Copyright, C. E. Harris, 1995, All Rights Reserved
Cap & ball revolvers are great fun for hunting varmints or small
game and for informaal target shooting.  They accomplish most
sporting tasks as well as a modern cartridge gun.  About the only
things you give up are reloading speed and chasing brass.
I don't recommend the inexpensive brass frame revolvers because 
they loosen up and go out of timing quickly if subjected to
steady use.  Firing "full" cylinder loads in a brass frame cap &
ball revolver is like using "+P" loads in an aluminum frame .38
Special.  If you have one of these you must give some thought to
appropriate loads.  Light target loads are essential to prolong
the life of a brass frame revolver, but they only delay the
inevitable.  If you intend to shoot a lot or use full loads more
than occasionally, don't even consider anything but a steel
frame.  Appropriate target charges for brass frame guns with
round balls are 15-20 grs. of FFFg or the same volume of Pyrodex
P in a .36 caliber or 20-25 grs. in a .44 caliber.
The most accurate traditional style black powder revolvers are
the steel-framed 1858 Remingtons.  These weigh 43 ozs., have an
8" barrel and solid top strap.  They are far more rigid than the
open-top Colts in which the barrel is held to the frame by simple
a barrel wedge inserted through the cylinder pin.  The steel
framed Remingtons can withstand steady use with as much sporting
black powder or Pyrodex as the chambers will hold.  The cylinders
on .44 Model 1858 Remington revolvers have a capacity of 35 grs.
of FFFg, which, with "strong" powder and a round ball,
approximates the energy of a .38 Special with 4" barrel firing +P
ammunition.  The Remington lock work is simple to clean and
maintain, is more reliable than the Colt, and less prone to parts
breakage.
The two most common reasons for replica cap & ball revolvers to
be inaccurate are because the cylinder throats are substantially
smaller than barrel groove diameter and/or the barrel is turned
in too tightly, constricting the bore at the forcing cone.  These
conditions cause significant velocity loss caused by gas leakage
around the ball.  This results in ball misalignment and
deformation which impair accuracy.
It takes 4 to 6 hours of careful hand work, not including sight
modifications, to "accurize" a typical replica revolver into a
precision small game or target arm capable of 2", six-shot, 25-
yard groups.  The first step is slugging the barrel.
Typical barrel groove dimensions of replica and original cap &
ball revolvers average .375 +/- 0.0015 and in the .36 cal. and
0.450" +/- 0.0015" in the .44s that I have measured.  Accurate
measurement of an upset slug pushed through a barrel having an
odd number of lands and grooves cannot be done with a standard
thimble micrometer.  This is because the micrometer faces would
rest on a land opposite a groove, giving an erroneous reading.  I
measured the slugs from my barrels using a V-anvil micrometer or
a V-block of the proper angle for the number of grooves, 108
degrees for 5-groove barrels or 128.6 degrees for seven groove
barrels.
It is important that chamber diameter be properly matched to the
barrel groove diameter, to obtain best accuracy. "Ideal" chamber
ball seat dimensions for a revolver are from .0010" to .0015"
LARGER than the barrel groove diameter.  Revolver chambers which
are only 0.0010" to 0.0015" smaller than groove diameter will
still shoot fairly well, because soft lead bullets are upset by
gas pressure in the forcing cone.  However, if the chambers are
more than about 1 percent smaller than the barrel groove
diameter, there is virtually no hope of getting ten-ring target
accuracy. This is because the bullet is forced to fit the
chambers during loading and cannot adequately obturate
symmetrically to seal the gases behind the bullet in the barrel.
To determine chamber diameter of the cylinder, remove the
nipples, seat pure lead balls in all six chambers of the empty
cylinder, using the loading lever, and drive them out from behind
with a 2-inch long 5/32" punch.  Then measure the balls with a
micrometer.  You should seat balls in all six chambers, because
it is not unusual for them to vary.
The chambers of original Colt and Remington cap & ball revolvers
I have measured generally run groove size +/- 0.0015", unless
barrels or cylinders have been swapped.  The majority of Italian
reproductions we have measured, regardless of make or caliber,
have tight chambers which are 0.002-0.005" smaller than groove
diameter.  Most of the dozen or so Italian replica revolvers I
have measured have .36 cal. chambers measuring .372-.373" and .44
caliber revolvers .445-.446."  Its no surprise that it is
difficult to get groups better than 3" at 25 yards with these
replicas as they come from the box.
Original guns approach 2" groups at 25 yards with proper sized
balls as long as the chambers are not deeply pitted.  Some
original revolvers I have seen have had the chambers lapped to
reduce pits, and this often improves them if done carefully so
the chambers remain round and of uniform diameter.
Correcting tight chambers is best done with a straight-fluted
reamer made for the purpose.  I bought my  .44 C&B finish reamer
from JGS Precision. This cleans up the entire chamber and results
in a mirror finish which requires no polishing. The resulting .44
C&B chamber has a .4515"  cylindrical ball seat .70" deep with a
gentle 5 degree taper bottoming on a .380" diameter stop surface,
which limits the depth of cut.  This reamer was intended to clean
up .44 cap & ball revolver cylinders for use by target shooters
wanting to use soft lead .45 ACP 185-gr. target wadcuttters, such
as the Saeco-Redding #131 or H&G #130BB.
