6.5/300 WSM vs. 6.5 Rem. Mag. case capacity difference?

[longrangehunter]

So I've been wondering, what's the case capacity difference between the 6.5/300 WSM and/or a 270 WSM and a 6.5 Rem. Mag.?

 

[DrMike]

270 WSM -- 79.50 grains of water
6.5 mm Rock -- 79.50 grains of water
6.5 mm Leopard --75.00 grains of water
6.5 mm RM -- 68.00 grains of water

 

[longrangehunter]

Thanks Mike. I was going to ask you in the first place since I knew you'd have an answer for me.

I started with IMR 7828 ssc and now I'm using Retumbo, and a 140 gr. GK but the group opened up a lot and bolt lift seemed to increase with any more powder then 65.0 grains, which was my starting point. I average 2992 fps 20' from the muzzle with that load. Not all that fast I know, but I stopped tinkering since the barrel life is so short, I only have 16 rounds fired through the gun. Not even broken in I know, but I've been too busy building a house.

Thanks again Mike.

 

[257 Ackley]

Cole -
which caliber are you loading for? I have the 6.5/300WSM and use MagPro with great results.

 

[longrangehunter]

Cole -
which caliber are you loading for? I have the 6.5/300WSM and use MagPro with great results.

It's a 6.5/300 WSM also. I have a great load using Retumbo and 140 GK, but not a lot of speed, but it does make bug holes after the first fouler goes down the tube. I just tried to attach a photo of a target only it kept saying the file didn't exist? Not sure what's up?

 

[257 Ackley]

What is the twist in your barrel and what velocities with Retumbo and 140GK? I have some 139 and 140 grain bullets to start working up loads for this spring. I only got a great hunting load with 130 grain Siroccos worked up last summer.

 

[longrangehunter]

What is the twist in your barrel and what velocities with Retumbo and 140GK? I have some 139 and 140 grain bullets to start working up loads for this spring. I only got a great hunting load with 130 grain Siroccos worked up last summer.

I have a Shilen Select Match 4 groove ratchet barrel with a 1 in 8" twist and a .300 neck. The load I developed produces an average velocity of 2992 fps 20' from the muzzle with 65.0 grains F215M primer and a 140 GK @ 2.4200" ogive length =/2.914 oal. My reasoning for using a GK is that the bullet does not have to be seated as deep as a lot of the other bullets out there and that I have had good success in making an accurate hunting load.

Speaking of which: I have a 100 ct. box of Berger VLD Hunting 6.5 mm 130 grain bullets that if anyone would like to try/use for load development? I will send them some for the cost of the shipping. Just send me your address and a USPS money order for the shipping and I'll send however many you'd like to test.

 

[SJB358]

Don't forget RL25. Works pretty well in my 264 with 140's, getting right around 3200 with the 140 AB and BT's. Pretty similar case capacities as well. That 264WSM is a sweet cartridge..