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Similar to hand-to-hand blades, I would expect bayonets to be sheathed in a non-combat situation, to avoid damaging/dulling the blade and hurting the people around.

However, it appears that (at least) Russian soldiers of the WW1/Civil War era kept their bayonets fixed to the rifle at all times, see, e.g., photos in the linked Wikipedia page (as well as many others).

While the overall length of the rifle was such that normally the bayonet was so high that it could not come into contact with anything outdoors and out of a forrest, still, why keep it fixed?

Doctrine, regulation, and technical necessity.

We observe that the Russians were the last to issue M1891 Mosin-Nagant rifles with a socket bayonet, when all other militaries had already switched to the more flexible sword-bayonet style.

There are a few marked differences between the two and resulting dispute in military doctrine:

The advantages of sword bayonets over spike bayonets are evident. Where a spike bayonet turns the rifle into a spear, a sword bayonet turns it into a glaive. Unlike spike bayonets, which can be used only for thrusting, sword bayonets can also be used for slashing, except for the épée bayonets. Twisting a sword bayonet in the wound was especially lethal. Before the advent of modern medicine after World War I, a soldier struck by a sword bayonet was very unlikely to survive.

Which makes one argument against the Russian practice obsolete: There was practically no edge to dull.

While the Finnish did use scabbards for this:

This was basically adopted into incrementalist doctrine from the 1881 infantry regulation. Soldiers were to be always ready, no longer in close formation, assumed to repel a cavalry attack – with their pikes/bayonets.

The Russian soldier with the bayonet on his rifle is a prime example of the reach argument in infantry tactics.

The doctrine regarding Russian rifles

Starting from the earlier M1856:

However, bearing in mind that the Russian military were not overly concerned with individual marksmanship and relied instead on massed ‘human wave’ bayonet charges, this potential for inaccuracy did not particularly concern the Tsar’s commanders. (Harriman)

In 1907, a carbine version was issued. Based on the designs of other European carbines, the M1907 had a 51cm barrel and no provision for a bayonet – a reflection of the fact that, at the time, Russian military doctrine required the cavalry to conduct its hand-to-hand fighting with sabre or lance. (Harriman)

In 1904, Russian infantry tactics still followed 19th Century lines, and had not progressed to match the capabilities of modern weapons ... When under fire, soldiers were to run while ‘stooping’, and use terrain for cover where possible. In the attack, Russian tactics called for the use of shock effect. Troops were to fire one rifle volley at the enemy followed by a bayonet charge. (Sisemore 2003: 71; quoted from Harriman)

Summarised here:

Bayonets
The bayonet, known as a shtik in Russian, was a socket type with a quatrefoil ground blade and a flattened, ‘screwdriver’ point. Russia was the last major power to issue a socket-bayonet for its rifles; and the adoption of an old-fashioned socket-bayonet at a time when most other powers were looking to knife-bayonets serves to emphasize the essentially conservative nature of the Russian military. No scabbard was issued, as Russian military doctrine required the bayonet to be affixed to the rifle at all times. The Germans, Austrians and Finns recognized the impracticability of this and issued leather or rolled sheet-steel scabbards for captured bayonets.
The original M1891 bayonet had a locking ring which slipped over the front sight and then turned to the right to secure it on the barrel. There are several different slots which give the blade a different orientation to the muzzle when the blade is fixed. Those bayonets made in Wiener-Neustadt for M1891 rifles captured by the Austrians have straight slots in their sockets. Sometime in 1915, an experimental bayonet designed by E.K. Kabakov was issued in small numbers. This was no more than the blade of a Berdan II bayonet welded to a simplified socket. It was not manufactured in great numbers, however, and suffered from being 44g heavier than the standard M1891 bayonet. While this does not seem a massive increase in weight, it would alter the bullet’s mean point of impact while shooting with the bayonet fixed. When the Soviets modernized the Mosin-Nagant rifle in the 1930s, the rotating locking ring was replaced by a spring-loaded button catch with a chequered head to make the bayonet easier to fix or detach.
_{Bill Harriman: "The Mosin-Nagant Rifle", Bloomsbury: Oxford, New York, 2016.}

The changes of doctrine explained from here:

B.W. Menning: "Bayonets Before Bullets: The Imperial Russian Army, 1861-1914", Indiana University Press: Bloomington, 1992.

