1858 Pietta nipple help

[Hullraiser]

This may have come up before but I need help with nipple replacement selection. The M6x.75 nipples will not work. Too large of threads.
This is a SS 1858 remmington Pietta.
Serial # 121827 I believe dates it to 1990. The square box has [AZ] I assume it's the original cylinder. Would the nipples likely be the 5.5mmx9mm? Or the 12x28 threads?

 

[swathdiver]

Probably the smaller metric. My AH Pietta Remington takes the M6 x .75 like all my newer ones. Go figure.

 

[Hullraiser]

Probably the smaller metric. My AH Pietta Remington takes the M6 x .75 like all my newer ones. Go figure.

Wished this one did. The m6 x.75 are more common & easier to find. I have another cylinder coming that probably has those in it

 

[Ammastor]

It does take the 6 x.75. I just bought some for all my Piettas. Piettas all take the same nipples. At least all the ones I have. and you can get them in #10 or #11. So you can switch as you need to.

 

[Hullraiser]

It does take the 6 x.75. I just bought some for all my Piettas. Piettas all take the same nipples. At least all the ones I have. and you can get them in #10 or #11. So you can switch as you need to.

That's what I thought too, but threads are too big. I ordered & received a new cylinder for remmington that also came with the smaller thread nipples. Not sure if cylinder was original or just different nipples in 1990 and it says pietta on frame.
Now I want to get the same nipples to fix old one for spare