View Full Version : .308 through a .270!!
September 6, 2005, 03:53 PM
I had the "OH SH**" moment of a lifetime two weeks ago at the range when I mixed up ammo and put two rounds of .308 through my Weatherby Vanguard .270.
Now I know I am the luckiest guy in the STATE. My gunsmith extracted the casing (the first one ejected fine, second one got stuck), checked the headspacing, barrel and says the gun is fine and safe to shoot.
Do you think it is safe to shoot, or should I send it back to Weatherby and get an X-Ray or some new parts?
September 6, 2005, 04:58 PM
I would send it back to the factory. I do have to ask how you can mistake 308 ammo for 270 ammo as there is quite a bit of difference?
September 6, 2005, 05:11 PM
Heh, I won't ask that question about how you can mix up ammo - couple days ago I watched a guy dump a couple gallons of diesel into his custom Harley. Anything is doable.
I agree - send the gun back to Weatherby with a nice "thank you" note, thanking them for building a firearm strong enough and safe enough to handle a mistake like that!
Huge props to Weatherby and glad you weren't hurt.
September 7, 2005, 06:51 AM
I did the opposite, shooting a too-small round. I pushed a .223 round into the SKS magazine. When I pulled the trigger, there was a "phhht" noise, no bang. Then smoke started pouring out of the receiver, down around the trigger, up around the bolt, etc.
The 223 round was a Wolf, steel cartridge, so it didn't stretch to fill the chamber, it just split like a banana peel. I took the gun apart, didn't see any damage. The bore was clear, the bullet must have gone out the muzzle with a speed of 50fps, it probably flew 20 feet.
I switched to 7.62x39 and the gun performed a lot better.
September 7, 2005, 04:52 PM
I ain't from Missouri, but, Show Me!!!!
September 8, 2005, 12:29 AM
I had a gun come into the shop once that way. The bolt on a 700 rem locked down, we beat the bolt open with a rubber mallet not knowing what was wrong, only that the owner said it kicked like mule and he couldn't get the bolt open. Once we got it open we could not read what kind of shell it was as the brass had flowed so much that all that was legible was 08. The owner admitted that he had been shooting a 308 as well. The gun checked out fine. Using some arcane method for making a proof round by heating the cartrige to a specific temp, the smith tested the action a second time and it still headspaced fine.
Sometime later we had a kid try to trade in a japanese 6.5. Kid said it kicked so hard his teeth hurt. It had been over stamped to 30-06, but when we looked at it, it was still a 6.5 mm bore, but some smith had run a 06 reamer into it but never rebored it or rebarreled it. it would feed and fire 30-06 just fine. Have no idea what the pressures were, but we shot into a water tank and those 180 gr corelokts looked pretty darn cool all swaged down to .264 and about 2 inches long
September 8, 2005, 07:57 PM
I wouldn't worry about that .270 that had a .30 bullet fired through it. That kind of thing happens pretty often and seldom is a problem unless the case bursts and wrecks the action. Bullets are surprisingly elastic and the pressure will force them into the bore even if they are too big.
Now, before flaming, note that I sure don't recommend doing this. I am only saying that firing an oversize bullet rarely causes any damage to the rifle.
September 8, 2005, 08:08 PM
When I said, "Show me," I just meant that I'd like to see a pic of the fired cases, if they're available. From a duuuuuuh standpoint, I don't see how anybody could confuse a .308 for a .270, for obvious reasons.
September 8, 2005, 08:15 PM
coyote77, I'm just thankful you weren't hurt. :)
September 8, 2005, 08:33 PM
This thread reminds me of something that I witnessed out at our local range. Guy also was attempting to fire what turned out to be the wrong ammo in his rifle. Like a .308 in a .270, the cartridge he was trying to fire was way too short, and, consequently, wouldn't fire.
September 10, 2005, 12:33 PM
Pretty common occurance. I have hammered open a couple of misfit combinations like that.
That is also how a lot of those low number Springfields got instantly disassembled, shooting 8mmx57.
September 10, 2005, 08:22 PM
Another combination that causes a lot of concern is the use of the 8x57js ammunition in rifles made for the 8x57j cartridge. Yet when I slugged the bore of a Model 1888 Commission Rifle (.318" groove/bullet diameter) that was supposedly rerifled or rebored or something (as indicated by the "S" over the chamber), I found the normal .311" bore, .318" groove. The "conversion" apparently consisted of nothing more than rechambering so that the larger neck of the new cartridge had room to expand. (The bore for both cartridges is the same, .311", rifles made after 1905 have a .323" groove diameter, vs. .318" for the old rifles.)
To see what would happen, I fired a couple of dozen rounds of modern 8mm, including WWII German service ball and AP ammunition, some S&B and some Yugo ammo. The result of "forcing that big bullet down the small bore", as someone put it? Nothing. Not only did the rifle stay in one piece, but there were no signs of any abnormal pressure.
That is confirmed by the fact that the Germans converted those rifles to use stripper clips (they originally used an "en bloc" clip) and issued the standard 8x57js ammunition with them to reserve units in both wars.
