Interesting Load Development Results

Jud96

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The 308 Norma is definitely a good one. It's what Winchester should have done intead of the win mag. Remington messed up with the Rums too. The 7 and 30 would be better on the 338 case and 338 would be better on the 30 case. But heck what do I know.
Shep
I agree with you 100%.
 

Mikecr

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Considering that some cartridges can erode the throat at a rate of .007" - .012" per 100 rounds...what is your solution for maintaining that "fine seating"?
You mentioned that seating changes ladders, so do you do another ladder then?
To begin, you should fully test seating before doing anything else. Afterwards, one ladder is usually enough. And the answer to maintaining seating is simply to log best CBTO and measure every round(always) to verify it's there -for the life of that barrel -for that bullet. If you choose best seating off the lands(OTL), you will never have to adjust it again.
The answer to fast erosion is to choose a cartridge/load with slower erosion.
 

Jud96

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I’m not arguing, but you realize 200 rounds in on a mild cartridge will have throat erosion. You may not have to adjust your CBTO, but you may have to in order to keep your groups very small. There’s some data out there that supports finding a consistent seating depth node that will keep your groups in the same point of impact across .010-.020 of throat erosion. I have tried that method some, but haven’t gotten the smallest groups with it. To me, if I notice accuracy loss, it’s simple enough to adjust the bullets a few thousandths until the groups shrink up and call it a day for another 100+ rounds.
 

Mikecr

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If you want to make your own thread describing your better methods, then by all means do so.
I'm not suggesting anything is wrong with your load development, nor your results.
I'm really glad you hit on these results.
 

JMW67

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The 308 Norma is definitely a good one. It's what Winchester should have done intead of the win mag. Remington messed up with the Rums too. The 7 and 30 would be better on the 338 case and 338 would be better on the 30 case. But heck what do I know.
Shep
Got to agree with ya here been shooting a 30-338 win as a elk rifle for years great round
 

25WSM

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Fits in a long action perfectly with the bullet in the case the proper depth. I don't know why it didn't get more popular. The 300 win mag became the go to even though it wasn't really better. This is of course my opinion.
Shep
 

Dog Rocket

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Washington State
To begin, you should fully test seating before doing anything else. Afterwards, one ladder is usually enough. And the answer to maintaining seating is simply to log best CBTO and measure every round(always) to verify it's there -for the life of that barrel -for that bullet. If you choose best seating off the lands(OTL), you will never have to adjust it again.
The answer to fast erosion is to choose a cartridge/load with slower erosion.
So, all the fast cartridges are off the table...

No 6.5 PRC's... no 264 Winmag...no 6mm Remington... no super 30 cal magnums... no 7mmSTW....that's the answer then?
 

25WSM

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Well powder choice and how hard you run them play a huge role in barrel life. Even the little very efficient 6ppc and 6 br eat barrels when run hard like in match barrels. So really the answer is to keep an eye on throat erosion and then chase it after it starts moving. On my match rifles I don't see much of any movement till around 700 rounds. At that point I set them back and redo the chamber to a fresh throat. Then I run them till they are dead. I get around 2000 rounds this way and stay competitive. I've put a bunch of my 2000 round barrels on varmint guns and got another 1500 rounds from them. My best kreiger I ever had has around 5000 rounds on it. It's been rechambered 4 times now and is only 26 inches long in a 6bra and it still shoots 1/4 moa in local matches. Barrel erosion is just something we have to deal with. But it can be motivated somewhat with how we use them.
Shep
 

ButterBean

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So, all the fast cartridges are off the table...

No 6.5 PRC's... no 264 Winmag...no 6mm Remington... no super 30 cal magnums... no 7mmSTW....that's the answer then?
He's a Legend Bud, Im sure he will come back with a snappy well thought out 6 page answer that will make no sense to anyone but him, I mean no offense but his way aint the only way
 

David Emerson

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Drayton,ND
Speaking of cold bore. Here’s the second target I shot for the OCW. See the “Fouler” target, that’s two shots from a cold bore from my original load. I think the cold bore on this rifle is good;). If you want to make your own thread describing your better methods, then by all means do so. I’m not new to load development or precision hunting rifles. I made this thread to share my interesting results and to show how two separate methods gave the same conclusion. As far as seating depth, I seated these 215s .010 off and they shot 1/8-1/4 MOA groups. I don’t think you can improve that lol. I suggest doing seating depth before doing OCW, velocity testing, ladder test, etc. This wasn’t a complete load development thread. Again, this was just showing my results from two separate tests and methods.

View attachment 221728
Such a small difference in powder that you could shoot it another time and change places.
 

David Emerson

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Fits in a long action perfectly with the bullet in the case the proper depth. I don't know why it didn't get more popular. The 300 win mag became the go to even though it wasn't really better. This is of course my opinion.
Shep
Marketing. I know people that would buy winchester shorts and toothpicks if they made them.
 

ntsqd

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Nov 16, 2015
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Upper SoKA
I've long thought the same, that Norma's presence in the US is such that the WM had a sizeable leg up from the start. Had nothing to do with actual performance.

.300 WM cases are good for something, it's easy to make .308 Norma's from them. :) I made 20 from some old Frontier .300 WM ammo after pulling the bullets with a Forster collet puller, and used them to send off seated bullet samples for setting the throat. Thinking that I might just use those cases & bullets for barrel break-in.
Curiously the same exact seating die setting for Sierra 195's when a Sierra 168 is seated instead produces a COAL within .003" of that for the 195. I did not expect that. I know that COAL doesn't mean a whole lot, but I still found it interesting that they were so close.

I've found that I can also use the Lee .300 WM collet sizer die on .308 Norma cases. Really didn't expect that to work, but it does.
 

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