Inspecting New Rifle Barrel

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charlesb
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Inspecting New Rifle Barrel

Post by charlesb » Wed Feb 13, 2013 8:53 pm

I recently purchased a bore-scope that allows me to take videos and still pictures inside of a rifle barrel, from either a head-on view, or a 90 degree view with the aid of a tiny 45 degree mirror that lets me inspect the lands and grooves in detail.

Looking in my rifles at home, I discovered what I expected... Copper and carbon fouling, chatter on both button-rifled and cut rifling, and so on. - And I thought that they were clean!

I still hesitate to inspect my 54 caliber muzzle-loader... I'm afraid of what I might find in there, it was well-used when I bought it.

Today I brought home a new rifle that had been on display in the rack at the gun shop, and decided not to fire the gun until I had had a chance to look at it with the bore-scope.

What I discovered was an amazing amount of dust! Near the muzzle it was really thick, and I didn't see uncluttered steel until the 17" bore-scope was poked all the way down the barrel, close to the chamber and bolt face.

Boy, was it dusty!

I guess I'll run a mop through there, and try again. - And I'll never assume again that a new gun is clean. Besides the dust, I saw a small amount of copper fouling, some of it blue-colored from cleaning I assume. This must have been from a factory test-firing. The copper was in a spot about 3/4 of the way forward from the chamber.

The gun is a Browning BLR Lightweight '81, in .308 Winchester. There was no visible chatter in the barrel, the interior finish was very good.

Nobody likes to think of their barrel having chatter in it, but the truth is that my custom Savage 16 in .243 Winchester has chatter - and it is by far the most accurate rifle that I own. - So chatter is not necessarily the kiss of death. This is why proper break-in of a new barrel can make a big difference on some guns, but makes little difference on others. The Savage was very carefully broken in.

Tomorrow morning after it warms up here in the mountains, I'll take the new BLR to the range to sight it in, and see what it will do with the ammo that I have on hand.

The videos I took average from 20 to 35 megabytes in size. I had to move the scope slowly enough so that I could observe detail, which takes at least 30 seconds, preferably a minute.

I own several websites, and will try to find one that I can park a few videos in, and provide links here without cluttering up this forum.
Last edited by charlesb on Sun Mar 10, 2013 1:28 pm, edited 1 time in total.

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bgreenea3
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Post by bgreenea3 » Thu Feb 14, 2013 1:37 am

Everything I've heard about borescopes and bore imperfections are similar to hat you are saying, there are some barrels that look awful but shoot great and some look great and shoot awful.

Looks like you are enjoying your new toy!
"Courage is being scared to death... and saddling up anyway."

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bigfatdave
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Post by bigfatdave » Thu Feb 14, 2013 4:24 am

In industrial applications, a boroscope inspection is interesting, but secondary to actual performance.

I've found the devices less than useful for predicting operation of equipment (good or bad).

And good for you getting your own, I always wonder where the ones I check out from tool issue have been.

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Post by Bullseye » Thu Feb 14, 2013 6:49 am

I knew you would soon discover that all barrels have some imperfections, and the chatter you saw on the rifling was normal, not excessive. Fouling is not a major hindrance either, any fired barrel will have some of this too. Corrosion and excessive throat erosion are purveyors of inaccuracy. Have fun with your borescope, you're doing exactly what you need to do play with it and gain experience on how to use it as an interpretive diagnostic tool.

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charlesb
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Post by charlesb » Thu Feb 14, 2013 6:11 pm

I got a chance to get away and shoot the BLR '81 today, despite it being Saint Valentine's day. The knick-knack shop that my wife wanted me to take her to would not open for a couple of hours, so I was able to finagle permission from the Boss.

I decided to try a new method of barrel break-in, and left all of my usual cleaning paraphernalia at home, only bringing a bottle of Hoppe's #9, and a "Bore snake" for 30 caliber to the range with me.

This worked out well.

My first target was not encouraging, but the shots were all on the paper due to the use of a laser "sighter-inner" gadget that I used to get the Nikon Pro-staff 3-9x40 more or less sighted in at home, putting the laser on a steel shed that was roughly 25 yards away. The shed was open, so the back wall was dark enough for the little laser. I adjusted the scope to put the cross-hairs on top of the red laser dot.

Image

The center of the group was 3" low, so I adjusted the scope, dribbled Hoppes #9 onto the bore-snake, ran it through the barrel once and fired three more shots. - Then I cleaned it again and fired three more shots. The resulting group was much more encouraging.

Image

It looked to be shooting 1" to the left, so I adjusted the scope again, changed to a reactive target, and fired a ten-shot group, cleaning every three shots, and once again when I was through.

Image

The reactive target had no lines, so I measured the two holes that were farthest apart with calipers at home, and will call it a 2 1/2" group.

I was shooting Federal Premium .308 Winchesters that had Sierra 168 grn, BTHP bullets. One box of the two that I bought with the gun ( $39.95 each! ) was burned up getting the gun sighted in and the barrel lightly broken in, so I have another box to whip out if I get a chance to shoot a pig, or a sheep. - It's too late for deer.

I optimistically brought a bipod with me to the range, only to discover when I got there that the gun had no sling-swivel studs. - Duh!

So I had to use the case to my spotting-scope as an impromptu shooting rest. I am sure that the gun is capable of shooting better than I can, but I won't be burning up any more of the expensive ammo trying to find out.

I do have a big box of Hornady 150 grain flat-base spitzers though, and will do some practice shooting with some reloads using those, being mindful not to re-adjust the scope. That way, if a hunting opportunity jumps up, it will still be ready to shoot the fancy Federal Premium stuff.

I am very happy with the accuracy I got, the gun is light and handy, and has a barrel-band so I figured that I could only expect so much.

The other gun that I considered was a BAR in 7mm Rem mag, and it was almost a pound heavier. I'm glad that I went for the little BLR.

Now I have Saint Valentines day duties to perform, but later this evening I will look at the copper and fouling with the bore-scope. I have noted that the gun did not settle down and start to shoot until it had four or five shots through the new barrel.
Last edited by charlesb on Thu Feb 14, 2013 7:41 pm, edited 1 time in total.

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charlesb
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Post by charlesb » Thu Feb 14, 2013 7:40 pm

Here's two shots from the BLR's barrel, showing a bit of copper fouling but not much. No extra cleaning done yet, just the quick bore-snake cleaning at the range that I described earlier.

Image

Image

* On rifle scopes: ( not bore-scopes )

I'd like to note that the Nikon Pro-Staff 3-9x40mm rifle scope with BDC reticule is the third one that I have purchased. This inexpensive scope is a real performer, I have had nothing but good luck with them. This latest one is slightly improved over the earlier model.

I have a Nikon Monarch 4-16x42mm (BDC) on my custom Savage .243 and it does give a better image - but not enough to really justify the added expense.

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