Accuracy Test Part II
Sharps Model 1851 "Slant-Breech" Carbine
feature By: William P. Mapoles Photos by John Harriman | November, 19
In Black Powder Cartridge News (Fall 2019) No. 107 we examined the accuracy and shooting characteristics of the Sharps Model 1852 carbine, and now we will test the accuracy of the earlier and completely different Model 1851. I have never seen a thorough, modern accuracy test of the Model 1851, so I found a good ’51 to do some “experimental archaeology.” The question is, “How good did they really shoot?”
The two regiments of United States Dragoons were the elite mounted troops on the frontier from 1833-1861, and they served from the Pacific Northwest to Mexico, and East to Florida. The U.S. Cavalry wasn’t formed until 1855, and the different types of mounted regiments coexisted until the first months of the Civil War, when the Dragoons were renamed “cavalry.” In the early 1850s, the Dragoons received some Model 1851 Sharps carbines for field testing, and they liked them so much that they immediately started begging for more. Here are excerpts from one such request passed through official military channels in April 1854:
“After six month’s careful trial in the field and in garrison, I am satisfied that Sharp’s Carbine is far superior for mounted service, taking also into consideration the liability to fight on foot, to any firearm I have ever seen. It is fired more rapidly than Hall’s carbine [.54 cal breechloading smoothbore] or the service Rifle [.54 cal muzzleloading rifle], with equal accuracy below two hundred yards and rapidly increasing superiority above that distance…I make no comparison with the Musketoon [.69 cal muzzleloading smoothbore], as it is inferior to the rifle or Halls carbine…The company would be doubly efficient with the Sharps Carbine than with the present arm[s]. Signed: Richard S. Ewell – Captain 1st Dragoons.1
At the time, Captain Ewell was stationed in New Mexico Territory, which included present-day Arizona, and he had several postings there up until the Civil War. Interestingly, he later went on to become a Confederate Corps Commander under General Robert E. Lee.
Christian Sharps knew that military sales to the Dragoons would be key to the company’s survival, and these initial purchases by the Army and Navy boosted sales significantly. The Sharps Company also realized the value of such testimonials, especially from people on the frontier, so they started publishing them as advertising to increase sales even more. You can say it was the Model 1851 that really kicked-off the company’s rise to fame.
Captain Ewell’s anecdotal evidence on the accuracy of the Sharps carbine is some of the best information we have, because the official government tests of the ’51 were not very thorough with respect to accuracy. That the Sharps carbine would supposedly shoot “with equal accuracy” as the muzzleloading service rifle (.54 Model 1841 “Mississippi”) is interesting, but let’s see if our shooting test bears that out.
The Test Gun – A Model 1851
This .52 military carbine is from the first year of production and is serial number 369. In that era, caliber was specified either by the gauge (32), or by the land-to-land measurement (.526 inch). A total of 1,837 carbines, and about 200 sporting rifles were produced from 1852 to 1855. In addition, the production overlapped with other models, like the Model 1852.2 The barrel is 21.5 inches long, and the sight radius is 17.5-inches. It has the small, early breechblock with a platinum ring inletted into the face, which was designed to reduce gas cutting on the face of the block from escaping combustion gasses. Platinum was used because it dissipated heat quickly and withstood higher gas pressure.
Sharps breechblocks became larger and larger over time, culminating with the “perfected” New Model 1859, that featured the patented Conant and Lawrence gas-seal cavity and plate. In theory, the Conant and Lawrence breechblock plate on the New Model 1859 is pulled forward into tighter contact with the chamber sleeve when fired. In contrast, the block on the Model 1851 is pushed to the rear, away from the chamber sleeve when fired. This results in more gas leakage at the breech. So, is this dangerous? No more so than shooting a revolver, providing the Sharps barrel is in fine to excellent condition, the receiver is within factory specifications, and the gun has been thoroughly examined by a competent gunsmith. I never felt any gas leakage on my face or arms while firing the ’51, and slow-motion video photography showed about the same amount of smoke coming out of the nipple as from the breechblock. I used a feeler-gauge shim to measure the gap between the face of the block and the chamber sleeve, and it came out to about .0015 inch. In the previous test, the Model 1852 gap was less than .001 inch, at about .0005 inch. This tiny extra amount of gap in the ’51 actually allowed me to fire a few more shots in succession before the block started to get sticky from fouling. Interestingly, I measured seven percussion revolvers of the era and the cylinder-to-barrel gaps were many, many times larger than the Sharps, running from .009 inch to .015 inch, with an average of .011 inch.
