Need help. Colt won’t fire

Yes, you may need new nipples.

But until then, another trick is to make a nipple shim using a thin piece of flattened wire.
Get a piece of wire from an old electronic unit, and wrap it around the threaded nipple base once to form a ring.
Cut it to size and then hammer it down flat, put it on the base and tighten.
Use two shims, or wrap the wire around the nipple base twice until you raise the nipple cone high enough to make contact with the hammer face.
You may need to find the right piece of wire.
Keep the plastic sheath on the wire if it helps due to using really thin wire.
If using thicker wire, then strip the plastic sheath off.
Keep experimenting until you can prove that the main spring tension is strong enough.
You only need to shim one nipple and then try it in different chambers.

Another trick to see if the .019 longer is needed is to tape or dot of super glue an .020 shaped shim on hammer face and see if it fires the primers first strike. If it does get the PIR-LI nipples.
Pull one out and if they are the 300 then I think it would be obvious to get the 319. IMO

The wire test above is a great way to make a shim to raise nipples if you are going to keep it that way and shoot powder and ball...but for simple testing on busting caps (no pun intended) only then you just need to unscrew the nipples an even amount of times...like 1 or 2 full turns etc, that will raise the nipple height for testing. Also do this on more than one nipple, its best not to only work on one nipple when it comes to testing. I actually once shaved down some stock pietta nipples down low enough so that the taper would grip cci 11s and remingtom 11s very well and i had to make shim washers out of the .005 thick sheet aluminum i used to make percussion caps from. Ended up having to use 2 or 3 layers of it to raise the nipples high enough to meet the hammer face.

Ok, well now I'm confused.
Possibles shop lists colt and uberti as 12x28 300, 11-50-166
Or
12x28 284, 11-50-196
Think the 284s are for older 70s models.

After some reading it seems the year made can change the thread and cone. The older uses 6x75 shorter cone and newer 12x28 longer cone. What a mess!

Found this in an archive:
Uberti changed nipple size around 1980 (??) from the short Pietta (M6 x .75 x .500 Long) to the current Uberti M5.5 x .9 Th. x .501 Long. Current Pietta nipples are 6x.75mm Th x .520 Long".
M5.5x.9 is supposed to be the 12x28 in measurement translation of Italian manufacture.

Cone length is over all length minus the length of the threaded area.
6mm x .75 would be a .2047 hole threaded to a pitch of .75
A 12 x 28, a .182 hole, is supposedly by Italian manufacture sam as 5.5mm x .9, .165 hole, which of course is smaller diameter and I believe a coarser thread. Don't know how they came to that since the starting holes are different per drill n tap chart.
Base dia is just above threads where it seats.

Cone length is over all length minus the length of the threaded area.
6mm x .75 would be a .2047 hole threaded to a pitch of .75
A 12 x 28 is by Italian manufacture sam as 5.5mm x .9 which of course is smaller diameter and I believe a coarser thread.
Only ones on track are .525 oal and 300 coneand .544 and .319 cone

Whats the overall length of the colt nipples and rem nipples. Something tells me the rem overall is longer providing longer cone measurement. Measure with calipers.

Russell13 said:

I measured them both with a caliper and the overall length is 1/2 inch on both

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The key dimension is the distance from the top of the nipple, where the cap sits, to the surface of the nipple that comes in contact with the cylinder. That is the length that determines how much of the nipple protrudes back towards the hammer. The length of the threaded section is pretty irrelevant.

Defective nipples...a sign of an Uberti.

J-Bar said:

The key dimension is the distance from the top of the nipple, where the cap sits, to the surface of the nipple that comes in contact with the cylinder. That is the length that determines how much of the nipple protrudes back towards the hammer. The length of the threaded section is pretty irrelevant.

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2 different nipples same overall can have different cone length. Track of Wolf states cone is overall minus thread. Just sayin.

Russell13 said:

Hey gang,
I took my Uberti 1851 colt navy .36 out today and couldn’t get it to fire. It would not set off the caps. I was using #10 cci and Remington caps, neither worked. After about 15 try’s on a single cap I got it to go off.
I first thought maybe I need to be using #11 caps, then I went and talked to another BP shooter at the range. A very nice guy he offer to try the gun with his caps. He couldn’t get it to fire. He told me my main spring felt very week and that was the problem.
Any suggestions or help would be greatly appreciated

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this is the one you received in the mail a few days ago? I would be contacting the seller and at least trying to get my money returned

Russell13 said:

I got it fixed and it didn’t cost a To much. I like the gun now that I have it working

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Now do your best to wear that sucker out!!

I have periodically needed to trim/file a hammer or a nipple to revive reliability also wrong caps will cause a similar problem.

Oops wrong thread...