Flash hole liner question

[Ben Meyer]

My rifle has one, it works, great ignition, nothing wrong with it. I was placing an order for some stuff and decided to get a new one/spare one, just in case. The threads are correct, it screws right in. But its noticeably longer than the original(which I dont know is THE original since I got the gun used and its 40 yrs old). The "original" has a slightly flared out front edge, so itll only screw in "so far." This new one does not.

Questions: can a flash hole liner be too long? This IS longer, but does that matter? Can it be screwed in TOO far? Also, the actual hole is smaller. My old one could be worn bigger, since I do poke the powder charge every time with a pick.

This is a $5 part, so no biggie to buy another, or NOT to. Just thought I'd ask.

 

[Ben Meyer]

I would think if the new one is TOO deeply screwed in, my cleaning rod would hit it protruding, which could booger up the threads and make removal impossible. But I dont know what the inside of a barrel looks like down there so again, I dont know.

 

[Jim Evans]

What rifle is it?

 

[Ben Meyer]

DGW TN Mtn Rifle, .50cal flintlock

 

[rafterob]

They are often installed and then filed flush with the barrel, at least with new installs.

 

[Larry (Omaha)]

Questions: 1. can a flash hole liner be too long? 2.This IS longer, but does that matter? 3. Can it be screwed in TOO far? Also, the actual hole is smaller. 4.My old one could be worn bigger, since I do poke the powder charge every time with a pick.

1. Yes, 2. Yes, 3.Yes Too long and it will cause fouling to build up and when you run a jag or brush down it will not be a good experience. The jag or brush can even get stuck. Not good!! The flash hole liner needs to be trimmed to the bore size. All of the FH barrel threads need to be used for a good install, but protruding beyond the bore diameter is a no no. 4. I doubt that your existing liner hole has grown in size unless it has seen several thousands shots. Put the new one in a drawer and most likely you will never need it. Some of my liners are 44 plus years without an issue.
Flintlocklar

 

[Zonie]

Flash hole liners are always made longer than they need to be. That is because the maker needs to provide something that will be long enough for the thickest barrel with the smallest bore available.

Ben Meyer:

For the liner to work properly, it must be the same length as the barrel wall is thick where the liner is going to be installed. If it is too long and sticking out inside the bore, it will prevent the cleaning rod from getting all the way to the breech.
I can say first hand, a liner that is too long will also cause mis-fires.
In one of the guns I built I forgot to trim the length of the vent liner. Taking it to the shooting range that way, I found it would only fire about once in every three attempts. Once the liner was trimmed to the right length, the rifle fires 99% of the time on the first try.

To trim a vent liner without damaging it you will need a metal cutting flat file, a pair of locking pliers like Vise Grips or a vise and a hexagon nut that has the same internal threads as the threads on the liner. You will also need something to measure the distance across the flats on the barrel, in the area where the vent is located.

Measure the distance across the flats and subtract the bore diameter from that value. Then, divide this answer by 2. That is the length your liner should be.
(For instance, if the barrel measures 7/8 of an inch, the decimal equivalent would be .875". If the bore size is .45 caliber, subtract it from the outside dimension and get .875 - ..450 = .425. .425/2 = .212 )

Measure the length of the new liner and write it down. Now, subtract the final length from that value. (If it is 3/8" or .375 and the final length is supposed to be .212, subtract .212 from .375 and get an answer of .163. That is the amount of material that needs to be removed. 5/32" is equal to .156 which is darn close to .163 so if you don't have a dial vernier caliper you could use it for the final length.

Screw the new liner into the nut with the "inside end" sticking out above the surface of the nut by the amount that needs to be removed. Now, clamp the nut in the vise or clamp it with the locking pliers.
Use the flat file to file away all of the material that is sticking out above the face of the nut. Once done, unclamp the nut and unscrew the liner.
It's a good idea to use the file to remove any burrs that might be on the liner and to dull the sharp edge of the thread.

Screw the shortened liner into the barrel and your done.

 

[Eterry]

They make the liners for a large array of barrel thickness, so each one has to be hand fitted to your particular barrel. Also the hole is left small, you can always drill it bigger, but not the other way around.
This isn't like car parts, they don't just swap out and done. That applies to most gun parts, especially black powder.

I agree, toss it in your parts box, you may need it someday.

 

[Grenadier1758]

Liners can open up. It generally takes a lot of high pressure shots to do that much wear. Most of us like a touch hole diameter of 1/16". If you have a set of fractional drill bits, see if the 1/16" passes through the touch hole of the new liner. What drill bit passes through the touch hole of the old liner?

Larry gave good advice. Many builders will only partially tap the touch hole so the liner stops at the point where the tip of the liner would begin to protrude into the barrel. Any excess length would be filed off from the outside flat of the barrel. Some rely on the counter sink on the front edge to locate the face of the touch hole liner with the barrel. Then you have to shorten the liner to prevent the excess length from entering the bore. NO matter what you install, you will still need to use a good anti seize lubricant in the threads so that the liner can be removed at some point in the future when the touch hole becomes too large.

