Pressure Signs Please Help

[yawn]

When you say the bolt lift is hard at what stage is it hard? is it right from the get go or is it the last part of the lift?

 

[RDM416]

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.

Good advice from pocketchange.

Either the area just above the base is expanding, or your case is too long (shoulder needs to be pushed back.)

Is the bolt stiff to close on an unfired round?

You can take a magic marker and color the entire case then carefully chamber then eject it. You will probably see scuff marks at the pressure point. I suspect it will be at the case web junction in the base.

I doubt you have damaged your rifle, but you need to back off things and get this problem solved. Cases that are hard to extract can scratch your chamber, cause excessive wear, even galling of the locking lugs, or can break an extractor.

 

[cabinfever]

last part of the bolt lift is the hard part. unfired and resized cases chamber and eject fine.

 

[yawn]

I think your problem may be more of a sizing issue than a pressure one. Have you fired new or once fired cases with the same load again just to check its the 3 times fired brass thats giving the problems? are the primers still firm to seat? And what load and barrel length?

 

[cabinfever]

primers are still seating firmly. Barrel is a 24 inch hart #5 light contour with a muzzy break. I'm bumping the shoulder .002 and the (3 times fired) unfired cases chamber fine.

 

[Tikkamike]

One of my most used practices for checking for excessive pressure is measuring the primer pockets. it has proven to be a very effective method. you dont want to see .2085. that means your poskets are being streched. I like .2070 and below. measure a new case and see what that is for a control. then just monitor that number each time you reload them. if you see that number growing your over pressure. back it off a half grain and see how that goes and so on.

 

[yawn]

Ok my thoughts are that a 180vld @ 3000fps from a 24"barrel seems to be getting up there but I dont know what load or even what chrono you are using. The signs you mention are not the typical over pressure signs you would see. Generally primers may flatten, bolt lift will get sticky (from the initial lift not just the last stage) the brass may flow from the case head into the ejector/plunger giving a shiny spot on the case head ( not the ring you mentioned thast moer of a sizing thing as well) primer pockets will loosen along with a few others. You dont apear to have any of the above.When the pressues get near max everything has to be just right for proper functioning. Im thinking there may be a die to chamber relationship problem thats not quite sizing the case enough to allow extraction after firing .The hard lift at the top of the bolt throw (sometimes called bolt click) is the first stage of extraction, if the chamber is tight and the die just a little large then this can be the result. I had this problem a year or so ago, the symtoms where exactly the same. . In my case the Redding FL match die was exactly the same size as the chamber so it wasnt sizing the bottom of the case at all.A thou out of the rear of the chamber and no more prblem.
You can drop the charge back to a point where it will function or get the die and chamber measured with some pin guages or maybe try a small base die.Sometimes even just another FL die will be enough.
Something to think about anyway.

 

[dakor]

I have ran into this with a 6mm-284 of mine with a Hart barrel. I tried everything under the sun and finally just dropped the charge back 1 grain and it went away. I had tight primer pockets minimum case expansion and still had the problem. 3000fps with a 180 Berger is getting up there out of a 24inch pipe. I would drop it back a half grain and shoot it over the chrony and then drop it another 1/2 grain and shoot it again. I would bet you might lose 20fps to 40fps total which is another sign you are peaking with your rifle and load. I would not worry with that High BC bullet you are using even giving up 100fps is not going to make a difference.