doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Ithaca Barrel Safety Concern

This is a question for you barrel/pressure experts. I recently discovered that my favorite NID skeet gun has had a modification that raises a serious safety issue. The right ejector guide pin evidently broke off at some point leaving a piece of it in the hole. A repair was made by adding a new pin in a different location requiring a new hole be drilled in the base of the barrel. The hole in the photo lower left is the original, the ho;e in the upper right is the 'new hole.' Notice how close it is the the edge of the chamber. All this came to light recently when I had Gunter dust up the lazy right ejector. The original guide hole had been filled with solder or something and was not viable before Gunter. I have shot this gun a lot but am now concerned as Gunter cautioned that it could blow and showed me a photo of one that did blow and the failure started at the guide pin hole. I do value body parts and am looking for a "fix" if there is one. Any suggestions?

I don't want to end up with this!

Don't have a fix for you, Walter--but I'd worry too. Not much metal left between the new hole and the chamber. And remembering Sherman Bell's destruction tests, at least one of those old Parkers blew out from where the extractor rod was placed, between the chambers. A whole lot more pressure than a normal load to get it to do that, but there was also a whole lot more metal between the extractors and the chamber walls.

Walt,
Possibly sleeving the chamber might save this. Maybe, maybe not.

Pretty scary looking to me. I think the failure would be a fatigue crack thru both webs and eventually splitting the chamber wide open.

Is that a 410 in the picture of the blown gun?

Chuck, a 28 ga., cause, we think a barrel obstruction as we were shooting Estate reloads that were known for separating plastic from base.
My "fix" is to have Gunter fit a new old stock barrel set(the one I had for sale). The original barrels are factory S/S that are rare in the NID world. I was hoping for a 'hail Mary" to salvage the, How about some smaller gauge chamber inserts?

If a good tig experienced welder opened the chamber side up and carefully filled it(it's no more than 3/4 inch ,right ?),re-chambered and polished , then had it put under x-ray to check for flaw's ...could that be a viable repair?

Just thinking out loud and trying to help.

I would use Briley full length tubes, choked or not
I have a 12 gauge Baker with a smallhole in one barrel and
am now using 28 gauge Briley tubes to keep it a shooter.
P.S. NOT the paragon
Mike

I assume it's a 12. So, I'd buy the Gaugemate Golds which are made to stay in the chamber while the empty is extracted.

If you went from 12 to 20, it would be a continous stainless steel cylinder which should take a lot of pressure off the chamber. I believe the ones from 12 to 16 have a longitudinal split. Call them to make sure. They might have some data on how much pressure is taken off of the original chamber.

I have patterned 12 to 20 a few times compared to the 12 pattern, the 20 ga Gaugemate out of the 12 bore gave about a 1" larger pattern.

http://www.gaugemate.com/purchase/gaugemate-gold

How about installing permanent gauge reducing inserts? Then no one will have a problem if the inserts are forgotton, since it is a safety concern.

I like the possibility Chuck raised - having the chamber sleeved. Perhaps Merrington or Kearcher or Orlen.

I have found all three of them easy to talk to.

Best,


Mike

The large photo also shows the barrel lug insert. I've never noticed before, but the actual barrel wall is very thin by the lug. To me it looks more fragil than the area by the hole.
Dave

Terc, are you referring to the rib extension? Looks to me as if there's almost as much metal separating that from the chamber as there was between the hole (now plugged) for the original ejector guide pin and the chamber, and a lot more than there is between the chamber and the hole that was added.

Walt,
the hole acts as a stress concentrator which can be visualized by imagining the stresses flowing in that area compressing as they go around the hole.
The problem is that its impossible to calculate that geometry as the thin wall between the barrel ID and the hole may fail but you don't know about the chamber material.
Sleeve the barrel and sleep at night.-Dick

Larry, I meant rib extension. My AM coffee hasn't kicked in yet.
Dave

I would have the the new pin hole welded closed and the old one drilled out like it should have been done in the first repair. Send it to Merrington or Kearcher and have them evaluate it. Shipping both ways would be cheaper than you medical co-payment if it fails and then you would have all that physical therapy to do.

That broken guide pin is probably hard. You may have to EDM it out. I have a friend that has made a business out of ELOX/EDM removal of bolts and other broken things like that for the last 37 yrs.

