Working on a Hatsan MPA. I had someone make me a piece that screws in place of the flash hider/thread protector. It extends past the muzzle, by about an inch and I have another piece of shotgun barrel (already tapped for chokes) that will slip into it. I plan on brazing the two together. Here's the question. My Hatsan's internal barrel diameter measures ~.720" and the extensions barrel piece measures ~.716". This is measured by digital calipers (don't have a bore gauge). If I had a lathe, I wouldn't be asking, I'd just go ahead and make the diameters match. I'm wondering if I'm being over concerned about this slight mis-match.
Screw on shotgun barrel extension. Build question
- Thread starter weasel1
- Start date
I know it's only a shotgun. But it seems to me that you'd have done better to have that machinist make up the whole extension so it included the threading onto the existing barrel as well as the extension with the threading to take the chokes. If he did it right it would have all been cut in one setup and thus all precisely aligned.
But hey, you're here now and have the bits. And since it's a thread on deal threre's no harm or foul to the shotgun if it doesn't work out.
The reduction is only .002 per side if your numbers are right. But that's still going to catch on the wad and the shot, if it's not a cup style wad, as it passes down the bore. It doesn't take a lot to remove .002 to .003 with something like a brake cylinder hone or careful use of some sandpaper or emery cloth wrapped around a scrap of tubing to give a snug fit. I'd have a go at opening it up so it matches or steps to more open at the joint. That way there's no doubt about it being OK.
But hey, you're here now and have the bits. And since it's a thread on deal threre's no harm or foul to the shotgun if it doesn't work out.
The reduction is only .002 per side if your numbers are right. But that's still going to catch on the wad and the shot, if it's not a cup style wad, as it passes down the bore. It doesn't take a lot to remove .002 to .003 with something like a brake cylinder hone or careful use of some sandpaper or emery cloth wrapped around a scrap of tubing to give a snug fit. I'd have a go at opening it up so it matches or steps to more open at the joint. That way there's no doubt about it being OK.
Ya, all one piece would have been better. The extension piece already had been tapped and neither one of us had a reamer or tap, so that's why I choose the path I did.
Regarding the screw on extension, preserving the barrel was at the forefront of the whole project. If the adapter failed ...oh well.
I managed to find my brake cylinder hone. Now I'm happy! Now onto sticking these two together. Silbraze or braze? I do have a mig welder, but my welds aren't that good.
1963beretta
CGN Ultra frequent flyer
- Location
- Vaughan, Ontario
Here we are so far:
That doesnt look as bad as what I was envisioning. In fact, Im pretty impressed with the outcome. Would love to see the final product when its complete
Because I want to. Because I can. Because it's the only shotgun I own and cannot afford another one right now. Because it's mine and I can do what I want with it.
Pick one.
Edit: Forgot one... Because if it pisses off one fudd, it's mission accomplished.
Pick one.
Edit: Forgot one... Because if it pisses off one fudd, it's mission accomplished.
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Locktite. There are a lot of types of Locktite to choose from, almost all more permanent than the standard red or blue stuff that most folks think of when the name comes up.
With enough heat, the permanent stuff will eventually give to wrench pressure,making it removable, should you wish at some future point, and installation will not require any heat source, as silver solder or brazing would.
At least, not until you wish to take it apart.
Cheers
Trev
1963beretta
CGN Ultra frequent flyer
- Location
- Vaughan, Ontario
Here it is complete. My welds are terrible. Many spot welds, grind it down... Swish rinse, repeat. Sure was nice to be able to select a target and knock it down.
Not bad! Good job. How long is the barrel now with this extension?
What's done is done and despite the weld appearance clearly it's working.
With a good amount of slip fit my own choice would have been the silver solder/silver brazing. A tiny spot is good enough to hold bandsaw blades together so it would have worked fine for this application.
Trev's suggestion of one of the modern adhesives is a good one too. If it's good enough to bond barrel liners it would have been good enough for this.
But it's all 20-20 hindsight now....
A hearty WELL DONE to an innovative solution. Now go find a FUDD to annoy
With a good amount of slip fit my own choice would have been the silver solder/silver brazing. A tiny spot is good enough to hold bandsaw blades together so it would have worked fine for this application.
Trev's suggestion of one of the modern adhesives is a good one too. If it's good enough to bond barrel liners it would have been good enough for this.
But it's all 20-20 hindsight now....
A hearty WELL DONE to an innovative solution. Now go find a FUDD to annoy
