#SONIC VS SUBSONIC ROUNDS HOW TO#

And, practically speaking, that's what makes shooting a competition a contest. So, I really don't believe the reason for the high velocities we see today is to overcome this transonic instability problem.Īt any rate, any instability introduced by the transonic region will contribute such a small force vector, compared to the remaining force from that originally imparted from firing, as to be relatively insignificant.

Assuming a measurable 1-to-2 inch deflection, at normal pistol ranges, directly attributed to this phenomena gives it too much importance as a ballistic factor, IMHO.ģ) ' This is also the reason why most modern centerfire rifles fire lightweight bullets at Mach 2+.' Many bullets in modern loadings will remain above Mach I far past it's useable range for accuracy, but I'm pretty sure that is for the purpose of trying to achieve the flattest shooter possible, not to overcome bullet instability as it decreases from supersonic to subsonic. There is also no known mechanism or method for dealing with the effect, except the selection of projectiles with excellent ballistic coefficient. The effects of ballistic drag, temperature, humidity and gravity are considered to be far greater than any instability caused by decreasing in velocity from super-to-sub sonic.

#SONIC VS SUBSONIC ROUNDS HOW TO#

The bullet has to travel really, really far downrange to approach the transonic transition, usually much farther than any shot the average shooter will ever attempt (800-1,500 yds).ġ) I've already commented on the 'bullet drop' aspect of this assertion, but just to reiterate, we do not know how to predict the specific effect on the bullet in flight, as it decreases through transonic.Ģ) It was only used as an example in the above quote, but I feel it necessary to emphasize that a 1'-2' drop caused by decreasing through transonic makes way too many assumptions. This is also the reason why most modern centerfire rifles fire lightweight bullets at Mach 2+. However, to a smallbore rifle target shooter, this is a really big deal. This is usually not a deal-breaker with pistol rounds because most pistol shooters will never fire at a target small enough and far enough away that a variation of, say, 1'-2' of drop will make a critical difference. Even the silhouette steel shooters treat it the same as rifle competitors.įYI one of the main problems with the supersonic-to-subsonic transition of a bullets is that it can make bullet drop unpredictable and irregular from shot to shot. For handguns, if you are not shooting silhouette IMHSA, I cannot imagine how it could ever be an issue. In fact this instability is probably one of several factors contributing to why we routinely shoot 'groups' at distance, and not single holes. Most long distance shooters ignore it, or better said, they deal with it by selecting the best ballistic coefficient bullet for their caliber bore. Point: The transonic region through which a bullet passes down range really has an unpredictable effect on trajectory. Can someone point me to a factory loaded subsonic cartridge that limits the hot expanding gases exiting the muzzle right behind the bullet to subsonic velocities? That is the muzzle report we hear, gas expansion, not the bullet. Point: Any noise made by a bullet is insignificant compared to the sound produced by the hot expanding gas exiting the muzzle as the bullet exits. Not exactly, subsonic means the bullet has slowed to below the speed of sound, not below faster than the speed of sound. Subsonic simply means the bullet is slow enough to not break the sound barrier, or has slowed to a point where it is no longer traveling faster than the speed of sound.

Sonic vs subsonic rounds