Pressure Signs Please Help

[cabinfever]

I'm shooting a custom 7mm WSM with a match grade barrel. I thought I had the perfect load as I have been getting excellent accuracy. It shot well with no pressure signs until the brass hit it's 3rd round. At the 3rd round the bolt was hard to lift and by the 4th round I could barley get the spent cartridge to eject. I noticed what looks to be a pressure band starting to form at the base of the bullet. I am shooting a compressed load but really didn't notice any pressure signs until now. Is it normal to get only 3 rounds out of brass when you are shooting a hot load? Could I have caused damage to the chamber by shooting these hot loads? What next? Do I live with the fact that I will only get 3 loadings from my brass or should I back down my powder charge. It sucks, because I was really pleased with the accuracy I was getting out of this load. Any suggestions would be greatly appreciated.

Anyone have a pet load for a 7 WSM that will push 180 bergers 3000 fps and still get 5-6 rounds out of their brass.

 

[justgoto]

Assuming you are neck sizing only...
...and assuming your powder isn't temperature sensitive and the overpressure signs aren't because of temperature increase...

I would full length size the cases that are hard to chamber/eject.

I sometimes get sticky bolt on some of my hotter charged loads, I'll simply bump the shoulder back slightly with my full length sizing die.

Pressure signs do not mean your cases are spent.

 

[BigSkyGP]

A ring around the back of the bullet, or around the back of the case?

I would back off your charge. If 3000fps is so important to you, then I would try different powders, with a better burn and less pressure to get your speed.

 

[cabinfever]

I am using retumbo which is a temperature stable powder. I full length and neck size after each firing. The unfired rounds chamber and eject easily it's ejecting a fired case that becomes difficult. Since this is a hunting rifle I need bullets to eject without any problem. Right now bolt lift is difficult to eject the spent cartridge. Never had bolt lift difficulty after the 1st two firings.

Mike

 

[EddieHarren]

Have you checked the length of your cases?

 

[cabinfever]

case length is still below sammi specs

 

[Mikecr]

Is this a magnum action, with enough barrel meat around the chamber?
Or something thrown together with less?

 

[cabinfever]

This is a Borden timberline short action

 

[Stormrider]

I have no idea if this will help, but it might. Try annealing a few of the cases that were sticking and see if that helps. You could possibly have brass that is work hardened and not springing back from the chamber after firing.

 

[jwp475]

Only 3 firings is a sign of HIGH pressure. Only anneal the neck shoulder, not below. I don;t think anealing or lack of is your problem

 

[cabinfever]

I was looking more at the case and bolt lift for pressure signs. I looked at the bolt face after shooting one of the compressed loads the other day and noticed a small brass ring. I cleaned the brass ring off the bolt face and fired another round. Same result. I am leaning more towards high pressure as the culprit. I appreciate all the help. As much as I hate to do it it looks like I'm going to have to tone it down and live with the lower MV.

 

[jwp475]

I was looking more at the case and bolt lift for pressure signs. I looked at the bolt face after shooting one of the compressed loads the other day and noticed a small brass ring. I cleaned the brass ring off the bolt face and fired another round. Same result. I am leaning more towards high pressure as the culprit. I appreciate all the help. As much as I hate to do it it looks like I'm going to have to tone it down and live with the lower MV.

You are definately experiencing excess pressure signs. 8 to 10 loadings is good IMHO

 

[GNERGY]

I would check to make sure your lugs and mating surfaces are clean and put a little oil on them.
Tarey

 

[pocketchange]

Measure just above the case head recess (in the same location every time.. mark with a sharpie),
if you notice ANY growth in the diameter,
you are over pressure. As in .0001 plus.

This is the most pressure resistant area of a cartridge and if it starts to increase.. BEWARE.