.350 Rem Mag case forming

4fifty8 said:
Picked up a tube cutter works pretty good way faster than hack sawing & clean cut. By coincidence hold cutter against flat surface & twist case to cut to length it's only 0.003" shorter than spec case length. ��

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Get an archery arrow cut-off saw... thank me later.
 
With tube cutter production rate much faster only couple minutes to form .350 RM case -

  • lube .338 WM case then force thru .350 RM form die
  • cut to length with tube cutter & de-burr
  • lube & FL re-size - done

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Using .300 Win Mag brass (tried W-W & PPU) neck OD +0.005" won't chamber probably neck OD's need to be reduced by that much, or to be so-called turned.


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I presume that your newly formed necks are actually what used to be shoulder on the parent brass - so likely thicker stuff?

If it helps, I looked at the SAAMI drawings for cartridge and chamber for 350 Rem Mag. There is a note on that sheet that all diameters are + .002" - so I presume the actual acceptable dimension is the dimension given, as minimum, with additional .002", as maximum.

For the cartridge, it looks like they call out a neck that is 0.388" with a bullet seated - the same diameter at case mouth as at case neck meeting shoulder.

For the chamber, it looks like the case neck at the shoulder is called out as 0.390" and at the mouth of the case neck is 0.389". So, using their minimum dimensions, looks like SAAMI wants minimum of 0.001" clearance between a loaded round's neck, and the chamber at the case neck mouth, then 0.002" clearance where the neck meets the shoulder. I have no clue what actual dimension your chamber is - but I suspect that 0.001" / 0.002" clearance is what you should be after?

For those that do not know, the "old school" sizing die with the expander ball, will scrunch the outside of the neck to be too small at the top of the press stroke, then pulling that expander ball out is supposed to open out that mouth to be concentric and the appropriate size for seating a bullet. So, one could play with the diameter of the expander ball, to get variance of "neck tension" on that bullet. Versus more "modern" bushing dies, that size the inside hole by pressing on the outside of the case mouth only - I would think that very much relies on the neck wall thickness, to end up with desired "tension" on the bullet.

I notice from your picture that you are measuring an empty case neck - it might be significant that the SAAMI drawing shows dimensions with a bullet in the neck - from various references here, I think the case neck gets "stretched" circa 0.002" when a bullet is seated - I am not sure what that translates to for increased outside neck diameter. But, as you found, idea is to get the round to fit snuggly to that chamber - whatever the actual numbers might be.
 
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Likely neck dimensional issues using .300 Win Mag brass now I know. I'll just stick with using .338 Win Mag brass to form .350 Rem Mag these chamber just fine. ✔️
 
I use .30-06 brass to make .257 Robt. The first step is using a .308 Win die to push the shoulder back and then use a tubing cutter to trim the neck to just over length. Using the pipe/tubing cutter I can get close to the length I need cutting down on the amount of brass I need to trim after sizing the neck down. It is also cleaner as no metal cuttings just little brass rings.
 
Yup! Picked up a minty Rem600 and made some brass from 7mm rem mag using a redding forming die. Did have the belted bulge issue and have ghe Larry Willis die coming. Hopefully range session this weekend
 
Nice rifle! 7mm RM brass another option then. Using unfired .338 Win Mag brass no issues I thought if using fired re-sized .338 WM brass belt bulge might be an issue so haven't tried that.
 
RCBS Hand Case Neck Turner

  • formed Hornady .338 WM brass to .350 RM no issues
  • other .338 WM brands formed incl. Winchester neck wall too thick won't chamber
  • Nosler .350 RM brass with bullet neck OD 0.383" - spec
  • Winchester .338 WM to .350 RM with bullet neck OD 0.391 - no go
  • picked up RCBS case neck turner & 35 caliber pilot
  • used neck turner reduced OD by 0.004" to 0.387" with bullet - chambers fine ✔️
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I watched the video, good on ya for doing that

but I still don't get how using the tubing cutter is easier or faster than running a hacksaw over the trim die like it is designed for
 
boxhitch said:
Does the trim die leave the brass with an over-size neck?
do you run it through a FL 350 sizer after?
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RCBS Manual downloaded from RCBS website says that cases are to be sized, trimmed to length and chamfered, BEFORE using this neck peeling tool - I presume that means the various neck pilots are sized to the inside neck diameter after sizing, not after firing. I used to have a similar tool made by Forster - called a HOT100 - Hand-held Outside neck Turner - did not make a lot of sense to me how it could work "accurately" unless the case neck was snug to that pilot - minimal to no "wobble" when rotating that case to trim mouth wall thickness - as per Forster advertising, the pilots were sized 0.002" to 0.0025" smaller than the bullet ultimately used - I do not know about the RCBS sizing.

That 0.002" undersize inside neck diameter is same as recommended by Richard Lee in "Modern Reloading - Second Edition" for re-loading that relies on "neck tension" to hold the bullet in position and allow powder to build up pressure - is not the technique used in all instances - I am pretty sure there was a technique with precision cut custom neck sizes, to size neck diameter so bullet almost could be "pushed through" with thumb pressure - bullets were seated long when reloading - idea was bullet would be "re-seated" and snug to lands when fired - no "jump" at all - I believe that was a "bench rest" - all out accuracy - thing - never seemed overly practical for hunting use. I am sure that the main guy in the Houston Warehouse experiments was NOT resizing his brass between loadings - relying on the precision sized neck in his chamber and fussing a lot with the brass case neck - so simply the expansion when firing was enough to let go of the bullet and size of his case mouth in chamber restricted how much larger his neck could expand in diameter - and he was only getting circa 0.020" 5 shot groups at 100 yards - I am very sure that I could not even measure that size of group!

I also had owned "one" 30-06 RCBS Trim die - it did nothing to the case wall thickness - just appeared to hold the case neck relatively snug to be sawed off to length - I do not think it was meant to substitute as a sizing die?
 
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With Redding form die after trimming & de-burring run formed case thru FL die & done if Hornady .338 WM brass otherwise neck turning next step for Winchester & PPU maybe others for my rifle.

Neck turning as required to meet rifle chamber dimensions.
 
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