To illustrate the difference in contemporary use:

Note that both soldiers are from different branches of the German imperial army. It's just about the bayonets –– and the reach argument respectively the form.
_{(Klaus Lübbe: "German Uniforms And Bayonets 1841-1945: 676 Pictures Of Soldiers With Their Bayonets", Niemann: Hamburg, 1999.)}

Finally, the most important reason is that it is with this exact configuration, with the bayonet attached, that this rifle was broken in. Removing the bayonet would decrease accuracy.

On the other hand, this rifle had some serious drawbacks. First of all, in all patterns prior to M1938 and except for the Cossack rifles, all rifles were intended to be carried and shot only with the bayonet attached. This caused the already long rifle to be almost the same length as the average mans’ height, extremely awkward to maneuver and carry, especially in forests and trenches. All rifles were zeroed in with the bayonet in place, so the removal of the bayonet seriously affected the point of impact and effectively required the rifle to be re-zeroed. Original pattern bayonet mounts were prone to becoming loose during that time, decreasing accuracy further.
_{Modern Firearms: Mosin-Nagant Rifle}

Due to barrel harmonics, attaching a bayonet can significantly affect the point of aim. A service rifle needs to be sighted in with or without the bayonet. The Russian's zeroed the Mosin Nagant with the bayonet attached, or in later models, folded open. Removing it would cause the point of impact to change by up to 12 inches at 100 yards. The bayonet needed to be attached to the rifle in order for it to work as intended. You'd best not lose it!

Increased rate of fire meant that by the mid 19th century, the days of bayonet charges were over. The bayonet became a close quarters or backup weapon. The stoic design of the Mosin Nagant, with its permanently affixed spike, may have stemmed from a different philosophy of conscripting peasant armies.

In a similar timeframe, Mauser utilized a sword bayonet that was easily removed and sheathed. The rifles were zeroed without the bayonet, which became more of an accessory. The addition of a lug for the pommel of the bayonet meant that it could be easily installed with a snug fit, improving accuracy. Mosin bayonets attached in a manner that made them needed to be fitted to each rifle, with a less positive fit. Most modern rifles see a minor POI shift with the bayonet attached, but the M1 Garand was notorious for not shooting well with it.

Projection of war-fighter image

According to Richard Holmes:

The act of fixing bayonets has been held to be primarily connected to morale, the making of a clear signal to friend and foe of a willingness to kill at close quarters.

"You play like you practice"

• Removing a sheath/scabbard on a permanently affixed bayonet will make the end of the rifle lighter - only slightly, but enough to affect aim since it is essentially the end of a third class lever.




• Adding the bayonet only in times of combat (or specific bayonet training) will similarly affect aim but also movement. Some of these bayonets were over a foot long and that changes the way you need to move, both individually and as a unit.




• By having a piece of equipment always there, it becomes an extension of the body. A soldier that routinely uses his bayonet to ring doorbells or grab his keys off the hook (just examples) can be more precise/accurate with his strikes.

Infinite Ammo

• Not only does a bayonet look menacing, but it takes the place of the spear, a weapon that doesn't need to reload, requires minimal maintenance and can be wielded effectively with minimal training.




• You never know when to suspect an ambush or surprise attack (otherwise it wouldn't be a surprise) Having a weapon that is always ready like the bayonet can be the last line of defense.

To be intimidating

A fixed, unsheathed bayonett on a rifle screams out "Keep your distance" to people in the vicinity. A rifle without a bayonett may be dangerour (loaded), or not. However, with a bayonett fixed, it is always dangerous.

Even nowadays, some guard units have their unsheathed bayonets fixed.

In Austria, guards performing sentry duty often use transparent magazines for their rifles, so that people can see the live ammunition. Thus, even without a fixed bayonet, the rifle of the sentry projects power, as the brass cartriges mean business.