Grouse45

Here's the first problem, everything isnt always perfect.

But in theory i would agree with you. But if the sabot doesnt obturate in those first few inches i dont believe you will see it?? Obviously load and pressure is what makes sabots and bullets obturate.

Grouse45

You actually got me thinking something. I have some undersized bullets. Next time im out, ill see if the sabots show signs of slipping with a light load. But i still dont think they will unless i reach obturation with the sabot. And to do that, ill need a pretty good load.

BuckDoeHunter

If the base cup of a plastic sabot, which I can deform between my two fingers, doesn't obturate almost imediately with the force of, lets say, 15,000-20,000psi (not a heavy weight load by any means) the laws of physics have gone totally bonkers and we should all hold on for dear life so we do not float off the planet.

bronko22000

I cannot believe for one second that a sabot slips the rifling upon firing. Besides the response from Harvester this is the reason I don't believe any slippage exists. First the bullet sabot combo has to be a proper fit to the bore. In other words, moderate but not excessive pressure should be required to force it down the bore and onto the charge. Also, it needs to follow the rifling down the bore (a spin jag is necessary) otherwise the rifling could damage the sabot and appear as slippage when viewed after firing.
If the combo is correct the sabot will immediately expand upon ignition forming a tight seal and engaging the rifling even tighter. I wouldn't believe that the bullet obtrurates much if at all because of the cushioning effect of the sabot.
Now my final word on this is because there is no evidence one way or the other I would have to side with a sabot manufacturer and physics logic.

ronlaughlin

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Grouse45

Ok Thanks!!

lemoyne

I have experienced a sabot bullet combination that went down the barrel much easier than normal , I just shot it into the burn. One of us the next time this happens should pull the BP and take the bullet and sabot home and measure them. It has been a very rare occasion for me to experience a "loose" load.

lemoyne

Since the pressure of the burning powder locks the sabot into the rifling the slippage that I worry about is between the bullet and the sabot.
Back when they first came out with the 1 in 20 twist the plastic in the sabot was not up to the twist and would some times tear the sabot to pieces, would it do that if it could slip?

bronko22000

Lee I would surmise that the slippage you are talking about is very similar to the way a tire slips on a rim from heavy footed drivers. Hard to believe but it does happen. One reason why tires need to be rebalanced occasionally.
I could see the bullet slipping in the sabot a bit initially but not the sabot slipping in the rifling.

Grouse45

It doesnt matter how its slipping, its slipping. To what extent is the key to more consistent accuracy.