Resizing help 7mm Rem Mag ?

[FITASC]

I've always got best accuracy with belted cases 2 die sizing them. First die sized only the body all the way to the belt. Second die was gelded sizing only the neck and set the shoulder back just enough to let the case headspace there centering the bullet and neck when the firing pin impact pushed the cartridge to its limits. 20 shots inside 5 inches at 1000 yards in each of two tests.

For ME, every bottle neck cartridge I have reloaded has always given the best accuracy and longest case life by neck sizing only after initial firing. 10-20 reloadings not uncommon

 

[Bart B.]

Delete

 

[Reloadron]

I have loaded no clue how many 7mm Rem Mag cartridges for my Ruger M77 MKII rifle. Started with a set of Lee dies and most recently RCBS dies. My first set of Lee dies worked just fine.

Run the ram to the top of its stroke. Screw full length sizer in, until it touches the shell holder. Then lower the ram and screw the die in 1/4 to 1/3 turn more. Raise the ram and tighten the lock ring finger tight. The decapper is retained by a collet. Should it be overstressed by an obstruction; it simply slides up without damage. To reset, loosen the decapper clamp and position the decapper flush with clamp end and retighten.

Right from the die instructions. This should be exactly what you are doing. Use a good quality case lube, that is important.

Using the above instructions should return a fired case back to SAAMI Specifications for the 7mm Rem Mag. Page 44.

Normally for a start you full length size the case and then trim the case.

Now if you are doing things as mentioned for setting up the die and if there is a die problem then you can send the die back to Lee questioning it or just buy a new die set from another manufacturer like RCBS or other. Once your loads work in either gun then worry about sizing for a specific rifle, till then just load to factory dimensions.

Just My Take
Ron

 

[bacardisteve]

I would separate for each rifle belted magnum brass doesn't last long at fl sizing everytime. Case life will be much longer of you just bump the shoulder .002 and re use the brass in the rifle it was fired from.

 

[Bart B.]

I've got over 20 reloads for 30 caliber belted magnum cartridge cases full length sizing them such as the shoulder is set back a couple thousandths so they headspace on their shoulder.

Bottleneck cartridges typically shoot most accurate when so resized. The bullets are well centered in the barrel to start with.

 

[reynolds357]

I've got over 20 reloads for 30 caliber belted magnum cartridge cases full length sizing them such as the shoulder is set back a couple thousandths so they headspace on their shoulder.

Bottleneck cartridges typically shoot most accurate when so resized. The bullets are well centered in the barrel to start with.

Agreed. That is how I size mine. Primer pockets are almost always my limiting factor.