Kid fired 158 gr. JSPs loaded with wad cutter charges.
I saw a guy do this with strange results. He wanted light loads but not nasty old lead bullets, so he loaded Speer JSPs with wadcutter level powder charges.
He was shooting them and getting holes in the target. With ear protection, we didn't notice the one that must have had a different report.
But when he got home and cleaned his S&W M15, he felt the patch "jump" and sure enough, the SOB had a bulged barrel.
We went back to the range and dug in the berm and found:
A lead core only. Remember, a hole in the target every shot.
A jacket packed with paper and cardboard.
A bullet with the soft nose rounded over to match the indention in the bottom of that jacket.
We concluded that the jacket stuck in the barrel but the core was inertia pulled and made it all the way to and through the target.
Then the next shot drove the jacket out, bulging the barrel, and pushing it all the way to and through the target.
Smith replaced his barrel for a reasonable fee.
Squib is a strange word for a bullet stuck in the barrel of a gun.
Right. In my youth, reading Gun Digest and old books, a "squib" was an extra light load for the home basement range. A stuck bullet was so rare as to hardly be mentioned.