.308 through a .270 - oh my...

Status
Not open for further replies.
I'd clean the barrel real good and have a local smith look it over. If you don't clean it before taking it in he will have to before he can inspect the bore. If he finds no damage I would take it back to the range, leaving all .308 ammo at home! Its probably OK but then again maybe not and a new barrel may be in your future.
Click to expand...

I don't know the pressure from each caliber but the barrel could be okay. LIke you said you still shot 30 rounds of .270 afterwards. I'm guessing those two .308 bullets left quite a bit of themselves in the barrel when they were sized down to .277. This could explain the inaccuracy of the next 30 rounds.
Glad no one was hurt.

I live by this rule, "If something does not feel right, stop and confirm."
 
are there really people who can't tell the difference between some rounds without reading headstamps?
Click to expand...

Yeah, there are. I'm one of them. I've been reloading and playing with various cartridges for nigh on three decades, and I have trouble. Just yesterday a friend brought over a rifle for me to look at. It's his pride and joy and he had a question about it. Remington 700 in .308, heavy barrel, stainless steel and one of those new 5R barrels. Anyway, he was aking questions, so I got out my box of dummy cartridges to demonstrate the answer to his question. There are nearly a dozen cartridges in that little box and I was having trouble picking out the .308 rounds. They're mixed in with .30-06, .243, .250 Savage, 7mm-08, all the others, and I had to rely on headstamp to find the two I was looking for.
 
I'm not knocking the OP for making the mistake he did, I do think it was unwise to continue shooting that day. I've seen ammunition mix-ups happen before as well, my BIL grabbed my .270 ammunition and ran one shot down his .280 Rem. Didn't do anything to the rifle but fire formed my case. I haven't however seen a larger caliber forced down a smaller bore.

I just can't imagine it not shredding the bullets and there might even be some crap in the chamber then needs to be cleaned out now. My guess is the barrel probably isn't bulged or it would be at least noticeable somewhere in the barrel, but it is better to CYA and have it checked out. I'd clean it real good and have the barrel slugged.

I guess in my previous post if I had done the same mistake twice I'd have packed it in for the day and checked my rifle out rather than run the risk of having a catastrophic failure of some sorts. My body is more important than getting a rifle on paper. Rifles are a lot easier to replace than a eye, face or a life.
 
Well, there ya go...Now you see why I shoot Nosler Ballistic Tips in my 270, 220, 223, 260 and sometimes in the 308. Color coded! Yup..yellow tips on the 270. Gotta love those Noslers. Ya think maybe they did that for a reason? I wonder.

As for making mistakes, I've read that we learn from our mistakes and the worse the mistake the more we learn. I think that's true, unless your mistake kills you.

Anyway, buy Ballistic Tips and remember your caliber color. No, I don't work for Nosler.
 
I like red and orange :)

Mistakes happen obviously the OP was in a hurry distracted ect...I've been shooting over 40 years so far no mistakes in the wrong ammo to gun dept.,although this metal fabricator of nearly 35 years just cut his first 3' steel rule in the shear last week :confused:....Sh!t Happens lol
 
Gimme a break fellas. I already admitted it was a matter of not paying attention, hurry, carelessness, stupidity - should I go on? I'm a man who can swallow his pride. Never heard this topic brought up before, so I figured gee, lets see if the 270 bullets will still fly - they did - but not straight... A call to TC, and probably after that, my gunsmith.
Ya'll have a good night
Click to expand...

We all make mistakes and up to a point I am ok. And a hell of a good job in being full up about it.

But then to shoot 30 rounds of 270 through a compromised barrel right afterwards? I would be curious what the thought process was there.

I did put 2 or 3 rounds of 45 GAP thorough my 45 acp one time. Once I realized what I had done I pulled it down and checked the gun with a teardown to be sure there was nothing about to go kaboom.

Ditto the time I put a 223 through the AK. Loading for my brother and I heard the odd noise and we stopped and I check it out and I shot the test rounds.
 
