A word of warning

Will this fit?
https://www.ebay.com/itm/Thompson-C...349672?hash=item1a5d2c89e8:g:4S4AAOSwDLVbjcXQ
or this?
https://www.ebay.com/itm/Thompson-C...on/Center+Arms&_trksid=p2047675.c100005.m1851

How could that damage the tumbler?

blowing the hammer back and it repeatedly falling into the half cock, etc. IMO it sounds like there may have been a flaw to begin with.

frontiergander said:

blowing the hammer back and it repeatedly falling into the half cock, etc. IMO it sounds like there may have been a flaw to begin with.

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Oh I see. I had a Lyman that would do that occasionally with a hot load.

I never understood the musket nipple idea. Yes, I know why but with a fresh load of Swiss powder, a good nipple, hot shot or ampco, uncle mikes stainless or even the BACO platinum nipple and Remington 11’s I’ve had very good service the past couple decades.
Wrt your current issue, ebay seems to have a good supply of tumblers and other lock parts.

Most likely 2 things happened, a somewhat weak mainspring and an improperly heat treated tumbler. I have seen springs break from heavy loads but shearing a tumbler is a new one. Learn something new every day.

If the heat treatment was done improperly the piece could be very brittle instead of hard and tough as was intended. I am interested to see photos as well.

Was it a musket nipple with a large hole or small hole ? I noticed the option of choosing a small or large hole at a website that sells them. I would imagine it would need a spring with appropriate tension to keep the hammer from flying back. I am guessing probably more than what would otherwise be adequate with a percussion cap nipple.

I am now wondering if it would be wise to use a musket nipple on a TC Greyhawk. A musket nipple would otherwise have been another option. That just leaves magspark and standard percussion nipples as options.

72Coupe,

I sent you a "conversation". I have better sources for T/C parts.

72coupe said:

Don't use a musket nipple on your T/C Hawken if you are using Triple 7. I did this for about 5 shots before the tumbler was sheared into 2 pieces.

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I would like to know how large was the powder charge of 777 and which granulation?
What type of projectiles were being loaded and if not round balls then what did they weigh?
How many times did the hammer reset before the tumbler broke?
Which brand of musket nipple were you using, TC or another brand?

grter said:

I am now wondering if it would be wise to use a musket nipple on a TC Greyhawk. A musket nipple would otherwise have been another option. That just leaves magspark and standard percussion nipples as options.

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I haven't heard of this happening before.
The tumbler looks like an inexpensive cast part than cost TC less than 5o cents to make.
It really depends on the details and could be an anomaly.
Resetting a hammer once or twice probably wouldn't break it in most cases.
But many TC lock parts are capable of breaking, that's why their guns had a lifetime warranty with free repairs which a lot of folks made use of.
It seems to be as much of an issue with using 777 as it is with the musket nipple.
777 should be loaded down by 15% which I doubt most folks put into practice, i.e. - only load 85 grains of 2F 777 instead of 100 grains of 2F Goex or Pyrodex RS.

I have always used uncle mikes hot shot nipple standard #11 cap. This will vent some of gases from vent hole in nipple. Worked great on my Thompson center new Englander that on occasion would blow hammer back. Not a good condition. Fellas, using musket cap is not necessary for good ignition. Good hunting.

72coupe said:

Arcticap the powder charge was 40 grains of 3f triple seven. I was using it in a 4H black powder class and this was the first time I had used Triple Seven in it. The projectile was cast from the Lee 50 cal muzzle loader mould. I have never weighed one but my guess is 275 grains. I have had this rifle for years and it has not been shot much. It was a kit given to me by a friend that didn't want to finish it.

The hole in the musket cap nipple appears to me to be quite large and I don't remember what kind in might be.

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Thank you.
Were there multiple hammer blowbacks before the part broke that would have served as a warning to discontinue using the musket nipple?
Or was there only one blowback out of the 5 shots?

In Feb., 2020, Frulk posted a thread about different brands of musket nipples for use with several of his TC .45 Hawken rifles. --->>> https://www.thehighroad.org/index.php?threads/installing-musket-nipple-in-tc-rifle.872560/

There's detailed photos and not a mention of hammer blowback or damage caused by regular use.
TC has been making replacement musket nipples for many years, and so have other companies, and they continue to make them.
I can only wonder if the nipple brand that you were using has a larger hole than other brands, or if your spring or other lock part had a weakness.
It's certainly worthy of a warning, but yet there's undetermined "causes" meaning possibly more than one cause.

It begs the questions of whether the part would have broke if using an #11 nipple or not, or a different powder or projectile.
It shouldn't have happened, but we're not sure about the extent of the risk, only that the potential exists.

It reminds me a of thread on another forum about a new platinum lined nipple where the new liner/insert totally blew out and damaged a lock part in a similar fashion.
Platinum lined nipples are a high end part and don't usually do that when brand new.
I asked if he knew where the nipple came from and he could only remember that it was bought 20 years ago.
So he did not know who made the nipple that damaged his gun, meaning that there's no recourse or way to warn the maker of a defective product.

Looking a Frulk's thread, it would seem not all musket nipples are the same, even though they all may carry some degree of risk to use.

Here's the thread about the platinum nipple insert that blew out and by coincidence, the Pedersoli Tryon tumbler also broke. --->>> http://castboolits.gunloads.com/showthread.php?404363-Broken-platinum-nipple

Most platinum nipples are constructed so that the insert can't blow out.
One poster mentioned that even when entire nipples blow out, the tumblers don't break.
But another poster said that breaking a tumbler is a known consequence of a nipple blow out.

A TC Hawken and the Investarms locks that are TC clones don't have traditional Vee mainsprings, but have a coil mainspring.
TC Hawken lock below:

https://www.shootersforum.com/threads/t-c-hawken-hammer-misaligned.14919/

72coupe, I can walk you through the installation of the T/C lock when you are ready.

FWIW, to anyone here looking for T/C parts, check with Ed Cain in Williamstown, WV area. Contact Ed at: [email protected]

He is the former co-founder & co-owner of Mountain State Muzzleloading Supplies in the same area. At one time, they were about the fourth largest muzzleloading supply company in the '80's, '90's and '00's until his partner past away.

Anyone who has a "MSM Super Rod" on their muzzleloader, or installed a MSM "Spitfire" nipple or ordered a MSM nipple wrench, will recognize the reputation of the Mountain State Muzzleloading Company. His late partner, Fred Lambert, authored a book on WV Longrifles.

Ed is always buying and selling T/C gun parts. I just ordered a Renegade rear and front sight from Ed for about $50.00, including shipping.

My experience with TC muzzleloaders is limited, but it seems that the locks on their guns are mediocre at best. My lock has some serious wear on it and now has shims made from a soda can keeping it from dropping hammer unexpectedly. It’s relegated to a range toy currently because of that and it does not get capped until it is on the shoulder and pointed down range towards the target. It has been neglected since the issue got worse, the bore may be trashed now because I know it has been left dirty for a while. Realistically it’s not much more than a stock anymore because the barrel is trashed, the lock is crap, and the stock is gorgeous. I have considered barrel replacement to a bigger bore but I just haven’t had a place to hunt or shoot regularly so I haven’t bothered.