300wsm to 270wsm

[ardeekay]

I just got a new rifle in 270wsm... and I have no brass for it, but have dies.. so I ran some 300 wsm thru the 270wsm sizer, and they look good.  I loaded them up with a mild load 130 bullet.  they fit the rifle fine, nothing tight, my question is... are they safe??  I heard that I might have too much thickness in the neck.  I don't want to wreck something...  Bob

[stimpylu32]

bob

The extra brass has to go somewere , in your case its in the case neck thickness , with a light load that has no chambering issues , I don't see were you will " wreck " anything , if you were using a close-to or at-max load that would be another matter all together .

stimpy

[ardeekay]

I shot them today, they were fine, I miked them and they were a tad smaller in the neck than some cheapie Federal factory loads that I broke down and bought... and they shot tighter groups, so I guess they are fine, no signs of being 'hot'..  I found some unprimed 270 wsm brass finally, they are on order..  thanks, Bob

[ardeekay]

Update... I shot them some more, along with some real 270 wsm brass, and noticed that the ones that I made out of 300wsm are developing splits in the neck, I am discarding them, am down to 6 out of original 10 in just 2 shootings.  As I get brass, I will elimate the 'neckdowns'... A year ago, I bought a 338Federal rifle, and didn't have any brass, only 338fed. dies, so I necked  UP some 308 brass, and that worked out fine, my observation here is that maybe its OK to go to a larger size (within reason) but not to smaller calibers???    Bob

[anweis]

when you necked down from .300 to .270 you increased the thickness of the neck, and the rigidity. Thicker brass is less elastic and more likely to crack.
As far as .338 Fed, i also reload that one, making brass from .308 Win. Here, the neck becomes slightly thinner. If brass is of good quality and i don't load close to max, the brass lasts very long. I have cases of Lapua and Nosler that i have reloaded more than 10 times already.

[yooper77]

Update... I shot them some more, along with some real 270 wsm brass, and noticed that the ones that I made out of 300wsm are developing splits in the neck, I am discarding them, am down to 6 out of original 10 in just 2 shootings.  As I get brass, I will elimate the 'neckdowns'... A year ago, I bought a 338Federal rifle, and didn't have any brass, only 338fed. dies, so I necked  UP some 308 brass, and that worked out fine, my observation here is that maybe its OK to go to a larger size (within reason) but not to smaller calibers???    Bob

Did you know the history of the 300 WSM brass before you resized it?  The neck splits because it work hardens if not annealed before firing.

I neck up and down all the time with zero issues.

I make 7mm-08 Remington from 308 Winchester brass, and I double check the neck thickness and measure the loaded cartridge neck to ensure it’s within specs.  I also make 338-06 A-Square and 35 Whelen from 30-06 Springfield brass.

I have also been successful making 243 Winchester brass from 7mm-08 Remington, 7x57 Mauser, 257 Roberts and 6mm (244 Remington) Remington brass.  I annealed them before firing.  The others obviously required trimming and neck measurements, but I have loaded them over 8 times so far.

yooper77

[charles p]

I used to form 25-06 brass from 30-06 cases.  Had many split necks.  I was young and foolish.  Everything was max load too.  Remember one day I shot two doe deer with one bullet.  Lined them up perfectly for a doubles shot.  Had to take my boot off to hammer the bolt open while one flopped around on the bank of a creek.  Fortunately it died before falling in.

[trotterlg]

Odd thing is, when you neck down the neck get longer but not much thicker.  The brass has to go some place, but it ususally is in the length.  If you annealed them after sizing I think you will have no more problems.  Larry