Thread: 'Subsonic' .22 ammo going off with a crack

Dirty barrel can cause it as well,build up of wax .

I love chucking a handfull of the .22s in the bonfire when the townies turn up.

I ended up returning the faulty box to gun city today. With nine rounds missing they gave me a different box of ammo from a different brand and reimbursed me the difference between the boxes' value. I cleaned my silencer today but it made no difference, so I'm keen to try the new box. Nice folk at GC Penrose.

Apparently the speed of sound depends mostly on temperature and not much on pressure or altitude.
https://en.m.wikipedia.org/wiki/Speed_of_sound

At 20C it is 1125 f/s
At 0C it is 1086 f/s and “Standard Velocity” ammo might creep over that.
I understand there are special low temperature ammo for biathlon to avoid the bullet going across the speed of sound and becoming unstable.
I wonder if this happens more in the autumn and winter. People whi shoot rabbits down in the McKenzie and Central might know more from experience …

I have heard (so take it with a yearly serving of salt) that gunpowder burns faster the older it gets. So if you had some sub-sonics that were close to breaking the sound barrier when they were made you might have a few cracking through it now they're older. Even now when I buy .22 subs occasionally 4 or 6 rounds still breach. So, hard to know for sure, but that's an idea.

I will say when I got the BSA international target rifle project a while back I was noticeably quieter with the nearly 29 inch barrel and subsonics.
Quite surprised after I shortened it to 19.
Little bit more expansion in the barrel and gases cooling maybe

Originally Posted by Bagheera

Apparently the speed of sound depends mostly on temperature and not much on pressure or altitude.
https://en.m.wikipedia.org/wiki/Speed_of_sound

At 20C it is 1125 f/s
At 0C it is 1086 f/s and “Standard Velocity” ammo might creep over that.
I understand there are special low temperature ammo for biathlon to avoid the bullet going across the speed of sound and becoming unstable.
I wonder if this happens more in the autumn and winter. People whi shoot rabbits down in the McKenzie and Central might know more from experience …

It's ducking cold around here at the moment. Running the 223 suppressor on the 22 is useful (more volume) Between the cold and high-ish elevation (200-300m) it's not unusual to have 2 in 10 rounds go 'crack' rather than 'woosh'.
the 18650 batteries don't last as long in the winter, tend to get about 4hrs out of a pair before needing to swap them out.