Blown Drum

[Osprey]

Interesting experience here last week on the last night of our early MZ season.  I'd been carrying my Ohio target rifle here on the farm, mainly becuase I just wanted to kill a deer with it.  Hadn't built it for hunting, just range matches, but figured what the heck.  Didn't see any deer I wanted to shoot, but the last night a fox came out at 40 yards with only 10 minutes of light left, and I hate foxes, so I rolled his red hide.  Didn't reload with that short amount of time left, just went on in to clean the gun in the house.  I thought the shot seemed louder than normal, but that's always hard to tell in the woods on a quiet night. 

When I went to pull the nipple for cleaning the whole drum was gone!  It had broke off halfway down the threads, snapped clean in two, drum and nipple must have blown out into the field when I shot.  Very thankful it happened when it did and not on the range line, especially considering I never planned on using it anywhere but there.

Anybody else have this happen?  Drum was seated tight on the lock plate, so I don't think it was from the hammer striking it too hard.  Flaw in the drum?  Maybe some rust in the threads??

[J Henry]

  Blew the nipple out of the drum once. Looked like rust ate the threads from cleaning and not getting all the cleaner out of the threads. Lucky for both of us, would appear.

[Pete G.]

That is the main criticism of the drum and nipple set up. I think that the drum was probably work hardened by repeated hammer falls and eventually cracked enough to separate. You can replicate this phenomena by repeatedly bending a piece of wire back and forth until it breaks.

The drum must be fully supported by the lock plate so as to not absorb the impact on the threaded portion of the drum itself.

[sqrldog]

I witnessed a drum break and come out of a rifle at a match once. Fortunately the drum went up and hit the tin top of the range and actually made a slight hole in the tin and fell behind the shooting line. The drum was a recent replacement that was slighly smaller than the replaced drum and wasn't supported by the lockplate. The hammer spring in the lock was also.very strong. All combined to cause a dangerous situation.  I am really not much of a fan of drum and nipple use. Tim

[smylee grouch]

What cal and barrel size was it? Also, what thread size was the drum?

[sqrldog]

15/16 .50 cal broke outside the barrel so thread strength barrel thickness wasn't a problem. May have been over torqued to line the nipple up, could be other reasons. Never really knew for sure it wasn't my rifle. In all fairnes I have a half stock Tn 15/16 late style rifle in .40 cal that I have shot thousands of times with a percussion drum and nipple set up that has given no problems. The drum is well supported by the lockplate. I still like a patent or semipatent breech the best on a percussion rifle. Tim

[Natureboy]

  I'm wondering how one can remove the drum and replace it.  I have a Traditions "Hawken," which was well-used before I bought it.  The drum seems to be bent forward, so that I had to file a bit of the lock plate away to remove and replace the lock for cleaning.  I'm concerned that, since the drum seems to be bent from use, it might break off, as in the first post.  Do they screw in?  The clean-out screw seems to be seized, and I haven't been able to remove it when I clean the gun, so I'm wondering if the drum itself might also be rusted in or somehow difficult to replace.  I want to be safe at the range and club shoots, so I would like to make sure the drum won't blow out and hit someone.

[sqrldog]

Not sure how the Traditions Hawken is designed, but its not necessary to remove the clean out screw to clean your rifle. It is mostly a by product of drilling the hole that goes into the barrel. Someone familiar with this rifle will need to answer your question. I usually remove the nipple to clean a percussion rifle.

[Natureboy]

  I also remove the nipple before flushing water in and out, and I assume the screw makes this easier.  I had to tap the nipple hole to 7MM because the threads wore out, so I think it might be wise to replace the drum.  I'm also wondering if, once the drum is removed, I could turn it into a flintlock.
That's not necessary, it's just me loving flinters.

[Osprey]

The drum was fully supported by the lockplate, that's of course something I make sure of during the build.  Got the threaded portion out last night without much problem, little PB blaster and a torch to heat it, backed right out.  Was at our local build group, 10 builders and longtime shooters, and none had ever seen a drum break like that before.  I"m thinking the most likely cause may be the overtorquing idea, as I've been known to have a heavy hand. 

Interestingly, for all the talk of worries of drums stripping out of thin walled barrels, in this case there were only three threads of the drum left but they held while the drum broke and blew.

