1/2" drum with 1/4" nipple okay???? Need help.

[Skychief]

My new rifle (and first drum equipped rifle for me), leaks for and aft where the nipple meets the drum.  As the nipple shoulder contacts the drum, the nipple's threads still show for and aft where the cylinder (drum) rolls away from the nipple.

The drum measures 1/2" o.d. and the nipple is 1/4 X 28.   As this is my first drummed rifle, I will plead ignorance about how a nipple should seat upon (within?) the drum.

Do I need to use a different nipple (possibly with narrow shoulder?   Should the drum's tapped hole be countersunk to make a level seat for the nipple?   Do I need to install a larger drum for a 1/4 X 28 nipple?...(hopefully not, as that will require lockplate work too).   ANY guidance very appreciated!

I did not find the leaks at the drum/nipple interface until cleaning after having shot the rifle.   How dangerous is this situation?

Please write back with possible remedies for my my leaky ignition system.   Photos of your drum/nipple arrangements would be helpful.

Many thanks in advance!

[wvmtnman]

Gas leaks are not good.  They can erode the threads.  Are the threads in the drum worn?  If so, replace the drum.  As far as the how the nipple is seated, I file that area down a little.  Not completely flat, but down enough so that the threads of the nipple are not showing.  Put the nipple back in, trace around the base of the nipple, remove the nipple and try to round the area as best as you can without cutting into the traced area of the nipple, to hide the flat area.
                                                                           Brian

[Skychief]

Thanks for your reply Brian.   As far as I can tell, the threads in the drum are okay.   I will take another look.   Are you suggesting that my drum and nipple sizes are compatible?   Is filing a flat nipple seat a commom practice?

Thanks very much!

[Acer Saccharum]

It's been so long since I looked at a Dixie catalog, but I thought they offered nipples in .005 diameter increases just for this kind of situation.

Before you jump the gun, so to speak, try a different nipple in the drum. The one you have may be undersized. 

Tom

[Acer Saccharum]

I would not file a flat seat on the drum for the nipple shoulder, as then the nipple will seat deeper into the drum, cutting off the passage to the main charge. Your kind of rig is dependent on thread fit.

[northmn]

For my drum and nipple arrangements I always used a flash guard or cup as sold by many suppliers at a very inexpensive price.  Saved on the stock and barrel finish. Try different brands of nipples first.  Use a good grease when you screw it in.

DP

[longcruise]

Was your drum pre-drilled and tapped for nipple or did you tap it yourself?  I was amazed to find that even after doing everything "right" in tapping a drum for nipple the fit was just too loose.  I got an oversize .255 tap and did the job over rather than removing the nipple.  TRSO sells the oversize nipples to fit.  It solved the problem.

But, first go with the advice above and try a few different brands of nipple.

[Skychief]

Thanks for the replies guys!  An update....I took the rifle to my friend and black powder gunsmith.   He recommended that he relieve the drum to form a seat for the nipple's shoulders to fit flush upon.   He will hopefully have it done by the weekend.   He thought that the nipple fit the threads well enough (1/4 X28).   We will see how things work out.

Again, many thanks for your feedback!