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BULLET DESIGN & LOADING SPECIFICATIONS FOR
THE BROWNING .40-65 BPCR
By Wayne McLerran
Wishing you great shooting,
Wayne
Updated 12/2/17

The .40-65 Winchester cartridge is arguably 2nd only in popularity to
the .45-70 Government for silhouette competition.  Approximately
1300 BPC rifles in caliber .40-65 were manufactured by Miroku for
Browning.  The rifles are popular and are common in matches around
the country.  The .40-65 is my preferred silhouette caliber.  My
experiences with the .40-65 Winchester cartridge in the Browning
BPCR are the basis for this article.  I will cover the results of testing
four well-known bullets and give you some ideas why I decided to
design a custom bullet for the rifle.  Also discussed is the only bullet
design software I’m aware of and design considerations I feel are
important when designing a bullet.

Without a doubt a couple of the key factors in loading accurate ammo
includes knowing the chamber and bore dimensions of your rifle along
with a basic understanding of the pros and cons of various bullet
designs.  The chamber and bore of the Browning BPCRs are very
consistent from rifle-to-rifle but there are slight differences which can
only be determined by making a cast or impact impression of the
chamber and throat of your rifle.  Also helpful is an elementary
knowledge of internal and external ballistics.  I don’t profess to be an
expert in any of these areas but have experimented with a few bullets
and formed some opinions why some may be better suited than others
for the Browning.  Other factors that affect bullet design and selection
include the type of bore conditioning techniques used.  For example,
will you be blow-tubing or wiping between shots?

Mould Suppliers
There are several custom mould manufacturers that will “cut” a
mould to your specification.  A partial list includes Hoch Custom Bullet
Moulds, Accurate Molds, Brooks Tru-Bore Moulds, Buffalo Arms Co.
(BACO), Sagebrush Products, Fred Leeth/Pioneer Products, Old West
Bullet Molds, Boomers Bullet Moulds, KAL Tool & Die, NEI Handtools
and Mountain Molds.  Custom moulds range in price from $100 to
$200, generally more than $150 for a high-quality single cavity mould
without handles.  BACO and several of the custom suppliers also sell
“semi-custom” high-end moulds.  Paul Jones (Paul Jones Precision
Moulds), arguably the most well known of the custom suppliers, has
retired.

A better option for a new shooter may be a “cataloged” (off-the-shelf)
mould until you’re convinced that BPCR shooting is for you.  
Redding/SAECO, RCBS and Lyman make a line of good quality moulds in
a price range of $70 to $90.  Although the dimensions may vary
slightly from mould to mould they will generally be sufficient to get
started.  Some experienced shooters continue to use moulds from
these manufacturers with excellent results.  If an off-the-shelf mould
results in excellent accuracy, there’s little or no reason to change.  As
you will find in the following discussion, the off-the-shelf and semi-
custom moulds I’ve tried so far, which were recommended for a
Browning by others, did not work out as well as I would have liked.  
But there are many moulds/bullets available that can be used in a .40-
65 cartridge.  I’m just not willing to spend more time attempting to
find one and decided a custom mould is the solution for me.

If you’ve made the decision to purchase a custom mould, the
manufacturer will need as much information as possible.  Most mould
manufacturers list ordering requirements on their websites.  The ideal
information includes a drawing with precise dimensions, expected
bullet weight and alloy used.  But many new BPCR shooters only have
a general idea what they want, hence the earlier recommendation of
starting with an off-the-shelf mould.

In lieu of supplying a detailed drawing, the mould manufacturer can
make an educated recommendation but will need some dimensions of
the chamber and throat along with the groove and bore (land)
diameters.  Sending a chamber cast, impact impression or lead slug
made by “slugging” the bore will also help but may not be necessary if
precise measurements are provided from the cast or impression.

Prior to designing a custom mould, I tested four bullets that were
suggested by shooters for the Browning .40-65.  All are bore-riding
designs, aiding in nose-to-bore alignment, and is discussed in further
detail in the section titled, Nose Design.  They were hand seated in
the case with the case lip slightly flared (belled), making bullet
insertion easier.  The flair was not removed; helping to ensure the
rear of the bullet is centered in the chamber.  Following are the
results.