@ Briandg, I agree, it was a STUPID mistake - the buck stops here. When I started loading the 308 into the magazine, it seemed a tad short and fat.
Click to expand...

Hey, my new friend, at no point did I throw in the S word, and don't think I should.

You made a couple careless mistakes, that wound up in a magazine full of the wrong ammo. Whether it was unlabeled boxes or other errors that put them on your bench doesn't matter. Fix your process and habits and it won't recur. Lesson learned, problem fixed. I've done careless things too. You should read the story online about my lathe accident. (slightly modified in nature.) That story nearly won me a pulitzer.

The point about the nosler bullets with colored tips, all calibers a different color, is a good suggestion. I use a chemical to blacken the brass of any 30-06 brass I use for my 742, and use only federal for it, to boot, so I won't switch brass to one of my bolts.

it seemed a tad short and fat.
Click to expand...

So, you noticed that there was something odd, but didn't consciously pick up on that cue. That was where I was going. But pawpaw stated that he wouldn't know one round from another in a box of mixed loads. That was what I was wondering, are some people unable to recognize it? seems that yes, some people can't

It's like faces. Shoot, everybody can tell the difference between two people, right? and recognize them? Apparently the differences between two very similar brass tubes are too subtle for pawpaw, at least, it seems.

This was really enlightening. Thanks for posting.

I agree that maybe your rifle will be fine. when the pressure built, that powder charge made for a 308 was given a 30-06 sized chamber to fit in, and it would have been a very light charge to be firing in a .270. We all know that the bullet would have been swaged down to fit the bore as it went through the leads, and that is the strongest part of the barrel, bar none. since it obviously got through, maybe that thing survived the swaging, maybe not. If nothing else, I'm pretty sure that the action should have been safe, and not warped or stretched. A simple rebarrel. Maybe even as simple as re-cutting the chamber and rethreading the barrel a a thread or two shorter.
 
wrong cartridge

TC must make a very strong barrel. I saw a picture of a 98 Mauser with the side of the chamber blown out. The bore had been undersized by rust and an 8x57 cartridge did the damage. In the same book, I believe, there is a picture of a 1917 enfield with the barrel blown up by firing an 8x57 in a 30-06. Kudus to TC
 
I had a scary moment the other day too. I loaded the cylinder on my aluminum framed Colt Agent .38, and tried to close the cylinder. two cartridges were too long and the cylinder wouldn't close. The headstamp revealed they were .357. Cold chill time. So glad they didn't chamber all the way.
 
I would not have posted this.....
Click to expand...

It took some real nads for this guy to come into the lions den here and openly confess to a mistake like this. I know that a lot of places he'd be flamed mercilessly. instead, it's allowed some of us to learn something.

I'm happy that he hasn't been flamed.

I probably wouldn't have posted it either. I'm not going to subject myself to ridicule.
 
anyway?

Hey, stuff happens. You got away w/it, now you gotta learn from it.

Anyway you can post pics of the brass, or at least advise what make brass? It must have streatched plenty, and still held...wow!
 
I probably would not have posted that, but only because it would have embarrassed me too much. The OP is more man than me to admit what he did. Geez, everybody makes mistakes, but it takes a real man to admit it. Beyond that, PO Ackley did some testing years back that was similar to the OP's mistake. It was very interesting reading. I hope the OP's rifle isn't damaged and I'm glad that he isn't damaged.

I spend most days using table saws, band saws, chop saws and such as that. Lose your focus at just the wrong time and you can lose a digit. It's good to be a bit scared. Keeps you on your toes. I worry about that moment of lost concentration and focus. Hasn't happened yet. But....
 
