Some of the old black powder cartridges of yesteryear can be quite
well-suited for use in the Contender due to their straight cases, husky rims and
modest operating pressures. I have been fascinated for some time with the
concept of putting together a Contender in one of these old-timers, specifically
one in caliber .40, able to use commercially available jacketed pistol bullets
(that are all the rage these days), and some of those lovely .40 caliber black
powder cartridge rifle cast bullet designs, like the Lyman 403169 and 403173
(that were all the rage in days gone by). Many concepts and candidates for this
project have come and gone; some very nearly came to fruition and others were
just fleeting fancy, but all carried the same basic attributes -- a straight
case about 2” long, a big rim, and a nominal .40 caliber bullet.
Regardless of the final case design chosen, barrel stock was going to be
needed for this project. T/C has established a website to sell off their “loss
leaders” (www.foxridgeoutfitters.com/netcont.html) at very friendly prices. A
blued 10” 10mm barrel was purchased as re-chambering fodder for this project.
Interestingly, it was found when the 10mm barrel arrived that it slugged out at
.404”, making it appropriate for one of the .403” bullet diameter .40 caliber
black powder rifle cartridges, loaded with slightly over-sized cast bullets.
Other 10mm T/C barrels undoubtedly will have a tighter groove diameter, probably
somewhere around .401”.
|
10"
T/C Contender re-chambered from 10mm to 40-50 Sharps Straight,
loaded with the Lyman #403169. |
|
The final decision to re-chamber to .40-50 Sharps Straight was made
based on the suitability of the bore dimensions, the ability to make cases from
.303 British (or .30-40 Krag) brass and the fact that dies are available from
Huntington’s (for either .403” or .408” bullet diameters). While visiting with
friend Cliff Labounty (of Labounty Precision Reboring), I mentioned that I was
looking for a .40-50 Sharps Straight reamer, and did he by any chance know
anybody that had one? He walked over to his tooling files, rummaged around for a
minute, pulled out a nice, clean, shiny reamer and said, “What? You mean like
this?”. After picking my jaw up off the floor, I had to ask what diameter bullet
it was for, and why on earth did he have a .40-50 Sharps Straight reamer just
lying around? It was indeed for the desired .403” diameter bullet and was left
over from a project he did for a customer about 10 years ago. This reamer had
cut exactly one chamber. Cliff offered to rent it to me for a nominal fee. I was
on Cloud 9 for the entire drive home.
First, I sat down and turned out a .40-50 Sharps Straight trim die from
7/8” round stock so as to simplify case forming operations. Next, I cut the new
chamber, which was straightforward. Case forming was next on the agenda; to
simplify this operation I took a 1/2” x 20 bolt, cut the head off and turned
half of the shank down to .396” and then cut a 10 degree taper down to about
.280” and polished it. This tapered expander plug threads into a standard RCBS
pistol flaring die body.
Instead of going through all of the gory details of what didn’t work,
let me just report the final case-forming protocol that worked very well indeed
(no cases were lost using this procedure). New .303 British cases were first run
over a .338” expander, followed by a .358” and then finally over the .396”
tapered expander plug. At this point, they were run into the trim die, trimmed
to 1.87” and de-burred. From here out, cases were loaded normally. Fire-form
loads were slightly “wasp-waisted” due to the difference in tapers between the
.303 British and .40-50 Sharps Straight cases (.30-40 Krag brass more closely
matches the taper of the .40-50 Sharps Straight and probably wouldn’t display
this minor wasp-waist). Also, there was a small “wrinkle” just aft of the case
mouth on the fire-form loads, where the original .303 shoulder was. This wrinkle
was “ironed out” by removing the de-capping stem from the sizer die and gently
running the loaded round into the sizer die just far enough to iron the wrinkle
flat (being very careful not to distort the bullet). An excellent fire-form load
is composed of the Lyman 403169 bullet (about 245 grains) over 32.5 grains of
H4895. This load is quite uniform shot-to-shot and approximately reproduces the
original black powder rifle ballistics from a Contender length barrel (1380
fps). Brass seems to be quite long-lived; no cases have been lost to date.
