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.270 Winchester vs .308 Winchester

So, let's answer that other Whatziss, the ammo one.  Most of you went for a variation of ".308 Winchester fired in a 30-06 rifle."

Which actually fit the information provided pretty well.  It was wrong, if only slighty.  It *was* a .308W fired in the wrong chambering.  The chambering of the rifle was .270 Winchester.  Meaning our bright boy shooter had himself a unintentional Gerlach gun - a squeezebore.

From left to right - .308W fired from a .270W rifle, regular .308W, .270W for comparison.

Here's the story, as related by SezaGeoff, one of our Australian correspondents.  The shot heard 'round the range was made Down Under.  Seza picks up the story...
If you look at the left one, you can see a straight sided case compared to a standard .308 Winchester in the middle. The length is the same, and there is only a slight shouldering at the front of the straight case that would allow it to headspace. It reminded me of the .401 Winchester, but that was semi-rimmed vice true rimless as here.

The truth is in the rest of the photo. P.O. Ackley was absolutely correct in stating that with freebore and neck relief you can do just about anything. My eldest daughter's boyfriend's friend has recently taken up centerfire shooting. Simon was at the range with Adam, and had his .308W on the bench with his .270W. As Murphy is always ready to strike (especially after Adam warned him about mixing the ammo), Simon managed to chamber a .308W in the Howa .270W and fire it. Apparently there was a very loud boom (without either wood or steel fragments), and the rifle wouldn't open! The Range officer came along to see what happened and eventually they coaxed it open. The primer fell out on the ground, but otherwise everything seemed OK!

I would have thought that it would have been the "blue pill" from hell, and I am not sure I would like to fire the rifle again until it had undergone some pretty searching examination! However, I believe that it has been examined by gunsmiths and passed as OK. It looks like the Nippon armouries can still produce decent products (I hope so - I have a few late model Brownings), but (unlke Simon) Ackley was only firing .270W down 6.5 Arisaka barrels, a difference of .277 - .264 or .013 inches. Simon managed to squeeze a .308 down the .277 bore - a difference of 0.031 inches. A spark-plug gap! At least he did have lots of neck relief and freebore (about half an inch)!

Adam had the case made up into the trophy pictured, but I think I would be staying a couple of benches over from Simon in the future - until he has shown himself to be a bit smarter with his gun and ammunition handling.

Anyway, all's well that ends well I suppose and at least no one was injured.
Here's some general information on the respective cartridges:
Caliber Comparison Data
270 Winchester Barrel Specifications.308 Winchester Barrel Specifications.
Common Barrel Twist Rate - 1/10Common Barrel Twist Rate - 1/12
Bore Groove Diameter - .277"Bore Groove Diameter - .308"
270 Winchester Reloading Specifications308 Winchester Reloading Specifications.
Bullet Diameter - .277"Bullet Diameter - .308"
Maximum Case Length - 2.540"Maximum Case Length - 2.015"
Trimmed Case Length - 2.530"Trimmed Case Length - 2.005"
Primer Size - Large RiflePrimer Size - Large Rifle

270 Winchester.
The 270 Winchester is based on the more popular 30/06 cartridge case that has been necked down to .277 caliber. Winchester began producing the .270 in 1923. The 270 Winchester is a great dual-purpose cartridge.  You can be use it for varmints sending a 100 gr. bullet downrange at  3,500 fps. or it can be used as a big game cartridge sending 130 grain bullets downrage at speeds of 3,100 fps, . with sufficient power out to the 400 yard mark for deer sized game plus using 150 grain bullets at 2900 fps. you can take out an elk out to about 250 yards.

308 Winchester.
The 308 Winchester was introduced to the public as a sporting cartridge by Winchester in September 1952.  At the same time, during what was to become the death throes of the Chief of Ordnance's office as a part of the great cartridge and rifle controversy this same cartridge was accepted by the U.S. military known as the T-65 in 1954 and was adopted (in a Byzantine display of hubris on the part of Ordnance) as the 7.62 Nato.

The 308 Winchester is a very good round for those wanting to use a 30 caliber bullet for hunting or large-bore target shooting but not wanting the felt recoil of a magnum rifle or the venerable 30-06. The 308 Winchester recoil is (to me) very tolerable when shooting 130-150 grain bullets.  Other opinions vary - especially amongst feather-merchants who don't have the same gravity well I have.

4 Comments

Thank you for the mystery report.  I learn something new every time I visit your site along with that of Say Uncle and the Rott.   I do have a close affinity for old Ned Kelly, one of my early childhood heroes (did I tell you I grew up with some Aussies as my neighbors in Montevideo?)  and on one raucous visit to Queensland I could swear I met him (or his grandson) at the Ettamogah pub..... Have  a great Christmas holliday all with copious adult beverages ( can't get Castelmaine XXXX  or Black Swan here in Michigan  and  Fosters is too close to ditchwater IMHO). 
 
I have not seen or hear of a Gerlach Taper Bore since I read Barssey's Infantry Weapons when I was...9 or so.
 
Fred - yer welcome!
 
I would quite like to have seen the bullet after all of this!