Necking Up Brass from .264 to .338 ?

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So I tried the search function but didn't come up with any answers for my particular question so I figured the best bet was to ask and if someone else can link me to said info great and if not hopefully someone has the information.

So I have a 338 RCM in the works and have Hornady brass thanks to some fellow members. My question is going forward as time goes on and brass wears they aren't making to much of this stuff anymore and it would be nice to get a higher quality of brass.

I happen to have some 6.5 PRC Gunwerks once fired brass. (once I have shot everything I will have 80 pieces total) I am using Nosler premium brass for my handloads so this is surplus to my needs at the moment.

Being a better quality brass what would be the process of necking this up to .338 for the RCM (Dimensions are almost identical so I figure a FL size at the end along with a fire form will be good)

Is the best option to use expander mandrels and go up in 2 or 3 increments ? say .284, .308 and .338 ? or could I use FL sizing dies and just use the expander balls ? I plan to send them off for annealing once I have them FL sized to reduce the work hardening from the necking up.

Any suggestions would be greatly appreciated. I am waiting on the reamer for the rifle so I have a little time to kill before then.

Cheers,
B
 
I have formed 243 Win in one pass from IVI 7.62 NATO - was most definitely a "grunt", but I do not recall losing any - but that is sizing the neck to be SMALLER. To make bigger, I did several new PPU 8x57JS into 9.3x57 - the Hornady 9.3x57 die has a tapered de-capper that seems to handle that fine - in one step. Your idea to do incremental steps might make for less effort - let us know how it worked out for you. Not sure how relatively "blunt" expander ball, like I see on RCBS dies, will work - would think if the expander ball end can enter the .264 case neck, sizing might work?

If you have access to a lathe - is possible to turn your own "expanders" to use in a Lee Universal flaring die - is what I did to take my "re-formed" 9.3x57 to be pretty much straight wall cases - before I got a .41 Rem Mag sizing die.

From various sources, I read that effective lube on outside and inside of case neck might help - is alleged that Imperial Sizing Wax about the best product to use. For the first dozen cases that I made into 9.3x57, I do not use any lube on the necks at all - but your mileage might vary - as they say ...

There is a CGN poster who does as you propose to 30-06 brass - then seats .366" bullets to use in his 9.3x62 - he has gone hunting game with the rounds made to "fire form".

Is also possible, as per some, to "fire form" - load up with small amount of fast powder like Unique or some shotgun powders (8 to 10 grains?) - fill case to brim with Cream of Wheat breakfast cereal and fire pointing straight up - case will more or less "blow out" to match to chamber - although often not completely. Was another CGN poster doing so to make brass for 458 Win Mag, from 300 Win Mag. I have done similar to make 458 Win Mag brass from 7mm Rem Mag brass - so no resizing, except to get parent brass to fit into rifle chamber - "blow out" the neck diameter with the COW. I think you usually get full and final fire forming by the second full house load or so.
 
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Potashminer said:
I have formed 243 Win in one pass from IVI 7.62 NATO - was most definitely a "grunt", but I do not recall losing any - but that is sizing the neck to be SMALLER. To make bigger, I did several new PPU 8x57JS into 9.3x57 - the Hornady 9.3x57 die has a tapered de-capper that seems to handle that fine - in one step. Your idea to do incremental steps might make for less effort - let us know how it worked out for you. Not sure how relatively "blunt" expander ball, like I see on RCBS dies, will work - would think if the expander ball end can enter the .264 case neck, sizing might work?

If you have access to a lathe - is possible to turn your own "expanders" to use in a Lee Universal flaring die - is what I did to take my "re-formed" 9.3x57 to be pretty much straight wall cases - before I got a .41 Rem Mag sizing die.

From various sources, I read that effective lube on outside and inside of case neck might help - is alleged that Imperial Sizing Wax about the best product to use. For the first dozen cases that I made into 9.3x57, I do not use any lube on the necks at all - but your mileage might vary - as they say ...

There is a CGN poster who does as you propose to 30-06 brass - then seats .366" bullets to use in his 9.3x62 - he has gone hunting game with the rounds made to "fire form".

Is also possible, as per some, to "fire form" - load up with small amount of fast powder like Unique or some shotgun powders (8 to 10 grains?) - fill case to brim with Cream of Wheat breakfast cereal and fire pointing straight up - case will more or less "blow out" to match to chamber - although often not completely. Was another CGN poster doing so to make brass for 458 Win Mag, from 300 Win Mag. I have done similar to make 458 Win Mag brass from 7mm Rem Mag brass - so no resizing, except to get parent brass to fit into rifle chamber - "blow out" the neck diameter with the COW. I think you usually get full and final fire forming by the second full house load or so.
Click to expand...

That's some good info,

Thanks,
B
 
Incidentally, I have used the cream of wheat method to form 240 Gibbs brass. It "mostly" works. Shoulders aren't quite square, it is messy (cream of wheat everywhere, lol) and noisy if you are doing it in the house. Had a fairly high failure rate until I either used new brass or annealed the ones I used first. FWIW - dan
 
Awesome thanks for the info everyone. I will be annealing then using expander mandrels to size up the neck then anneal and FL size prior loading. Trimming and neck turning may have to happen at some point during but I will cross that bridge when I get to it.

Cheers,
B
 
I haven't done 0.264" to 0.338", but I've done 0.308" to 0.410" in one pass without issue.

If your 338 RCM dies have an expander that is as gradual as the Lee SE2360, it should work in one pass assuming its minor diameter is under 0.264", and it probably is.

Lee SE2360.jpg
 

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The neck stretched from .264 to .338 = .074.
That's quite a stretch of the neck.
You will start with approx .014 neck thickness and arrive at ? .
If it works the overall diameter with a bullet seated will be less than using the correct brass.
This can create problems with seating in the die you may have very lightly seated bullets.
I do know 7RM can be stretched to .338W with no problems.
 
Honestly there's a decent amount of 338rcm hornady brass out there if you look for it. Buy it when you find it. I have 25 cases that are on their 7th full house reload and the primer pockets are just now getting a bit loose. Hornady brass is pretty good stuff. Especially if you get it annealed. Mine isn't. I have 150 new brass that I have yet to open. That should last quite a while
 
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