Shotgun nipple size

[Oldnamvet]

I have a BP muzzleloading dbl bbl shotgun imported by Navy Arms. Maker was Pietta. I haven't fired it in about 20 years and last time I cleaned it, I stored the nipples separate from the gun. Yup, now I can't find them. :banghead: Which thread nipples does this shotgun have? It is in like new condition and I plan on taking it bird hunting once I get it functional again.

 

[Plink]

Most of the imports (CVA, Traditions, etc) use a 6mm x 1 thread. Lyman uses a 6mm x .75. I'm sure one of them would fit. Most likely the 6mm x 1.

 

[ccyooper]

Seems like my Navy Arms magnum double has 1/4x28 nipples. You can use a 1/4x28 bolt as a "gauge" of sorts. Just be careful you don't cross thread...

 

[Plink]

If 1/4x28 works, that's a standard nipple also. Thompson uses it, so you can probably find a replacement at a local shop. Good luck