Shooting Test Results
Figure 1: (L to R), BACO JIM409400M4 “Money Bullet”, Lyman Snover
410663, Paul Jones 40001 Creedmoor, SAECO 740

As displayed in Figure 1, the following bullets were tested: BACO’s
JIM409400M4 “Money Bullet”, Lyman Snover 410663, Paul Jones 40001
Creedmoor and SAECO 740.  16:1 alloy was used for the BACO Money
Bullet and Lyman Snover, 25:1 with the Paul Jones Creedmoor and
SAECO 740.  The cartridge overall length (COAL) was determined with
the bullets seated to contact the leade.  Once the COAL was
determined, each bullet was loaded with a range of powder amounts
in one grain increments starting at approximately zero compression up
to 0.250” of compression depending on the bullet design.  Swiss 1.5Fg,
0.060” over-powder wad, White Lightning lube and Remington 2-1/2
(large pistol) and Winchester WLP (large pistol) primers were used.

Since a blow tube was used, with the exception of the SAECO 740, 10
cartridges plus 2 for fouling the bore were loaded for each powder
increment and fired at 200 yd. at separate poster board targets using
bench mounted cross sticks.  The average velocity, extreme velocity
spread and standard deviation was recorded for each shot.  
Subsequently, each bullet hole was closed and taped from the back of
the targets in order to inspect for signs of bullet tipping.  With vertical
spread being the main selection criteria, the best load was selected
for each bullet.  See Figures 2 thru 5.  Note that the vertical spread of
all were approximately 1MOA (2”) or better at 200 yds.
Figure 2
Figure3
Figure 4
Figure 5
Next, after 2 shots to foul the bore, 10 cartridges of the selected
loads were fired at 500 meter poster boards with ram size targets.  
See the results below.  During all testing, the bore was cleaned after
each 12-shot string.  Needless to say, testing required many hours of
loading and shooting.  A total of 600 cartridges were fired during
seven sessions at the range.  Including target evaluations and
documenting the results, approximately 70 hours was required to
complete the exercise in addition to 35 lbs. of alloy, over 5 lbs. of
powder, 600 primers and wads.

500 Meter Results

SAECO 740:
The results were poor with only 2 out of 10 bullets hitting the target.  
I attributed the poor showing to a combination of the short length and
lighter weight coupled with the marginal aerodynamic nose design,
believing the bullet became unstable as the velocity dropped due to
the high drag nose.  Also, the mould was slightly out of round.  The
driving band (body band and base band) diameters varied by 0.003” as
the bullet was rotated.  Or it may just be that the bullet is too short
for the Browning 16:1 twist rate.  Regardless, I’m not planning on
spending additional time and effort to figure it out.

Lyman Snover 410663:
The Lyman Snover loads were a little better with 5 out of 10 bullets
hitting the target.  The relatively poor results were most likely due to
inadequate lube capacity for the warm (95 degrees) shooting
conditions.  No muzzle lube star was evident afterwards.  The bullet
has a good reputation when used in the Browning, so I may retest the
bullet when wiping between shoots.  The Lyman tends to shoot well if
bore fouling is controlled by favorable shooting conditions (mild
temperatures and relatively high humidity) or wiping between shoots.

Paul Jones 40001 Creedmoor:
The results were good with all shoots hitting the target within a 12”
vertical spread.  Although the nose shape is very similar to the SAECO
740, it holds up better than the SAECO at longer distance due, in my
estimation, to the longer length and additional weight.  Also, it
carries plenty of lube for blow tubing in the hot and dry central Texas
summer conditions.  By the way, since Paul Jones has retired, if you’
re interested in trying his 40001 Creedmoor bullet design, Steve
Brooks (Brooks TRU-BORE Bullet Moulds), the well-known custom
mould manufacturer, offers a mould for the identical bullet.

