7mm-300wsm reloading

[21buck]

mw185, Use the full length die to resize the 300 wsm to a 7mm. Lube it properly and run it thru the die. There are no other items necessary.

You could anneal the neck and shoulders before you load them. Make sure that the length is correct. and you are good to go for the first firing.

Second loading, I extend the expander and primer pin a bit farther down. What you want is the die to engage enough to pop the primer out and resize the top of the neck , not the entire body of the case. Take your time and it will work out easily. You do not want to extend the expander and primer remover too far. Be careful in your adjustment . Check case length.

When do you resize full length? Normally after 4-6 reloads and always with brass to be used on hunting trips. This is important that the cartridges feed smoothly and effectively.

[dirtball]

If it were me I would buy a Redding Type S full length sizing die and a couple of bushings to neck the 300 WSM case down to 7mm and a Redding 7mm WSM seating die.
Once you work out what bushing gives you the proper neck tension and you start shooting the rifle, adjust the full length sizing die so that it sizes the case and bumps the shoulder just enough to allow the bolt to close easily.
Dave

[21buck]

Why do you feel that you need a 7 mm necking die. I use RCBS dies. They are good and last . I.e. 7mm/300 wsm full length resizing die. You have a 300 wsm case and want to make a 7mm x 300wsm case. follow previous instructions and you have a 7mm x 300 wsm case , length to check, primed, powdered, and bullet seated.
I don't understand the problem of going from a 300 to a 7mm. Another example , 30-06 to a 25-06 . Use a 25-06 full length die on a 30-06 case and you have a 25-06 case.

21 buck

[dirtball]

Originally Posted by 21buck

Why do you feel that you need a 7 mm necking die. I use RCBS dies. They are good and last . I.e. 7mm/300 wsm full length resizing die. You have a 300 wsm case and want to make a 7mm x 300wsm case. follow previous instructions and you have a 7mm x 300 wsm case , length to check, primed, powdered, and bullet seated.
I don't understand the problem of going from a 300 to a 7mm. Another example , 30-06 to a 25-06 . Use a 25-06 full length die on a 30-06 case and you have a 25-06 case.

21 buck

The 7mm WSM and the 300WSM do not have the same body length or neck length and dies are either "Custom Dies" or adapted from 300 WSM.
Read the link I provided in the post above and you will see a drawing of the two side by side.
Dave

[21buck]

I would strongly suggest that you look at RCBS dies. Once you have a 7mm/300wsm full length sizing die , you can form your 300 wsm into the 7mm x 300 wsm cases. Be sure to lube them adequately. There are no other dies or inserts to contend with. Measure , trim as necessary, prime, powder, bullet to the correct length and you are good to go.

[mw185]

Sorry, still need some clarification.Dave-when you say redding fl type s is this die stamped 300wsm?. 21-when you say 7mm/300wsm full length die is this die actually stamped 7mm wsm?

[dirtball]

RCBS makes a set of dies for 7mm/300 WSM. It is a Special Order and has a price of $143.00, and according to Midway will take 90+ days to get.
RCBS 2-Die Set 7mm-300 Winchester Short Magnum (WSM) - MidwayUSA

You could call RCBS to see if you ordered it direct from them if it would be faster.
BUT any set of dies that has a "standard" neck diameter that sizes the neck down much more than necessary and then expands the neck back out with an expander ball/mandrel usually results in a case that is not concentric at all.
I still think the 300 WSM Type S FL die with the appropriate bushings is the way to go.
JMHO

Dave