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WyoChukar
PostPosted: Sun Mar 10, 2019 5:01 pm  Reply with quote



Joined: 16 Jul 2015
Posts: 2124
Location: Hudson,Wy

I figured that some here might like to see this since shotguns do occasionally take a fall, often with the bearer of said gun. Over the years I have encountered an few of these, having been responsible for the first one long, long ago. These can be removed if one is careful and has the necessary tools and materials. For an example I will use a Parker 10 ga. barrel that I repaired today. The gun came into my possession with unexpected damage. Not cool.

Such dents can be pressed out in stages, a little at a time, with steel mandrels. Conveniently, bottle neck mechanics sockets in a wide variety of sizes can cover most of what is needed. I will admit that I turned one of these to do the finishing work since I had one that measured .752" at the small end and I needed to finish up at the original choke diameter of .748" I reduced the small end of this socket to .749" to compensate for the slight spring back of the barrel steel.

To begin I chose the largest diameter socket that would pass through the damaged area, oiled it, and lightly tapped it in with a small hammer until the bottleneck radius slightly opened the dented area. I could have used a slightly oversize straight shank mandrel (with radiused or tapered tip) and drove it through from the breech end also. Remember, oil the mandrel, be gentle with the hammer, and strike squarely. To remove the mandrel, I lightly tapped it from the breech end with a long steel rod.

Next, I used a socket with tip diameter of .720, then one that just happened to measure .742. I have a lot of sockets. One could go to a pawn shop with a pair of dial calipers and buy a bundle of various sockets for use as dent raising mandrels.

As matter of fact, I used sockets to check nominal bore diameter too. A socket with an external diameter of .778" would fit down the bores from the breech end with noticeable resistance. One that measured .776" fit with slight play. Not too hard to call that one. .777" is the main bore diameter in both bores. That's great quality control, especially considering the work was performed about 120 years ago.

Anyway, back to the dent. Now I was getting very close to done, close enough that I modified the socket mentioned above. Removing only .003" from the diameter did not require lathe work, just a high speed drill, socket adapter, file, various grades of sandpaper, and lots of careful measuring.

Once satisfied with measurements and polishing, I inserted this final "mandrel" and once agin tapped it in lightly with a small hammer. At this point things looked mighty good, but the dial calipers revealed that the dent area was still .005" tight. This is due to natural spring back of steel. This quality varies with steel type and hardness, but is always prevalent to some extent.

Now comes the touchy part that makes a body nervous: intentionally side loading the mandrel. I reinserted my socket become mandrel, and struck (lightly) the edge closest to the dent location, several times. I tapped it free from the breech end and measured. Closer, but no cigar: .003" out of round.

The final touch came by once again tapping the mandrel in, inserting a socket extension (one advantage of the socket method) and then executing light but brisk little taps to the extension, perpendicular to the bore and in the direction the dent needed to be pushed out, while firmly securing the far end of the socket extension in my free hand. Sneak up on this carefully! It's better to gradually get to where you need to be than to beat things too hard.

All said and done, total diameter now varies only .001". I will take that any day. Most guns I have measured have been more out of round as issued.

Most folks won't want to tackle this, preferring to pay someone else to perform this repair. That's never a bad idea. However, knowing a procedure like this may be the only option to save an otherwise ruined hunt/ road trip far from home. If nothing else, hopefully I have provided some insight into reversing a disaster.

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Last edited by WyoChukar on Sun Mar 10, 2019 5:07 pm; edited 2 times in total

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WyoChukar
PostPosted: Sun Mar 10, 2019 5:04 pm  Reply with quote



Joined: 16 Jul 2015
Posts: 2124
Location: Hudson,Wy

Post script: The oil film on the mandrel is a good indicator of uniform contact once things get "round".
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Pine Creek/Dave
PostPosted: Sun Mar 10, 2019 5:13 pm  Reply with quote



Joined: 17 Mar 2017
Posts: 2786
Location: Endless Mountains of Pa

WyoChukar,

Nice job sir!