Once-fired .303 British brass can also be used to form .40-50 Sharps
Straight cases, but a small percentage (about 5%) will be lost due to the necks
tearing out during the neck expansion steps. In addition, most .303 British
chambers are cut quite generously, so once-fired brass is usually rather grossly
expanded just forward of the web. While this expansion can be sized back down to
form .40-50 Sharps Straight cases, it creates an over-worked and weakened case
in so doing -- and weakens it right where the strength is needed most. Factory
new .303 British brass is cheap enough that it just makes sense to go that route
to form these cases.
A little bit of history -- the .40-50 Sharps Straight was introduced in
1879, and was one of the last of the Sharps family of cartridges. The Sharps
Rifle Co. went under in 1881. It is the smallest of the Sharps line, and was
presumably designed as a moderate hunting and target cartridge, similar to its
curvaceous cousin, the .40-50 Sharps Bottleneck. Original ballistics for the
.40-50 Sharps Straight had a 265 grain lead bullet sailing forth at 1410 fps.
Obviously, black powder was the original propellant, but contrary to the name,
these cartridges were only charged with 40 to 45 grains of the smoky stuff. The
Sharps Rifle Co. was not alone in reaming these chambers, Winchester and
Remington also made single-shot rifles for this cartridge. But the writing was
indeed upon the wall -- repeating rifles, smokeless powder, higher velocity and
flatter trajectories left the .40-50 Sharps Straight in the dust of the Old West
and the history books, to die quietly with the last of the ravaged buffalo
herds.
Several of the design features of the .40-50 Sharps Straight case make
it very well suited for use in the Contender, however. It is a rimmed case,
simplifying extraction. It is essentially a straight case with only a modest
amount of back-thrust accentuating taper. The 1.88” case has an appropriate case
capacity and powder column length to be efficiently exploited in Contender
length barrels. And it’s a cute little bugger -- it looks kinda like a .45-70
that got left out in the sun and shriveled up and shrunk just a little bit. It
needed a good home, so I gave it the best one I can think of -- the
Thompson-Center Contender.
Due to back-thrust considerations, the .40-50 Sharps Straight must be
held to 40,000 psi peak pressure or less in the Contender. I have tried to keep
things in the 30,000-35,000 psi range in my loading for this cartridge (I
estimated these pressures by using the pressure data provided by the “Load From
a Disc” calculations. I completely ignored the suggested powder charges. Using
powders slightly slower than those identified as “ideal”, I worked up to the
velocity that correlated to the chosen pressure ceiling. Measuring case
expansion at this point provides a tangible method for approximating this
pressure with faster and slower powders. Remember, these are only estimated, not
measured, pressures.). If you want to hot-rod your Contender, J.D. has any
number of well thought-out wildcats that will make your heart go all a-flutter.
The aim in resurrecting a 120 year old cartridge was not to “push the envelope”
in terms of what could squeezed out of some helpless old geezer, but rather to
explore a comfortable “fit” between the old and the new. Kept within these
moderate pressure levels, the .40-50 Sharps Straight can still push a 245 grain
cast FP (Lyman 403169) at 1600 fps from a 10” barrel, 300 grainers at 1400+ fps,
and the 200 grain Hornady XTP at 1800 fps. “Load From a Disc” calculations
suggest that a 14” barrel picks up only 100 fps over these numbers. The .40-50
Sharps Straight is clearly very much at home in a 10” T/C.
Some of you might very well be asking at this point, “A 245 grain cast
bullet at 1600 fps? A 200 grain XTP at 1800 fps? Why not just shoot a .44 Magnum
Contender?”, and you would be raising a very good point indeed. For a given
bullet weight and shape, a .40 caliber bullet will have better sectional density
and aerodynamics, so trajectories will be somewhat flatter and impact velocities
will be a little bit higher. In addition, penetration should be deeper for .40
caliber cast bullets than for a similar weight and design .44 slug. Does this
mean that the .40-50 Sharps Straight is a more powerful, harder-hitting
cartridge than the .44 Magnum when both are fired from a Contender? Maybe, but I
doubt it. I prefer to think of it as the .40-50 Sharps Straight being in darned
fine company as a useful handgun hunting round. The .40-50 Sharps Straight has
an old-world charm, flavor and charisma that a modern, mass-produced generic
revolver round just can’t muster. Coupling that antique-stained, 19th-century
panache with solid hard-core hunting capability, and wrapping it up in a
case design ideally suited for the Contender was sufficient reason to build one.
Some will understand that, some won’t. So be it.
