I bought a cool 03-A3 sporter off gunbroker, advertised as 30-06. I got around to shooting it, bolt closed on a factory round just like it should. Pulled the trigger, felt a little funny. Not much kick. This is what the case looks like. What do you think it is chambered for? 300 Win mag wouldn't close.

I saw a 308 Norma on gunbroker that looked exactly like that rifle... That was a few weeks ago. However, it WAS advertised as a 308 Norma magnum.....

That was my guess too

Cerrosafe is your friend!

You are lucky that you didn't damage yourself or the rifle. Almost everyone would assume that a 1903 Springfield would be chambered in 30-06, but there are rifles out there that have been rechambered without the 'smith having the courtesy to stamp the barrel with the new chamber.

Bearrr264 had a case separation in a Savage 99 that had been rechambered from 300 Sav to 308. When he fired the rifle with a 300 Sav cartridge, the case separated and the escaping gas blew the "cheeks" of the stock out, causing high velocity wood fragments to spray the right side of his face and neck.

Dang, never had anything like this happen before. I'd say an old 03-A3 action is still pretty strong.

NO question about it.. Get that chamber cast asap before you even attempt anything else..

Dang - you were one lucky dude on that shot.. I'd make sure I leave some 'proper' feedback on the seller.. He's lucky he's not sued over that one..

The first custom rifle I ever bought, about 30 years ago, was a .270 Win built on a Mauser action. It was a beautiful rifle by a well regarded custom gunsmith and a very fine stock maker. The rifle looked to be unfired. I bought it at a gun show because I knew the stock maker and was aware of the gunsmith's reputation.

The first round I fired blew a primer. I was using a mild hand load made with new W-W brass. I had been hand loading for about 30 years at that point and had never had a blown primer. I packed up and did what I should have done first: I went straight to my gunsmith and had him check the chamber.

As you might now expect, the headspace proved to be excessive. He was able to remedy the problem and the rifle became one of my favorites over the years, taking many critters throughout the western U.S. However, I learned my lesson. I never take any rifle that is not factory new to the range without having the chamber checked by a gunsmith.

Redneck's chamberd cast.
Pam spray
silly putty
3 pipe cleaners
wooden dowel

Interesting problem here. EDIT - wow, after seeing your latest picture it definitely blew the shoulder out! But the case bulged in the weak area immediately ahead of the case head, leading one to believe there is no support for the case walls. I.E. the chamber diameter is MUCH larger than 0.473. The -03 is a CRF action, correct? Has the bolt face been opened up for a larger diameter?

9.3X64 is about .025" larger diameter than .30-06 but close to the same length.

The bolt face has been opened up. I'm thinking its a 308 Norma. Anyone got a case to donate to me to experiment? I like the rifle so I decided to keep it. ($100 refund for my troubles). Ringworm, got any directions for the redneck chamber cast? With the refund I got $280 in it.

here it is next to 30-06 fired in a 30-06

Holy cow. You are lucky, that thing didn't split and cause all kinds of havoc. Count your blessings!!

Looks a lot like a 30-338, 308 norma magnum or even a 338 win mag next to that 30-06 case..

tag. really interested in what this will turn out to be.

My thought is .30-338 or .308norma.

Jack

I tried a 300 Win Mag and the bolt wouldn't close on it.

It's definitely not a 300 win mag. I can tell that just by looking at the picture of the blown out case. Looks more like 308 Norma. The 308 Norma magnum case is 2.559" long. You could almost measure the distance to the shoulder on the blown out case and see if it matches anything in the books. Keep in mind, many 1903's were re-chambered to 30-338 and 308 Norma magnum back in the day. Have you measured your bore diameter? It could even possibly be a 338 win mag.

That's some good brass!

That's what I was thinking. Probably good ol R-P or Norma...

Be sure to let us know what it is once you have determined.

Regards,

tag for the results

That is scary, glad you weren't hurt. Have to say that would make a cool 30-338 or 308 Norma if that is what it turns out to be.

To me it looks very much like a 9,3x64 Brenneke case, obviously necked down to .30 caliber.

I built an 8mm wildcat based on that case and yours looks pretty much alike.

In any case, anyone rechambering a barrel for a different cartridge should have marked it on the barrel.

I had a Springfield Sporter kinda like that one and it was .308 Norma mag.

Yup. Looks .308 Norma to me too.

It's HXP (Greek) brass that a got from the CMP for my Garands. I'll get my calipers out over the weekend and do some measuring

Dang. Quick, buy a lottery ticket, in case you're STILL that lucky! I'd agree on "To the gunsmith, now!", that is a good idea.

I saw a custom Springfield 03 several years ago that had been rebarreled to 8X57MM and the barrel wasnt stamped. The seller had a couple boxes of 8MM ammunition with the rifle and it had a very nice German style stock. Just struck me as odd to rebarrel to that caliber.

pretty sure I have a 308 Norma Mag. What do you think?

I think quite a few '03's were rechambered to the Norma round. My dad had one that was handed down to him.

back when 03A3s were being rechambered to magnums was before the 300 winchester magnum came on the scene

many 06's were opened up to 308 norma

here's the ammo

http://www.selwayarmory.com/hsm-308-norma-180-gr-grand-slam-sp-box-of-20.html

pull the bolt, measure the bolt face

call brownells get the cerro-safe

buy a no-go magnum headspace gauge (works for any belted magnum except 224 weatherby)

if everything checks out, tie it to a tire and fire it

measure all aspects of the case compared to new factory

looks like a bargain magnum

Still need a .308 Norma cases? Pm me if you do.

This may be worth the time it takes;

Pull the barrelled action and see if it is stamped under the wood.

Jerry

I've told the story of my son's pre-64 ".30/06" here a time or two. The case from that episode ruptured, spraying his face with bits of powder, etc., blew the extractor off the bolt, and bent the floorplate. He worked at the store where he bought it and they took it back to send to their central gunsmithing center for analysis and repair.

He grabbed it when it first came into the store, so it was never test-fired into the snail they had. He did most of their test-firing so it would have likely gotten him anyway, except he would have been wearing a face shield and apron instead of just shooting glasses.

I bought some ammo, but thanks for the offer.

Just took it apart, no marks on it anywhere

308 Norma Mag. First time I ever did that. Interesting. Whats the best way to mark it other than just punch mark it?

Laser engraving?

You have yourself a RIFLE!

First rifle I ever bought was an '03-A3 in .308 Norma. Man, what a gun! Heavy, but with a military sling wrap, standing offhand, I could keep every round on a paper plate at 200 yards. And it wasn't me.......

Bought it from Randy Pitney when we were both students at UAF.. He later became UAF rifle team coach. Kept trying to buy that gun back from me for some reason....

when I'm dead and gone the next guy will know what caliber it is

you shaved your legs for this?

Doesn't everyone?