Neck up or down for 7WSM?

[Dshooter]

Hey guys, just wondering which would be the better route for my 7WSM. Brass being unavailable, should I neck up 270wsm or neck down 300wsm? Anyone have experience on which is better/more case life...any input is appreciated. I can get either brass rather easily.

 

[Steve Blair]

I neck up .270 WSM to make .300 WSM because Norma .270 WSM is ~$1.12 whereas the cheapest Norma .300 WSM is ~$1.50. Either way would work fine but it's very easy to run an expander into the neck. [br]
http://www.bullets.com/search/?s=category%3abrass%2cbrand%3anorma&s=cartridge:.270+WSM&o=1 [br]
Remember that the 7mm WSM shoulder is a bit forward and you need to engage the lands when fire forming.

 

[jcm24m]

Don't forget to anneal first, it helps!

 

[Steve Blair]

Don't forget to anneal first, it helps!

[br]
They are annealed from the factory. I've expanded hundreds of .270 to .300 in two steps with no problem. Now, annealing after expanding is necessary.

 

[Dshooter]

If I went with WW 270wsm I should anneal before running through the expander then? I need to buy an expander mandrel....

 

[Steve Blair]

I do not anneal before expanding, they are annealed from Norma. Annealing after expanding is a very good idea because the neck will have been work hardened by expanding.

 

[Dshooter]

Excellent! I'll look into Norma brass as well. I have an abundance of winchester available...

 

[Dshooter]

One last question; after expanding, should I anneal then run through the FL 7wsm die?

 

[conor m]

Dshooter , there is a differance between 7wsm ,and the 270wsm (300wsm) brass . is your gun a 7mm /300 wsm or a 7mmwsm

 

[Dshooter]

It is chambered 7mm WSM

 

[Dshooter]

I would be fire forming these cases as you would with any wildcat.

 

[MagnumManiac]

I would be fire forming these cases as you would with any wildcat.

May I ask why?
If you were going the other way, 270/300WSM, into 7mm, then yes, the shoulder needs to move forward by .042", but the FL die should take care of this difference.

May I suggest you size these cases gradually, checking a case after sizing until a case just chambers with a slight crush/interference fit, this will mitigate any potential for early case head separation from excessive stretching. I would start with the die one full turn AWAY from the shell holder, then adjust 1/16 turn at a time as above.

Cheers.

 

[Dshooter]

Hey guys...all the input is valuable to me since this is the first time I've had to work brass to change calibers. So what I understand, expand neck to 7mm, then anneal, then run through the FL die slowly working the die down to get correct or near correct headspace, then fireform? I've seen where people run VLDs jammed to help create the shoulder when fireforming?

 

[Timgunner]

I have the same problem you do. I shoot a 7mm wsm and have tried both 300wsm and 270wsm brass. I have found that 270wsm brass is easier than 300wsm. All you need to do is load a moderate load of powder and seat your 7mm bullet right into the 270wsm case. Make sure to seat the bullet long so that it jams securely into the lands. (I was just touching the lands and being a little careless with seating depth and ended splitting a case in half because of excessive headspace) It is cheaper however, to use 300wsm brass because you can fire form it using the cream of wheat method. The cream of wheat method also saves barrel life because you are not shooting needless rounds down the barrel. You will need to neck size the brass down to 7mm and leave a shoulder on the neck so that it will provide a crush fit when chambered. Load 15gr of unique pistol powder, cover with a bit of toilet paper then fill to the neck with cream of wheat and finally cram toilet paper in the case mouth to hold the cream of wheat in the case. Make sure to load and fire the cream of wheat rounds with the muzzle pointing up so you don't accidently dump cream of wheat into your rifles action and barrel. Also don't fire into the wind unless you want to get dusted with cereal.

 

[Timgunner]

To go from 270-7mm you do not need an expanding mandrel just seat the bullet into the case and the bullet will expand the case neck for you. Also, You don't need to anneal the cases until after fireforming.

 

[Changeling]

Hi Timgunner. Neck UP always when you can.
When you neck up the brass is expanded and doesn’t enter the shoulder area, when you neck down the brass will go to the shoulder (more chance of donuts)!

Just remember, when compressed down the brass has to go somewhere (to the shoulder) , but when expanded the whole area of expansion will grow smaller/thinner, no problems relative to your question.