But, without the chamber neck reaming, the pressure level could be dangerous, and that is why U.S. ammo makers keep the 8mm Mauser at a fairly low pressure. So I don't recommend firing modern 8mm in unconverted rifles made for the 8x57j ammunition.
September 11, 2005, 09:57 AM
Sorry you had the be---- scared out of you but there was nothing to be scared of! P.O.Ackley fired larger dia. bullets through smaller bores by just enlarging the neck to accomodate the case. Since the 308 is short engough to sit in that 270 chamber you had the same effect! Don't worry about your weatherby (while I don't care for Weatherby cartridges the actions and bbls are 1st rate) it came through fine (either the MK5 or Vanguard) !
Had you had a longer case where the neck could not have alowed the bullet to exit it would have been a very unhappy ecperience!
Check out that ammo carefully and DO NOT shoot anybody elses ammo!
Harry B. :)
September 11, 2005, 11:43 AM
Harry, if he'll post pics of the fired brass, I believe we'll be able to spot a substantial difference from what P.O. was doing. ;)
September 11, 2005, 11:48 PM
Sometime later we had a kid try to trade in a japanese 6.5. Kid said it kicked so hard his teeth hurt. It had been over stamped to 30-06, but when we looked at it, it was still a 6.5 mm bore, but some smith had run a 06 reamer into it but never rebored it or rebarreled it. it would feed and fire 30-06 just fine. Have no idea what the pressures were, but we shot into a water tank and those 180 gr corelokts looked pretty darn cool all swaged down to .264 and about 2 inches long Quite the story - would love to see pics of those too.
Most mismatched ammo stories I know of involve smaller diameters going through larger stuff... Usually no problems. But larger bullets down a smaller bore - Yikes - glad no one was hurt and post some pics! :eek:
September 13, 2005, 03:07 PM
After getting tired of hearing that inadvertently firing a 7.62 NATO round in a .30 M1 rifle would blow the gun up, wipe out the county, or cause the world to end in a ball of fire, I did it while a couple of my detractors (they are legion) ducked for cover. After three clips of GI 7.62 Ball, they conceded that the danger had been exaggerated. The only result was that the fired cases had no neck, looking a bit like rimless .45-70 cases.
The 7.62x51/.308 is larger at the shoulder than the .30-'06 and normally can be seated in the longer chamber only with some force. But the M1 has sufficient seating power due to its powerful operating rod spring that it will almost always chamber the shorter round with no problem. Headspace is not perfect, since the case is being supported by wedging into the chamber, but there is no danger. While the .308 bullet will not be as easily forced through a .270 bore (.277 groove) diameter barrel, the pressure rise will not be that great. The chamber situation is the same as the .308 in the .30-'06 chamber; the .308 will wedge in. Usually the extra force required to chamber it serves as a warning sign.
(The .270 is not, some writing to the contrary, based on the .30-'06 case; it is a necked down .30-'03 case, which is why it is longer than the .30-'06.)
September 13, 2005, 06:57 PM
"The only result was that the fired cases had no neck, looking a bit like rimless .45-70 cases."
Exactly! Let's see those pics of that .308 brass!
September 14, 2005, 08:33 AM
Just before deer season one year a guy at the range asked me to look at a .308 case that had lost its bottleneck. He had borrowed the rifle from a cousin who'd said it was a .308. Knowing what he would find, I pointed to the inscription on the barrel and asked him to read it to me since I didn't "have my bifocals with me". "Chambered for 30-06 only", he read. Then he got defensive: "But my cousin [I]told[/I} me it was .308." All I could do was nod and suggest his cousin hadn't shot much and remembered incorrectly. I figured, having got him to try doing it once, he'd be reading barrel stampings from then on.
Here is an analogous pairing: Sunday drivers and once-a-year shooters.
You've discovered one of the reasons I've never bought one of those pistol range bags that let you start with a pocket full of live rounds on one side of a divider and then have you drop your empties into the other as you shoot. It's a clever idea, but even if you only own one gun, you could always have some helpful range gremlin pick up and toss in an incompatible round, thinking he's doing you a favor.
MTM and other brands of plastic ammo cases come in different colors and the 20 rifle round slip-top boxes are so cheap (less than a dollar in quantities of 10) that I put semi-permanent labels on them. I usually label them to indicate both the chambering and the particular gun the loads were worked up for. I then never use them for anything but loads for that gun.
Permanent labels can be burned in with a soldering iron or a wood burning tool, but they usually come out hard to read clearly and the process stinks and has to be done outside. I prefer canning jar labels with clear tape over top. These could be removed, if I retired a gun, with Goo Gone.
September 14, 2005, 05:06 PM
Hmmmmm. One post; no follow-up. Looks like we're "talking amongst ourselves," guys! ;)
September 17, 2005, 01:05 AM
"...My gunsmith extracted the casing (the first one ejected fine, second one got stuck), checked the headspacing, barrel and says the gun is fine and safe to shoot..." Why don't you trust your smithy?
"...my cousin said...my brother-in-law said..." Same thing.
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