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Thread: Difference in 30-338/308 Norma

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    Member bigswede358's Avatar
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    Default Difference in 30-338/308 Norma

    What if any is the difference between the 30-338 and the 308 Norma Mag? I have heard the 30-338 is a little hotter but my 358 Norma would like a little brother.

  2. #2

    Default Not Much

    The real difference in in 30-338 and 308 Norma Mag is the cost of brass, the 338 WM brass is made by all manufacturers and is much cheaper and more available. The rifles have basically the same ballistics and can be built on the same actions. GOOD LUCK...!!
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    I've also been told that 338 WM bras can be necked up for use in the .358 NM, so with that in mind I would think they would be near identical, but I don't have case dimensions in front of me.
    Vance in AK.

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    Thumbs down

    Ballistically they are very similar. The 30-338 is the 338 Winchester necked to 30 caliber maintaining the same headspace dimension. The Norma case (308 or 358) is longer by about .020 to the shoulder and has about .020" greater headspace dimension. That is a lot of headspace! Do not fire 338 win brass in Norma chambers! The 308 Norma will hold a bit more powder than the 30-338.

    This is the third time this particular caliber has been mentioned in just such a way, and there is always someone who say to use any old brass that looks close.

    If the dimensions of a case don't matter to you why bother reading what's stamped on the barrel, just buy what ever ammo is cheaper.

    Oh, yeah! Norma brass is expensive and that is a good reason to forget about the calibers but don't think you can safely use Win mag brass in a Norma chamber.
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  5. #5

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    Have owned one built on a remington action with a krieger barrel loved it and so did the doctor that offered me more for it than I could turn down.Great rifle and very accurate shot in the 4s at 100 yards and 5shots into 6 inches at 500 yards as long as I did my part it shot better than I could on any given day. Doc shoots deer with it out in west texas 584 long steps is his longest shot so far he now has bought all the new laser rangefinding gadgets so he will know exactly how far he is shooting ok I guess if thats your thing I know my limits targets are one thing game is another.The point here and to answer your question you will be very happy with a 30-338 of the 5 I have loaded for and the one I owned they all were very accurate and easy to reload for I will build another one some day and keep it. The Normas are fine calibers but Murphy is on the money as far as the brass goes it is expensive and there is enough difference in the two to get you in trouble if you try to use 338 brass just not worth the trouble good shooting Ronnie

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    Here is some data for the 30-338

    http://www.reloadersnest.com/frontpage.asp?CaliberID=52


    And the 308 Norma

    http://www.reloadersnest.com/frontpage.asp?CaliberID=64

    I am a Norma Cartridge fan. Yeah Norma brass is expensive. So is good beer...
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    Quote Originally Posted by Murphy View Post
    Ballistically they are very similar. The 30-338 is the 338 Winchester necked to 30 caliber maintaining the same headspace dimension. The Norma case (308 or 358) is longer by about .020 to the shoulder and has about .020" greater headspace dimension. That is a lot of headspace! Do not fire 338 win brass in Norma chambers! The 308 Norma will hold a bit more powder than the 30-338.

    This is the third time this particular caliber has been mentioned in just such a way, and there is always someone who say to use any old brass that looks close.

    If the dimensions of a case don't matter to you why bother reading what's stamped on the barrel, just buy what ever ammo is cheaper.

    Oh, yeah! Norma brass is expensive and that is a good reason to forget about the calibers but don't think you can safely use Win mag brass in a Norma chamber.
    Murphy:
    With a belted case that headspaces on the belt, how can .020 clearance at the shoulder be unsafe.

    Wouldnít the shoulder just move forward .020, and fire form to the chamber?

    Over on another forum, I heard someone complain that new brass for some belted cases was as much as .043 less than a fired case.

    At the range last year, I picked up some 300 WM brass that had evidently been fired in a 300 Weatherby. Other, than the almost missing neck, it looked great.
    I donít think this is a good, idea and wouldnít advocate it, but I think it illustrates the safety of headspacing with a belted case.

    I shouldnít think that unsized 300 WM brass would fit in a 308 Norma chamber, because the shoulder and the case are both longer. If it chambered it could certainly be unsafe.

    Also, if the 30-338 is the same shoulder length as the 338, at 2.040, isnít that .045 shorter than the 308 Norma at 2.085, rather than .020? (From Lymanís 47TH)

    Anyway, Iím sure you know more about Wildcats than I do.
    Smitty of the North

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    Smitty,

    You're right about the shoulder length it is about .045" or .042" difference depending on which reference I use. I was running from memory and struck out. But that is a lot. No it isn't headspace since the belted mags headspace on the belt.

    Yes the brass will just fireform to the chamber and fit quite well. If it is new brass that is still soft enough to form, it may be OK. But that brass stretches almost all of that dimension just in front of the belt. This is a common cause of failure in belted brass. The brass then becomes very thin at that point and subsequent firings can seperate the case. When this happens gas can get past the case head and push the magazine out of the rifle. (depending on the model of rifle how they are damaged).

    No one who is knowledgable about this sort of thing advocates fireforming with full loads and a bullet for this type of case. Usually it's the Bullseye and Cream-o-Wheat technique.

