Tell me if im wrong.

[Montana338mag]

So i was shooting with a guy a while back and the brass that he shot had a shiny mark about 1/8th of the way around the case head where the plunger contacts the case head. This was on factory and reloads. I told him it should be fine since there are no ejector marks and primers look fine. So i decided to have him chamber a reload and eject it and sure enough without firing it the case had the faint shiny mark. That should be from the base not getting sized quite enough but told him not to worry unless they get hard to chamber or he gets bolt click. So am i wrong that if there are no ejector marks (half moon) or flattened primers it is fine and probaly just a rough plunger? Everything ejected fine and nothing out of the ordinary, no heavy bolt.

 

[CatShooter]

So i was shooting with a guy a while back and the brass that he shot had a shiny mark about 1/8th of the way around the case head where the plunger contacts the case head. This was on factory and reloads. I told him it should be fine since there are no ejector marks and primers look fine. So i decided to have him chamber a reload and eject it and sure enough without firing it the case had the faint shiny mark. That should be from the base not getting sized quite enough but told him not to worry unless they get hard to chamber or he gets bolt click. So am i wrong that if there are no ejector marks (half moon) or flattened primers it is fine and probaly just a rough plunger? Everything ejected fine and nothing out of the ordinary, no heavy bolt.

What is a "Plunger"????

 

[Montana338mag]

The ejector on the bolt face. Sorry i call it a plunger.

 

[FearNoWind]

...I told him it should be fine since there are no ejector marks ... So am i wrong that if there are no ejector marks (half moon) or flattened primers it is fine and probaly just a rough plunger? ...

The ejector on the bolt face. Sorry i call it a plunger

We have a problem here, Montana. If "plunger" = "ejector" then the marks couldn't be caused by a rough "plunger" if there are no ejector marks and the "plunger" is the ejector.
I'd suggest you wait until you have more experience before you advise your fellow shooters concerning over pressure indicators.
While flattened primers may indicate over pressure, you can have primers that look pretty normal, even with over pressure, and primers that are flattened to some degree, even without over pressure. Not all primers are the same ....
Furthermore, heavy bolt lift may or may not be an indication of overpressure.

 

[Montana338mag]

I have plenty of experience but if you have ever ordered parts for a bolt some manufacturers call the spring loaded ejector in the bolt face a "plunger" because it is able to move in a up and down fashion. Now im not talking about raised "ejector" marks that are smeared. I am talking about a small shiny spot about 1/16th of a inch in width that is the same size as the tip of the ejector. So before you start calling people inexperienced please be up to date with diffrent terminology. And no there is no high pressure as i stated even if you chamber a round and not fire it and then remove it they will have this. I will attach a photo.

 

[Montana338mag]

You can see the mark on the "mag" on the head.

 

[Mikecr]

A plunger is a type of ejector, as a standing blade is a type of ejector.
'Pressure problems' are often more about the problems(and their real cause) than actual pressure.
He could have a rough plunger, foreign material, and/or bolt lugs out of true. Flattening primers can be caused by excess head spacing. Difficult extraction could be caused by a bad sizing situation, and loosening primer pockets by excess chamber clearances and/or not enough barrel steel around the chamber, or poor breech support. Bad extraction/bolt click can also result from poor action timing. A lot of things manifesting with pressure, described as pressure problems, while not actually caused by pressure.

With any new chamber I run a test on once fired brass to determine 'MyMax' pressure per velocity calibrated Quickload. This is incremental load increases while measuring the webline with a blade mic. I'll see growth, then a ~level plateau, and then runaway. That point is continuing yielding and FL sizing is required for yielding. From what I've seen, there is no a reason to go beyond the point of needing FL sizing. Even if the gun can handle it just fine, it isn't viable for your brass. Where this actually falls w/resp to SAAMI max doesn't matter a bit. Could be a little above or below. Common notions of pressure 'problems' during this testing, again, separate problems to solve -not pressure.

 

[Montana338mag]

A plunger is a type of ejector, as a standing blade is a type of ejector.
'Pressure problems' are often more about the problems(and their real cause) than actual pressure.
He could have a rough plunger, foreign material, and/or bolt lugs out of true. Flattening primers can be caused by excess head spacing. Difficult extraction could be caused by a bad sizing situation, and loosening primer pockets by excess chamber clearances and/or not enough barrel steel around the chamber, or poor breech support. Bad extraction/bolt click can also result from poor action timing. A lot of things manifesting with pressure, described as pressure problems, while not actually caused by pressure.

With any new chamber I run a test on once fired brass to determine 'MyMax' pressure per velocity calibrated Quickload. This is incremental load increases while measuring the webline with a blade mic. I'll see growth, then a ~level plateau, and then runaway. That point is continuing yielding and FL sizing is required for yielding. From what I've seen, there is no a reason to go beyond the point of needing FL sizing. Even if the gun can handle it just fine, it isn't viable for your brass. Where this actually falls w/resp to SAAMI max doesn't matter a bit. Could be a little above or below. Common notions of pressure 'problems' during this testing, again, separate problems to solve -not pressure.

I agree. But if it does it on a case that isnt fired its not pressure. This case has .002" shoulder bump and the bullet doest touch the lands. Body is .001" smaller at shoulder/body junction and web. I figured it had to be a rough ejector.

 

[Bullet bumper]

It is most likely just the edge of the ejector hole is raised up slightly due to excessive pressure when drilling , reaming whatever . If the primers are fine and extraction fine then it's not a pressure issue .

 

[lamiglas]

I have seen this once on a bolt that had some work done to it. the "plunger" hole had a sharp edge and caused the brass to smear when the bolt was cycled. I'm not saying that is what it is but it looks and sounds like it could be. The Smith that did the bolt work said he forgot to put a light chamfer on the hole after he faced the bolt. after he chamferred the hole, the problem went away. if it is shaving brass he will want to get it fixed.

 

[bigngreen]

I've seen it a few times, turned out to be a little crud under a plunger style ejector that was keeping it proud of the bolt face in battery and would just swipe the case head, could be rough or just sharp as well.

 

[Montana338mag]

Popped it out and polished it and sure enough there was a bunch of gunk under it. Cleaned it and took the sjarp edge off around the hole. Helped a ton when just cycling some through it. The spring is either a coil to long or excessively strong because holy cow what a pain to compress it.

 

[Montana338mag]

Also i took a pin punch and compressed it all the way down. Took a bit of force but hes ok with it.

 

[Mikecr]

You know, there can be too much ejector force, and nothing good in that.
This can force a chambered round into hard skew, and when fired, create a crooked case w/resp to it's case head. This will open groups within a couple reload cycles.
Personally, I would have swapped for a lighter spring, or cut it down a bit. No need for throwing cases over to the next bench. Just clearing the port is enough.