Blowing out primer at below recommended start load 300WM

[windfall]

asdf

 

[Dave Bulla]

Don't ya just love it when you get answers you can be sure of and then they're topped off with an offer to fix the problem for free?

 

[TNBilly]

Hate to say it but looks like you'll be looking for another gunsmith. Mike's website states he's closing shop!

 

[windfall]

Don't ya just love it when you get answers you can be sure of and then they're topped off with an offer to fix the problem for free?

yup, doesn't happen often in life

 

[windfall]

Hate to say it but looks like you'll be looking for another gunsmith. Mike's website states he's closing shop!

Ya, but I'm happy for him. He's a rare breed of guy.

 

[243winxb]

300 Weatherby's are known for extra Freebore

throat my rifle's barrel and lengthen the freebore to get the pressure down

Compare SAAMI chamber drawings of the 300 WEATHERBY MAGNUM http://www.saami.org/PubResources/CC_Drawings/Rifle/300%20Weatherby%20Magnum.pdf to the 300 WINCHESTER MAGNUM http://www.saami.org/PubResources/CC_Drawings/Rifle/300%20Winchester%20Magnum.pdf When having a custom barrel chambered, a dummy round may be supplied to the gunsmith, with the bullets you will be shooting, with a set COL. My 243win barrel came chambered for a 70gr bullet. I wanted to shoot 85 & 90gr. My mistake not to supply a dummy round. Live and learn.

 

[Jaxondog]

You are 1.5 grains under minimum suggested starting. that's if your scales are correct, could be more. In rifles it is bad practice to undercharge, especially if using fast burn powder's. With the case laid out level in the barrel an undercharged shell will have more powder surface to ignite, resulting in higher or extreme pressure. Lord help ya if the powder is laying below the flash hole. Sounds like you may have several variable's, this is just one of them.