I have a Hopkins and Allen underhammer in .45 caliber. I use tripple seven usually. I loaded 70 grains of triple 7 over a patched ball yesterday and the nipple was blown out of the gun. I dont think 70 grains of powder is to much. Maybe the nipple wasnt tightened all the way down. Any other reasons this might happen?
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Nipple blowout
- Thread starter David454
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Ed Cigallio
32 Cal.
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I saw this happen with a drum one time. I know for a fact it was loose! I made a comment the other day about patent breaches in these guns. It would be a major improvment for this very reason.
Ed
P.S.: I would consider that a pretty hot load for a 45 ball.
Ed
P.S.: I would consider that a pretty hot load for a 45 ball.
JayDee Flohr
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Check the threads when you install a new nipple. Could be worn out or it possibly was loose. If it was loose, blowing out can damage the threads.
A patent breech wouldn't make any difference. Loose threads or worn out threads don't care what they are in.
A patent breech wouldn't make any difference. Loose threads or worn out threads don't care what they are in.
If anyone is interested, taking Hodgdons recommendation of reducing the volumetric powder load by 15 percent one can easily calculate what a 70 grain, 777 powder load is equal to.
In this case, it equals 80.5 grains of black powder.
Synthetic black powders generate their pressures a little differently than black powder does but a 80 grain powder load in a .45 caliber barrel shooting a patched roundball in Lymans tests generated over 15,000 psi with GOEX 3Fg and Pyrodex RS powders.
IMO, for a black powder gun that's getting up there, although I'll admit it is in the neighborhood of a good hunting load.
A 15,000 psi load was creating a load of 657 pounds of force trying to blow that nipple out of the breech.
In this case, it equals 80.5 grains of black powder.
Synthetic black powders generate their pressures a little differently than black powder does but a 80 grain powder load in a .45 caliber barrel shooting a patched roundball in Lymans tests generated over 15,000 psi with GOEX 3Fg and Pyrodex RS powders.
IMO, for a black powder gun that's getting up there, although I'll admit it is in the neighborhood of a good hunting load.
A 15,000 psi load was creating a load of 657 pounds of force trying to blow that nipple out of the breech.
rafterob
62 Cal.
It seems to me I have read alot on this forum that 777 burns hotter than BP. Even with BP, burn through is not uncommon on nipple threads from the hot gasses generated. That may have been an issue or maybe loose fit to begin with. As others stated, look for thread wear in the drum. Have seen a couple that needed to be drilled and tapped slightly oversized and fitted with a new nipple sized accordingly.
While triple seven is an unpredictable witch's brew and 70 grains is a stout load, the problem may also lie with the rifle. H&A underhammers used an odd-ball nipple thread, 1/4X32. Some people have thought it clever to re-tap to the common 1/4X28. That really cannot be done, you end up with about 1 1/2 good threads and the rest are mangled. Or sometimes they just force a 1/4X28 nipple into the 1/4X32 threads which mangles both threads.
I'd suggest you examine the barrel threads very carefully with strong light and a magnifier. If the threads are good (which I doubt) Track of the Wolf carries the proper 1/4X32 nipple. If the threads are stripped or mangled you'll have to re-tap for an oversize nipple. Track of the Wolf can help you there as well with oversize taps and nipples.
Those H&As have been around for a long time and most have been through several owners. More than a few have suffered damage by Bubba Gunsmithing.
I'd suggest you examine the barrel threads very carefully with strong light and a magnifier. If the threads are good (which I doubt) Track of the Wolf carries the proper 1/4X32 nipple. If the threads are stripped or mangled you'll have to re-tap for an oversize nipple. Track of the Wolf can help you there as well with oversize taps and nipples.
Those H&As have been around for a long time and most have been through several owners. More than a few have suffered damage by Bubba Gunsmithing.
