Stupid question from a smoothbore shooter

[Smokey]

In a rifled barrel, is the caliber measured across the lands, or the grooves?

Example: A .54 caliber rifle.   
A .530 roundball plus a .010 patch. 
.010 x 2 = .020 + .530 = .55 ! 

That combination is too big, unless the caliber is measured from land to land. So which is it?

[Ohio Joe]

In a rifled barrel, is the caliber measured across the lands, or the grooves?

Example: A .54 caliber rifle.   
A .530 roundball plus a .010 patch. 
.010 x 2 = .020 + .530 = .55 ! 

That combination is too big, unless the caliber is measured from land to land. So which is it?

Measure across the Lands...

Example; A Green Mountain .45 caliber Barrel measures .450 off the lands - and .470 in the Grooves...

I use a .015 to .020 patch in my .45's with both .440 and .445 balls...

You could probably use a .530 ball and a .015. .018, or even a .020 patch and get good results in your .54... I feel a .010 patch is way to thin and you'll get blow by of gasses which will effect your accuracy.

[Smokey]

[/quote]

Measure across the Lands...

Example; A Green Mountain .45 caliber Barrel measures .450 off the lands - and .470 in the Grooves...

I use a .015 to .020 patch in my .45's...

[/quote]

Ohio Joe, with that thickness, should I expect to swab the barrel for fouling every couple of shots?

[Winter Hawk]

Depends entirely on the gun and the powder.  If the bore is smooth, (not talking about a smoothbore barrel! ) it will stay "clean" a lot longer than if it is rough.  Goex burns a lot cleaner for me than some of the other brands.  In the .45 I can shoot all day with FFFg but do swab between shots with FFg.

Also, as far as the diameter, the cloth patch will compress a lot, so a .530 ball with .015 patch may sound like it's .560 diameter but it will squish down to fit inside the grooves and seal them so you don't have combustion gas escaping through them.

~Kees~

[Ohio Joe]

Ohio Joe, with that thickness, should I expect to swab the barrel for fouling every couple of shots?

It depends a lot on the grade of the powder and how tight the patch and ball combination you use. And of course your patch lube. I use just plain ol' spit on patches and with a tight patch & ball combination I can shoot the 20 shot Rendezvous Match in July (Four - 5 shot Matches back to back) without swabbing even once / though I will admit I have to go a bit heavy on the spit towards the end.

All rifle barrels are different and if you have to swab between some shots - well,,, you sure wouldn't be the first my friend. 

[Hank in WV]

I have never had to wipe between shots using a liquid lube.

[Ohio Joe]

In the .45 I can shoot all day with FFFg but do swab between shots with FFg

Kees, pretty much the same here... I can go about 8 shots in a row with the 2fg in my .45's, but after that it's time for swab...

3fg Goex - same as you for the most part, but admittingly towards the end of a 20 shot Rifle Match out here in NW Nebraska in July, those last couple shots calls for a bit more spit if you can work it up on the firing line in 100+ degree dry heat weather in July... It can be done however...

(And no, I didn't borrow any spit from Rondo) 

[rollingb]

I have never had to wipe between shots using a liquid lube.

Same here!   

[Smokey]

I have never had to wipe between shots using a liquid lube.

Liquid lubricant?  Spit, or store-bought?

[Hank in WV]

I have used spit with great results. I just can't make enough of it so I for the las ten years or so , I use a mix of Balistol and water at about a 5/1 mixture. Shoots great and is easy to clean up with just cold water. You may want to use something else while hunting in cold weather.

[Smokey]

I will try .530 roundball with a couple of different patches. I will get both .010 and .015 and see which works best.

[Hanshi]

Yes, across the lands.  Since rifling can vary in depth with different make barrels that needs to be considered.  As a shooter of rather tight loads, I patch with canvas (.023" - .024").  My radius groove barrels (.016") need thicker material anyway.  But I also use the same material in square cut groove barrels (.010" - .012").  I like to get at least some compression in the grooves as this allows unlimited shooting without having to wipe the bore.  I use TOW mink oil for hunting but really like Hoppes #9 BP lube for everything else.

Example: In my .45 (.012") with both .440" and .445" ball I use the canvas material for good, snug loads.  In the .50 with .016" rb grooves I use a .590" ball and the same thick canvas.  The smoothbore needs a little more room so it gets .012" flannel.