How does Firestorm's removable breech REMOVE?

[Naphtali]

My rifles have breech plugs that were never intended to be frequently removed and installed. Thompson/Center's Firestorm apparently has a breech plug intended to be routinely removed.

What is different about Firestorm's breech plug threads or assembly or thread configuration -- whatever -- that allows safe removal and installation?

I refuse to believe the "secret" is merely witness marks. I also doubt they use acme threads. Their rifles are marketed to relatively unknowledgeable users. I am interested in how the result has been accomplished safely.

[RCL]

http://www.tcarms.com/mlrifles/firestorm/index.html

[crow_feather]

Naphtali,

I am sure that my good friend Randy Wakeman, who is all knowledgable in the area of pyrodex and alternative ignitions, will be more than able to answer your question.

As for removing the plug, I seem to read about a lot of people having problems doing just that.

C F

[Naphtali]

RCL: the link you included is advertising blurb only. The patent identified by number at the link refers to shape of combustion chamber.
*******
crow-feather: "Problems" is one of the reasons for my query. In these litigious times, people will sue at the drop of a hat, regardless of their own responsibility.

That T/C and other manufacturers have designed their products to be disassembled AT THE GAS SEAL and have not been sued to Chapter 11 indicates that maybe disassembly is not as foolish as it appears, which brings us back to the question: How is the breech seal configured?

[Dutch/AL]

I've got a Firestorm, and removing the breech plug is as simple as knocking the pin out of the forestock, and removing the barrel from the stock. Then using a special wrench that is supplied, (crescent wrench would work too) you simply turn it counterclockwise and unscrew it from the barrel. At that point there is nothing else to remove. It's really easy and super quick. As for the threads they look a little deeper cut than most threading, but other than that it doesn't look at all unusual. It does have a cone shape to it where the blackpowder or Triple 7 settles.

Yes I agree that Randy Wakeman is a really knowledgeable guy especially when it comes to muzzleloaders.  :grin:

[Naphtali]

Dutch/AL:

The conical shape pertains to patent (ignition).

BUT the threads and male-female configuration of breech plug threads and mating surfaces in barrel's breech -- that's what interests me.

I haven't gotten more information on how these surfaces mechanically mate to provide both a 100 percent gas seal AND easy, non-threatening removal-and-installation of the seal (that is, the breech plug).

I could tell you what I suspect is how the repeatable seal is achieved, but "suspect" and 50 cents will get you a cup of coffee.

So far, T/C has not identified how they do this. I don't understand why, though. Any journeyman machinist could measure various dimensions and surfaces to get their solution. so this is clearly not proprietary.

[Dutch/AL]

Naphtali, I see exactly what you are asking now. I'm not a machinist so I couldn't tell you for certain, but maybe it's simply the length of the threads.

At any rate, even with 150 grain loads, there is no blowback thru the threads, or residue left in them to clean out after shooting. In other words the design works like it is supposed to with no tradeoffs.

I like mine so much, I'm thinking of trading it in on a stainless model, or possibly just keeping the one I have a buying a stainless too.  :grin:

[AndyHass]

A lot of MLs have removeable threaded plugs.  Depite the variety of designs, what they all seem to have in common is a long threaded section (1-1.5 inches), and relatively fine, deep threads.  With moderately good machining, it is no surprise you don't get blow-thru.  The threads usually have a grease to fill in any space as well, and the length of time there is any pressure there is a few milliseconds at a time.