Can anyone explain this to me?
 

Can anyone explain this to me? I just got this Sig P250 and after about 20 rounds or so this happened! I thought it might have been just the maybe the case was packed to hard but then it happened again about 30 rounds layer! Any help would be great!

Type and brand of ammo? Caliber? And is the base ripped or blown?

My first instinct would be to change ammo. But you really should also get a Smith to look at your gun.

It was plinking ammo from the range (I use it all the time and this is the first time it has happened) I thought I might have been the ammo to so I loaded some federal and same thing! It is .40 in the compact model. Another guy said it looked like something called "firing out of battery"

My 10/22 ruger will do the same thing if it gets to happy and excited . It looks like the round is firing before it is chambered fully . Fire it but examine the breech each shot and make sure it is locked all the way forward , if not then that may be your problem

Being as that you changed ammo and it still happened leads me to believe Its the firearm. I advise caution. Have a gun smith look at it before any more shooting. Better to pay than lose an eyeball. But to answer why. I don't really know the cause.

Start with a gun Smith. May want to look at your cleaning and lube technique.

thats something you need to contact sig over. they will want the case as well. looks like a flawed gun.

That looks like the round is not supported completely by the chamber.

Back to the manufacturer. Include a photo of how a new round sits in the barrel. Chances are the feed ramp area.

BACK TO SIG!!! That is bad. It was not surprising when you first wrote "range" ammo. Presumed reloads and probably not very well done. BUT when you said it did the same thing with new Federal ammo? Send it in.

That was my first thought. Here's a pic of the results of a Glock infamous unsupported chamber.