How to check the condition of the bore

[Aaryq]

Howdy, folks.
I have a Chi-Com SKS and aside from removing the bolt and looking down the barrel, I don't know how to check the condition of the bore without taking it to a gunsmith. How can I do it and what do I look for?

 

[DnPRK]

A visual inspection using your issued Mk1 eyeball is what the gunsmith would do. Hold the rifle so you can see a white surface (e.g.wall or piece of paper) through the bore. (You do not want to look directly at a light source because it will only serve to blind you). It takes a little practice, but you can learn how to focus your eye starting at the near end then gradually move down the bore. You are looking for imperfections of the lands and grooves - pits, land edges that are not sharp, roughness, debris in the corners of the lands, Etc. If you practice and get good enough, you can follow a single groove for it's length through the bore.

 

[AmishFury]

well one way is to remove the reciever cover and bolt... no need to use a gunsmith since the reciever cover is removed by a simple latch and pin

another is to pull the bolt back until it locks place a piece of white paper angled into the reciever and place the receiever under a light source (paper reflects light into the bore)

pull the boly back and use a bore light... bore lights are cheap and great for checking bore condition on any non-muzzle loading firearm (except revolvers) without disassembling (great for gun shows/shops)... i carry a bore light with me almost all the time... you never know...

as far as what to look for?
imagine this without the little bit of dust

the bore should at best have sharp lands a bit of a shine to it and no pitting

darkness and pitting are the most common concerns just don't confuse dirty bore with dark

example of pitting in a bore

dark and pitted bores can be safe to shoot provided the pitting is not too deep accuracy may or may not be poor with such a rifle (pitting in the grooves has less effect on accuracy than pitting on the lands)

 

[Slamfire]

Amishfury did a good job of getting bore pictures. I found it very difficult to get my camera to focus on the rifling.

Anyway, let me add to this. Look for rings and shadows. Pictured is a nice new Colt made M1911 barrel. As it came from the factory on a series 80 Colt Targetmaster. Expensive pistol. As you can see the bore is bright, the edges of the lands square. However, see a ring? Rings and shadows near the muzzle are very bad things. Near the breech, like this, doubtful you will notice anything on paper, but I would not buy this barrel if I saw this. When you point the barrel at a light, rotate the barrel. If the shadow of a ring or spot moves with the rotation, the barrel should be investigated further.

I purchased a mint condition pre 64 featherweight barrel, screwed it on an action and it head spaced perfectly and took it shooting. Accuracy was awful. Maybe 6 inch groups at 100 yards. After bedding and experimenting with free floating versus pressure bedding, I just looked down the front of the barrel. There was a shadow, less than an inch from the muzzle, a shadow that rotated as the barrel was rotated.

Somewhere in a previous past someone had shot the rifle with something in the muzzle, and bulged the barrel.

My bolt gun gunsmith took a reamer and counterbored the barrel. This was a last ditch effort, and it more or less worked. The barrel now shoots within two inches at 100 yards. Cost me more money than I wanted to put in that barrel.

 

[Golden Hound]

You want it to look something like this:

 

[mtngunr]

The muzzle is the most important area, and checking the first inch or so is usually a good indicator of overall bore condition....simply shove a small piece of clean white patching about an inch into the muzzle, then use a bright flashlight and a min. 3x magnifying glass to get a detailed view of grooves and lands.