The Rifle Archive

by Fred Ray on August 17, 2006 · 0 comments

During a discussion about the bore diameter of the Jacob’s rifle (about which I will have more to say later), Bill Adams got carried away with his micrometer and checked a number of other rifles, Enfields and Lorenzes, as well. The results, as you can see below, were rather surprising. Keep in mind that quality control and mass production were not what they are today, and the idea of standard sized, interchangeable parts was a relatively new one. Then too, many rifles and cartridges were made by marginal contractors who produced shoddy goods, and even the best quality goods varied a lot.

To some extent the differences in bore size were compensated by the fact that the bullets were soft lead and had an expanding base (and thus conformed to the bore), but this could only cover so much difference in size between the bullet and bore. At some point accuracy went downrange, one reason why precision rifles came with their own bullet mold. If you had a .60 caliber rifle and an undersized bullet, you essentially had a smoothbore or worse. Thus the importance, as I mentioned previously, of sharpshooters using the British-made Pritchett bullets, which were much more consistent than most, England being at the time the hub of the Industrial Revolution.

Thus, it’s pretty obvious that some rifles were better shooters than others, and I don’t doubt that there was a bit of swapping around to match the best shots with the best weapons, who then got the best ammunition. As Bill points out, however, a war was on and both sides simply had a lot of arms and ammunition dumped on them unsorted. The ordnance officers for the most part had little real knowledge of the fine points of weaponry and little time to learn. This being the case, it’s not surprising that most of these weapons did not perform up to their theoretical specifications, and firing ranges tended to be closer than the weapons specs might suggest.

Historians often stress looking at paper archives, finding patterns and drawing conclusions from civilization’s mundane records such as state and municipal reports; census records, birth, death, court and probate records; and the like. Yet these old guns form an archive of their own, one seldom consulted by historians, most of whom know little about the subject. There has been intense debate, for instance, about how the new Minie rifles affected tactics and how far (if any) the engagement ranges differed from the days of Napoleon. Most pundits have made their arguments based on the theoretical ranges of the weapons as demonstrated in testing, or lately (as with Brent Nosworthy and Paddy Griffith) by searching the records for estimates of the actual engagement ranges. Yet one has to understand what these weapons were actually capable of in practice to know why the men who used them did what they did. Weapons drive tactics, and tactics drive strategy.

I’ve included Bill’s comments from two emails below in the extended section. They are worth reading.

While miking the Jacob’s bores, I did a random check of P53’s and P56’s that were nearby – rather interesting:

Type I – .584
Type II – .586, .586, .592
Type III – .578, .582, .590, .576, .579, .579, .586
P56 – .584, .578
(I didn’t check the gauge markings on the barrels, I was just plugging a vernier into the muzzles. Some of the pieces may have been 24 bores.)

All of the above arms have good bores without noticeable muzzle wear. It seems that the earlier pieces had larger bores on average; therefore a larger diameter .568 bullet with paper patch would likely have performed well. The Type III arms have smaller bores on average – excepting the two at .590 and .586. That isn’t an indication of defective arms, it’s simply an indication of lack of quality control. None of the pieces checked were machine made arms. Varying bore sizes are also common among US produced rifle muskets. The US contractors received less money for a 2nd or 3rd class arm that might have had a bore that was oversized.

Consider the following: the government (US or CS) accepts good quality arms with oversized bores — the US accepts them as 2nd class and pays less, the CS gets them as part of a batch shipment — the arms are not issued by bore size, so one soldier might have a 1st class .580 rifle musket while the guy next to him has a 2nd class piece at .584, or a piece that was rejected by the government (typical of Savage arms) and acquired by the soldier’s state and that rifle is in .591 calibre. The ammunition issued comes from a variety of contractors and a wide variety of diameters and powder qualities and granulations. Even if the men had the chance to sight in their rifles, after several days in combat, their cartridge boxes would probably have mixed rounds from different makers, with different weight bullets. No wonder that there were so many misses. Privates Smith’s .578 rifle with .575 bullets might shoot great, while Private Herkimer’s .594 rifle with .550 bullets might be less accurate than a smoothbore because the bullets came out of the muzzle flipping end over end.

One of the things that shocked me when I first read the analysis of ammunition recovered from the Modern Greece was the wide variances in bullet weights and diameters. The only way that a Confederate soldier or sharpshooter could be assured of consistent accuracy was if he got machine swaged ammo from the same manufacturer. The Richmond ammo and Macon Enfield ammo may have been of outstanding and consistent quality, but some of the ammo coming from small labs was definitely inferior. The federal contractors also supplied a lot of trash with poorly cast bullets and poor quality powder.


As a matter of fact, after noticing the wide range of bore sizes, I decided that it would be a good idea to check a larger grouping using more scientific methods than leaning over a gun rack with a digital readout caliper. I was somewhat amazed. I didn’t expect the bores to vary so much. I did a check of Lorenz bore sizes several years ago and discovered that they varied greatly. Being an Enfield afficiando, I assumed that even the low end Enfields had bores that were somewhat close to standard sizes. I should have known better! I miked a number of US and CS .58 arms and found that some were .60 cal.

Enfields arrived in both 24 (.58) and 25 (.577) bore. I have never seen any records to indicate that the arms were issued by calibre or that any effort was made to get the correct ammo for them. A 25 bore on the tight end of tolerance would be considerably smaller than a 24 bore on the wide end of tolerance. Several of us test fired Spanish “Enfields,” the Modelo 1857 infantry rifles & rifle muskets. The arms were rifled with four grooves and shot well with the correct ammo — the problem was that no two were the same bore size and bullets had to be specially sized for each weapon. The bore sizes varied from .571 to .595.

Imagine the soldiers with Model 1854 Lorenz arms in 13.9mm, which is .556 calibre. They were often issued .54 US style ammo, which had a .535 projectile. While 13.9mm was the standard Lorenz bore size, the various contractors supplied them in calibres ranging from .556 to .59. I think that the US Ordnance Dept made an effort to issue the same calibre guns in a regiment, but their efforts were likely thwarted between the port of entry and the final point of issue. There were probably many units that had “.54” Austrians mixed with .556, .57, .58 and even .59 cal arms. They likely all got the same .535 US style ammo.

The Confederates received standard 13.9mm Austrian arms until the Federals defaulted/canceled their contracts and the .58 arms destined for the US wound up going to the CS.

Logistical nightmares in the middle of a war…

Mike Vice quoted the old military historian’s maxim to me last week: “Amateurs study battles; professionals study logistics.”

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