Pine Creek/Dave
L.C. Smith Man

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Charles Hammack
PostPosted: Sun Mar 10, 2019 5:16 pm  Reply with quote
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Location: Central Missouri

Glad your fixing the Ole girls up , just removed a dent in a Spanish Sable this evening, took the dents out of a dozen sets of barrels over the past few weeks.

Nice pic's showing anyone how to tackle this on their own , if you have the time show the folks the plugs to use to remove the dents , sure is nice bringing the Ole guns back to life.

Regards , Nick
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Ohio Wirehair
PostPosted: Tue Mar 12, 2019 9:04 am  Reply with quote



Joined: 24 Jul 2016
Posts: 546
Location: Ohio

Very ingenious incorporating a socket set,I like it. That bore looks pretty rough,savable or wallhanger?
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WyoChukar
PostPosted: Tue Mar 12, 2019 2:31 pm  Reply with quote



Joined: 16 Jul 2015
Posts: 2124
Location: Hudson,Wy

We'll know after testing. If it fails in any way, I will save the mono bloc and sleeve in a new barrel set.

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John Singer
PostPosted: Wed Mar 13, 2019 5:13 am  Reply with quote



Joined: 03 Sep 2014
Posts: 398
Location: Rochester, MN

Did you fire the gun to determine point of impact vs. point of aim?

I have done similar repairs on several guns using sockets as mandrels.

I have also adjusted the point of impact on several SxS shotguns. I have found that many inexpensive do not have properly regulated barrels.

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WyoChukar
PostPosted: Wed Mar 13, 2019 11:40 am  Reply with quote



Joined: 16 Jul 2015
Posts: 2124
Location: Hudson,Wy

Not yet, the gun will first be remotely fired with very stiff loads to ensure a certain amount of safety margin before I proceed to point of impact etc. My vintage gun expert looked at the bore pitting last night and told me it was nowhere near as bad as my photos made it look. Still, proceeding with caution. The goal is to bore out the pits and chrome line the bores to alleviate future rust issues. Pits and rust hold moisture, residue etc. and tend to grow. Don't need that.

I have corrected guns that didn't shoot straight. with a fixed choke gun, it's actually pretty simple. My 10 ga. O/U was almost an entire pattern off P.O.I. Fixed in 20 minutes.

I have never experienced a shift of impact by returning a damaged muzzle to its original shape or from reaming a choke on a gun I previously tested for P.O.I.

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John Singer
PostPosted: Wed Mar 13, 2019 1:20 pm  Reply with quote



Joined: 03 Sep 2014
Posts: 398
Location: Rochester, MN

WyoChukar wrote:


I have corrected guns that didn't shoot straight. with a fixed choke gun, it's actually pretty simple. My 10 ga. O/U was almost an entire pattern off P.O.I. Fixed in 20 minutes.

I have never experienced a shift of impact by returning a damaged muzzle to its original shape or from reaming a choke on a gun I previously tested for P.O.I.


You are faster at correcting POI than I am. It usually takes me an hour per barrel and several cartridges/patterns.

I agree to that I have never changed POI by reaming a choke. The ream follows the axis of the bore.

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WyoChukar
PostPosted: Wed Mar 13, 2019 8:03 pm  Reply with quote



Joined: 16 Jul 2015
Posts: 2124
Location: Hudson,Wy

The truth of how I change the P.O.I.? Some may cringe, but I use a Dremel sanding drum on the parallel section of the choke. I do this outdoors where I can remove a tiny bit of metal in the direction the pattern needs to migrate, fire the gun from a rest, and continue incrementally. It's best to put masking tape on the barrel and mark it precisely so you don't get it backwards when you turn the barrel around to do the work. Afterward I hone and polish. It takes a delicate touch and a bit of skill to keep the tool "square" with the bore and end up with a still round exit, but it is quite effective.

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John Singer
PostPosted: Thu Mar 14, 2019 2:03 am  Reply with quote



Joined: 03 Sep 2014
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Location: Rochester, MN

I use essentially the same technique. It is very effective.

It takes me longer when I use a egg beater style manual drill.

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