerably fouled, so I have to believe, either the gun was returned by someone, or Mossberg allowed the product to be boxed and shipped with no protective coating on the hardware.
I've purchased more new firearms over the years than I will ever recall, most being handguns, Sigs, Glocks, and Ruger being the majority, and every one had sufficient element protection, usually taking an effort to completely clean off.
When I say this gun was fouled, it took a little effort to even work the piston out of its bore, the pistons seal rings were well fouled and the barrel was left with plenty of residue to corrode with time.
It will also require a mag spring adjustment, as I have to try and "mimic" a blast cycle by hand as hard as I can go to get it to load from the magazine.
I am really starting to 2nd guess my decision to go with Mossberg at all.

 

[CaddmannQ]

Well it sounds to me like you bought a "demonstrator."

Some gun dealers will take their friends out to the range and let them shoot various weapons, to try and sell them. I have such a friend & I bought more than one gun like this.

But often dealers aren't very good about cleaning and oiling.

When I said my guns were leftovers, most of them were bought brand new but under various conditions.

One had been bought and returned almost immediately because the owner was arrested and had to give up his gun. More than one was purchased by someone who failed the background check and had to give it up. Two were guns that Davidsons has been selling as a "Davidson's exclusive" for well over 2 years including the 50th Anniversary Ruger 10/22.

So these were guns that had been fired maybe once or twice and then had been sitting in stock for months and sometimes years, untouched and unsold and unoiled.

The fact is the manufacturers don't seem to put a lot of Lube on the guns anyway nowadays, because they don't want to create a fire hazard with the cardboard boxes and oil. They're probably skirting the DOT regulations as it is. So anyhow, more than one of these guns had minor rust in the mag tubes or fingerprint rust on the outside of the barrel.

One had obviously been sitting on the shelf iat this sporting good store for years, and had been handed around and looked over and scratched a little. But aside from that it was a high-quality gun and with a little elbow grease it looks almost perfect. I paid less than two-thirds of the normal price.

Almost all of my guns were bought at a reduced price because of these factors, yet with a little clean up every one of them turned out to be nice guns.