    If a case that is headstamped the sane as the chamber is .043" shorter to the shoulder something is wrong and I wouldn't fire it.

    Headspace is usually only.006" difference between the Go and the NoGo gages. Some belted case are less. But this .045" gap in the front of the shoulder which would be h/s dimension on a beltless case, is not a good thing. I think it does not show good judgement to fire a round with that much slop. I watched a guy destroy a really nice Steyr rifle by firing a 7-08 round in a 7x57 chamber, just a few thousandths difference.

    Either of these two cartridges would be very good rounds but they are not the same and it is a mistake to take them as being interchangable.
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  9. #9

    Default mistaken

    [quote=Murphy;

    Either of these two cartridges would be very good rounds but they are not the same and it is a mistake to take them as being interchangable.[/quote]

    I've read this entire thread and reread it and nowhere has anyone suggested that these rounds are the same or interchangable. The only comments made are that they are close in ballistic performance and are capable of being chambered on the same actions.
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    Murphy:
    Thanks for getting back to me on this.
    (Regarding my 7mm RM.) If Iím reading my RCBS Precision Mic correctly, I am about .038 shorter to the shoulder with Rem. Unfired, compared to Fired and Sized brass. (This isnít an average, but a comparison of just the two cases.)

    My usual practice has been to fire form NEW brass with a light load, maybe even with a light for caliber bullet, and a light to moderate load, but I have made and successfully used hunting loads from New Unfired brass. Iíve been OK so far.

    Iíve read that it is common practice to have a lot of space at the shoulder in brass or loaded ammunition for belted cartridges because of the safety factor the belt provides. However, until recently, I wasnít aware that the difference in shoulder length could be so great. Iíll pay more attention to this in the future.

    Iíve always heard that the incipient case separation at the head of a belted case was due to repeated sizing of the shoulder too short for the particular chamber. And, that the same can be true of a rimless or rimmed case.

    Thereís quite a bit of difference in the shoulder lengths of the 7mm-08 compared to the 7x57, and of course, neither of them have a belt.

    This is probably off-subject, but I think belted cases have taken a bad rap. Any problems Iíve had with loading belted cartridges, were all due to my believing the stuff about how hard they are to reload.
    Smitty of the North

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    Quote Originally Posted by brav01 View Post
    The real difference in in 30-338 and 308 Norma Mag is the cost of brass, the 338 WM brass is made by all manufacturers and is much cheaper and more available. The rifles have basically the same ballistics and can be built on the same actions. GOOD LUCK...!!
    What does this mean?

    If the difference is the price of brass that implies they are the same. What exactly are you saying here?

    What is Vance saying here?

    [I've also been told that 338 WM bras can be necked up for use in the .358 NM, so with that in mind I would think they would be near identical, but I don't have case dimensions in front of me.]


    This is leading someone to beleive that 338 can be used to make either 308 or 358 Norma.
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    Murphy asked "What is Vance saying here?"
    "I've also been told that 338 WM brass can be necked up for use in the .358 NM, so with that in mind I would think they would be near identical, but I don't have case dimensions in front of me."

    I was speaking of near identical ballistics if the cases were so near in dimension.
    I believe Bidswede was asking of the ballistics of the 30-338 compared to the 308NM, not case dimensions.
    Sorry if I messed anyone up.
    As far as using 338WM brass for the 358NM, the Speer Manual #12 says "If factory brass cannot be readily found in your area, cases can be made by necking up .338 Winchester cases & fire-forming." I've read the same thing in several other places. I haven't tried it yet myself. I have a .358NM that supposed to be wandring this way from my brother in law, but you know how those brother in law things go :-)
    Vance in AK.

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  13. #13

    Default difference

    The original question delt with the ballistic performance not the manufacture of nor interchanability of Norma brass. As stated the ballistics of these rounds are very simular and both calibers can be chambered in the same action size, I'm very sorry if you read this to mean the brass was the same. The 338 WM brass is more readily available than Norma brass and far less expensive. The best 308 NORMA brass is made from 300 H&H brass according to my 1987 DONNELLY, pg.355. I also NEVER said you could make 308 Norma out of 338 WM.
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    Default Yes Balistic difference

    I was speaking of near identical ballistics if the cases were so near in dimension.

    As far as using 338WM brass for the 358NM, the Speer Manual #12 says "If factory brass cannot be readily found in your area, cases can be made by necking up .338 Winchester cases & fire-forming."

    Yes, as a matter of fact I was asking about ballistics but that has raised questions about case dimensions. The 30-338 is made by necking down 338 win mag brass and fireforming, i have heard this is also how to make 308 Norma brass, is this untrue?
    And yes you can use 338 win mag brass necked up and fireformed to make 358nm. Last year I turned my Rem. 700 77mag into a 358 nm and my father in law his Ruger mark 1 77mag into one also. We both fireformed 338 win mag brass to make 400 pieces of 358 nm brass between us. Both rifles shoot extremely well. We haven't had any problems with the brass at all.

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    Default Loading Belted cases...