My Lyman 403169 mould drops bullets that run .407” in diameter.
Originally, I was sizing them .404” to match the groove diameter of this
particular barrel, but accuracy, while acceptable, was less than what I had
hoped for. Thinking that perhaps I was distorting the bullets by sizing them
down that far, I bought a “.406” sizer die (which actually sizes bullets .4055”)
and accuracy immediately improved. This led to an interesting observation: when
attempting to extract unfired, loaded rounds, a few of these cases would
display sticky extraction. Due to the mechanical advantage of the closing
Contender action, no resistance was felt upon closing, but things were
definitely sticky upon opening. This is a clear sign of a tight chamber, and
more specifically, very little neck clearance. Measurement of the loaded rounds
revealed that some were running as much as .4255” at the neck, while a chamber
cast revealed a chamber neck of only .426”. I like tight chambers just as much
as anybody, but when you’re dealing with less than .0005” clearance, then all it
takes is a little bit of powder fouling, bullet lube or a cartridge that is only
ever-so-slightly out of round and you’ve got problems with both excessive
pressures and difficult extraction. This problem could be solved by either
thinning case necks (by reaming or neck-turning) or by relieving the chamber
neck. Since the RCBS resizing die was actually doing very little actual sizing
of the case (i.e. a very good fit between chamber and die), there was a
concern that thinning the case necks might possibly lead to a situation where
the sizing die would not reduce case mouth diameter sufficiently to provide
adequate bullet pull. Therefore, it was decided to relieve the chamber neck to
.429”. This was accomplished with a .429” throating reamer. Please note that
this modification would not be needed for anyone shooting .403” (or smaller)
bullets, as the reamer dimensions are fine for that scenario. This modification
was made necessary by my shooting over-sized .4055” cast bullets in a .404”
barrel, which is incompatible with .403” diameter (or smaller) cast bullets.
|
403173 (left) and the
403169 (right) shown in both solid and HP form. |
|
My 403173 mould drops bullets that are significantly out of round. I
have hand-lapped the mould to try and “true it up” and that has helped, but it
still isn’t round (diameters range from .402” to .405” depending on where it’s
measured). In spite of this, these bullets actually shoot just fine.
In general, the best accuracy for both of these cast bullets seemed to
come in the 1350-1450 fps ballpark. Whether this is due to the alloy used (wheel
weights), the nature of this particular throat, or just part of the
“personality” of the .40-50 Sharps Straight cartridge, I don’t know, and frankly
I don’t care. As mentioned earlier, the motivation behind this project was to
reproduce the original BP ballistics in a hunting handgun, not red-line the
pressures in an effort to get every last shred of velocity possible before
something came unglued.
Based on my experience with the .444 Marlin Contender, I tried using
magnum primers to see how they would affect accuracy. In contrast to the larger
.444, the .40-50 Sharps Straight didn’t show any real preference for the hotter
spark, and in fact some of the most accurate loads were assembled using regular
primers. Perhaps this is due to the smaller case capacity of the .40-50 Sharps
Straight, or maybe it’s the lower operating pressures, but either way regular
primers seem to work just fine. I haven’t tried pistol primers yet, but there
may be some benefit from their use.
As far as powder selection goes, the faster powders (4227, 5744, etc.)
were generally disappointing. 4198 did turn in a few good loads, but overall the
best accuracy was consistently turned in by powders of more moderate burning
rate. If I had to choose a single powder for use in the .40-50 Sharps Straight
Contender, it would have to be IMR 3031 -- easy to light, moderate pressures and
excellent accuracy. H4895 would be a close second choice, and for the very same
reasons, and Acc. Arms 2520 was also quite good. Quite surprisingly, virtually
all of the loads tested using Re 7 turned in horrid accuracy. Ken Waters noted
similar behavior in his study of the .40-50 Sharps Bottleneck (published in
Handloader, #163, May/June 1993). I expected Re 7 to be very well suited for
a cartridge of this capacity and configuration, but for whatever reason, these
two just don’t play well together.