 

[ord sgt]

It depends on the thickness of your barrel. Compare the liner to the muzzle end of your barrel. The liner should only be the same width as one wall of the barrel. I have had to shorten the length of some liners. the long liners would interfere with my breech scraper and cleaning rod after a day of shooting.

 

[ADK Bigfoot]

Your new liner appears to be too long. As covered above by others, you need to file it to fit. I had a second-hand flintlock that kept damaging the cleaning jag. I found the liner protruded just enough to get in the way. I shorted it slightly, reinstalled, and no problems.

ADIK Bigfoot

 

[EC121]

If a liner is not installed deeply enough, when filing it down to the flat. you can file into the inside cone. Then you get a knife edge flash hole( or if you go too far into the cone a huge hole) that will burn out faster than one with a bit of channel left in it. Also the vent pick will wallow out the knife edged hole if you aren't careful. I like to see just a bit of flat in the hole. It doesn'r affect the speed, but the hole will last longer.

 

[hanshi]

Liners should be considered (semi) permanent. They do not need to be removed for cleaning or any routine work. In my particular case, whether with new liners or with the ones already installed, there are a few steps I always take with them. 1. Drill out the hole to 1/16". 2. apply anti-seize lube to the threads. 3. install the liner into the barrel. 4. check to see if the liner extends into the bore. 5. Remove liner from barrel. 6. If the liner is too long it is dressed down to fit; either way I will always use a Dremel Tool to enlarge the cone and leave the flash hole with a roughly 1/32" web. Rarely is it necessary to perform each step of this process. The anti-seize makes it possible to remove the liner if the need exists.

 

[Ben Meyer]

What is in my gun looks like the 1st pic. What I got looks like the 2nd pic. I got the wrong one. Oh well, I'll order a new one.

And I agree, I never remove my flash hole liner unless I dryball the gun. Havent done that for a long time but it sure makes that easy to deal with. I do use antiseize on it whenever I DO need to remove it.

 

[Newtire]

All of the above. A lot like a spark plug being too long, if it gets carbonned up because it protrudes into the bore, it boogers up the threads in the hole when unscrewing it.

Since this is something encountered occasionally in an engine, sleeves (not "Heli-coil" but similar) are made that reline the hole. I wonder if this is the way a qualified smith would repair such damage?

 

[Capnball]

Flash hole liners are always made longer than they need to be. That is because the maker needs to provide something that will be long enough for the thickest barrel with the smallest bore available.

Ben Meyer:

For the liner to work properly, it must be the same length as the barrel wall is thick where the liner is going to be installed. If it is too long and sticking out inside the bore, it will prevent the cleaning rod from getting all the way to the breech.
I can say first hand, a liner that is too long will also cause mis-fires.
In one of the guns I built I forgot to trim the length of the vent liner. Taking it to the shooting range that way, I found it would only fire about once in every three attempts. Once the liner was trimmed to the right length, the rifle fires 99% of the time on the first try.

To trim a vent liner without damaging it you will need a metal cutting flat file, a pair of locking pliers like Vise Grips or a vise and a hexagon nut that has the same internal threads as the threads on the liner. You will also need something to measure the distance across the flats on the barrel, in the area where the vent is located.

Measure the distance across the flats and subtract the bore diameter from that value. Then, divide this answer by 2. That is the length your liner should be.
(For instance, if the barrel measures 7/8 of an inch, the decimal equivalent would be .875". If the bore size is .45 caliber, subtract it from the outside dimension and get .875 - ..450 = .425. .425/2 = .212 )

Measure the length of the new liner and write it down. Now, subtract the final length from that value. (If it is 3/8" or .375 and the final length is supposed to be .212, subtract .212 from .375 and get an answer of .163. That is the amount of material that needs to be removed. 5/32" is equal to .156 which is darn close to .163 so if you don't have a dial vernier caliper you could use it for the final length.

Screw the new liner into the nut with the "inside end" sticking out above the surface of the nut by the amount that needs to be removed. Now, clamp the nut in the vise or clamp it with the locking pliers.
Use the flat file to file away all of the material that is sticking out above the face of the nut. Once done, unclamp the nut and unscrew the liner.
It's a good idea to use the file to remove any burrs that might be on the liner and to dull the sharp edge of the thread.

Screw the shortened liner into the barrel and your done.

That really sounds like the last word in fitting a liner. The way I did it on my buddy's gun was to take the lock and old liner out. Run a correctly sized cleaning jag down the barrel then I used the depth gauge on my caliper to determine the outside surface of the barrel to the inside surface of the barrel. Worked like a charm. I did make sure there was no interference between the liner and the jag afterwards.