That ain't the shells it's your gun. It's firing out of battery. You need to have it run through by a good smith. The shells are fine.

Just strange that I show 50 rounds of federal shells before this with no problems. This was the first Winchester round from a brand new unopened box.

See if you can fire your gun without fully closing the chamber. Try it several times in different positions of closing.

If not, it's the shell.

Or a bolt that isn't fully locking closed.

That shell expanded to it's size as a result of the bolt being open,or opening when the shell went off, which isn't supposed to happen.

I came home and tried to see if the gun would fire in several different open positions. It would not. It would only fire after closing the bolt completely. You could hear and feel a definite click when the bolt closed. It would not fire until you heard and felt the click. I talked to my brother today. He had this happen in a 16 gauge auto last summer. The first time it happened, it was when my 10 year old nephew shot it. My brother put in another round (probably not the smartest thing) and it did the same thing. He was shooting the cheap Winchesters as well.

It's your gun, and your call, so if you are convinced it's the shells I wish you the best. I just wanted to make sure you had all the information you need to make your decision and not hurt yourself or others, which I feel I have done. Dropping the trigger group on a Rem 870 is literally a 30 second job and would tell you a lot, and I am sure there are even videos on youtube showing how to do it, but I understand you not wanting to mess with it since you believe it is the shells causing the problem.

I personally don't understand what would make a "cheap" shell cause the bolt to open, but that is just me. Is it the lack of powder? Cheap wad? Aluminum base? Light shot charge? Why wouldn't a good stout loaded shell, operating at a lot higher pressure, cause the same thing to happen?

Good luck and be safe my friend.

This. It nocking your earplugs out was from the blast coming out of the parcially open bolt. That can not happen with the bolt fully closed. The safety mechanism that keeps the gun from firing with the bolt open is a machanical device that can at times fail.

I have experienced this first hand only with a bolt action 243. A friend was putting a shell in the chamber and I was standing on his right. For some reason the gun fired with the bolt about 3/4 closed. It exploded the shell on the back end just about like yours. It felt like someone punched me in the face and the unburned powder made little blood marks all over my face. My ears rang for two days.

I will bet a $100 that she'll was fired out of battery! The tell tell sign is how the metal is pealed back. . No way that can happen if the shell is fully in the chamber. It would be impossible. Get that gun checked out BEFORE you shoot it again.

To me, the fact that it was excessively loud and sprayed you with powder is a sign that the action was either partially open or came open upon firing. I don't see any other explanation for those two occurrences.

Maybe it's an issue that can't be recreated without a live shell being fired. I agree that it needs to be taken to a gunsmith before trying to shoot it again with new shells.

Call Winchester, surely they have more experience to reach a conclusion. They'd be happy that it is the gun and not their shells. Don't shoot the gun until is is checked out.

I know of 3 pumps that would fire upon closing the chamber if the safety was off. 2 are in the river the other I have no clue where it ended up. None of those 3 guns ever had shells blow back and peel apart like the hull you posted.

If it is the gun, i'd bet the chamber was closed enough to let the firing pin hit but not fully closed to lock down upon firing.

I'd contact the gun and the shell manufacturers.

I agree. That gun fired out of battery. Get it checked out before you hurt you or someone else!!

Call me before throwing them in the river next time, i'll take them off your hands, and even give you a few bucks for them.

Took it to a gunsmith in Oxford yesterday. Man was in his 80s and seemed to know his stuff. This guy worked for Remington in the past. He played with my gun for probably 15 minutes. He said that the action was not 100% closed when it discharged. He said that he didn't think it was open more than 1/16 of an inch. He said that it looks like my extractor may have worn a little preventing everything from closing 100%. He told me that he would completely tear down the gun and check every part and replace anything that looked suspect. He had enough parts to build probably 20 Remington 870s. Said he would have it back in my hands tomorrow.

If it was mr. Wallace Gatlins, you can bank on it bieng right.

That's him!!