The nipple appears to be an original early Sharps, and it has a large orifice, which is only slightly smaller at the top end. Upon firing, I noticed that the funnel shape of the flash channel from the face of the breechblock through to the top of the nipple seems to concentrate the escape of gas from the nipple. To remove the nipple, a special Sharps spanner wrench is required.
I had the nipple measured by an engineer (Rick Dunbar) with an optical comparator, and he discovered that this early nipple had Whitworth threads of .268 X 28. I have never seen this in print before for early Sharps products, likely because nobody ever checked it. Sir Joseph Whitworth proposed this thread in 1841, and it was the world’s first screw thread standard. At some point later, the threads were changed by Sharps, and the outside body was changed to fit a more conventional nipple wrench. We determined that a modern .265 X 28 nipple would possibly work as a replacement; however, please note that this is .015 inch larger than a standard .250 X 28 nipple. Always measure first to be sure of a tight fit.
If you have never owned a percussion Sharps, the barrel throat, or bullet seat as it was called, can be hard to envision, so here is a description from an old Sharps catalog:
“[The bullet] seat is bored slightly conical, the exact shape and diameter of the [bullet], so that the bullet, when properly forced to its seat, has its axis exactly [centered] with that of the bore.”
My ’51 throat has a slightly different angle than the Model 1852, which was tested previously. As a result, the paper cartridges would not seat quite as far into the throat, as with the Model 1852.
The 1851 barrel has six grooves of approximately equal width, but the grooves have a hump in the bottom. In other words, the grooves are convex in shape. I haven’t noted this on any other Sharps model. The twist is uniform. Actual measurements of the Model 1851 bore are follows: .527 inch land-to-land, and .543 inch groove-to-groove (edges), giving a groove depth of about .008 inch. In contrast, the groove depth on the Model 1852 was a very deep .012 inch. The barrel and receiver had some active rust on the inside, and it benefited greatly from a good cleaning and shooting.
The sight is of the first type “squirrel’s ear” design, which is actually two sights in one. There is a fixed battle-sight set for about 125 yards, and then there is the squirrel’s ear with a separate sighting notch that is adjustable for higher elevation. The front sight is a rounded brass blade. I used the battle sight at 100 yards for the test.
The Robbins & Lawrence factory made these carbines for Sharps, and the test gun has the initials of Richard S. Lawrence on the left side of the barrel near the breech, which is very rare. My guess is that he might have randomly spot-checked guns to ensure quality. Additional pictures of this gun can be seen on page 104 of the excellent new book, Sharps Firearms Vol. 1 – The Percussion Era – 1848-1865, by Roy Marcot, et al.3 Everyone who is curious about percussion Sharps rifles should have this book.
The Right Bullet and Lubricant
To be consistent with the previous test of the Model 1852, I used the same Sharps mold.4 The bullet is a close copy of eight excellent museum specimens found at a pre-Civil War Dragoon fort that had several “slant-breech” models. The average weight of my bullet was 455 grains (pure lead), with the top band measuring .531 inch, the middle band measuring .539 inch, the bottom band at .548 inch, and the ringtail about .460 inch. My bullets were not weighed for the test, but they were visually inspected for uniformity after casting. I used un-weighed bullets because Sharps bullets were not typically weighed during this era, and I was looking for historic accuracy results, not modern pinpoint accuracy. Early Sharps literature recommended tallow for the bullet lube, but it was too hot outside for tallow during this test, so I used a mixture of tallow and beeswax that stayed semi-solid in the 90-degree heat.
Finding the Right Powder Charge
The use of hot, fine powder would give higher pressure on firing, and would probably increase the gas cutting (micro-striations) on the chamber sleeve and block of the 1851, which was first discovered in an 1850 military test.5 This is probably why Christian Sharps recommended slower, coarser powders for his guns. Therefore, I selected GOEX FFg and Swiss 1½ Fg for my shooting, with the same test protocol as in the previous issue of this magazine. In addition, Peter Schiffers has determined that Swiss 1½ Fg is the closest modern powder to the original government “musket powder.” He did this by chronographing powder removed from a variety of original cartridges made during this era.6 Paper cartridges manufactured in U.S. Arsenals used this powder, and Sharps likely used a similar grade. For this test, all powder was measured from a very accurate, original flask, in order to simulate historic un-weighed powder charges. Averages from the flask were verified with a scale.
