flame cutting of the 15-22 upper

[straightshooter47]

anyone have a incident of what could be considered flame cutting on the interior of the upper receiver?

http://i241.photobucket.com/albums/ff271/texan610/IMG_2066.jpg


http://i241.photobucket.com/albums/ff271/texan610/15-22-1.jpg


http://i241.photobucket.com/albums/ff271/texan610/15-22-4.jpg


this cavity is after about 5800 rounds of CCI blazer 40gr. HV.
it lines up exactly where the bolt closes to the breechface of the barrel

 

[chuck s]

Nice big photo. Not sure if it's bigfoot, a space alien, or what.

With no scale, nor reference where this might be I've no clue where to look in my rifle.

Got a photo taken from farther away and something you can put in there so we can judge scale?

-- Chuck

 

[Scuds03]

I can see/tell where he is talking about. If you hold the rifle upside down and look at the plastic of the reciever just above the chamber, opposite side of the feed ramp you can see there is a gouge being worn into the polymer in his pics. I really dont think it should be doing that, e-mail S&W with your photos and see what they say about it. I had a problem and they got back to me through e-mail within a day.

 

[Rustpot]

Really hard to tell if there's actually polymer being cut away with all of the carbon buildup. Perhaps your bolt is not longer seating on the face of the barrel from grit?

If your cases aren't split it's not flame cutting. It it's from the normal cycle of the case being extracted it shouldn't be concentrated in that one spot.

Clean your gun, get better lighting and focus, and try the pic again.

 

[Squirrels Worst Night]

Wow bro, did you do all those rounds at once? At least thats how dirty it looks. I really dont think all those pits and cuts are supposed to be there but I do suggest cleaning your gun alot better then that. In the least it will make your gun look purty.

 

[chuck s]

Good photos!

No evidence of this on my rifle, but I'm at about 2000, not 5000 rounds. This is probably cosmetic. A good cleaning and monitoring this for additional wear is probably a good idea. Should be no gas leakage in this system, but it is blowback and the receiver will get dirty.

Not sure if they still sell baby bottle brushes but they work well in the receiver. Same brush is probably sold at the gun store as the Ninja Tactical Special Forces Delta AR15 Upper Receiver Brush for big bucks!

-- Chuck

 

[straightshooter47]

thanks for the input gentlemen...i just called it flame cutting (for lack of a better term) because when i first noticed it, it looked exactly like what you'd see on the under side of the top strap at the cylinder/barrel gap of a 357 revolver.

i first became aware of it at about 2000 rd. count, and at that point it looked like a scribe line made with a sharp instrument even with the end of the barrel . what is shown in the photos is after approx. 5800 rd., and the scribe line has became a cresent shaped cavity with some carry over "speckling" into the ejection port. there is nothing on the top of the magazines along the same plane of this cavity.

the range i shoot at has a concrete floor and likes for you to police your brass, so i've probably seen or handled 60% of the cases fired through this rifle...no case head splits, bulges or separations, nothing out of the ordinary for a fired .22 case.

also just for the record, this rifle has proven to be extremely reliable...out of the total rounds fired, i would say i've only had maybe 10 failure to feed (and most of those could be attributed to not loading the magazine correctly), zero failure to fire, and zero fail to extract/eject. this was accomplished while using ten different magazines, three of which are first revision. the CCI blazer ammo is all from one lot/case, and has been utterly reliable, with most 10 rd. groups shot off the bench right at 1.5 MOA

i've already replaced the upper in question and have sent it to S&W for their inspection and comments.