Have a WSM donor. What to build?

[JTB]

This is the 7 WSM 195gr and 270 WSM 170gr side by side. These are fired from M70s. The 7mm is close to max length for a factory magazine and I lengthened the 270 magazine to give me an extra .125". The 7mm is firing 2950 with 67gr of Retumbo. 7mm OAL = 3.050". 270 OAL = 3.100

 

[SnowbirdUT]

I would build the 7mm WSM instead of the 270 WSM if you can get 2950 fps with the 195 gr 7mm bullet. I am only getting 2980 fps with my 270 WSM.

The 195 gr bullet has a highr BC which will more than make up for the slight reduction in MV.

 

[LoneTraveler]

If you want a Walking Hunt Mountain Rifle weighing in at around 8 lb. with scope, Stainless steel action and barrel, Go with the 300 WSM, And the action and stock you have. This is the 300 WSM's nich. Short action light mountain rifle at near 300 WM power.
Factory Ammo is around with many good loads and bullets available. A walking hunt rifle is a 300 yard, with practice 400 yard rifle. Nosler 180 Gr. partition bullet critters go FLOP. If you want a long range rifle, Shooting long heavy bullets you may have to start over on the drawing board.
GOOD LUCK in your decision and HAPPY HUNTING.

 

[FEENIX]

Unless the OP has change his mind, the criteria is ...

I would like to stick to a cartridge that I can buy off the shelf.

 

[Pulpwood]

Since you talked about elk , my vote would be 300wsm. I have both and enjoy them but elk are big animals . Both calibers will take elk but marginal shots the 300wsm would be a better choice in my opinion. Build it and enjoy

 

[LoneTraveler]

The other thing I would consider and go with the 300 WSM. If you Elk hunt North West USA. Or British Columbia/Alberta Canada you may be hunting in one of these critters back yard and a gun shot is like ringing his or her dinner bell.
With the damage I have seen a 300 WSM 180 Nosler Part. do to Elk and Caribou, I have hunted Alberta , About 50 miles from where this picture was taken and not felt under gunned.

 

[elkaholic]

Since available ammo is a primary concern, I would go 300 wsm. The 270 and 7mm are much less likely to be available everywhere. Besides, the 300 has a lot of versatility!....rich

 

[FEENIX]

Since available ammo is a primary concern, I would go 300 wsm. The 270 and 7mm are much less likely to be available everywhere. Besides, the 300 has a lot of versatility!....rich

Ditto!

 

[RockyMtnMT]

I am with everyone on going with the faster twist. With the yardage that the OP has given that appears to be 600y max there is no reason to go with the big heavy, slow MV, short point blank range, slower impact vel, less shock on impact. I could go on... All of the wsm cartridges mentioned will do what the OP wants with good bullets running in the low to mid 3000's mv. And do it with more ease of making the shot with better terminal performance. All the talk about big heavy bullets, particularly in the wsm factory rifle, cause case capacity and magazine feeding problems.

The big heavies simply do not do anything better until ~1000y and beyond. They might give you a 2" wind advantage at 800y but suffer everywhere else. Impact vel is a better comparison than energy when using a quality bullet. Energy is an arbitrary figure good for comparing different cartridges around the campfire. If the task is beyond 1000y then the big heavies win. But only after 1000y.

With all that said larger caliber bullets offer better terminal performance. There is no replacement for displacement. 7wsm with 140g to 150g bullets with non disintegrating projectiles would be my choice for this OP.

Steve

 

[calib]

Just seen the off the shelf portion

 

[FEENIX]

How does a 6.5-300wsm sound? No turn brass and get a 147 to 150 grain at 3250plus? Got a Smith near by who just put one together and they have ran it up over 3300fps with 150 grain in bertram brass and got great brass life.

See post #46.