Chris: a good idea at this point is take that rifle to a good reliable gunsmith in your area first. Have him slug the barrel for you and observe its receiver real carefully. Doing so, He will immediately know if your rifles barrel has been ruined? and or its receiver too. After your gunsmiths opinion and depending on how recent your purchase was? Maybe after calling Thompson to send in your rifle in for a look-see under its warranty period? They may at their discretion help you out? Or, after hearing your tale of woe (misfortune) maybe not? I hope this thread has been helpful. Your first concern should be: Be grateful no one was hurt.:) >A rifle can always be replaced my friend.<;) SSMcG
 
Last edited:
.270 and .308 share the same parent. The 30-06
Click to expand...

Probably misleading to say this. The .30-06 is definitely the parent of the .270, but this

http://riflemansjournal.blogspot.com/2011/02/history-30-80-wcf-origin-of-308.html

shows that the closest ancestor of the .308 was probably the .300 Savage, which was used for prototyping at the Frankford Arsenal.

Their final case was called the FAT 1E3. Which was real similar to Winchester's .30-80 WCF cartridge under development in 1948...

It is fair to say that the Army was trying to duplicate the performance of the .30-06 in a shorter, lighter cartridge. And the .308 nearly achieves this. Except for ranges greater than 600 yds, they are just about equal.

Examples of parent/offspring relationships follow. These are all "necked down", but the offspring can also be "necked up" -

Parent: .30-06 Springfield
Offspring: .270 Winchester, .25-06 Remington

Parent: .308 Winchester
Offspring: .260 Remington, .243 Winchester

If you stand the parent and offspring side-by-side, the case head to shoulder dimension generally remains consistent. Neck diameter and length will vary, of course.

If you stand the .308 and .30-06 side-by-side, you can see there is no parent-offspring relationship... :)

OP - Glad you were not injured. Even though the only two bottleneck cartridges I have are the .30-06 and .243, I am aware they use the same shellplate and have identical diameters at the head. So, I'm not about to tempt fate by having loose cartridges in a pocket, and assume I get them all at the end of the day. I may have done that in the past, but with your example as a lesson, I'm now going to load a leather cartridge carrier in good light, for the rifle I'm taking out. Then I know if I reach for my belt, I'm getting the correct ammunition.
 
Last edited:
Heheh you are lucky! Good on you for still having your head and all your fingers. You must have been spewing when you realised what you did mate!

See if you can get it replaced on warranty!

Joking.

No harm done.
 
Could you post pictures of the fired 308 brass? I would be very curious to see how the primer condition and the overall condition of the brass.

I highly suspect that pressures were very high but you did not mention blown or pierced primers. That is good.

What you did is very dangerous but you managed to have good luck. I believe you have all fingers and toes because the 308 had lots of free bore before it entered the chamber throat, thus reducing pressures, and because the bullets did not "tip". Or at least plug up the bore raising pressures to the point that the case would have burst.

What did happen was that your 308 bullets were swaged down a 277 bore.

I would first clean the throat out with a combination of JB bore paste and Sweets. There may be a big thick layer of copper in the throat.

If that does not fix things it will take a bore scope , cerrosafe castings, and a barrel gage to figure out what is out of tolerance.
 
i suggest keeping on shooting 308s now. that cool that you turned a 270 into a 308. not serious. but you are pretty lucky, 1 would have been enough.
 
Safety Complaint -- Our society has gone to the point where things are SO SAFE that it takes 2, 3, or 4 mistakes for something to to go wrong. This breeds complacency and leads to unintentional carelessness.

I've done it and seen it happen with others in a lot more than the firearms venue.

I have even done the 270 in 30-06 routine and wondered why nothing was hitting the paper even at 25 yards. In my case it was a similar size and shape cartridge and too lazy to put my readers on to check the headstamps, coupled with assuming I had the right ammunition.

Back to the complaint -- safety is a state of mind, of habitually thinking through and checking, double checking, etc. Even then things go sometimes go wrong.

An old saying I first heard is "Ya pays yur dime and ya takes yur chances!" This is why I have difficulty judging someone else's actions unless it's obvious they are deliberately ignoring safety issues. I've seen that happen also -- at the cost of many lives.
 
Status
Not open for further replies.
Back
Top