Underhammer nipple blowout!

[silverfox]

WV Hillbilly: The numirick arms barrels are bored to a flat with a guard ring around the nipple. I guess cause I'm not looking at the gun this is about .50 size hole across the flat. It would reduce the barrel thickness some. Mine is the round target barrel 1" so would not be a problem for me. I can see in some of the smaller octagon barrels it might become one. Now to observe further if the barrel is that thin wouldn't the nipple stick up into the barrel and creat a cleaning problem. If not the nipple threads would have to be very short. Maybe thats why they used the 32 thread to get more grip in the thin barrel. Understand this is just my opinion. Fox :thumbsup:

 

[WV_Hillbilly]

WV Hillbilly: The numirick arms barrels are bored to a flat with a guard ring around the nipple. I guess cause I'm not looking at the gun this is about .50 size hole across the flat. It would reduce the barrel thickness some. Mine is the round target barrel 1" so would not be a problem for me. I can see in some of the smaller octagon barrels it might become one. Now to observe further if the barrel is that thin wouldn't the nipple stick up into the barrel and creat a cleaning problem. If not the nipple threads would have to be very short. Maybe thats why they used the 32 thread to get more grip in the thin barrel. Understand this is just my opinion. Fox :thumbsup:

My barrel is 15/16 inch octagon, .45 caliber, 32" long, and has a brass flash cup installed; but there is no recessed ring where the nipple is threaded into the barrel. So my barrel wall thickness is roughly 1/4 inch. The nipple shank is short enough (or the barrel wall thickness is thick enough), so that it (the nipple) can not extend into the interior of the bore. That would make for some bizarre ignition properties, I would think; aside from causing cleaning and loading problems.

I think one reason they used fine threads is to make sure that the nipple doesn't get cross threaded when started. It also would provide more threaded area over a shorter distance as you mentioned. I can logically see that milling a flat on a round barrel for the nipple makes sense; but the amount of material removed should not be enough to cause a problem. If that is true, then a "shorter" nipple ought to have been selected to begin with.

I don't know how small (distance across flats) the octagon barrels are on the smaller calibers. At least on mine and these currently manufactured Deer Creek guns, ALL the barrels are supposed to be 15/16 inches across the flats. I can't say about the older Numrich mfd. guns or other different models.

I've seen some OLD guns of various types that have really "short shanked nipples" due to their octagon barrels being small. Obviously the designers of long ago also knew better than to extend the nipple into the powder chamber area.

I still think that the nipple "blowing out" had to be from a manufacturing defect (or perhaps an incompetent machinist/operator), the wrong thread nipple being installed, OR the tap used was the wrong size. It is strange that it held for that long without failing earlier though?

IF the barrel wall thickness is truly that "thin", then it has to be re-threaded to a fairly high TPI nipple, or it might happen again. Besides that, keeping the overall nipple length correct so that the hammer face strikes the nipple squarely is important.

Shoot Safely!
WV_Hillbilly

 

[MRW]

I fixed a underhammer barrel that HAD a 5/16 nipple hole in it this way and it is simple, if you have access to a lathe. Get a fine thread 5/16 bolt drill it through with a # 3 bit, tap that out to 1/4-28 THEN recess the bolt head to the depth it is as thick as the bolt head with a larger bit so the body of the nipple will set flush with the outside of the barrel( this is only necessary if you have a close tolerance for hammer clearance with the nipple), file or cut end of bolt to thickness of barrel, thread adapter into barrel snug with a wrench, screw in nipple snug down , load gun, cap nipple, shoot gun, this type of fix will allow you to REMOVE the fix if the nipple thread ever mess up and you should then be able to replace it with another adapter.

 

[Pittsburghunter]

Wow that sounds real scarey!! You must immediatly pack that gun off and send it to me and I will depose of it down right properly. We don't want our brothers from another mother hurt in this way. :bull:


If you can't fix it your self find a good gunsmith and you will be fine. It sounds like an easy fix but I hate tapping holes and would not blame you in the least to have it fixed by a gunsmith. It should not cost that much and you will feel safe shooting it. ( Just have the smithy shoot it first in front of you)

Good luck I think the rifle will be fine.

 

[Slamfire]

Numrich has been out of business for quite some time now, even sold their parts business to Gun Parts Inc. Back when they started sellin' them there wasn't any standard for nipple size or threads. I don't think you can drum up much of a case against them. The nipples have a four sided head, not a hexagon. If your's was different than that that's probably what happened. If you go to the Possible Shop's site and look for nipples you'll see them offered and the application is listed right there. :sorry:

 

[WV_Hillbilly]

The nipple of my .45 cal. H&A underhammer blew out, stripped out when I pulled the trigger.

Can I repair this, oversize nipple or other repair, or is my barrel just shot?

Thanks

I forgot to ask this... was there any damage to the hammer or spring (trigger guard)? Did it drive the hammer back into "full-cock" position? Did it sting your hands a bit?

I'm always interested in safety, from years of working around potentially hazardous and deadly "thingies". Safety was, is, and always will be first and foremost. I guess for me, it's become a habit.

I didn't notice that you said whether you found the nipple?

If so, were the threads off of it, or what did it look like?

Shoot Safely!
WV_Hillbilly

 

[flintlockmdj]

5/16X24 niples are also avalable for #11 caps.

 

[CoyoteJoe]

Slamfire is right, when the H&A was new there really was no "standard" American nipple thread since there were no American repos being made, H&A stood alone there.
Ruger still uses a non-standard nipple thread, 12x28 in the Old Army.
When the H&A's original nipple is threaded through the original flash cup the nipple does not protrude into the bore significantly.
Some underhammer shooters like a long nipple to reach into the center of the bore, thinking that igniting the powder charge in its' center is a good idea. I doubt that but a long shank nipple doesn't cause any problems that I'm aware of and I have used them, you just need to get them wet to soften fouling before removing them.
Those old H&A's have stood up to lots of use and abuse over the years and I have no doubt that this was a case of some previous owner,(who knows how many) replacing the 1/4x32 nipple with a 1/4x28 and that may even have held for years but after being removed and replaced many time it finally just "had enough".
Another issue to consider in repair is the hight of the nipple above (or really "below") the barrel. The nipple recess in the hammer is rather small and as the hammer swings in an arc a too tall nipple will cause the hammer recess to miss the cap. I've done that.-- :shake:

 

[Slamfire]

I don't know about them long nipples, I remember puttin' Autolight sparkplugs into a VW instead of Bosch. Can you say Helicoil?

 

[walruskid1]

my h&a underhammer has a recessed 1/4 x32 on the factory barrel. i have another .50 with a aftermarket barrel that has 1/4 x28 with full wall thickness.