BACO JIM409400M4 Money Bullet:
The BACO Money Bullet results were excellent with all shoots hitting
within a 10” vertical spread.  I really like the aerodynamic nose
design resulting in increased velocity and flatter shooting
characteristics.  The BACO design has the 1st three body bands
(includes the nose band) reduced with the remaining four bands at
0.409” (includes the base band).  Therefore, in order for the bullet to
contact the leade for alignment, the bullet seating depth is only
0.200”.  And a minimum of 69grs of powder is required to fill the case
with a 0.060” wad, resulting in a velocity of 1345 fps.  Although it
performed admirably, it’s my belief that with all driving bands the
same (0.409” to 0.410”) diameter, and with deeper lube grooves, the
bullet could be accurately loaded with less powder and fewer exposed
lube grooves and “stand up” better in the central Texas summer
heat.  Although the muzzle lube star was thin, the bullet held
sufficient lube during the tests, but the worse testing condition was a
very humid 95 degrees.  Based on the lube capacity I would not be
surprised to find that it “runs out of lube” as the temperature
approaches 100 degrees and the humidity drops to 30% or so.

Design Software
The aerodynamic benefits of various nose designs and the overall
design of a cast bullet is a subject on which I’m certainly not an
expert.  What little I do know is likely just enough to get me into
trouble.  Therefore I must rely heavily on the knowledge and
experience of others.  I will suggest that if you are considering a
custom mould made to your specifications, one of the quickest ways
to come up to speed on the various aspects of bullet design and
develop a basic understanding of the pros and cons of a variety of
shapes and dimensions is to purchase a cast-bullet design software
program.

There are numerous programs available that will provide exterior
ballistic data on the flight of a bullet once the bullet characteristics
are defined.  Many are free or can be downloaded for a nominal fee.  
But finding an affordable good bullet design program is another story.  
Researching what is available results in either expensive computer
intensive programs for military projectile design or very basic limited
programs offered by bullet suppliers or bullet equipment
manufacturers.  The only affordable, comprehensive cast-bullet design
software programs that I’m aware of are sold by TMT Enterprises
(http://www.tmtpages.com/).  Three programs are available: Basic,
Advance and Professional, and an Ultimate Companion Module.  Once
the bullet design is completed the software provides a bullet
specification file (see Figure 6) ready to send to a custom mould
manufacturer.  TMT Enterprises’ website will give you a good
overview of the program capabilities.  Considering the cost of moulds,
reloading supplies and time spent finding an accurate bullet, the
programs are relatively inexpensive.
Note – Keep in mind, to successfully design a bullet that closely fits a
chamber and bore, a chamber cast or impact impression and bore slug
will be required to determine the chamber, throat and bore
dimensions of your firearm.
Figure 6: Typical .40 Caliber Money Bullet Specification
Figure 7 is the results of using the Ultimate Companion Module to
overlay the images of the case and bullet over the chamber.  Since
Browning designed the throat of the .40-65 BPCR with a freebore
diameter 0.002” larger than the groove diameter, TMT’s software
identifies the transition from freebore diameter to grove diameter as
the freebore leade.  Also note the throat includes the freebore,
freebore leade and leade, and the chamber transition step is included
in the freebore length.
Figure 7: Browning .40-65 Chamber with Case & Money Bullet
Bullet Design Considerations
If you decide to have a custom mould made it’s definitely worth
spending some time researching and becoming familiar with the
features and dimensions of a bullet besides the diameter, weight and
length.  The following are discussed in more details below: bullet
length, driving band diameters and contact lengths, lube quantity and
contact length, location of the lube grooves, nose design and alloy
mix.  Other design considerations include: tangent and secant nose
shapes, ogive radius, meplate diameter, center of pressure (C.P.) and
center of gravity (C.G.).

Bullet Length
A well-known bullet designer and shooter determined that the
preferred bullet length in the Browning is 1.375” to 1.400”.  One
longer would potentially become unstable in the 16-twist bore.  The
four bullets displayed in Figure 1 have a length of 1.400” or less as
noted below.  The SAECO #740 is the shortest of the four and resulted
in the worse accuracy in the 500 meter tests detailed further on in
this article.  Since others have reported success with the bullet in 16-
twist barrels the length may not be an issue.  There could have been
other reasons for the SAECO 740 poor showing.  Refer to additional
comments on the bullet under the section titled, Shooting Test Results.