This reamer is pilotless and intended to be guided by a jig plate
and bushing.  Reaming all six chambers can be done by hand in
about an hour and requires no power driven machinery.  The mild
steel used in these revolvers cuts easily when a sharp reamer
turned and fed in slowly with plenty of cutting oil.
After the chambers have been reamed, a larger ball is required to
provide a proper tight fit in the modified chambers.  A round
ball used in a cap & ball revolver must be 0.005" larger in
diameter than the largest chamber to be accurate in heavy loads. 
If only light target loads (less than 800 f.p.s.) will be used, a
ball only 0.003" larger than chamber diameter is adequate.  The
ring of lead cut from a ball in seating forms a short cylindrical
bearing surface which engraves in the rifling.  A minimal tangent
contact of the ball is not adequate except for the light loads.
Occasionally a revolver will show "necking" or constriction of
the forcing cone.  This is caused by excessive tightening of the
barrel into the frame.  Correcting this requires lapping the
breech end of the barrel to remove the "choke."  The usual method
is turn a brass lap 0.001"  under bore diameter, which enters the
bore easily and passes without resistance until it reaches the
constriction.  Charge the lap with 200 or 220 grit and work it
with oil in the breech end of the barrel until it passes freely. 
Then cast a lead lap in the bore and repeat the process with 240
grit and oil.  Work mostly on the breech end of the barrel, until
you feel uniform resistance throughout the barrel's length.  It
is OK for a slight constriction to remain as long as the bore
size diminishes from breech to muzzle and not the reverse!
Getting cap & ball revolvers to shoot where you look has always
been problematic.  Most original Colt percussion revolvers and
replicas are sighted to strike from 8" to a foot high at 25
yards.   The 1858 Remingtons have a groove on the top strap for
the rear sight, which is easier to deal with than the crude notch
behind the hammer nose of the Colts.
Most Remington replicas are sighted for conicals and shoot about
6" to 8" low at 25 yards with round balls.  This is preferable to
having a gun which shoots high, because it is easy to file down
the front sight to adjust elevation.  Conical bullets are 
usually less accurate than round balls because of the slow
32" twist, which copies the barrels of original guns.  A 16"
twist, as used in the Ruger Old Army, would provide better
accuracy with conical bullets or .45 185-gr. soft lead wadcutters.
The undersized Italian nipples on reporoduction guns should
always be replaced with Uncle Mikes or Tresco Ampco nipples of
proper size to provide a snug fit with CCI or RWS No. 11 caps.
Undersized caps will blow off from the blast of firing adjacent
chambers and also increase the frequency of cap jams.
While the Remington design, with its solid top strap is more
rigid and accurate than the Colt, its cylinder is prone to bind
from powder fouling unless it is properly handled. The cylinder
pin must be coated with heavy grease when assembling the gun. 
Each time you reload place drop or two of Break Free, Dexron ATF
or Marvel Mystery Oil on the cylinder pin.  Hold the muzzle up
and spin the cylinder so the oil will run into the arbor.  This
will keep the gun working smoothly.
After enlarging the chambers of my reproduction Remington from
their original .446" to .4515," I changed to a .457" ball, as
used in the Ruger Old Army.  Shooting otherwise comparable loads
the pooled average of thirty six-shot groups with a selection of
loads shrunk to 2-1/2", a significant and useful improvement.
Cabela's $99.95 steel frame .44 Remington Army Reproduction
Average of Five Consecutive Six-shot groups at 25 yards.
                ORIGINAL CYLINDER               REPEAT TEST
                .446" CHAMBERS                  AFTER REAMING
                BEFORE REAMING                  CHAMBERS TO .4515"
Bullet
and Powder      Vel             Group Avg.      Velocity        Group Avg.
Charge          @ 10'.          5 x 6 shots     @ 10 ft.        5 x 6 shots
.451" cast round ball                           .457" cast round ball
25 - P          801, 22 Sd      2.68            845, 34 Sd      2.90
25 - 3F         772, 31 Sd      2.72            756, 27 Sd      2.20
30 - P          943, 51 Sd      4.10            947, 29 Sd      2.20
30 - 3F         858, 57 Sd      3.21            885, 32 Sd      2.42
Pooled Avg. of 20 targets
with round ball         =       3.18            Pooled Avg.  =  2.43
.451-180 Buffalo Bullet                         .457-190 Buffalo Bullet
30 - P          855, 27 Sd      3.02            857, 48 Sd      2.95
30 - 3F         793, 64 Sd      2.82            795, 17 Sd      2.78
Pooled Avg. of
ten targets with
Buffalo Bullet          =       2.92            Pooled Avg.  =  2.87
Grand Avg. of thirty                            Grand Avg. of thirty
targets with original                           targets with chambers after
.446" chambers          =       3.09"           reamed .4515" = 2.58
In Home Mix We Trust, Regards, Ed
--- msged 2.05
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