doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Back-boring tubes to lighten them?

Lloyd, I actually did not surmise that your gun was a Flues. I just got lucky when I mentioned the three I have that blew up and became parts guns. As I said, all were pretty darn thin without any honing or boring being done. I'd guess that they all had some minor obstruction like a wad left in the bore or a plug of snow. I think some minor obstructions near the muzzle will often get blown out as the charge rapidly compresses the air in the barrel. But at some point when the obstruction is too deep or too heavy, and the barrel walls are too thin, the pressure takes the path of least resistance and ends up bulging or splitting a tube. It looks as if two of these three blown Flues guns I have would have injured the shooters left hand, while the burst in the 16 ga. was a bit further forward.

I know what you mean about the number of heavy charges that likely got fired in many of these old vintage doubles. I've told the story here several times about one hunting buddy's younger brother who used to routinely fire 3" Magnum shells out of his Dad's light 20 ga. Ithaca Flues. I think he was lucky to not do any damage to himself or the gun. And even today, there are a lot of very intelligent people who think that low brass shells will always be low pressure.

Speaking of the Deliverance types, you'd have loved the goober who came to my house last November to pump my septic tank. It hadn't been pumped since I built the house about 9 years ago, and the township had passed an ordinance requiring that septic tanks be pumped every 3 years. We had a fairly wet fall and it had rained for several days prior to the Honey Dipper truck arriving, so I suggested to the driver that he back in to the tank so that he would be facing slightly downhill when he pulled out with the loaded truck. Einstein felt better about doing exactly the opposite. While he was pumping the tank, he kept commenting about how great it looked and he couldn't believe that the amount of solids was so low considering how long it had gone without pumping. He kept asking me what I was doing to keep the system working so well and he kept telling me "Whatever yer doin'... keep raht on doin it!" He talked like Ed Good writes. He had rubber gloves on, but he kept touching his face with the same gloved hands that touched the suction hose and nozzle. He could have flossed with clothesline rope because about every other tooth was missing and the ones he still had were rotten. As I remained upwind and thought about how much better my job is on my absolute worst days, I noticed the tires on the truck were pretty bald. No way they could have ever passed State Inspection. Well guess what? Between the bald tires and the loaded truck facing slightly uphill and the wet lawn, he got stuck when he tried to leave. I had to get out some chains and fire up the tractor and pull him out. He kept spinning the tires as I was pulling him which made matters worse, and he left some nice ruts in my lawn. He was so thankful when I got him pulled out that he jumped out of the truck and grabbed my hand to shake it as he thanked me. He was sure his boss would fire him if he got stuck again, so obviously this wasn't the first time. Getting fired from that job would be a blessing. I didn't touch anything with my right hand until he got half-way down the driveway, and I rushed into the garage where I had a jug of Clorox, and then ran to a spigot to disinfect my hand. I just hope his other part-time job isn't in the food service industry.

Lloyd, Did you look at Drew's picks and see your concentricity and striking problems? They are obvious in those section photo's.

Look up Terry Lubzinski's Optimus restoration. The barrel work specifically.
That barrel man was honest, and Terry quite astute.

CZ, I did a search under Optimus and didn't see Terry's name in the 8 pages going back to 2008. Another gun, maybe? Gil

He bought a rare Optimus that idk, was found on the bottom of the ocean or something, and sold at auction.
Most people were scared off. paid maybe 12 and stuck 10 into the rehab.
In the resto, as reported here, the barrels needed to be honed out to remove corrosion and pitting. The barrel man said, hey, wait a minute. You can't get there from here. I can only go so far in the lapping for all kinds of reasons. You won't get what you want. It is best to stop here. Leave a better average wall thickness, but more pitting.

An honest craftsman not blackholing his patron.

It wasn't the Optimus story, it was the integrity I wanted Lloyd to read about.

Between that report and Drew's examples, the op should kinda see the picture.

That resto might have fallen into shadow.

CZ: I did see the section pictures that Dr. Drew provided. Clearly, the issues with concentricity would be a real problem for anyone trying to work on those barrels. I guess I'm hoping they are representative of lesser-quality guns from a foreign manufacturer who didn't have to bear much responsibility for quality issues. American makers, Ithaca included, didn't have that luxury. At the turn of the last century, reputation was critical as almost all marketing was word-of-mouth. If my measurements of this gun indicate such an issue exists, I simply will not proceed.

THANKS Lloyd.
As an indulger of all that is needlessly complicated, I'm not against extensive modeling before cutting.

D Amos already pointed out how the dynamics are effected.
You could model mat'l removal in 2" increments for fun. Maybe find a swing effort or MOI that suited you. or not. Lots of cg fun right there. And nothing but pencil lead on the shop floor.

Implementing is then a whole 'nother thing though.

From just about everything I have read on the subject, final barrel striking and polishing is virtually always done after the barrels are joined and the ribs installed. As such, the barrels are naturally going to be thicker between the ribs. Any subsequent refinishing over time that involves striking and polishing after dent removal is going to further thin them. I have no way of proving it, but I have heard of more than a few guns from quality American gun makers that had exceedingly thin areas, and allegedly had never been honed or otherwise refinished. I'd be interested in hearing what kind of measurements you get in your 20 ga. Flues Lloyd.

I keep a 20ga Flues here to remind me how gun peddlers like to ____the unwary. $450.00 tuition payment.
Paper thin to start, then honed to useless ness. I'm not shooting it.

Then, since I didn't learn the first time, I bought another at auction, hoping the barrels would bail me out. ha! The left
tube was crudely sleeved at 12 inches, and just so happened, was photo'd from the right side.
No returns.

Recontouring 20ga Flues barrels will be like repairing used aluminum foil.
Buy a NID.