Bullet Lengths:
BACO JIM409400M4:                1.400”
Lyman Snover:                            1.380”
Paul Jones Creedmoor:                1.375”
SAECO 740:                               1.320”

Driving Band Diameter
A common reloading technique to increase accuracy is selecting a
bullet with driving band diameters that can be used in un-resized fire-
formed cases which fit the chamber dimensions as close as possible.  
But this is not feasible in the Browning due to the generous chamber
neck diameter averaging 0.436”.  Under firing conditions the case
neck outside diameter (OD) will expand to match the chamber neck
inside diameter (ID) and then shrink, generally 0.001” or so, allowing
for extraction.  The result is an average fire-formed case OD of
0.435”.  Assuming the case wall is 0.011” thick (0.022” inclusive) the
diameter of the ideal bullet driving bands would be 0.413” for slip
fitting to 0.414” with 0.001” of tension.  But a bullet with either
dimension is not a good idea because the Browning freebore and
groove diameters average 0.411” and 0.409” respectively.

Besides the fact that the body bands will not fit into the freebore or
throat, firing a bullet 0.004” to 0.005” over groove diameter is risking
accuracy problems.  The chamber-to-throat transition step and bore
will squeeze the bullet to a smaller diameter, resulting in body band
and base band fining (an irregular base) which can have a negative
effect on accuracy.  Additionally, if a bullet with driving band
diameters larger than 0.411” is used, the bullet must be seated
deeper in the case since it would be too large to slide into the
freebore, resulting in less powder capacity (limited velocity) and,
depending on the nose design, loss of nose alignment and support from
the freebore, leade or bore.  Therefore, a bullet with driving band
diameters of 0.409” to 0.410” is the solution, which means resizing
the fire-formed case neck to a smaller diameter.

Driving Bands Contact Length
To hold sufficient lube when blow tubing BPCR bullets typically have
several, relatively long and deep, grease (lube) grooves separated by
body bands.  Therefore, while keeping in mind the required bullet
length, weight, nose design and total lube contact length, the bullet
designer has to make a trade off of lube groove lengths versus the
lengths of the driving bands (body bands and base band).  Another
consideration is lead fouling tends to be directly proportional to the
length of the driving bands.  The longer the bands the more “bearing
surface” contacts the bore, increasing the possibility of bore leading.  
Realistically, 0.025” is likely the lower limit of a body band length.  
Many common bullet designs feature body band lengths of 0.050” to
0.060” with a few approaching 0.100”.

The base band length is another consideration.  Since gas-check bullets
are not allowed in sanctioned NRA silhouette matches, BPCR bullets
must have a base band designed to handle the high pressures of
expanding powder gases and prevent or minimize gas blow-by while
retaining its shape, which is critical to maximizing accuracy.  
Therefore, the base band is typically longer than the body bands,
significantly more so in some designs.  In lieu of having no analytical
data to support a specific length or range of lengths, I use the base
band design of several successful bullets, which have lengths ranging
from 0.075” to 0.100”.

Lube Quantity & Contact Length
When wiping between shots, lube volume is less of a concern and the
lube grooves can be relatively shallow.  In fact some shooters that
wipe between shots have reported success with bullets without lube
grooves.  The bullets were cast or swaged with a rough surface and
dipped in lube.  But when using a blow tube, not only must the bullet
carry sufficient lubricant to coat the bore to the muzzle to eliminate
leading, the lube is also essential in helping to keep the powder fouling
soft from shot-to-shot; especially in hot and dry condition.  Two
factors are important when designing lube grooves: volume and
contact length.  Adding up the length of the lube grooves determines
the lube contact length.  A well-known bullet designer and shooter
found through rigorous testing that 0.250” of lube contact length is
the minimum necessary for blow tubing.  The length and depth of the
grooves determines the lube volume or carrying capacity.  Although
the lube contact length may be adequate, if the grooves are not deep
enough to carry sufficient volume the bullet may run out of lube prior
to reaching the muzzle.  A good method to determine if the bullet
holds enough lube is to check the muzzle for a lube star, lack of which
indicates insufficient capacity or possibly poor quality lube.  But the
presence of a lube star does not indicate adequate contact length.  
For example, if the lube grooves were deep but very short the lube
quantity may be sufficient but much of it would not be available to
lubricate the bore and would be thrown out of the grooves as the
bullet exits the muzzle, creating a lube star.