Billnpatti
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Certainly, your load is a bit hot but the H&A should be able to handle it. Poorly tapped threads are not unique to H&A or even to just poor quality guns. I had a Pedersoli .32 cal squirrel rifle that was a sweet rifle but one day at the range, the clean-out screw blew out of the drum and flew down the firing line. :cursing: I have no idea where it went and fortunately it didn't hit anyone. When I examined the clean out hole, I saw that the hole had been drilled oversize and there was very little mating surface on the threads. The screw just stripped out and went flying. I re-drilled and re-tapped the hole for a larger screw and the problem was solved. It is possible that the nipple hole on your H&A may have been slightly oversize and not allowed a good mating surface for the threads. If this is the case, you will just have to re-drill and re-tap the hole for a larger nippple thread. Your problem will be solved. Then consider your chosen powder charge. Do you need to use that much powder? It may well be beneficial to reduce your load. :thumbsup:
Just my opinion....it's free and worth every penny of it. :haha:
Just my opinion....it's free and worth every penny of it. :haha:
Thanks for the replys! I think ill just go with the over sized nipple. Then there should be no question about the threads. Have any of you changed the barrels on one of these guns? Maybe a green mountain barrel in 50 caliber would be my other way to go.
I do remember some of those H&A underhammers having that strange 1/4-32 nipple so I looked in the latest Dixie catalog to see what was available.
The answer in their catalog is.....nothing.
That thread got me to thinking.
Dixie lists a "Colt" nipple that is a ".225-32 Long" so it is possible that sometime in the guns past this nipple was put into it.
That thread is .025 undersize so if it was used that could explain why it blew out.
Dixie also shows a .245-32 nipple (NP1340) that would be closer to the right size.
An old Dixie catalog says that the H&A used a .245-32 nipple so that may be a possible solution if the barrels threads are still in good shape.
Of course, all of this begs the question, is the guns barrel tapped for a 1/4-32 nipple?
That really should be resolved before anything is done to the gun.
To do that, Dave should take the gun to a hardware store or a machine shop and have the barrels threads inspected to determine exactly what the thread pitch is.
If it is a 1/4-32 Dave should call Dixie and ask them if they still have any "NP1316" nipples.
Those were shown in their 1987 catalog and they may still have a few left.
If the barrels threads are bad the only solution I see is to have the barrel tapped for a 1/4-28 Helicoil screw thread insert and a short Helicoil installed.
That would allow the use of standard sized nipples.
By the way, this is exactly the reason helicoil inserts are used, and although some folks don't like them they are stronger than the original threads and they will work just fine in this application.
The answer in their catalog is.....nothing.
That thread got me to thinking.
Dixie lists a "Colt" nipple that is a ".225-32 Long" so it is possible that sometime in the guns past this nipple was put into it.
That thread is .025 undersize so if it was used that could explain why it blew out.
Dixie also shows a .245-32 nipple (NP1340) that would be closer to the right size.
An old Dixie catalog says that the H&A used a .245-32 nipple so that may be a possible solution if the barrels threads are still in good shape.
Of course, all of this begs the question, is the guns barrel tapped for a 1/4-32 nipple?
That really should be resolved before anything is done to the gun.
To do that, Dave should take the gun to a hardware store or a machine shop and have the barrels threads inspected to determine exactly what the thread pitch is.
If it is a 1/4-32 Dave should call Dixie and ask them if they still have any "NP1316" nipples.
Those were shown in their 1987 catalog and they may still have a few left.
If the barrels threads are bad the only solution I see is to have the barrel tapped for a 1/4-28 Helicoil screw thread insert and a short Helicoil installed.
That would allow the use of standard sized nipples.
By the way, this is exactly the reason helicoil inserts are used, and although some folks don't like them they are stronger than the original threads and they will work just fine in this application.
smokehouseman
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I have a TC Hawken .50 caliber I shot one day a couple of years ago and I was using Triple 7 with 70 grains of powder. With the very first shot the hammer blew back into the full cock position :shocked2: , when I inspected the nipple I discovered it was loose....................... then I vaguely remembered not tightening it down. My intent was to put a dab of anti-seize on the threads and at the time I didn't have any available. I sent the gun back to TC and explained what I thought had happened and the lock was replaced. My first thought was it had something to do with the powder but in retrospect I think the blame rest with the most likely suspect..............yours truly and not a powder issue. Your situation may be entirely different but that's what happened with me
I've had a number of H&A underhammer rifles in 45 caliber and my most accurate load was about 80gns of 3f which would move the hammer to the safety position and clear the nipple of the used cap. Always made sure the nipple was in tight and never had a problem. :thumbsup:
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