JR Carbine .40, is this normal or cause for concern ?

[SmokeyBonez]

So I noticed little burrs on my muzzle end when I first purchased this JRC .40 about a year ago. I have been noticing it more lately, they appear to be what may be hairline splits that line up with the contours of the rifling, but they also may just be the same burrs with a touch a paranoia on my part.

It has had about 700 rounds through it and has functioned well with mostly 165gr AE, and I haven't damaged the muzzle in any other way (dropping, dings etc). Wondering if any other owners have noticed the same thing and this may be normal or I should consider getting a replacement barrel ??? I got into firearms about a year ago as well, so if this is a stupid question, take it easy on me as I am still a lernin

It was tough to get a decent pic so I took three. Your thoughts would be appreciated guys, thanks.

 

[j_06]

carbon buildup. Normal stuff I use a q-tip soaked in wipeout or hoppes and rub it on and let sit. Usually comes off with another dry tip. Pic wise try using a white background it seems to help the focus if that was your difficulty.

Everything else I own has a nice crisp star though. Might be from having a more abrupt crown?

 

[Kano]

I have the same thing on a .22lr I have. If it still shoots well, then don't worry.

 

[SmokeyBonez]

Thanks for the responses