Sticky bolt lift & brass

[muleman1953]

I've been working up loads for a 300RUM, with 225BTHP Match bullets and Retumbo. I started seeing some slight pressure signs at 96gr and the gun shot great at 95.5. Even though I'm not seeing Pressure on my brass it is starting to have the last of the bolt lift hard to pop up & pull the spent case out. I've even had 2 that pulled of the Extractor & I had to push out with a rod. I've checked most everything & I'm thinking now it's Pressure even though the brass Mics out & looks OK.
Any Thoughts, I could use some Advice, maybe I'm overlooking something.

Thanks in Advance, Wayne

 

[barnesuser28]

does your brass have fouling on the outside of the case necks?

 

[muleman1953]

Yes, What's that mean?

 

[Biggs300]

Clean the case lube from your brass and you will notice less fouling.

 

[barnesuser28]

it could be excessive carbon fouling in the neck area of your chamber, read this http://www.longrangehunting.com/forums/f28/338-lapua-cases-stuck-savage-gun-90320/ green788 explains it in detail

 

[Bart B]

I started seeing some slight pressure signs at 96gr and the gun shot great at 95.5. Even though I'm not seeing Pressure on my brass it is starting to have the last of the bolt lift hard to pop up & pull the spent case out.

It is normal when loading that hot of ammo to have the bolt bind a bit when it's opened. Hodgdon data lists 89 grains of Retumbo as a max load with a 220 grain bullet producing 61,000 psi. Plus, if the bolt face is out of square too much, that'll also cause a sticky bolt lift. And if you're just neck sizing the fired cases, that will double the chances of having a sticky bolt lift from insufficient clearance between the chambered fired case and the chamber walls.

Did you check the fired case heads of any signs of brass extruding into the bolt face cutouts? A bump on the case head where the ejector hole/slot was when it was fired indicates pressure's 75,000 to 80,000 psi.

I'd back off that powder charge to 89 grains and see what happens.

 

[Max Heat]

Does the brass show a circular "bright" pattern, right around the outside of the primer pockets, but NOT extending all of the way to the edges?

I've been experiencing that lately (along with & caused by, a tight bolt), so I have NOT been firing the gun. I did try lowering the powder charge by 5 grains, but the result was still the same. So I am thinking that there must be excessive head space. Since I have a new barrel on order, I'm not doing anything until that barrel is ready to go on.