sub-sonic question

[chupacabrachus]

I've got a quick question for all ya'll. A friend of mine (who doesn't really know anything about firearms) and I were talking about sub-sonic .22LR ammo the other day. He was making this big deal about how much quieter it would be ( I don't think he's ever shot it) than regular 'high-velocity' 22LR. I've shot .22 Subsonic in a 10/22 and a p22 before with no percievable difference in sound (whilst wearing ear plugs, anyway... maybe w/ out them it would be more easily discernable.) However, he thinks that shooting .22LR out of a bolt-action rifle, since the casing isn't ejected and all of the sound comes out one hole rather than two, would be considerably quieter with such a rifle (or a lever-action, or any non-semiauto for that matter). I've never tested it (neither has he) so I don't know if it would make much of a difference. I've also looked into supressed .22LR semi-autos in which most of the barrel is a supressor, and know that those still have a ~120dB report with subsonic ammo(if I remember correctly, do not quote me). To me that still sounds like it would not be too quiet. Anyone familiar w/ 22LR subsonic? Anyone able to settle this quarrel?

[mr0w1]

Originally Posted by chupacabrachus

Anyone able to settle this quarrel?

Yes.

I've a friend with a suppressed P22. We shot 4 types of ammo out of it, sub-sonic, standard velocity, high velocity and hyper velocity. The hyper is just ungodly loud anyway, and very very loud (to the point that you'd still probably need plugs) through the suppressor. The high velocity is still kinda loud -- from 100 yards away it still sounds like a gun going off, but like it's a long ways away. That's what he uses most in his gun (the high vel) simply because it's cheapest, and still quiet enough to shoot all day long.

The standard vel and subsonic make almost the same amount of noise out of the suppressor, with the subs just edging the standards out for quietness. With those, the sound of the bullet hitting the coke can and the sound of the action is louder than the report of the gun. I'd LOVE to shoot a suppressed bolt gun with standards or subsonics. It'd be quiet.

My preference -- for best accuracy and quietness, standard velocity is the way to go. Standards are generally more accurate than highs anyway, and silence much better than highs. The subs are only marginally less quiet but get significantly less accuracy.

Hope that helps; just my un-scientific observations.

[mcb]

My father sighted his CZ in with Remington’s 'Sub-sonic' ammunition. This ammunition still has a good report but out of that long barrel (24") bolt gun it is relatively quiet; IMO noticeably quieter than stander velocity. That same ammo out of my shorter barreled 10/22 is noticeably louder. The shorter barrel increases sound levels as the gases exit the barrel at a higher pressure and thus are more likely to be super sonic. Also the semi-auto action make is louder, at least to the shooter, as your friend suggest as high pressure gases are vented in two places and one of those places is much closer to the shooter.

Remember that Remington Sub-sonic and other match ammunition is just barely below the speed of sound. Remington sub-sonic and most match ammo is about 950-1050fps with the sound barrier being ~1100 fps depending on atmospheric conditions. They want to be below the speed of sound for the bullet's stability sake not to control the sound level. So these loads that are barley sub sonic still likely produce a super sonic crack when the gases leave the barrel at super sonic velocities even though the bullet is just below the super sonic.

I have an old Winchester 67 single shot bolt gun that has a 27 inch barrel. That is a very long for a 22RF. Found it in my grandfather’s utility close after my grand parents passed away and I refurbished it. The riflings are in mediocre condition and with 40 grain standard or high velocity 22LR ammunition it will occasionally tumble the bullets. So I shoot CCI's CB Long ammunition in it. The CB long uses a 29 grain bullet (same bullet a 22 short would use) on a long/long rifle case and they are listed at 710 fps. I suspect they are going slower than that in my 67; as most 22RF ammunition reaches maximum velocity with ~16 inch barrel. A Longer or short barrel results in lower velocities with most 22RF ammunition.

With the very slow CB Long out of that long 27 inch barrel the firing pin hitting the cartridge is the loudest thing you hear. Not only is the bullet sub sonic but the gases exiting that long barrel are also sub-sonic. The gun is quieter that an air-rifle, even a red-rider. And let me tell you about tearing up some chipmunks.

Major ramblin'
mcb