A good example of marginal, I consider it inadequate, contact length
and insufficient lube quantity when using a blow tube is the Lyman
Snover with a contact length of 0.200" and lube capacity of only 1
grain.  It's a nice looking bullet with an aerodynamic nose design, and
under the right conditions it can be very accurate, but when the
ambient temperature increases and the humidity drops the shallow
lube grooves can become a liability when blow tubing.

Listed below are the total lube contact lengths and lube capacities
(weight in grains) and volume (in cubic centimeters) of the four bullets
in Figure 1.
Paul Jones Creedmoor:                0.340”, 2.2gr, 0.15cc
BACO JIM409400M4:                0.250”, 1.5gr, 0.11cc
SAECO 740:                               0.300”, 1.4gr, 0.10cc
Lyman Snover:                            0.200”, 1.0gr, 0.07cc

Location of the Lube Grooves
Another design consideration concerning lube grooves is the location of
the grooves.  Note that one of the lube grooves in Figure 7 is located
directly under the chamber transition step, which is a good practice
when loading BPCR ammo.  As the relatively soft bullet obturates
(expands under pressure), unless prevented by lube, lead will fill the
transition step and may be smeared back along the driving bands or
remain in the chamber step as a lead ring.  Both can have a negative
effect on accuracy.  The ideal configuration places a lube groove
under the transition step when the bullet is seated at the preferred
seating depth.  Should you prefer that the bullet contact the leade to
aid alignment, then the dimensions from the contact point to the
transition step should be determined and used to define the location
of a lube groove, which is easier said than done even with accurate
chamber and throat dimensions.

Nose Design
As mentioned in the Design Software section, I don’t know enough
about the aerodynamic benefits of various nose designs to discuss the
subject intelligently other than noting that the Money Bullet nose
design is very aerodynamic, resulting in a bullet with a high ballistic
coefficient.  And based on bullet tipping tests it holds up better (more
stable) at longer distances than other nose designs I’ve tried in the
Browning.  My hats off to the late Dan Theodore for popularizing the
“Money Bullet” design.

Concerning bullet alignment, it should not come as a surprise to
anyone that it’s one of the most important factors affecting
accuracy.  One method to ensure nose alignment of a cast bullet with
a nose larger than the bore is to force the nose into hard contact with
the leade.  Another technique is to use a bullet with a bore-riding nose
design with a nose diameter that closely matches the bore diameter.

When starting BPCR shooting I choose to go with a bore-riding nose
design simply because the Paul Jones #40001 bullet could be seated
much further out of the case, resulting in additional powder capacity
and higher velocity.  At the time I did not appreciate the alignment
benefits of using a bore-riding design, which allows the full length of
the nose to slide into and ride (rest) on the bore.  But to utilize the
nose for alignment the diameter of a portion of the nose must
matched the bore (land) diameter as close as possible and still slide
into a fouled bore with minimum resistance.  When using a blow tube,
a nose diameter of 0.001” less than the bore (land) diameter is usually
sufficient to allow for fouling.  If the nose diameter is significantly
smaller than the bore, alignment will be compromised even with
adequate obturation (bullet expansion).  In that case it helps if the 1st
body band wider than the nose is forced into firm contact with the
leade.  When wiping between shots the nose diameter can approach
the bore diameter since there is little or no fouling to interfere with
the nose when chambering a round.

Alloy Mix
Having limited experience with various alloys I don’t intend to make a
recommendation on the preferred mix for a specific bullet design
other than to pass along what has worked for me.  BPCR shooters have
reported success with relatively soft 30:1 (lead:tin) alloys to the
harder 16:1, with some reporting that wheel weight alloys, typically
containing antimony, work well for them.  Having accumulated around
1000 lbs. of wheel weight alloys, I plan on experimenting with it in the
future.

Some shooters use a softer alloy to ensure a loose fitting bullet
expands (obturates) quickly when fired to completely fill and align the
bullet in the throat and bore.  My definition of a loose fitting bullet is
one that does not closely match the throat and bore dimensions.  
Others firmly believe that if a bullet with a diameter smaller than the
groove diameter is seated out to almost touch the lands and is fired in
a bore with an oversize freebore, it will obturate, filing the freebore
and self-align prior to being forced into the leade.  I disagree with
these approaches, firmly believing that a bullet out of alignment with
the bore will not be symmetrical after it obturates.  So what has
worked for me so far?

