It Should Not Have Happened

Terry Blauwkamp’s Reloading series

Terry Blauwkamp is a seasoned hunter, gun-expert and reloader. He has been to Africa more than 20 times. Terry has been a consistent part of DSC Publications through his reloading column.

This is one of those stories that is just too amazing to comprehend. Not only should it NOT have happened, but the fact the no one got hurt and no gun was blown up is beyond comprehension.

A year or so ago, I wrote about a fellow that fired a 270 Win. cartridge in his 7mm Remington Magnum. Well, the case ruptured, and blew out through the bottom of the magazine, pretty much destroying the stock. Over the years I’ve written many articles about what I call “Another day at the range,” as every time I think I have seen it all, up jumps the devil.

Well this was one for the record book.

A fellow was out at the range with me recently, and I did not give it too much attention as he had two or three rifles that he was shooting off the bench, and I was doing much the same a couple benches over. All was going well when all of a sudden, he is cussing and swearing and standing over his gun trying to get the bolt open.

I looked over and asked what happened. He said he had no idea, but smoke was coming out of the action, which meant he had certainly blown a primer because of some obstruction or overload with excessive pressures that stuck his bolt.

I suggested he wait a little bit to let the gun cool off (as it was 28 deg), and the brass case in the chamber cool and shrink a little bit to help open the bolt. I was afraid that if he kept forcing and beating on the bolt handle it would break off and further complicate matters. The rifle was a Remington M700 and over the last 50 some years, I’ve had lots of them and never broken a handle off, but there’s always a first time for everything.

After a little while he did manage to get the bolt open and ejected a straight-walled cartridge case. He picked it up and showed me, and all I could do is say, “What the heck is that?”

Now the investigation begins. What caliber was the case he ejected? The numbers on the base of the case were barely legible but I could make out 308 WIN. And what caliber was the gun he was shooting? A 270 Winchester!

Now my first thought was that a .308 Win. would not fit in a .270 Winchester chamber. Well, it did, so what must have happened is that he loaded a .308 cartridge instead of a .270 by mistake.

Be careful. Somehow that .308 cartridge might fit in a .270 case.

Let’s look at the facts a bit more. A .308 Winchester uses a .308 inch diameter bullet and a .270 Winchester uses a .277 diameter bullet, so upon firing, that bullet must now be squeezed down to exit the barrel. I can’t find any data on it ever being done in a test rifle and the pressures recorded, but it must be enormous. The fact that the gun even held together is a miracle in itself.

I remember many years ago I stuck a bolt and blew a primer on a .270 Win. and had no idea why. Bolt finally opened, and a .270 case came out minus a primer. I did not shoot any more of that ammo, took it home and disassembled it to verify powder weight, etc. While pulling the bullets with a .277 collet, I hit upon a bullet that it would not fit. Hummm, the puzzle is starting to make sense.

So, I took a caliper and measured the bullet at the case mouth and it was .284 diameter. I pulled the rest of the box I had loaded, and found another one. Obviously somehow… somehow… a few 7mm (.284 ) bullets got in that box.

The 270 cal were 150 grain SPBT and the 7mm bullets were 160 grain SPBT, but to look at them they were virtually identical. When seating them, the case necks must have been thin enough to let the .284 bullet be pushed into the case without any signs of unusual resistance. Quite often the seating die would have not allowed it to seat, but all depends on the dies specifications.

I can’t blame the bullet manufacturer, as I then remembered I bought that box at a gun show a long time ago, and it is certainly possible that the seller found a few loose bullets that looked what he thought were .270’s and tossed them in the box without measuring them.

All I can say is to BE CAREFUL over and over again. Don’t be distracted at the range or loading bench. Stupid little mistakes can happen and the consequences severe.

Feel free to write me anytime at if you have anything that needs help.

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