Especially due to the "release" of silencers for hunters*, the topic of barrel length has become a bigger issue again in recent years. In many hunting, weapons and ballistics forums, you can now find posts in which people eagerly discuss how the barrel length in conjunction with the respective caliber affects the effectiveness of the bullet, its velocity, trajectory and energy. Many who now want to retrofit their rifle with a barrel thread for the purpose of silencer use will now be aware of this topic. The barrel is usually shortened in the course of such reworking.

Many people are therefore afraid of such an operation on their gun and fear above all that they will have problems afterwards with regard to accuracy. But how do barrel length and caliber really interact? And by how much does a barrel shortening reduce the bullet velocity and the bullet energy while maintaining the same laboratory setting?

Since there are simply too many parameters that are important for bullet velocity, this unfortunately cannot be answered with a blanket formula. In addition to the caliber, parameters such as case volume, bullet shape and combustion behavior of the propellant powder are also relevant. Especially with the latter, individual deviations can occur with each cartridge.

Even with standard rifle calibers with case lengths in the range of 60 to 65 millimeters, such as 7 x 64 or .30-06 Spr., these deviations usually result in velocity differences of 30 m/s to about 50 m/s with barrel lengths between 660 millimeters and 510 millimeters.

The extent to which barrel shortening increases these differences almost always depends on the combination of barrel, caliber, bullet type, etc. used. However, a fundamental loss of performance can usually be documented after barrel shortening. However, it should be said here that in the case of barrel shortening to the extent recommended by gunsmiths, this is usually within spheres that do not entail too many consequences for the hunting use of the weapon. Whether a bullet with more than 160grs. hits the target with 780m/s or with 740m/s should hardly make a difference for the hunting success, even in the case of a movement hunt, in which, as is well known, one also shoots at moving game.

It is therefore always important to obtain the expert opinion of a specialist beforehand, usually the trusted gunsmith, and to ask him about the planned barrel shortening, also with regard to the caliber used and the laboratory used.

It is generally known that different loadings of the same caliber fired with one and the same rifle can lead to different point of impact positions. In the same way, bullet velocity and bullet energy also vary depending on the laboratory. On the other hand, these properties may vary when the same laboratory load is used with two different weapons of the same caliber.

It should be noted that the shooting result depends on so many parameters, of which barrel length and caliber are only two, that the hunter should always make sure that the selected combination of weapon, silencer and ammunition will lead to the desired result in terms of point of impact and bullet effect. If a non-negative deviation is detected after mounting the silencer or any other structural modification of the weapon, it should be tried out with which other laboratory the desired result is achieved again.

*Meant is the amendment of the WaffG from 01.09.2020, after hunters should be allowed to use silencers in hunting nationwide.