Displaced air ?

[Charlie-NY]

Here's a dumb question:

When I start a tight sabot down the 28" barrel there's a significant volume of air in the barrel that will be displaced as the sabot/bullet is forced down onto the powder charge. Is all of that air forced out through the tiny hole in the breech plug? Is this a factor in why a tight sabot is hard to load?

 

[michiganmuzzy]

Even if it didnt escape somewhere. That small volume of air is so easily compressed that you would be hard pressed to measure it. Imho it has no effect on difficulty loading a tight bullet.

 

[Charlie-NY]

A 28" column of air could easily be compressed into a 3" column that's already filled with powder and bullet???? I seriously doubt that. Try pushing a bicycle pump down when lightly putting your thumb over the outlet. The air has to go somewhere or the sabot would be pushed back up. Maybe it escapes around the sabot, I don't know.

 

[deermanok]

I would imagine that air would escape back up the barrel via the grooves of the rifling.

 

[michiganmuzzy]

A 28" column of air could easily be compressed into a 3" column that's already filled with powder and bullet???? I seriously doubt that. Try pushing a bicycle pump down when lightly putting your thumb over the outlet. The air has to go somewhere or the sabot would be pushed back up. Maybe it escapes around the sabot, I don't know.

Its air, a light gas, not a liquid. You can seriously doubt it if you like, but an air pump is not a gun barrel. If youre lloading with light pressure than the size allows air to pass the bullet. Youre asking a question you already know the answer to.

 

[Dwayne]

A 28" column of air could easily be compressed into a 3" column that's already filled with powder and bullet???? I seriously doubt that. Try pushing a bicycle pump down when lightly putting your thumb over the outlet. The air has to go somewhere or the sabot would be pushed back up. Maybe it escapes around the sabot, I don't know.

You are correct. . . .The air escapes one of two places. . .out through the nib/flashhole, or space between
the barrel and the sabot/concal. Most all of it escapes within the first 30 seconds or so. The leftover pressure
escapes at a much slower speed as the pressure recedes in the barrel.

If you are fast enough, you can actually push down that sabot and the pressure will be great enough to throw
your rod out the front of your barrel as the pressure pushes back the sabot.

Yes, air is a thin gas, and yes it can be compressed. But when you compress it with your rod, it will escape out
where the least resistance is. Chances are, if it didn't escape out, you would probably never be able to seat
a lot of Sabots against the load, unless it is an exceptionally tight fit.. . .and I mean tight.

 

[ronlaughlin]

Just load the sabot without the breech plug in place; one will learn a tight sabot is a tight sabot; air has nothing to do with it.

 

[MrTom]

Just load the sabot without the breech plug in place; one will learn a tight sabot is a tight sabot; air has nothing to do with it.

We have a winner!

 

[fishhawk2700]

Gee, I'm glad someone solved that mystery. It was keeping me up at night thinking about it.

 

[Steelheader323]

Load a saboted bullet in your bore remove breech plug and take a look with a light if one sort on the other side. It’s not exactly an air tight seal. Sabots are made of a soft plastic for a reason to engrave into the rifling and create a gas seal