The Sharps Company recommended 55-60 grains of powder in their early instruction sheet on making your own paper cartridges. This made a longer cartridge than the chamber would hold. The cartridges had a paper tail that was cut off, along with some of the powder, by the knife edge on the front of the block when it was raised. The paper tail and excess powder were then shaken off onto the ground. If you firmly press the cartridge into the throat to the same depth each time, you get a surprisingly similar charge in the chamber. Imagine using a muzzleloading-powder measure where you completely fill it and mound it up on top, and then you strike the powder off level with the top of the measure (called “stricken measure”). Similarly, the knife edge on the block does the same thing to the paper-cartridge tube. It cuts the tube in about the same place each time if seated fully in the throat. As with muzzleloaders, there might be a slight difference in the powder charge from one shot to the next, but it has been proven many times that exact bullet weight is more important than exact powder weight for accurate shooting with black powder. You can be off a grain or two with the powder and still get decent groups. To get a more perfect seat in the throat as fouling builds up, it helps if you wiggle the cartridge around a bit to push the powder residue out of the way.
Since my 60-grain paper-tail cartridges would not go as deep into the throat as they did with the Model 1852, more of the cartridge was left sticking out of the back. Therefore, more of the powder was cut off by the block, with about 50 grains remaining in the chamber, and 10 grains ending up on the ground. With my flatbase, paper tubes, which fit the chamber length exactly without any paper/powder having to be cut off, only an average of 48 grains of GOEX and 47 grains of Swiss would fit. I even had to use a 36-inch drop tube to get this amount into the flatbase paper tubes. By comparison, I was able to get 53 grains into the paper tubes for the Model 1852. Years later, the New Model 1859 chamber was lengthened to hold a full 60 grains, with the volume enhanced by using a flatbase bullet (e.g., no ringtail).
There is, of course, another way of loading a percussion Sharps when you have no paper cartridges. You can push the naked slug into the throat with a stick, and then add loose powder behind it in the chamber.7 Caution! With this method, you can get much more powder into the chamber than with a paper cartridge, thereby greatly increasing the pressure and stress on the receiver. Don’t be tempted to overload an original Sharps, because the iron (not modern steel) receivers are not considered very strong. Therefore, I recommend the safety of lighter charges, and the better burning characteristics that you get with paper cartridges in this small action.
The Cartridge Tube
As we know, hot burning paper can be left in the chamber after firing; however, with this gun it happened only once during the course of firing about 70 shots. Back pressure usually sucks the paper out of the muzzle. Nevertheless, it is a good safety practice to look down the bore after each shot.
I used Charlie Hahn’s flatbase paper tubes for the record strings after experimenting with paper-tail cartridges to establish the proper length and powder charges. None were nitrated/impregnated. The Hahn tubes were closed on the powder end with thin tissue paper and Elmer’s School Glue.8
Precision construction of the paper cartridges is critical for accurate shooting, and Christian Sharps was well aware of this. He preferred using girls and women in the factory to make the cartridges, because they had better manual dexterity than men. Child labor laws were not an issue. Indeed, it is really pitiful to watch a ham-handed, fat-fingered male trying to make a paper cartridge.
Chronograph Results
About 10 shots could be fired in succession before the block started to bind from fouling. Only twice did I have to resort to the old trick recommended by Sharps of spitting on the top of the breechblock to free it up. I did not want to take a chance of bending the lever of this rare old gun, so I cleaned the barrel with a wet patch, followed by a dry one, after every 6 shots. This was also to simulate historic conditions in the field where the barrel might not be wiped out until after a hunt or a skirmish. A coating of axle grease was used on the block, instead of Sperm whale oil as recommended by Sharps, because the grease stays put longer and better reduces the gritty friction from the fouling.
GOEX FFg chronograph results for a 10-shot string using an average of 48 grains from the powder flask were as follows: Average Velocity – 753 feet per second (fps); Extreme Velocity Spread – 26 fps; Average Deviation – 6.5 fps. Throughout all tests, CCI “extra strength” musket caps were used. Note that extreme velocity spread is the difference between the fastest bullet in the 10-shot string, and the slowest bullet in the string. Average deviation is the average difference in velocity between each shot, plus or minus from the average velocity. (ex: 6.5 fps average difference in velocity from one shot to the next).
SWISS 1½ Fg chronograph results for a 10-shot string using an average of 47 grains from the powder flask were as follows: Average Velocity – 829 fps; Extreme Velocity Spread – 24; Average Deviation – 6.9 fps.