It’s pretty simple.  For bullets such as BACO’s JIM409400M4 Money
Bullet and Lyman Snover 410663 with aerodynamic streamline noses I
use 16:1 alloy to eliminate the possibility of nose slump or setback.  If
the alloy is too soft the nose may slump back along the axis of the
bullet, resulting in possible bore leading, especially in a dry bore since
the nose is not lubed.  Nose slumping will also decrease the ballistic
coefficient, resulting in lower velocities and possible instability,
especially at longer distances.  But keep in mind that when using a
harder alloy it’s more important that the bullet dimensions closely
match the throat and bore dimensions in case the harder alloy does
not adequately obturate.  18:1 or 20:1 alloy may work just as well
with these bullets but I have not sufficiently experimented with either.

For bullets with a significant amount of nose-to-bore contact I’ve
settled on 25:1.  Examples are the Paul Jones 40001 Creedmoor and
SAECO 740.  I tried 30:1, 25:1 and 20:1 alloys with the Paul Jones
mould and found no real benefit of one over the other.  I believe it’s
because the mould produces bullets with very uniform dimensions that
closely match the throat and bore of my rifle, and my loading
technique ensures chamber and bore alignment.

My Baseline Bullet Features & Dimensions

For Blow Tubing
When using a blow tube in central Texas summer conditions, the bullet
will have the following features and approximate dimensions: Length
of 1.400”, diameters of all driving bands (body bands and base band)
of 0.410”, a 0.800” long “Money Bullet” nose design with a diameter
of 0.399” (to allow for fouling).  The 5 lube grooves would be 0.060”
long and 0.030” deep with a total lube contact length of 0.300” and
hold a minimum of 1.75grs of lube capacity.  The bullet would have a
base band length of 0.100”, four 0.050” long body bands and weigh as
close to 400grs as possible depending on alloy composition.

For Wiping Between Shots
When wiping between shots, since lube capacity is less critical and
fouling should not be a factor, an appropriate bullet would have the
following features and dimensions: length of 1.400”, diameter of all
driving bands of 0.410”, a 0.800” long “Money Bullet” nose design
with a diameter of 0.400”.  The base band length would be 0.100”.  
To increase the weight the two rear body bands would have a length
of 0.075” and the five lube grooves would be 0.050” long and 0.025”
deep and hold a minimum of 1gr of lube capacity.  The two forward
body bands would have a length of 0.050”.  The bullet will weigh as
close to 410grs as possible depending on alloy composition.

=======================

After evaluation the four bullets pictured in figure 1 I decided to
switch from blow tubing to wiping between shots.  Not being satisfied
with the four bullets including BACO’s JIM409400M4 as discussed
earlier, I requested BACO make a mould to my Money Bullet design for
wiping between shots.  BACO decided to add it to their .40 caliber
bullet mould selection as JIM410410M3.

Figure 8 is the specification I sent BACO, which they later listed on
their website as JIM410410M3.  If you’re wondering why TMT’s
software was not used to create the specification, it’s because I
decided on two different body band lengths to allow positioning one of
the lube grooves under the chamber transition step when loaded.  I
don’t know if the current version of TMT’s software will handle
different body band lengths but the version I have will not.  
Figure 8: Bullet Specification Submitted to BACO
Figure 9 is a photo of the actual JIM410410M3 bullet and cartridge
loaded with the bullet.  It may not be obvious but BACO made some
minor changes.  The bullet is close to the specification I sent with the
following changes: the 1st lube groove is slightly longer than the rest
and the body bands are slightly longer than I specified.  I expect that
BACO “played” with the design to obtain the requested weight.  It
weighs 408grs with 16:1 alloy and right at 411grs with 20:1 alloy,
which is what BACO used for the sample bullet shipped with the
mould.  The lube capacity is a little over 1.3grs.  After experimenting
with the bullet I prefer it over all the others I’ve tried so far.
Figure 9: JIM410410M3 Bullet & Loaded Cartridge