While at the range last week, some hapless shooter placed a .300 Savage round into his .25-06, closed the bolt, and fired it. The only reason I knew that this happened was that he came over to me and asked if I could help him get the bolt open on his rifle. I noticed he had a .300 Savage M722 Rem. and some .300 S. ammo lying there.

We had to pound open his bolt w/ a rubber mallet. His rifle, BTW, was a Marlin X7 in .25-06. A couple of taps and the bolt came back. We knocked the fired cartridge out w/ a cleaning rod. It was a .300 Savage case that now looked like a straight wall case. I didn't think it possible that a .30 caliber bullet could go through a .25 caliber bore without blowing up the gun. But that's what happened. My question is: Will that gun be safe to shoot? Could the rifling be ruined? The extractor did break off and will have to be replaced. He is taking this gun to a reputable gunsmith, but I may never see this guy again and I was just wondering what the final outcome of this gun may be.
joe

If the headspace checks out and the broken parts are replaced it will likely be fine. Barrels are amazingly tolerant of mismatched bullet diameters. Hot gas from ruptured cases is a much bigger problem.

What Glen71 said.

If the case was intact, then the bore simply served as a swage to reduce the bullet diameter from .308 to .257.

It will be fine. You all probably remember the story in the American Rifleman from the 50s; a guy takes his 6.5 Jap Arisaka to a gun shop and says that the brass is hard to extract. He shows them some 30-06 brass, but the rifle is still 6.5 caliber. He said he rechambered it to "06, and had to grind the reamer pilot down to get it to fit. And he had killed deer with it. No damage to the rifle, or shooter. And I have heard of (never tried it but I should) shooting .45 ACP ammo through a 30-06 with no problems. Bullets are very malleable; as as stated, as long as you don't get escaping gas. That is a bad thing.

quote:

Originally posted by dpcd:
It will be fine. You all probably remember the story in the American Rifleman from the 50s; a guy takes his 6.5 Jap Arisaka to a gun shop and says that the brass is hard to extract. He shows them some 30-06 brass, but the rifle is still 6.5 caliber. He said he rechambered it to "06, and had to grind the reamer pilot down to get it to fit. And he had killed deer with it. No damage to the rifle, or shooter. And I have heard of (never tried it but I should) shooting .45 ACP ammo through a 30-06 with no problems. Bullets are very malleable; as as stated, as long as you don't get escaping gas. That is a bad thing.

Seems like I remember the guy complaining about the recoil!

You are absolutely right; he complained about the recoil; everything else was normal. See, your brain is aging better than mine.

Had a couple cousins shoot a 7.62x39 through a .243 rem 700...it was near dark and they had shells mixed in their pockets one was shooting the sks the other the rem....shot a beaver but didn't know why there was a trail of blue smoke so of course they fired another one to confirm what they saw lol!

quote:

Originally posted by Joe R. Lock:

....I didn't think it possible that a .25 caliber bullet could go through a .30 caliber bore without blowing up the gun.
joe

I'm thinking you mean the other way round.

One hell of a "squeezebore", I wonder what the velocity was.

There were pictures around the internet a couple of years ago of a Savage 270 rifle that had shot a 308 round through it. The 308 bullet had apparently headspaced on the 270's neck.

The rifle turned out to be fine.

And they do live and walk among us.

quote:

Originally posted by Oddbod:

quote:

Originally posted by Joe R. Lock:

....I didn't think it possible that a .25 caliber bullet could go through a .30 caliber bore without blowing up the gun.
joe

I'm thinking you mean the other way round.

One hell of a "squeezebore", I wonder what the velocity was.

You are correct. I editied my original post. Thanks for pointing out the mistake. I am getting old and forgetful, you know. In fact, I should take a lesson from the guy at the range who used the wrong cartridge. I should probably only take one rifle at a time, lest the same thing happen to me.
joe

It does seem that bullets of larger than bore diameter can and do successfully pass through barrels of the wrong caliber. That being said, it is possible that damage to the locking lugs and action can occur without bursting a barrel. I think that a very close examination of the lugs and action would be in order before shooting again.

I had a customer bring me a Ruger 77 in 25-06 that he fired a 308 Win. through. The bolt stop and the clip, that holds the extractor on, were the only parts damaged, other than the Hogue stock and the bottom metal. Ruger replaced the rifle for him at factory cost. Made a believer out of me when it comes to investment cast actions.

Wow, in 2009 a shooter in Namibia managed to shoot a 308 through a 25-06 rifle made on a Musgrave RSA action and he was lucky that the bits that blew off didn't injure him.

Written up in the SA Magnum sometime during the year.

The barrel will be fine. The action is the issue. The bolt will need to be checkd for cracks etc. Have the bolt lugs & recess been set back?

I have see a CZ / Brno rifle in 25'06 which had fired a 308 Win round. The action was cracked in several places and so was the bolt! The stock was broken too! That Marlin must be a very stron action indeed!