Be careful about using a over sized bore brush.I did the same once and I spent about two hours trying to get it back out.
It was a new brush,most likley a cheap one now that I look back on it, but I pushed it all the way down and on the return stroke it would not budge so I gave it a twist and it snapped.
I spent 2 hours trying to get it back out.
The final method that worked was loading the barrel up with WD-40,tying a fishing hook to my .22 cleaning rod and snaggng it.
I will never do that again,lesson learned.