Ran into signs of pressure sooner than expected with .300WSM. Need input

[Punisher]

Every now and again, I will have a scratch show up from the extractor. I can't find any more of the brass I had that was showing the circle from the bolt face, but this is what the scratch looks like. Having been through the same thing and reading the other responses here, I'm thinking you are fine. After you shoot the brass and get it sized for your chamber, that circle will go away.

 

[Canadian Bushman]

Its hard to tell in the pic posted, but it looks like some excessive body expansion in front of the web.

Not much, definitely nothing to worry about, but it would confirm some of the other members theories of excessive headspace upon initial firing.

So i gonna say the same as the others, fire again and let us know.

P.S. I started lightly sanding case heads to remove ejector marks to avoid confusion.

 

[Punisher]

Pic of scratch on case head.

 

[918v]

Hey gang,

I've been a bit of lurker and finally registered. First post.

I got a Browning X bolt in .300 WSM recently I just shot it for the first time this weekend. I picked loads below published data limits and was surprised to see some signs of overpressure.

I loaded two batches, all with new Win brass, CCI magnum primers, Barnes 168 TTSX. Loaded to just fit in the magazine (which happened to be 0.020 off the lands).

I loaded some sighters and then some increasing powder charges to find out when I ran into pressure signs so I could know my upper limit and start developing an accurate load.

First batch was H4350. Hodgdon lists 61.0 as a start with a velocity of 2908 and a max of 64.5 and velocity of 3034 with a 168gr sierra HPBT.

I loaded up some sighters at 63.5gr H4350 and that was the only charge I ended up shooting as I started to get light ejector marks. No flattening of the primers or heavy bolt lift, but a light ejector mark on all but two of the 7 rounds fired.

My velocities: 2979, 2972, 2978, 2961, 2977, 2958, 2983.

Very happy with the consistency but I didn't expect ejector marks on the brass at that charge or velocity.

Next batch was RL17:

64.0gr sighters

3060, 3068, 3049. All with ejector marks with no other signs of overpressure.

85 degrees, 1200ft elevation.

So what do you guys think? I would appreciate any input, especially from those that reload this caliber with those powders. Of course I realize that each chamber and barrel can vary but I am curious what others are getting.

Thanks,

John

Based on your pics I don't see any pressure signs. A slight ejector mark isn't really a pressure sign. It becomes a pressure sign when brass flows into the hole and is shaved off by the turning of the bolt.

But I would back the bullet off from the lands. Solid copper bullets cause pressure spikes that close to the rifling, regardless if they have driving bands or not.

 

[tailbon3]

My 300 WSM cases show the same ring right above the webbing just like yours, even when I back the powder charge all the way down to starting charges. With RL19, I get black soot on my case necks from the low pressure. One thing I had to do is make sure to clean ALL the resizing lube off my cases. A little bit of lube will increase the back thrust against the bolt face and possibly cause those ejector marks. You may even need to clean the chamber in your rifle. From what I've read, Mr. Ackley showed that you want plenty of friction between the case and the chamber.

Here's the link to with a picture of my case.
http://www.longrangehunting.com/forums/f28/does-case-look-ok-77820/

 

[Dentite]

Based on your pics I don't see any pressure signs. A slight ejector mark isn't really a pressure sign. It becomes a pressure sign when brass flows into the hole and is shaved off by the turning of the bolt.

But I would back the bullet off from the lands. Solid copper bullets cause pressure spikes that close to the rifling, regardless if they have driving bands or not.

Thanks for the info.

 

[Dentite]

My 300 WSM cases show the same ring right above the webbing just like yours, even when I back the powder charge all the way down to starting charges. With RL19, I get black soot on my case necks from the low pressure. One thing I had to do is make sure to clean ALL the resizing lube off my cases. A little bit of lube will increase the back thrust against the bolt face and possibly cause those ejector marks. You may even need to clean the chamber in your rifle. From what I've read, Mr. Ackley showed that you want plenty of friction between the case and the chamber.

Here's the link to with a picture of my case.
http://www.longrangehunting.com/forums/f28/does-case-look-ok-77820/

Thanks for the info. The brass was cleaned well. I do frequently using sizing was but on these I used RCBS lube and I hate wiping down cases so following sizing, all the brass was washed and dried prior to loading.

This is a new rifle and I did clean the bore, but not the chamber. You may have a good point that my chamber may have been excessively lubed from factory lube not being cleaned out. That is something to consider. I will clean the chamber and see what happens. Thanks.

 

[Canadian Bushman]

My 300 WSM cases show the same ring right above the webbing just like yours, even when I back the powder charge all the way down to starting charges.

Typically this means your chamber is on the upper end of tolerance.

One thing I had to do is make sure to clean ALL the resizing lube off my cases. A little bit of lube will increase the back thrust against the bolt face and possibly cause those ejector marks. You may even need to clean the chamber in your rifle. From what I've read, Mr. Ackley showed that you want plenty of friction between the case and the chamber.

Absolutely, a very good point!