I have a smith corona 03 chambered in the 308 Norma. As cool and different as this cartridge is...I have no use for it..Im not a hunter. Merely a paper puncher and as much as bigger is better that's not always so. Chances are it may stay the way it is but maybe not. Any thoughts to what I might be able to convert it to. Similar cartridge dimensions and minimal alterations/ modifications. I'd really like to utilize the existing bolt assembly. I just don't need this much power as much as I love the cartridge. 22-30 caliber suggestions preffered. Doesn't have to be mainstream or particularly easy to be had. Please and thank you!!
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converting a 308 norma magnum to....?
- Thread starter mattL46
- Start date
You could convert it to 300 Win Mag with minimal effort, just run a reamer into it. You may need to do some magazine work, check that first. Or you could rebarrel to one of the 2.5" magnums: 264 Win Mag, 7mm Rem Mag, 270 Weatherby, 7mm Weatherby, etc.
Interesting bit o' history: in 1964 Winchester started introducing the 2.5" magnums, designed to fit in a "standard" length action because it was the most common length for both milsurp and commercial actions. Winchester was releasing cartridges one at a time, to make the most of the exposure and hype. The 264 and 458 had been introduced a year earlier, causing a huge media event and much hoopla, and the brass was available. Norma, seeing where this was going pretty quickly, introduced the 308 Norma Magnum, a 30-caliber magnum based on the 2.5" case, and got a lot of press for doing so (Remington did the same for the 7mm cartridge). This kind of torqued the folks at Winchester, who could not just introduce a similar cartridge with their own name. So they decided to outdo themselves, and redesigned the cartridge they already had ready for release so it would beat the 308 Norma Mag by 10%. They lengthened the cartridge, gave it a distinctly more blown out case with a sharper shoulder, and managed to gain about 150 fps over the 308 Norma Mag. They released the cartridge with much fanfare, and since the gun rag writers were always cheering anything that went faster, they jumped right up and cheered for the big boys at Winchester. For several years, the 300 Win Mag and 308 Norma Mag were all the rage, then the Winchester started to gain traction because no one chambered factory rifles for the 308 Norma Mag except Schultz & Larson (a Danish firm) So long story short, Winchester's media plan to trickle their new developments out one at a time kind of bit them in the butt, but it all worked out in the end. The 300 Win Mag was followed by the 338 Win Mag, which was later wildcatted to 30-338, an almost exact copy of the 308 Norma Mag. History repeats itself.
Interesting bit o' history: in 1964 Winchester started introducing the 2.5" magnums, designed to fit in a "standard" length action because it was the most common length for both milsurp and commercial actions. Winchester was releasing cartridges one at a time, to make the most of the exposure and hype. The 264 and 458 had been introduced a year earlier, causing a huge media event and much hoopla, and the brass was available. Norma, seeing where this was going pretty quickly, introduced the 308 Norma Magnum, a 30-caliber magnum based on the 2.5" case, and got a lot of press for doing so (Remington did the same for the 7mm cartridge). This kind of torqued the folks at Winchester, who could not just introduce a similar cartridge with their own name. So they decided to outdo themselves, and redesigned the cartridge they already had ready for release so it would beat the 308 Norma Mag by 10%. They lengthened the cartridge, gave it a distinctly more blown out case with a sharper shoulder, and managed to gain about 150 fps over the 308 Norma Mag. They released the cartridge with much fanfare, and since the gun rag writers were always cheering anything that went faster, they jumped right up and cheered for the big boys at Winchester. For several years, the 300 Win Mag and 308 Norma Mag were all the rage, then the Winchester started to gain traction because no one chambered factory rifles for the 308 Norma Mag except Schultz & Larson (a Danish firm) So long story short, Winchester's media plan to trickle their new developments out one at a time kind of bit them in the butt, but it all worked out in the end. The 300 Win Mag was followed by the 338 Win Mag, which was later wildcatted to 30-338, an almost exact copy of the 308 Norma Mag. History repeats itself.
mapsjanhere
New member
Your problem is the .530 bolt face - that's the magnum size, so there are very few target cartridges in that range. You might be able to try some rimmed cartridges like the 30BlaserR or 7x65R, but they're not really all that much weaker than a 308 NM with moderate loads. OTOH, a new bolt for a 1903 cost $25 at Numrich, so your rebarrel might as well include a fresh bolt face, allowing you to pick anything with a standard .47 case - use a 8 mm Kurz if you want unusual and easy to shoot.
