Squibs

[Shiro]

This is not really a practical question, just curiosity.

I understand the threshold muzzle velocity where rounds tend to turn into a squibs is well below 1000fps. But just out of noobosity, for a bullet with average contact area (say the M80) and a 16" stainless barrel what is it? Is it really small, 100fps, 10?

I was creating a descending charge ladder for a sub sonic load and started to wonder, how far below subsonic you can go safely.

Assuming the cartridges are consistant and work as intended, are there any warning signs before you reach the threshold? Huge ES, etc.

Regards,

[dellet]

I don't think any one will be able to answer exactly. I have never had a bullet leave the muzzle of a 16" barrel less than 800 fps. and there is no way of ever knowing the speed of a squib before it stopped in the barrel.

Erratic readings may or may not be a clue. Many times high spreads are due to low powder density and that will vary by powder choice.

When working a subsonic load down I can't think of a reason to keep dropping speed once you get below 950.

[smustian]

For a minimum I think you would measure FPS with a cartridge loaded with NO powder and fire it with just the primer. More than likely the bullet would stop in the first part of the rifling and you have a squib. Your troubles start when you shoot and the bullet does not hit the target or is unstable when it hits showing a "key hole". The absolute lowest charge you want is when the bullet exits the barrel and drops onto the shooting bench. Best option is get a chrono and stop when you see velocities around 950.

[dellet]

For a minimum I think you would measure FPS with a cartridge loaded with NO powder and fire it with just the primer. More than likely the bullet would stop in the first part of the rifling and you have a squib. Your troubles start when you shoot and the bullet does not hit the target or is unstable when it hits showing a "key hole". The absolute lowest charge you want is when the bullet exits the barrel and drops onto the shooting bench. Best option is get a chrono and stop when you see velocities around 950.

If I have a 100 MOA rail and a lot of adjustment in my scope, do you think that would be enough so I could get that load zeroed?

[Shiro]

Makes sense. I shot a competition with wax projectiles in .45 colt brass when I was younger. They were only charged with shotgun primers... not going to try it with metal bullets I was just checking the image in my head of bullets dropping out the muzzle. Thanks for the feedback

[plant.one]

For a minimum I think you would measure FPS with a cartridge loaded with NO powder and fire it with just the primer. More than likely the bullet would stop in the first part of the rifling and you have a squib. Your troubles start when you shoot and the bullet does not hit the target or is unstable when it hits showing a "key hole". The absolute lowest charge you want is when the bullet exits the barrel and drops onto the shooting bench. Best option is get a chrono and stop when you see velocities around 950.

If I have a 100 MOA rail and a lot of adjustment in my scope, do you think that would be enough so I could get that load zeroed?

you dont even need all that. as long as you dont try zeroing it much past 2" or so

[BlackLight]

As already suggested, just don't go there. A squib can ruin more than merely the barrel

[ncorry]

I've had a 220SMK in a 9.5" Core15 barrel chrony at 540 FPS. Several others in same charge chronied 580-600 range. Those loads would not work in my Leonidas with 8" barrel. I don't know the maker of the barrel in the Leo. I had to sacrifice a steel cleaning rod to get the two of them out (not at same time). By the way, they are freaking HARD to get out.

[Shiro]

Thanks for the suggestion, I do not plan on trying to find the speed. I just figured with all of the force it takes to etch groves and move a bullet down a barrel, if a bullet makes it out, it can not be at zero feet per second. Out of curiosity I was wondering how far below 100fps it was.

The suicide cult idea had occurred to me also.

Ian

[Shiro]

I've had a 220SMK in a 9.5" Core15 barrel chrony at 540 FPS. Several others in same charge chronied 580-600 range. Those loads would not work in my Leonidas with 8" barrel. I don't know the maker of the barrel in the Leo. I had to sacrifice a steel cleaning rod to get the two of them out (not at same time). By the way, they are freaking HARD to get out.

Interesting.

Glad you did not scrap you barrel!