    This is outside the original question but still applies since it is about belted magnums.

    They aren't difficult to reload. Same procedures apply for both rimless and belted. The precaution is about setting the shoulder back each time the case is resized. This WILL result in a seperated case. On the first firing with new brass, the brass is soft and will stretch easily and of course it will fit the chamber. Brass at 60,000 psi is like bubble gum. It will fit the chamber but this stretch weakens the case in a critical area. The belt and cartridge head form a gasket to prevent the high pressure gas from escaping the chamber and wrecking the action, the gun and the shooter. When the case separates just in front of the belt, gas can cut a lengthwise slot in the case head and exit the action. I can assure all of you, when this happens it will be a memorable event. This seperation can also occur in the sizing die and you'll extract only the head and belt. Then the fun begins when getting the body out.

    When a loading manual say fire forming, this very likely means with inert filler and fast burning pistol powder. (corn meal and Bullseye) When we use this technique it pushes the shoulder forward. When we load with a bullet and fireform it stretches the case at the webb just ahead of the belt.

    The belted case are loved by the brass and ammo makers because so much slop is allowed around the shoulder due to the headspace dimensions. Headspace is from the bolt head to the front of the belt. The shoulder doesn't have to touch and the cartridge just lays in the chamber and the only alignment is from a bullet fitting loosely in the throat of the chamber. They are very sloppy. That's why they show great improvement when they are handloaded and headspace on the shoulder.

    I've loaded for over 100 calibers, many of them I've designed myself and developed the load data for them and at least two dozen other wildcats. I load and fire over a 100 rifle rounds every week and often twice that number. I've seen many problems that most handloaders never see. I give advice freely based on my experience not on what I've heard or read about something someone else did. I'm not guessing or speculating but I realize full well the same experience may turn out differently for others.

    I seem to confuse the issue more often than not. I try to offer something beyond the initial question because of what I've experienced with the situation and try to prevent difficulties. This rarely works. I think to prevent further confusion I'll steer clear of handloading advice and just sit back and moderate. Life is good.
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    Please don't do that Murphy, the rest of us will be much the poorer for it.
    I for one find your posts EXTREMELY informative, & look forwrd to them.
    I also agree completely with what you are saying about fireforming with hot powder & inert filler. Makes sense plus it's easy to do in the garage & doesn't cost me a bullet, just a bit of powder & a primer.
    Vance in AK.

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    Murphy, I have got to disagree with you. I have a 308 Norma and I use 338 brass in it. Using a full length resizing die to neck down the 338 win leaves a second sholder upon which to head space. After fire forming it will go right in without any problems. On the necking up for the 358, one would have to expand the neck beyond 358 (375?) then neck it back down to 358. This I have not tried and bet you would lose some brass in the process.

  18. #18

    Default Agreed

    [quote=Vance in AK;77524]Please don't do that Murphy, the rest of us will be much the poorer for it.
    I for one find your posts EXTREMELY informative, & look forward to them.
    I also agree completely with what you are saying about fireforming with hot powder & inert filler.

    I second the motion, MURPHY. Just trying to set the record straight,on my part, not trying to DIS you guy. I like your input.
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    Quote Originally Posted by OldRgr View Post
    Murphy, I have got to disagree with you. I have a 308 Norma and I use 338 brass in it. Using a full length resizing die to neck down the 338 win leaves a second sholder upon which to head space. After fire forming it will go right in without any problems. On the necking up for the 358, one would have to expand the neck beyond 358 (375?) then neck it back down to 358. This I have not tried and bet you would lose some brass in the process.
    Hey, I don't mind if folks disagree with me. In fact I would prefer that they do when they have a better way or can offer something further, just as you have done. Yes, you're right, that works great. I've done that my self many times. Make a false shoulder to headspace the case for the first firing. Of course this is much better than just load and fire. You obviously understand what's going on and how to make brass that will last. No problem with the 338 Win brass being a little shorter.

    Another real good way to make 308 Norma is use 300 Win Mag brass and push the shoulder back a little at a time 'til it fits. I get a few oil dents but they iron out. There are lots of good ways to make brass for odd calibers and it can be done cheaper and safely.

    The first belted magnum I ever owned was a 308 Norma, I've been loading for one and making brass for about 35 years. It has always been hard to find brass for it and I couldn't always afford Norma brass. I once got a good buy on Winchester 458 brass and that works very well for 358 Norma because it is annealed and forms very well. Like I said a little short doesn't matter. That is also the best way to make the 416 Taylor or the 375 Taylor (375-338).
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    Murphy:
    This kinda stuff is interesting to me.

    I read a post somewhere, where a guy used 300 WM brass for the 358 Norma because the shoulder was longer. The necks were longer after resizing, but instead of trimming them, he had the neck of his rifle chamber extended. He could also safely fire 358 Norma factory loads.

    I've been keeping this in mind, because I've toyed with the idea of rechambering a rifle to 358 Norma.

    It sounds like it would work. Whatcha think?

    And, Thanks for the "head up" regarding excessive shoulder space with belted cartridges. As I said in a previous post, I didn't realize it could be so great.

    Smitty of the North

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