Jim Watson
New member
I assume you want to keep the same bolt and therefore the belted magnum bolt face and extractor because it is turned down for scope use and has a low scope safety installed.
Rechamber to .300 Win Mag is more of the same. More recoil than I would want without major big hair in the sights, sounds like it is for you, too.
Rebarrel to 7mm R.M. or .264 W.M. would be very straightforward.
If your paper punching does not require rapid fire, you could rebarrel to one of the WSSMs. A .243 WSSM is about as fast as a .240 Weatherby, and a .224 WSSM is not far from a .220 Swift in ballistics. But they are so short and fat that it can be a challenge to get them to feed out of a box magazine.
All my paper punching is single shot, I even have a "sled" for my long AR and a tray over the magazine follower of my bolt action, so that would not bother me.
Rechamber to .300 Win Mag is more of the same. More recoil than I would want without major big hair in the sights, sounds like it is for you, too.
Rebarrel to 7mm R.M. or .264 W.M. would be very straightforward.
If your paper punching does not require rapid fire, you could rebarrel to one of the WSSMs. A .243 WSSM is about as fast as a .240 Weatherby, and a .224 WSSM is not far from a .220 Swift in ballistics. But they are so short and fat that it can be a challenge to get them to feed out of a box magazine.
All my paper punching is single shot, I even have a "sled" for my long AR and a tray over the magazine follower of my bolt action, so that would not bother me.
Scorch thanks for the info although I'd like to steer away ( down) from the 300 win mag class. But like maps said and what I was afraid of ( although its not a big deal) I'm going to need a fresh bolt face. I'm thinking 35 whelen or something of the likes. Maybe even lower Just don't need the punishing magnum power I have now.
If you're thiking 35 Whelen, (same bolt face as the 30-06 family), then there are almost unlimited options. If recoil is a concern then 35 Whelen is probably not what you want. Once you get into the heavier bullets, even at slower speeds recoil is on par with, or heaver than the .30 mangums with 180 gr bullets and lighter. The 35 Whelen is a good hunting round, but not a top pick for punching paper.
As long as you're going to have to replace the bolt, and you want it for paper punching I'd look at 30-06 or any of the rounds from that family.
As long as you're going to have to replace the bolt, and you want it for paper punching I'd look at 30-06 or any of the rounds from that family.
@jmr40 Recoil was not neccesarily a concern just usefulness and after I posted that I got to thinking about it and I have to agree with you. I mainly just have always wanted a whelen. So to revise my post recoil is not the issue ( although I don't look forward to pointlessly punishing myself) its usefulness. Let's talk cartridges with any powder capacity between 22 and 30 that are known for excellent accuracy that are fairly easy to gather components for. Not looking to replace the bolt like Jimwatson said mine has a "scopeable" handle and " scopeable" safety lever. But i do know to take advantage of wider possibilities i will! Any and all thoughts considered!! Thanks Jmr40
Every way I look at this I see a lot of money spent for very little gain. I'd either keep it as is, and handload to suit my needs. Or sell it and just buy what you really want. You can load it down to 30-06 levels at about the same cost as loading for a 30-06. Good .30 caliber bullets are everywhere. Load up to full power if and when needed.
At the time, Norma indicated that the cartridge was not intended for factory rifles. It had been developed specifically as a "Magnum" load for M1903, M1903A3 and M1917 rifles, which were cheap surplus at the time. The conversion from .30-'06 was fairly easy and made that $29.95 rifle into a Magnum, capable of taking any game in North America. (OK, the .30-'06 could have done that, but the .308 Norma Magnum would presumably do it better.)
