need help figuring out the boore dia of a rifle

[edwardc]

  call me dumb  but i cant seem  to get  a straight answer  off my gauge etc 

bore  is 11mm or .4 of an inch ( just under 1/2 inch ) 

its  for an early rifle  that i have had  for 3 years 

thanks  for any help 

ed

[Bob Roller]

  call me dumb  but i cant seem  to get  a straight answer  off my gauge etc 

bore  is 11mm or .4 of an inch ( just under 1/2 inch ) 

its  for an early rifle  that i have had  for 3 years 

thanks  for any help 

ed

Multiple 11x.0394 and you'll get .4331.

Bob Roller

[Standing Bear]

Is that land to land?  Or groove to groove to groove?  Or???   If groove to groove it is likely a .40 cal.

[edwardc]

  it  was land to land

a modern 38 spsl  bullet fits  the barrel  ok  and with a patch fits tight 

[bob in the woods]

I shoot a .395 ball in my .40 cal.  My friend shoots a .380 ball in his.
Is there not a stamp /cal. mark on the underside ?

[edwardc]

No

the rifle  is more then 140 years old   built by  Caswell in New york state 

i found a pistol bullet in the barrel  that must have been in there  for 100 years
it looked just like a civil war revolver bullet 

the powder  was like a hunk of $#@*

[smylee grouch]

Well if you have the breech plug out, you could grease and slug the barrel.

[edwardc]

breech plug is no longer  out 
i did  not do the actual work  was done for me

  a 38 special round fits nicely with out a patch  and tight with one
as i said  the round removed by other person was a conical  pistol round  might have even been a modern bullet from a hand gun round that fit just right
slightly hollow base

i have a 36 cal and that's too small  but with 2 patches  would fit  nicely if need be

was there a 43 caliber RB rifle ??

or maybe the rifle was a 36 and is just worn down  to 38 or bigger

i have not shot B P since 1985  a lot has changed

smylee grouch  how  do  you slug a barrel ? melt lead  and pour down barrel  and remove ?




 

[Longknife]

edwardc, remove breech plug, lube barrel, drive and oversize ball down the barrel, mic slug that has been formed to the bore size....

[JohnnyFM]

Sounds to me like you've got yourself a .38 cal rifle.  Nice!  Maybe a ball from one of those Navy Colt's will work with a nice thick patch.  That would save ya a lot of trouble finding lead ball for sure.  From what I've heard, many original rifles were what we would term "odd" calibers.  Of course, "odd" calibers aren't limited to old.  I have a great shootin' rifle gun with such a hole in it. The barrel is by a famous maker and is stamped ".54" right on the belly but it refuses to take the "normal" .530 ball unless I use a patch so thin it only has one side to it (0.05") and that burns up every time.  Dang useless.  Now a .520 roundball with a nice thick patch of linen or pillow ticking works perfect and shoots even better.  So, what I really have is a .53 cal rifle gun.  And I didn't even have to pay extra for it just to be different.
Kind regards,
Johnny

[Steve-In]

If you have access to a drill set you can get close to bore size by inserting the shank of the drill into the bore.  Slugging will give you groove size. I am guessing an odd number of lands and grooves so that makes it difficult to measure with calipers.  I have access to gage pins from .0625 to .750 so I am spoiled.  Also the muzzle may be worn to a taper so the drills will go deeper.

[Hungry Horse]

 It sounds like it is a .38 cal. rifle. The bullet molds made by the Italian firms that produce revolvers make period correct molds for cased sets. These molds are almost always undersized for revolvers. But, the correct size ball for a .36 cal. revolver is around .375. A ball from one of these molds that is a little less than .375 might be just the ticket. These molds also mold a conical bullet as well, which might be fun to give a try.

     Hungry Horse

[edwardc]

after  using a different measuring device
i get  the following 

0.408.5 in

so  a .375  with patch  might work  nice 


after using a cabelas dial measuring device  i got 25 exact ( or 3 o clock exact )

i also have a half stock barrel almost the same age  and size  and i made a slug  out of that  its 0.402.0 exact 
it  also fits  the rifle  and  is loose fitting







any opinions ??