These are very good numbers for accurate shooting, especially considering the minimal cleaning of the bore, and not weighing the powder or ball. Interestingly, the velocity numbers are roughly the same as in the previous test with the Model 1852, even though 5-6 grains less powder were used (different chamber and bore dimensions). Extreme spread and average deviation were also very similar.
Accuracy Test Results
All groups were fired from the benchrest position, using front and rear bags, at a distance of 100 yards. Wind speed averaged 0-8 miles per hour for all shooting sessions. The bore was cleaned between the five-shot groups. All groups were measured center-to-center of the two widest shots.
• GOEX FFg at 753 fps
Four, five-shot groups were fired: Smallest Group – 3.125 inches; Largest Group – 4 inches; Average Group Size – 3.5 inches. One ten-shot group was fired and it was 5.63 inches; however, eight shots were contained in 2.37 inches, with two flyers enlarging the group.
• SWISS 1 ½ Fg at 829 fps
Four, five-shot groups were fired: Smallest Group – 1.69 inches; Largest Group – 3.63; Average Group Size – 2.63 inches. One 10-shot group was fired and it was 2.25 inches. Lighting conditions were perfect, my eyes were functioning perfectly, and there was no wind.
This Model 1851 clearly preferred the Swiss powder, and I definitely found the “sweet spot” for accuracy. I was gob-smacked by the Swiss group size, especially when I shot a 1.94-inch group, so I shot another group to rule out luck, and I got a 1.69-inch group! Next, I shot the 10-shot group that really blew my mind and confirmed the accuracy. I guess the ghost of Christian Sharps was there to help me!
Conclusion
This was the most accurate military carbine I have ever shot with open sights; modern or historic. I have experimented with many Civil War carbines, and not even the Maynard or the Smith carbines shoot this well with factory equivalent loads and original sights. I can definitely understand why the Dragoons were so desperate to get their hands on more of these, especially given the longer shooting distances “Out West.” Otherwise, the troopers were stuck with smoothbores or muzzleloading rifles. In the end, the Dragoons didn’t get a full complement of Sharps carbines until 1860-1861.
The bullets from this Sharps Model 1851 carbine are not very fast, nor do they have a super flat trajectory, but the killing power of this large, heavy slug is nothing to sneeze at. There were published testimonials of killing big game up to 450 yards away, and this was sensational news in the muzzleloading, round-ball era. In addition, penetration of the bullet was good, passing through-and-through wolves, deer, and even black bear. One Captain Henry Skillman became infamous for being a dead shot at 300 yards during Indian attacks, something he repeated on multiple occasions. I’ll leave you with a final quote about the impact of the Sharps 1851 on the frontier. It is from mountain man Bill Hamilton, then in California:
“Six of us traded our Hawkins rifles for Sharps rifles brought in by immigrants. [Very probably Model 1851 carbines.] These were the first Sharps we had seen, and we found them most effective weapons…We had a gunsmith re-sight them...and securing [sic] a lot of tape caps and ammunition. We practiced for several days. They were equal in accuracy to our old rifles and far superior in effectiveness.”
References:
1. Edward W. Marron, Jr., “Sharps Firearms Chronological Transcriptions, U.S. Army Ordnance Department 1848 – 1855,” Sharps Collector Association, 2016, page 126.
2. Frank Sellers, “Sharps Firearms,” Beinfeld Publishing, Inc., North Hollywood, CA, 1978, page 43-44.
3. Roy Marcot, Edward Marron, Jr., Ron Paxton, et al, “Sharps Firearms, Vol. 1, The Percussion Era, 1848-1865,” Northwood Heritage Press, Tucson, AZ, 2019, page 104.
4. Thanks to Pat Kaboskey for providing me with the mold for this, and the previous test. He also sells competition grade cast bullets of all shapes and sizes, and can be reached at cwbulletman@aol.com.
5. See endnote 1, page 56, Major Mordecai’s Test Report about striations and the DuPont powder used.
6. Peter Schiffers, “Civil War Carbines…Myth vs. Reality,” Mowbray Publishing, Woonsocket, RI, 2008, page X. He has tested and experimented with the primary US carbines of the Civil War.
7. David Thorn, a great gun historian, once experimented with this paperless loading technique, and his article can be found in “Sharps Collector Report”, Volume 23, Number 3, page 21.
8. Charlie Hahn’s paper tubes for your percussion Sharps can be obtained by calling (410) 627-4726 or by writing etb9601@gmail. com.