The RCBS die set does not provide adequate bullet pull to load 10mm
(.400”) jacketed pistol bullets in the .40-50 Sharps Straight, nor was it
intended to. Since this was originally a 10mm barrel, I wanted to at least see
if the 200 XTP could be shot with any kind of accuracy (in spite of the fact
that they were .004” undersized). Therefore, to load these bullets, I resorted
to “neck-sizing” the cases with a 10mm carbide sizing die, flaring with the 10mm
flaring die and then seating the bullet normally. This overworks the case neck
somewhat, but worked sufficiently well for assembling a few test loads. A load
of 38.0 grains of Acc. Arms 2015 BR, sparked with a Fed 215 primer gave right at
1600 fps with the Hornady 200 XTP. Accuracy was good, although point of impact
(not surprisingly) was considerably lower than with the heavier cast bullets.
This is a mild load and it should be possible to push this bullet another 200
fps faster (or so) and still stay within the back-thrust limitations of the
Contender. Nonetheless, a .40 caliber 200 grain XTP at 1600 fps should be deadly
on deer as it is.
One of my favorite ways to fire-form brass is to use fire-form loads
during my summer varmint hunting. There’s more than enough shooting to be done
and it gives me some preliminary familiarity with the new gun. Varminting with
the .40-50 Sharps Straight was an eye-opening experience. Trajectories were much
flatter than anticipated, especially for a long-forgotten old-timer. Even at a
leisurely 1100 fps, the 403169 was surprisingly destructive to rodent flesh, and
higher velocities only added more spectacle. The .40-50 Sharps Straight would be
just about perfect for hogs, or that late season doe-hunt, or....
Just for the record, the .40-50 Sharps Straight should make a fantastic
lever-gun round; a truly definitive north-woods black bear carbine. I would
expect the conversion to be quite straight-forward. If anybody does this, I’d be
very interested in hearing about your results.
The .40-50 Sharps Straight didn’t get much of a chance back in the 19th
century to show its stuff. The Sharps Rifle Company went under shortly after its
debut and the field of small arms cartridge design was evolving rapidly towards
higher pressures, smaller bores and a fashion statement involving belts. Now
that we’re waltzing our way into the new millennium, perhaps the .40-50 Sharps
Straight can prove its mettle in a different kind of single-shot, the
Thompson-Center Contender.
Loading data for the .40-50 Sharps Straight 10”
Contender |
(re-chambered from
10mm), with a .404” groove diameter. |
Cases formed from Frontier .303 British brass. |
WLR primers unless otherwise noted. |
|
Lyman 403169
(sized .4055” @ 245 Gr.) |
|
|
|
|
Powder |
Charge |
Velocity |
Comments |
|
|
|
|
IMR 4227 |
25.0 |
1272 |
Sticky cases,
vertical stringing |
AA 5744 |
25.0 |
1358 |
Mediocre, warm |
IMR 4198 |
27.0 |
1327 |
OK |
IMR 4198 |
30.0** |
1531 |
Poor |
Re 7 |
28.0 |
1199 |
Poor, large velocity
variations |
Re 7 |
31.0** |
1384 |
Poor |
AA 2015 |
30.0 |
1317 |
OK |
AA 2015 |
33.0** |
1424 |
Bad |
IMR 3031 |
33.0 |
1452 |
Very accurate |
H322 |
31.0* |
1308 |
|
H322 |
34.0** |
1447 |
Good |
AA 2230 |
31.0* |
1246 |
|
AA 2230 |
33.0** |
1420 |
Good |
H4895 |
32.5 |
1383 |
Very accurate, mild pressure, very |
|
|
|
consistent velocities (+/- 2 fps) |
AA 2520 |
34.0* |
1468 |
|
Varget |
36.0** |
1306 |
Decent |
|
|
|
|
* = CCI Large Rifle Magnum primer |
** = Fed 215 primer |
|
|
|
|
Lyman 403173
(298 grain FP when cast with WW) |
(all of these loads
used Fed 215s) |
|
|
|
|
Powder |
Charge |
Velocity |
Comments |
|
|
|
|
IMR 4227 |
25.0 |
1425 |
Poor |
AA 5744 |
25.0 |
1300 |
Very bad accuracy |
IMR 4198 |
29.0 |
1425 |
OK |
Re 7 |
30.0 |
1382 |
OK |
AA 2015 |
33.0 |
1470 |
Very accurate, best load |
H322 |
33.0 |
1449 |
OK |
AA 2520 |
34.0 |
about 1400 |
|
Varget |
35.0 |
1320 |
Very accurate |
H4895 |
37.0 |
1339 |
Accurate |
|
|
|
|