Walt,i hope you get it fixed.The trouble is you will probably always think about the chamber when you shoot the gun! Bobby

Hi All:

If it were mine, I would have it welded to enable me to sleep at night.

The other suggestions appear to be rather suspect for future owners/shooters. I think that welding would be a safer "fix."

I remember a mentor of mine who had his fingers on his left hand removed via a blown shotgun blast. Nobody ever figured out what happened to cause the failure!

Good luck on your choice,

Franchi

The problem with this issue is that the hole will not likely clean up when either sleeving the chamber or entire barrel. More like halfway thru the hole would clean up. This may be better than what you have now, but not ideal. If you bore it out so large as to clean up the entire hole, you run the risk of thinning the barrel up front of the chamber, an issue much like lenthening chambers. A sleeved chamber or barrel gets part of it's strength from the outside of the original barrel and part from the new sleeve. Sleeving will be an improvement, but may need to go down in gauge, as Miller has alluded, to gain some additional wall to make up for the partial hole that will be leftover. As Dick can no doubt attest, this is the kind of thing structural engineers spend countless hours analyzing with tools like finite element analysis. This is a tough one. Welding isn't the do-all, end-all solution here. A weld is akin to a casting. Would you shoot a cast steel barrel?

Are NID barrels soldered together or welded? What is possiblility of replacing the damaged barrel only or finding and fitting another set of original barrels? I sure wouldn't fire that barrel any longer and would be concerned about any welding around that chamber area as well.

I agree with my friend, KyJon. Fill the new hole, redrill the old hole, reinstall an original ejector.

Jerry,
I believe the breaches are brazed together with the lump. Ribs are soft soldered, of course.

Another problem with welding these barrels is the weldability. Yes, anyone with a TIG can weld them, but the last time I did it on an American gun of this vintage, I kept chasing cracks. This is indicative of high carbon content in the barrel steel, beyond the .30% that is normally considered the limit of "weldability". This area is probably the single most critical area of the barrel, or gun, for that matter, and the "flaw" is of a particularly nasty orientation and size. Trusting a weld of an essentially unknown alloy for your wellbeing is more than I would gamble.

P.S. Most modern barrel steels are 4140 today. 4140 is another "non-weldable" alloy, which can be welded, but has the propensity to produce flaws in welds due to the .40% carbon content. Although I have no factual data on NID barrels, I suspect they are either 4140 or very similar.

In the L C Smith Plans & Specifications book, even quite early on, while the bbl steel was not specifically called out it was listed as having approximately 40 points carbon. At that early date it was likely something like a 1040 or perhaps a 1340 (Manganese steel). By the time the Nid came along as Chuck has said it very well may have been made of a higher alloy steel as 4140. In any case 0.40% carbon can lead to welding problems. It is a real shame someone drilled that hole so close to the chamber.

I do think Miller's idea of a 20g chamber sleeve is probably a safe solution as it adds wall to the chamber and reduces hoop stress from the smaller diameter at the same time. A sleeve from piece of 4140 or 4130, heat treated to about low 30s which would add tensile strength without overly reducing fatigue and fracture toughness, would be something to consider.

I like Chuck H idea,
fix it the right way and it'll last forever.

Chuck;
I do agree a good chamber sleeve shoud work, but I don't want to take credit un-justly. I don't recall for sure now who suggested that but it wasn't me. Is there another Miller posting?

you could have a tight fit steel rod inserted into the hole and soft soldered in place. This would fill the void and not have to worry about weldability

Sorry Miller,
It was 2holer.

Gunny,
the issue is not filling the hole, but rather the remaining effective wallthickness and its ability or lack of ability to carry the loads. A soldered plug won't add to the load carrying ability in any meaningful way.

What if you filled the hole and disabled the ejectors?

No problem at all Chuck, just didn't want to take undue credit. I can easily see where it would be easy to recall 2-piper for 2holer.

Rick,
the issue is that virtually all of the load expanding this area of the chamber is being held by the little remaining web identified by the red arrow. The web identified by the yellow arrow isn't of much help in carrying the load if at all. It may even be worse than that. The load may fail the web between the chamber and the gunsmith hack's hole and then cascade thru the web to the original hole then thru the even thinner outer web between the original hole and outside.

I want to thank everyone for your help. I believe I will start with chamber sleeving, also will talk with the names mentioned.
Best to all, Walt