[P.W.Berkuta]

I concur with the over-torque answer - stretched the threads which elongated the metal at the junction of the major diameter of the drum & the threaded portion (sharp shoulder - weakest area) resulting in seperation .

[D. Taylor Sapergia]

I once heard someone say, "wind it in 'til it goes soft, and then back it out a quarter turn!"  YIKES!!

[JBJ]

Taylor, that's scary!
J.B.

[B.Habermehl]

Right or wrong, on the realitively few percussion guns I have built, when building the gun I inlet the lock with about .015 of shims under the barrel tang. The drum is installed before inletting the lock. The tang bolt must be backed off to allow lock removal for normal cleaning. Maybe I'm going a bit overboard about the lock plate support thing but my machinist side of me likes the resulting firm sandwich. BJH

[Old Ford2]

Interestingly, for all the talk of worries of drums stripping out of thin walled barrels, in this case there were only three threads of the drum left but they held while the drum broke and blew.

If your threads were 3/8-24 and you had a 15/16    .50 cal. barrel ( which is very thin on the walls) you would have about 5.25 threads contact. Still not a lot, but doable.
THREE THREADS!!!
Not much metal holding the drum, especially when you consider that a normal load will produce 18000 psi.
I would prefer a thicker wall.
Fred

[Bob Roller]

Right or wrong, on the realitively few percussion guns I have built, when building the gun I inlet the lock with about .015 of shims under the barrel tang. The drum is installed before inletting the lock. The tang bolt must be backed off to allow lock removal for normal cleaning. Maybe I'm going a bit overboard about the lock plate support thing but my machinist side of me likes the resulting firm sandwich. BJH

Yea,verily this man,BJH speaks the truth. I have seen old guns with back action locks and an unsupported
drum and nipple and I had one blow out when I was about 15 or 16.
The existence today of a drum and nipple is all the more reason to make the gun into a flintlock and then
the worry about three threads holding an unsupported drum will vanish.

Bob Roller

[smallpatch]

Bob,

AND, you never have to worry about running out caps!!

[D. Taylor Sapergia]

I have only once built a rifle with a drum and nipple.  It was in my very early days of building muzzle loading rifles, and it was with components supplied by the client.  The latter of those two scenarios will never happen again.  I insist upon providing the parts for every build now. Then I know what I'm working with, and can take responsibility.

In the case above, the rifle had a 13/16" parallel barrel, and in .45 cal.  The Drum supplied had a 5/16" x 24 journal.  It concerned me that there was precious little contact in the barrel wall, and in the end, I was right....the drum blew out.  My fix solution was to convert the rifle to flint, and install a 3/8" x 24 stainless shop made vent liner.  The rifle was stolen shortly after that, and has not surfaced in these 40 years since.

Now, I have made drums and patent breeches with drums since that time.  But I make the drums myself and use a 3/8'x 24 tpi journal, which provides much more strength in section.  I made a jig for tightening the drum into the side wall which simply involves a 3/8" thick steel plate with a 1/2" hole drilled through it, and an allen screw to jam the drum.  Once the drum is bottomed firmly, I stamp it and the barrel with a witness mark on the side flat forward of the drum.  Then it can be removed and returned to the same tension each time, but that only happens a very few times during the build.  The last thing that gets done, is drilling and tapping the nipple seat.  And I never drill right through for a "clean out screw!!"  It does not bother me if the shaft is larger in diameter than the side flat of the barrel...I have seen very few original rifles that were otherwise.  This gives confident strength in the threaded journal in the barrel wall, and also sufficient metal into which to seat the nipple.  And always, the drum is supported by metal to metal by the lock plate.

I see no reason, if you are careful about these details, that drums cannot be used for rifles such as the Bedford Co. rifle.  I believe the Vincent is another such rifle.  Start with a barrel with a decent wall thickness, and carry on.  Roger Fisher's favourite rifle has a drum and nipple and has been used successfully and safely for dozens of year and some 40,000 rounds.  Just one contemporary example.

