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Questions regarding properly sizing belted cases

 
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  #8  
Old 05-02-2013, 06:51 PM
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Re: Questions regarding properly sizing belted cases

not to confuse anybody, i was of the impression that the 7stw case was made from the 8mm mag case necked down. havent payed attention to case length between the 300HH case and the 8mm mag but thought the 8mm was longer. i owned a 7stw for 10yrs or so but always used stw brass.
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  #9  
Old 05-02-2013, 07:11 PM
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Re: Questions regarding properly sizing belted cases

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Originally Posted by MR.SWIFT View Post
not to confuse anybody, i was of the impression that the 7stw case was made from the 8mm mag case necked down. havent payed attention to case length between the 300HH case and the 8mm mag but thought the 8mm was longer. i owned a 7stw for 10yrs or so but always used stw brass.
SWIFT, you are correct on the parent case,( 8 mm Mag). It can however be formed with any of the full length 375 HH based cartridges. Sometimes it may be a single or double stage affair, but with the right brass, it's worth it. With things being the way they are right now, sometimes it just makes sense to " expand your horizons a bit" .
With Norma brass as the base, the final product will be awesome!
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  #10  
Old 05-03-2013, 04:59 PM
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Re: Questions regarding properly sizing belted cases

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Originally Posted by Greyfox View Post
Having gone through a few different lots of Norma brass in my 300 WM, if have found it to be very consistent in neck wall thickness running .0145". Great brass, but it should be for the price. With once fired cases I will neck size only for 4 firings, then use a body dye and FL size to .002" shoulder push back. All dyes used are Redding. I have found neck alignment with the case, and bullet run out to be consistently less then .002" by using a Redding S dye, with the busing sized to .002" of neck tension. I will back off the bushing knob on the S dye a small fraction of a turn so you can faintly hear the bushing click due to slight looseness in the dye. This seems to allow the bushing to float and follow the fire formed neck. I'll use a very small amount of Imperial wax on the neck. I have not seen the expander on my specific dye cause alignment issues but I remove it anyway. I will anneal the cases after every 4-5 firings. I have used this approach for several belted case cartridges I have loaded for and it seems to produce very good accuracy, ES and case life. IMHO.
Greyfox, when using S bushing dies, are you neck sizing in 1 stroke, or do you rotate cases. I've done that and ended up with very concentric necks, but accuracy was a little less than with necks sized in one stroke. Got me to thinking that could be causing inconsistent neck tension.
I'll back off the bushing knob just a bit as well
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  #11  
Old 05-04-2013, 07:07 AM
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Re: Questions regarding properly sizing belted cases

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Originally Posted by 7stw View Post
SWIFT, you are correct on the parent case,( 8 mm Mag). It can however be formed with any of the full length 375 HH based cartridges. Sometimes it may be a single or double stage affair, but with the right brass, it's worth it. With things being the way they are right now, sometimes it just makes sense to " expand your horizons a bit" .
With Norma brass as the base, the final product will be awesome!
I've heard that and have thought of doing that. I have 0 experience with such case forming. I would.
Think forming 300 HH brass would be a single step sizing, and then fire forming. Can it be ran through a standard FL die for sizing? Can fire forming be done at moderate loads of different components than I'm using for my real loads?, powder, primer, and bullets.
Been thinking about trying it. Sounds easy enough
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  #12  
Old 05-04-2013, 08:00 AM
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Re: Questions regarding properly sizing belted cases

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Originally Posted by cerwin View Post
Greyfox, when using S bushing dies, are you neck sizing in 1 stroke, or do you rotate cases. I've done that and ended up with very concentric necks, but accuracy was a little less than with necks sized in one stroke. Got me to thinking that could be causing inconsistent neck tension.
I'll back off the bushing knob just a bit as well
I have never found the need to rotate during the neck sizing process with Redding dyes. If I have had a neck alignment issue I have found the problem to lie else ware. I have tried collet dyes, rotating and not rotating, and while many swear by them, I have found it difficult to get consistent neck tension, and low ES. Just my experience.
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  #13  
Old 05-06-2013, 08:19 PM
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Re: Questions regarding properly sizing belted cases

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Originally Posted by WapitiBob View Post
Since all our action truing and reloading is about concentricity and parallelism, I find it odd that nobody takes once fired brass and single point turns the neck ID concentric to the case od.
Turning the neck od with a neck mandrel gives uniform neck thickness but it's not concentric with the od of the case. You then have to shoot the brass to get the neck od to conform to the chamber and hope the id stays concentric.
Hmmm, I think maybe your making a good point. Something to think about
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  #14  
Old 05-06-2013, 08:27 PM
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Re: Questions regarding properly sizing belted cases

Quote:
Originally Posted by Greyfox View Post
I have never found the need to rotate during the neck sizing process with Redding dyes. If I have had a neck alignment issue I have found the problem to lie else ware. I have tried collet dyes, rotating and not rotating, and while many swear by them, I have found it difficult to get consistent neck tension, and low ES. Just my experience.
I'm neck sizing only without rotating and they are coming out, for the most part good. Best is .0005, and worse being .003
Even at that I'm getting some good accuracy. This rifle is a tack driver. I'll post pics of groups
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