doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Barrel Fitting Basics ??

Hi all. A while back I restored a Savage 430. Although I know this type of gun is not generally the kind discussed here, I'm sure many who have owned one of these would agree that they a pretty nice little guns. Anyway, my gun is a 12 ga and I've got the crazy idea to fit a set of 20 ga barrels to it. The poor man's two barrel set if you will. I've determined, through research, that frame sizes were the same for the gauges offered. I've obtained all the needed parts from Numrich (forend, fe iron, spring, barrels, etc) and managed to mess my first set of barrels up. At only $59 for a NOS set I'm not out too much.

Anyway, to get to my question, what exactly are the basics of fitting a set of barrels ? I'm familar with smoking the breech end to get a final fit, but a little uncertain of how to file the hook to the exact diameter of the hinge pin. The NOS barrels have the hook on the lump started but it is no where near final size. On my first set, I filed the hook too much. I got the barrels to fit, but they do not lock up tight. My thought is I need a file the same diameter as the hinge pin and with that I can begin slowly filing the hook until I get the barrels to rotate in.

I understand that I will have fitting work to do on the FE iron and perhaps in other areas, but this is just a fun little project to attempt. Any suggestions from anyone who may of done this before would be greatly appreciated.

Thanks

Vince

go get the hook welded and start over.smoke the hook take the high spots off and it will match the pin.

Larry potterfield of a Midway USA has a great YouTube video on barrel fitting on a Parker lifter. It deme strayed exactly what you are asking about.

You would have to take very precise measurements of the old barrel and put these measurements to the new barrels.

I think your hardest part is going is going to get the c/c from a 12 ga receiver to a 20 gauge barrel for it to fire.

You would have been ahead by paying to have someone else do the job for you. You need to have the hook welded up now and start over. Or just send it out and have them do the job.

When learning it is best to pick a set of orphaned barrels and fit them. Most of the times the fit is very close to begin with. Unfit barrels could be a nightmare to get right even with experience.

Vince,
Good luck with your project. I've never attempted something so ambitious but I have welded up a hook on a Husky hammer gun to put it back on face. I used a local micro welder to put just a little material on the hook surface without affecting the hardness on the rest of the hook. I instructed him to add material uniformly until the gun would just not close. I then used a ceramic sharpening rod and smoke to final fit. I got lucky; it only took about 15 minutes.
Good luck and have fun!
Phil

Thanks all for the replies so far. In no particlular order, yes I could of paid someone to do this, but what fun is that ? I already have a second set of barrels so I am going to try again. I know I could of had the hook welded up on the first set, but like I said a set of barrels is $59 from Numrich.

Hi David. I believe the firing pins will line up fine (I think that's what you meant when you said c/c ??) The breech/monobloc is the same dimensions in both the 12 ga barrels and the 20 ga barrels. I thought about trying to make the new hook match the old hook with some sort of template, but I have to brainstorm that one more.

If anyone else has any ideas I'd love to hear them. In the mean time I'm going to find a file the same dimension as the hinge pin (or as close as possible) and begin taking the hook back little by little.

Thanks for the input

Vince

A trick of old European barrel fitters is the following:

Remove the cross pin. Fit the barrels in the action so they fit every where.

Once you have that fit done, place a 1mm thick shim at the bottom of the standing breech on the flats, put the barrels on, clamp them tight down on the flats and against the breech face. In this position they will make full contact at the front, on top of the cross pin hole, and the back, the bottom of the breech will touch the breech face. The shim does not allow the barels to sit down on the flats.

Now mark through the cross pin hole the circle of the cross pinn on the front lump.

Cut, fit the front lump and the barrels are ready to smoke fit down onto the breech.

As in all cases of seemingly complex procedures, there are simple ways to do it.

Additionally you can slot the front lump for a removable shoe and that way you have the luxury of making many fitting mistakes since the most you can damage is the replaceable shoe and not the lump itself. You can do the same on the lockup area of the rear lump.

I did this removable shoe on my SXS prototype, made with 3D printing but barrel fitted in the traditional manner. It was shown here some time ago.

One more thought on fitting. It seems that no one uses scrapers these days. Almost all discussions and net videos on fitting show files and/or abrasives. Scrapers can be superb fitting tools, as they remove metal precisely and in controlled amounts with no gouging.

OK a lot of comments about hooks etc. but if trying to fit a set of barrels of a different calibre have you considered the following -
the width and size of the lumps.
the distance between centres of a 12 and 20 bore gun.
the position of the loop .
will the 12 bore forend wood fit the 20 barrels with out looking stupid and will the connect up or are you planning separate forends.
The width across the face of the 12 as compared to those of a 20 as well as the height above the flats .
Probably a couple more things I've missed but those are main ones .