[Daryl]

My target pistol, converted to cap lock for the purpose of competition, has a 7/8" .45 barrel. It has a drum and nipple arrangement with about 6 or 7 engaging threads I believe. I do not remember what the actual thread was, but it was fairly snug all the way on as the tap I used seemed to match the drum perfectly. The lock plate supports the bottom of the drum and the single lock screw must be removed to remove the barrel for cleaning.  Since it is a target pistol with an 18" twist, I an using 25gr. 3F for round ball and up to 30gr. with a 200gr. slug.  Both shoot extremely well, with a 5 shot bench group at 38yards giving me just under 1 1/2" centre to centre when sighting it in last summer. I was happy with that.

[Dphariss]

Interesting experience here last week on the last night of our early MZ season.  I'd been carrying my Ohio target rifle here on the farm, mainly becuase I just wanted to kill a deer with it.  Hadn't built it for hunting, just range matches, but figured what the heck.  Didn't see any deer I wanted to shoot, but the last night a fox came out at 40 yards with only 10 minutes of light left, and I hate foxes, so I rolled his red hide.  Didn't reload with that short amount of time left, just went on in to clean the gun in the house.  I thought the shot seemed louder than normal, but that's always hard to tell in the woods on a quiet night. 

When I went to pull the nipple for cleaning the whole drum was gone!  It had broke off halfway down the threads, snapped clean in two, drum and nipple must have blown out into the field when I shot.  Very thankful it happened when it did and not on the range line, especially considering I never planned on using it anywhere but there.

Anybody else have this happen?  Drum was seated tight on the lock plate, so I don't think it was from the hammer striking it too hard.  Flaw in the drum?  Maybe some rust in the threads??

This is not unusual. They are made of a material that has very poor shock resistance (unlike the iron used in the past) either from the hammer strike or the internal pressure and is made even worse by the machine work done on the part which has sharp corners (stress risers).  But of course pointing out that modern ML parts are made of unsuitable materials and are not properly made is frowned upon here. This danger is why I don't make drum and nipple guns (I had one blow off and go through a screen door when I was about 17-18). With the plethora of patent breeches available there is no justification. Had the drum failed at some event and hit someone in the right place it would be bad, very bad.

Dan

[JBJ]

Perhaps one of the resisdent metalurgists would be so kind as to weigh in here and offer some suggestions for a useful steel alloy to use in making a drum. I for one would much appreciate such a suggestion.Thanks.
J.B.

[Bob Roller]

Perhaps one of the resisdent metalurgists would be so kind as to weigh in here and offer some suggestions for a useful steel alloy to use in making a drum. I for one would much appreciate such a suggestion.Thanks.
J.B.

I have made a few drums out of grade 8 bolts with a 1/2" diameter shank. Cut the head off and turn the threaded part down and rethread to whatever you need. As I recall,I made them 5/16x24 for small barrels.
These bolts are usually found in good auto supply shops like NAPA.

Bob Roller

[JBJ]

Bob, I have done the same but wondered if there was a better path to follow.
J.B.

[Dphariss]

Perhaps one of the resisdent metalurgists would be so kind as to weigh in here and offer some suggestions for a useful steel alloy to use in making a drum. I for one would much appreciate such a suggestion.Thanks.
J.B.

If a person INSISTS on using the weakest possible design for percussion ignition then the drum needs to be made of a high quality hot rolled alloy that has been annealed and contains no lead, phosphorus or the lubricating material.  I think even hot rolled 1010-1018 would be OK but it should be something more than welding shop quality. The rebate for the threads needs to be radiused at the shoulder so as to reduce the risk of it breaking off at that point. The threads should not be cut all the way to the shoulder for the same reason. The barrel should be 1" unless the caliber is over 50 then larger is better. This will give a long threaded portion but its very difficult to seal the threads at the bore end without a shoulder to seat the threaded shank against. There is still the problem of the shooter being struck by cap fragments and other debris on firing since there is no fence to prevent this. The drum needs a flat seat for the base of the nipple the seal  against to reduce the risk of gas cutting the nipple threads. This applies to patent breeches as well.

[JBJ]

You have touched on an important point - there does need to be a rebate (modest countersink) in the barrel to accept a radius left at the shoulder of the drum, Turning the threaded portion of the drum square (no radius) to the abuting face of the drum is asking for trouble. Yes, cap fragments can be an issue but I insist on using a flash cup AND shooting glasses. The close fitting flash cup seems to work very well and also prevents residues from being blown around the breech area. Not very HC but that's what works for me. BTW, thanks for the input.
J.B.