Necking down to 6.5 saum

[DazzH]

I am going to use Rem 7mm saum brass and neck down to 6.5mm in two stages using bushing dies. Does excessive neck sizing cause excessive runout and if so, is it best to use a sizing button to help straighten out the necks. Anyone have any other tips to help with getting this to go well.

 

[brianc74]

I use a 6.5/300 RSAUM FL die in one stage, then I neck turn into the shoulder a bit, trim to length and fireform

 

[DazzH]

Thanks for the reply Brianc94.
After you have sized down and neck turned I wouldn't have thought fire forming would be necessary? as there are no body dimension or shoulder angle changes to the case. Do you find that necking down works the case to the point where the brass requires annealing sooner than it would normally? Also what powders have you tried.
Thanks
Darrin.

 

[brianc74]

There are suttle changes, so I do fire form. The rifle that I have is up for sale at this time, I only have shot in it 60 times. The rifle was to be my wifes, not no more. I have only tried H4831 sc 55.5 Federal215M with 130 Accubonds. This load shot for me in the .2 .3 at 100 yards 5 shot.

 

[palma]

I have some experience necking down 7mm RSAUM brass to 6.5mm. There wasn't any time to worry with annealing or fire forming -- my barrel was toast in less than 500 rounds. I recommend finding a load quickly as well. Virgin brass shot well for the short time that the barrel was good.

 

[brianc74]

I fireformed the creamweat method, this worked great for me

 

[edlongrange]

BrianC74

I have a 6.5mm-300 RSAUM Improved (40 degree) in development. What mixture did you use for your fireforming - powder (type and amount) and cream-of-wheat (brand - for grain size - and amount)? Did you use a plug? If so, type and size (thickness)?

BTW, I am blowing out the diameter a bit at the base of the shoulder and starting the 40 degree from the base of the original shoulder, not blowing up and out - so the neck length is longer and the powder capacity is about unchanged. These notes in case you were thinking I'd need a heavier fireform load due to possible increased case capacity.

Thank you and God Bless!