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338 NM to 338 NMI. 338 LM to 338 LMI

I have a few barrels that are chambered in 338 Norma, 300 Norma, and 338 Lapua.

1. Can I run a 338 NMI chamber reamer into a Saami 338 NM Chamber?
2. Can I run a 300 NMI chamber reamer into a Saami 300 NM chamber?
3. Can I run a 338 LMI chamber reamer into a Saami 338 LM chamber?
4. For my 338 LM, should I just go to 33XC instead for less hassle?
5. How arduous is it to get Improved Dies made?

Thank you for your input.
 
I don’t see why the improved reamer wouldn’t clean up a normal norma though many don’t like running reamers into used barrels.
Bullets central has some improved Norma dies for the 35 degree shoulder.
 
I don’t see why the improved reamer wouldn’t clean up a normal norma though many don’t like running reamers into used barrels.
Bullets central has some improved Norma dies for the 35 degree shoulder.
I would think so too. Hopefully it is just a short reaming job and maybe set the shoulder back on the barrel for headspace?
 
It depends on how the older reamer specs match up with the new reamers. Many, many ways for this to go badly. Good luck is all can say! Personally I would not do this.
Yeah, I'll have to have my gunsmith check the improved reamer specs. If it saves me the cost of 3 barrels, that are good shooters, then I think it is worth it.
 
Alex,

Is the 338 Lapua Imp more accurate than the 338 Norma Imp? I have a Sako TRG 42 in 338 Lapua and its had a lot of rounds through it, It still shoots pretty good groups but the throat is starting to show wear and firecracking. I had thought I would switch over to the Norma round when I re-barrel it.
 
I do a lot of norma and lapua imps. No you cant just run them in. You will have excessive headspace.
I’m guessing the intersection of the shoulder (between the normal Norma and improved Norma) is near the normal datum so the inner portion of the shoulder near the neck junction wouldn’t clean up at normal headspace?
 
Alex,

Is the 338 Lapua Imp more accurate than the 338 Norma Imp? I have a Sako TRG 42 in 338 Lapua and its had a lot of rounds through it, It still shoots pretty good groups but the throat is starting to show wear and firecracking. I had thought I would switch over to the Norma round when I re-barrel it.
That I cant say. We have done more target work with the lapua. The norma has been all hunting rifles. Id have to assume its right there with the lapua but it does require drop tubing. The main reason for the norma is mag feeding. If your going single shot Id do the lapua. It shoots so well I have been temped to try it in 1k br many times. The 10 shots in heavy is the only reason I havent. If it was 5 shots it would be competitive.
 
That I cant say. We have done more target work with the lapua. The norma has been all hunting rifles. Id have to assume its right there with the lapua but it does require drop tubing. The main reason for the norma is mag feeding. If your going single shot Id do the lapua. It shoots so well I have been temped to try it in 1k br many times. The 10 shots in heavy is the only reason I havent. If it was 5 shots it would be competitive.
Cool, Thanks, May just stay with 338 Lapua and do the Improved.
 
I called Manson Reamers today and spoke to them about my question. Their opinion was, that it is possible though not common. If they design the reamer right, it will basically just clean up the chamber then my gunsmith can set back the shoulder on the barrel-action junction and cut back a thread or so.

Now because I am using a 1-1/16 thread tenon, I should not load these cartridges to max pressure but instead back them off slightly so I don't get sticky bolts and have issues extracting. Which is fine with me because I hate loading to max pressure anyways.

For resizing he said he can make a resizing die reamer and that he recommended I go to a 1 inch diameter die rather than the usual 7/8 inch die to ensure I can properly resize the web above the extractor groove.

Lastly he recommended a 35 degree shoulder as it's a little less stress on the brass than the standard 40 degree shoulder during fireforming.
 
I called Manson Reamers today and spoke to them about my question. Their opinion was, that it is possible though not common. If they design the reamer right, it will basically just clean up the chamber then my gunsmith can set back the shoulder on the barrel-action junction and cut back a thread or so.

Now because I am using a 1-1/16 thread tenon, I should not load these cartridges to max pressure but instead back them off slightly so I don't get sticky bolts and have issues extracting. Which is fine with me because I hate loading to max pressure anyways.

For resizing he said he can make a resizing die reamer and that he recommended I go to a 1 inch diameter die rather than the usual 7/8 inch die to ensure I can properly resize the web above the extractor groove.

Lastly he recommended a 35 degree shoulder as it's a little less stress on the brass than the standard 40 degree shoulder during fireforming.
Manson has a page dedicated to Ackley Improved cartridges that has been posted on their site for years.

If you read it, You will see that the Ackley improved cartridges are about 0.004 shorter than the standard chambering. So what they told you is what has been the case for a long time, P.O. Ackley designed these cartridges so that you could still shoot factory rounds if needed or if that was going to be your method for fireforming.

This is why you must turn off one thread in most cases to be able to chamber the Ackley properly. You can use the standard cartridges go gauge as a no-go gauge if you stop chambering when the bolt will close about half way on a go gauge, After tightening the barrel, It will only close a little above half way. The case will have slight resistance when it's chambered.

Now on the 338 Imp. I do not know how many thous shorter it is, If it even is, Their are lots of improved cartridges and many of them have their own designs and specs.
 
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