Jim
Jim
Jmr40 beauty is in the eye of the beholder...and a lot of money would be spent if you had to purchase a gunsmith...I don't so I'm not too worried about the money. My biggest expense would probably be the barrel. And your right about loading down. I've considered that too...just not sure I want to mess with it and sometimes think I might want something different. Its definitely not going to happen tomorrow IF it happens at all. I have 30 cal bullets and powders and brass for forming...that's expensive too. By the time I add dies I'll almost have a DECENT barrel in a chambering that suits ME.
And,for the history sake,Norma rented reamers to the US gunsmiths to do the .308 and .358 conversions.The market was ammo.
I have a 30-338,essentially the same cartridge.Before I built the rifle,I computer matched velocities and BC's at my hunting altitudes to the Leupold Boone and Crockett reticle.Using a 200 gr Accubond at 2900 fps and a 300 yd zero for crosshair center,I hit the reticle marks to 600 yds,and the windage on the crossbars is good for 12 mph.
I have read the Army Marksmanship Unit used to use the 30-338 for 1000 yd competition.IMO,it has an advantage over the 300 Win Mag for bullet seating room in the magazine.(the 30-338 is a shorter case)
There is one important caution.It is possible the feed rails on your receiver were altered to feed the larger dia magnum cartridge.If so,you may be quite disappointed when all of your standard 30-06 dia cartridges spit out the top of the rifle when you cycle it.
If the receiver has not been altered,go on e-bay and search"1903 springfield bolt".There are plenty,cheap.If you need a scope bolt,there will probably be some.
Very early low number Springfields had some strength/heat treat issues.Boltsfrom this era will have handles tuned straight down.The later bolts show a sweep back.
Look at a Criterion barrel .Thjey are made to be a direct replacement for a Springfield.There is a 1903 and a 1903A3 version.They come nicely threaded and short chambered,parkerized,extractor notch cut,sight details,etc.On an unaltered receiver,itwill come up tight with just a touch more to go to align the witness mark.If the receiver has been faced square,you may have to set it back a thread.
Its not a Kreiger,but Criterion is a subsidiary of Kreiger.Price is under $200.
I have a 30-338,essentially the same cartridge.Before I built the rifle,I computer matched velocities and BC's at my hunting altitudes to the Leupold Boone and Crockett reticle.Using a 200 gr Accubond at 2900 fps and a 300 yd zero for crosshair center,I hit the reticle marks to 600 yds,and the windage on the crossbars is good for 12 mph.
I have read the Army Marksmanship Unit used to use the 30-338 for 1000 yd competition.IMO,it has an advantage over the 300 Win Mag for bullet seating room in the magazine.(the 30-338 is a shorter case)
There is one important caution.It is possible the feed rails on your receiver were altered to feed the larger dia magnum cartridge.If so,you may be quite disappointed when all of your standard 30-06 dia cartridges spit out the top of the rifle when you cycle it.
If the receiver has not been altered,go on e-bay and search"1903 springfield bolt".There are plenty,cheap.If you need a scope bolt,there will probably be some.
Very early low number Springfields had some strength/heat treat issues.Boltsfrom this era will have handles tuned straight down.The later bolts show a sweep back.
Look at a Criterion barrel .Thjey are made to be a direct replacement for a Springfield.There is a 1903 and a 1903A3 version.They come nicely threaded and short chambered,parkerized,extractor notch cut,sight details,etc.On an unaltered receiver,itwill come up tight with just a touch more to go to align the witness mark.If the receiver has been faced square,you may have to set it back a thread.
Its not a Kreiger,but Criterion is a subsidiary of Kreiger.Price is under $200.
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I can guarantee they were altered. The rails would have to be opened in order to feed a cartridge with a .530" belt size. The rails are approximately .510" apart on an unaltered 1903 rifle in 30-06.I'd be willing to bet the feed rails were altered.