Question about pictured vent hole.

[Sartana]

I have been doing some reading on the forum regarding the size of vent holes. Seems most folks talk about a range of 1/16" to 5/64". Well, pictured is the vent hole on my musket (.54 cal smoothbore, Kibler Colonial kit). You can also see a 1/16" and 5/64" drill bit next to it to give you a size perspective. Needless to say, this vent hole is smaller than either. Have not had the chance to fire it off yet, but just curious as to some thoughts on what I am seeing. Thanks!

 

[ord sgt]

How well the vent hole lines up with the pan is another question. If it's right at the top edge of the pan or just slightly lower, it should be just fine. Put the lock into place and get your rifle to a place where you can shoot.. That will give you your answer.

 

[Tom Compton]

It’s like ordering a steak cooked medium and getting medium rare. It can be cooked more but not uncooked.

Shoot it as is, then if needed, you can open it up. Go to Harbor Freight and get a set of number drills. Open the touch hole up one number at a time And fire 5-10 shots or more before going any further till you are satisfied.

 

[Grenadier1758]

The touch holes are often supplied undersized. It is a normal part of load development to enlarge the touch hole if needed.

Gives you a clue as to one reason to have a set of number drills as well as a set of fractional sizes.

 

[Zonie]

I have been doing some reading on the forum regarding the size of vent holes. Seems most folks talk about a range of 1/16" to 5/64". Well, pictured is the vent hole on my musket (.54 cal smoothbore, Kibler Colonial kit). You can also see a 1/16" and 5/64" drill bit next to it to give you a size perspective. Needless to say, this vent hole is smaller than either. Have not had the chance to fire it off yet, but just curious as to some thoughts on what I am seeing. Thanks!

View attachment 36687

To me, it looks like whoever built it left the vent hole as it comes from the supplier.
These vents in the insert always have a small hole thru them. This allows the builder to adjust it to whatever is needed to get reliable ignition. Some builders are fans of the smallest hole that will work even though it may not always give reliable ignition. Others like the idea of drilling the hole towards a large size like the 5/64" you mentioned.

I would suggest that you use that 1/16" drill to make the hole larger. It will be an improvement over the one your vent liner currently has.

 

[oldwood]

I agree w/ Zonie...Sub 1/16" touch holes in vent liners can give unreliable ignition.
oldwood

 

[Tom A Hawk]

Well...the white lightning liners come with a small vent and I had to drill the one I put into a .54 1" barrel out to 1/16" in order to get reliable ignition. However, two white lightnings installed in 7/8" .40 and .50 barrels fire instantly without alteration and with no misfires what so ever. I would suggest trying it as is before deciding.

 

[jager43478]

It’s like ordering a steak cooked medium and getting medium rare. It can be cooked more but not uncooked.

Shoot it as is, then if needed, you can open it up. Go to Harbor Freight and get a set of number drills. Open the touch hole up one number at a time And fire 5-10 shots or more before going any further till you are satisfied.

If u shoot 2f u can get away with a larger hole. The larger hole will allow 3f to come out when loading. I use a .055 ths. hole it works fine for both.

 

[Tom Compton]

If u shoot 2f u can get away with a larger hole. The larger hole will allow 3f to come out when loading. I use a .055 ths. hole it works fine for both.

True. When I did shoot FFF back in the late 80s early 90s I had a vent pick/plug to prevent self priming or blowing powder out the touch hole when a ball was seated. Had a leather Boot lace on it that looped over the cock.

Now I shoot FFg in everything - .32 to .62, flint, percussion, rifle, pistol.

Hmmm, I have one can of FFF and I think I know where that plug is. May see how FFF works w a 1/16” touch hole again. But FFg has provided more consistent velocities. Great! Another experiment project to get me shooting more

 

[Tom Compton]

Glad the smaller touch hole works for you Jager. That’s why I suggested the OP try it as is at first then open the touch hole in small increments until he’s satisfied.

