Smith corona 03 A3 caliber trouble

Is the 1903A3 action capable of taking a .308 Norma Magnum?

The case is 2.56" long, the .30-06 is 2.494. That seems to me it would be enough to cause real problems.
 
Tha action can take the cartridge length but once the feed rails have been altered to feed those cartridges you can't go back to 30-06.
 
It will be easier to neck 7mm Rem mag up or 338 Win mag down than to form 300 Win mag. The shoulder is further forward on the 300 forcing you to move that shoulder back. If you do this, you'll need to neck ream the finished 308 Norma case or you may have problems later. I used 338 cases since I don't like to form anything from a cartridge that I already use(7mmRem mag&300 Win mag). This precludes the faint possibility of misidentification of ammo by someone other than myself. In addition, necking 338 down allows you to precisely control the base to shoulder length preventing or reducing the possibility of case stretching during fireforming.
 
That makes sense mobuck. I did buy a hand full of 300 mag brass from a friend...I'll look into getting some 338 and tinkering with it. Any other steps required to neck down? Mind explaining how you do it? And how much needs to be removed from the 300 mag considering I'm already out of pocket on them and should try to use them. @ east bank thanks for the heads up!!
 
Normally, you can just run the lubed .338 cases into the 308 Norma sizing die. You need to make some careful adjustments so that the formed cases fit very snugly in the chamber for the initial firing. Otherwise the cases can/will stretch creating a hazardous case failure situation. Size the parent case only enough to allow closing the bolt with thumb pressure. Lube the bolt lugs so you don't gall the lugs and recesses. You want the bolt to close with resistance indicating the case is contacting the sholder of the chamber rather than just being held by the extractor.
After sizing, you'll need to trim the case mouths. The cases formed from 338 may come out slightly under minimum length in which case you should trim all cases to the length of the shortest case in the lot for consistency.
I honstly can't remember how much has to be cut from 300 cases but you'll have to cut off some before sizing or the parent case neck will contact the upper end of the Norma sizing die.
I actually made more cases from 300 H&H than I did from 338 after I scored a good deal on a lot of H&H brass and that is much more tedious than using 338 as the parent.
 
Not trying to be a bother but do you mind detailing these careful adjustments you speak of. This case forming is a first for me. How do I get a good snug fit? If its too loose? Is it a matter of slightly running the die in deeper?
 
You want the formed case to fit the chamber snugly in the shoulder area rather than having that dimension loose and the case supported by the belt. You'll have to make this adjustment by trial and error until the bolt will just barely close with moderate force. In this way, your formed cases will achieve best fit in your chamber and provide the longest life. This adjustment is made by incrementally pushing the parent case further into the 308 Norma sizer.
Most reloading manuals go into detail regarding maintaining proper headspace on belted magnum cases(preventing case separations).
 
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