Reloading 270 WSM

[Joe C.]

Just asking those that have worked with them. Are they super sensitive to pressure? I know you have to keep an eye on it no matter the round, but my Model 70 in 270 WSM seems extremely sensitive. For example, I’ll be at a mid book load, add .5 grain and them the bolt is very hard to lift. Cases look fine until the hard bolt lift. Rifle has been cleaned and borescoped with nothing abnormal. Bullet isn’t jammed into the rifling. Is the 270 WSM just more temperamental than I’m used too? Also I’m going to quit being lazy and do load work up over a chronograph. This is my first time working with a WSM.

I’ve got a great load with RL23 and 130gr Partitions. The loads I’m working on now is Staball HD with 130gr Partitions, and 145gr ELDX with RL26 and Staball HD. I also plan on starting working up an E-Tip load.

Edit: also with it being a short mag does it take smaller powder increases to get magnum performance, as apposed to what full length case magnums require?

 

[Blkram]

I have not handloaded for my current rifle (LH Browning X Bolt All Weather 23" barrel) in 270 WSM as yet. The factory ammo tried to date is not showing any pressure signs and producing good performance (Nosler 140 gr AccuBond at 3073 fps and producing 0.565" 3 shot groups at 100 yards. Federal 140 gr Trophy Bonded Tip at 3156 fps and producing 0.396" 3 shot groups at 100 yards.
And unfortunately, I do not my data from handloading for my first rifle in the cartridge (Rem 700 B&C Edition 26" barrel), and can only recall that I was loading with the 140 gr AccuBond great accuracy (approx. 1/2" groups at 100 yards), but velocity was about 200 fps slower than expected.
If I recall correctly, I was using Re-22, using data from Nosler's Reloading Guide, up to max listed. And I did not have the rifle long enough to see if velocity improved after shooting a couple hundred more rounds through it. I did not have any pressure issues in that rifle.

Dr Mike has done a lot more loading with various bullets and powders for his 270 WSM (Model 70 FWT), and would be a better reference for you. If I recall correctly, his rifle's preferred load was with the 130 gr E-Tip. He also has done a lot of handloading with all of the WSM cartridges, and can give you a better assessment of common issues with the WSMs.

Your pressure issue could be a headspace issue (I had one with my 300 WSM; I only have these two WSM), or a chamber issue. A gunsmith may be able to assess and let you know.
Have you measured the fired cases to check dimensions? Might verify if there is a potential chamber issue.

 

[Joe C.]

Thanks for the response. My next step was going to get a Forster Go/No Go gauge, because the chamber feels snug when closing. What’s on more set. Lol
I have also had to pay close attention to the OAL gauge, because book OAL’s have been long when chambered.

 

[DrMike]

The WSM cartridges are not overly sensitive. I treat them as I would any longer cartridge.

 

[Joe C.]

Thanks Mike for the input. My RL23 load with Partitions is great. It’s an upper load I think, as it has 66gr of RL23 and a 130gr Partition. As far as the other testing I’ve done proves the rifle much more sensetive to powder charges than book manuals say it should be. ….".i do have resistance closing the bolt on new brass. Just enough to notice. I’m seriously contemplating getting a Go-No Go gauge. Will be taking my chrono from now of with this one. Chamber and bore looked fine with a scope. I’ll try bumping the shoulder back with the help of my headspace gauges.

Edit…Fired cases holds 83.6 grains of water as apposed to 79.1 in GRT.