Looking at Grenadier’s chart the surface area of a 1/16” hole is almost 50% more than that of the .055 - more and probably faster heat transfer. That led me to larger touch hole.

Everything is a trade off tight ball/patch or easy loading, grease lube or spit patch, etc. The shooter has to find what combination best suits his desires.

 

[Art Caputo]

If it’s an unmodified Kibler it has a White Lightning liner that has a relatively small hole, I have installed a couple and would suggest opening it to 1/16” to start out with your 54cal.

 

[SDSmlf]

Looking at Grenadier’s chart the surface area of a 1/16” hole is almost 50% more than that of the .055 - more and probably faster heat transfer. That led me to larger touch hole.

Your math made me look. The increase in area from a .055 diameter to .0625 diameter is more like a 29% increase.

I usually start with a 1/16” diameter touchhole, but typically end up at 5/64” for what I perceive as the fastest and most consistent ignition. Everyone needs to find out what works best for them in their gun by shooting it.

 

[Flintandsteel]

I open all my white lightning liners to 1/16” to start. Can’t remember ever opening one further.

 

[tenngun]

I bought a gun third hand one time. The first owner half built and buggered it up. Sold the parts and the second guy did a poor job of finishing it. He couldn’t get a touch hole liner for some reason, bought a nipple and filed that off. Then it wouldn’t shoot.
He sold it to me for a lot cheaper then the parts.
I refinished it. But the tiny hole just didn’t work. Took a carbide bit to get through and get it to fire
It was still God awful ugly but it shot. I gave it to a friend who has since passed away and I don’t know what became of it.

 

[Tom Compton]

Your math made me look. The increase in area from a .055 diameter to .0625 diameter is more like a 29% increase.

I usually start with a 1/16” diameter touchhole, but typically end up at 5/64” for what I perceive as the fastest and most consistent ignition. Everyone needs to find out what works best for them in their gun by shooting it.

You are right. Thanks for the correction. Not sure but mental math or wrong line or thx again.

Still a large increase in area for the heat flash.

 

[Grenadier1758]

Your math made me look. The increase in area from a .055 diameter to .0625 diameter is more like a 29% increase.

If you do the math from the perspective of the 0.055" diameter to the 0.625 (Area of 0.0625-Area of 0.055)/ Area of0.055 = 29%.
Or as a reduction from the perspective of a reduction from 1/16", (Area of 0.055-Area of 0.625)/Area of 0.0625) = -22.6%

The percentage change depends on how you want to look at the change.

 

[SDSmlf]

If you do the math from the perspective of the 0.055" diameter to the 0.625 (Area of 0.0625-Area of 0.055)/ Area of0.055 = 29%.
Or as a reduction from the perspective of a reduction from 1/16", (Area of 0.055-Area of 0.625)/Area of 0.0625) = -22.6%

The percentage change depends on how you want to look at the change.

Understand that. I was commenting about the ‘almost 50%’ number.

 

[Grenadier1758]

When you go from a 1/16" diameter vent hole to a 5/64" vent hole the change in area is 56% increase from the area of a 1/16" hole.

(Area of a 1/16 - Area of 5/64)/ Area of 1/16 = 56.25%

 

[Robby]

Whenever I use a liner I never enlarge the hole and have never had a problem. I even test them out with no primer powder and the only one I can remember not firing was because of an old flint that wasn't putting out much spark.
Robby

 

[Flinty Scot]

My flint has an insert with an Allen wrench socket. It acts well as a funnel when I need to filter some priming powder if it gets reluctant to fire (usually I figure I've either pushed fowling down into the breech or have used too much alcohol to dampen my cleaning patch and not allowed it to dry) It will occasionally self-prime, too, if I forget the feather.
I've not tried to measure the hole. I'll probably have to get a numbered drill set to use as go/no go gauges, unless someone can suggest another method. I have no gauge or caliper that will fit in such a small hole.

Seems to work well, if I do my part. I've tried to move it w/ an allen wrench, to check size/thread but not very hard. I'm a perfectionist but don't want to screw up what's working.