[Bob Roller]

after  using a different measuring device
i get  the following 

0.408.5 in

so  a .375  with patch  might work  nice 


after using a cabelas dial measuring device  i got 25 exact ( or 3 o clock exact )

i also have a half stock barrel almost the same age  and size  and i made a slug  out of that  its 0.402.0 exact 
it  also fits  the rifle  and  is loose fitting







any opinions ??

Get a set of small hole gauges that expand in the bore by turning a stem and then get a reading with a real micrometer NOT a
VERY NEAR caliper with a dial. These gauges are an expanding ball type and not telescoping or "snap" Gauges.

Bob Roller

[Dewey]

If you have access to a drill set you can get close to bore size by inserting the shank of the drill into the bore.  Slugging will give you groove size. I am guessing an odd number of lands and grooves so that makes it difficult to measure with calipers.  I have access to gage pins from .0625 to .750 so I am spoiled.  Also the muzzle may be worn to a taper so the drills will go deeper.

I have the same problem (uneven number of L&Gs), also - on an old original Leman heirloom caplock. There is no way to remove the plug (frozen for over 100 years), so I have never been able to determine the bore size.  Thanks for the idea about using the drill bits !!!   

[Hungry Horse]

 I wouldn't even consider shooting it unless I could inspect the breech plug. If heat, and Areo Kroil won't get it out, it's welded in, or Loc-tited.

  Hungry Horse

[edwardc]

so  if  i have a 38 cal rifle   what size round ball should i use ??
i have 350 ( for another gun ) would  that work  or is it too small ?

thanks  all  for any help

[Mike_StL]

No

the rifle  is more then 140 years old   built by  Caswell in New york state 

i found a pistol bullet in the barrel  that must have been in there  for 100 years
it looked just like a civil war revolver bullet 

the powder  was like a hunk of $#@*

Did you measure the diameter of the pistol bullet that you removed?   Since there was a powder charge, the owner was planning to shoot it.

[Longknife]

so  if  i have a 38 cal rifle   what size round ball should i use ??
i have 350 ( for another gun ) would  that work  or is it too small ?

thanks  all  for any help

.370--.375....You can try the 350 but depending on groove depth you will need a VERY THICK patch to seal the grooves.....and accuracy will suffer....

[Daryl]

Must find the actual bore (& grooves) diameter, then use a ball that, for an old barrel, is about .010|" smaller than the bore. 

The groove diameter is good to know for figuring out how thick your patch will have to be.  If you are unable to ascertain these measurements - seek help to find them from someone with the appropriate knowledge & skill.

However, the important # is the bore size #.  Once you have that, subtract .010" and that is the ball diameter.  With that ball, you can simply use a .020||" to .024" patch and you are good to go for all but excessively deep rifling.

[edwardc]

350 is  way too small

370 is close  to what i need
the rifle is or was very lightly used  by the overall cond  etc
its more of a star rifling  then the typical lands and grooves

if i could get a good pic  of  the muzzle end  i could show  what  i mean

[Daryl]

Many of the muzzles of old rifles, were oddly & decoratively filed.  Some indeed, had very weird narrow and knife or wedge cut grooves.  If the rifle has VERY narrow grooves & wide or squared lands, you may have to use a smaller ball than .010" under bore size, but then a much thicker patch will be needed.

Knowing the exact bore and groove diameter would be MOST helpful.

[WadePatton]

The easiest, most fool-proof way I've found to measure the diameter of a bore to .001"

is to use machinists' pin gauges.  They come in sets or you can buy them individually.

[frogwalking]

If it is an old rifle. It probably has an odd number of lands and grooves, which makes it difficult to mike. Even if you slug the bore, your slug will not have a land directly across from another land, thus a mike problem.  I think the idea of fitting a bullet or mandrel of known size is maybe the easiest way to get a true measure, land to land.  If a .38 special is very tight with a patch, depending on the patch thickness, it sounds like it is 36 caliber, or .36+ a few thousandths.

[smokinbuck]

I've got an old unmarked barrel that I built around thinking it was a .36 caliber. Turns out it is .38 caliber and handles a .375 RB with .015 patching very well.
Mark