Ejector marks OK or not OK

[eddywitay]

I was working up a load for my 7mm stw and a load that shows promise is putting ejector marks on my case heads by the manual It is a mild load 77.3 grains of RE-25 with Cutting Edge 160 max bullet.The bolt is not sticky or hard Is It ok to go with a load that puts ejector marks on the case heads the mark looks like a nice circle

 

[Steve Blair]

Some brass is softer than others and will show pressure earlier. Regardless, if the case head is showing circles and bright ejector smears, the pressure has pushed the case head into plastic deformation and is a potential problem. The pressure tolerance of cases can differ considerably by manufacturer or even lot. Some things to check: [br]
Both the cartridges and chamber are free of lubrication
Headspace is correct on the sized case and not pushed back too far
Case neck has adequate chamber clearance
Shoot over a chronograph and make sure the load is as mild as you think it is

 

[jcampbellsmith]

Also check that the trim length is correct. Regards JCS

 

[Shynloco]

if the case head is showing circles and bright ejector smears,

Some things to check: [br]

Headspace is correct on the sized case and not pushed back too far

Sleepygator,
Started noticing on one of my 6.5X55 loads, that I'm getting those dull rings early (Lapua Brass) and that bright ejector smear you speak of. The headspace has been checked and is good. But now I'm wondering if I'm pushing the shoulders back just a bit too far. I use an RCBS Precision Mic to measure every casing after firing and before resizing. I'm getting .004 movement consistently and now am wondering if I should not bump the shoulder quite as far based on your comments. Any thoughts?

Alex

 

[Elkbane]

Eddywitay,
Are these NEW cases you are shooting for the first time?

Reason I asked, I've had this happen once on new cases where the shoulders were well back from the dimensions of my chamber. What happens is the firing pin drives the case forward, then ignition happens, then the casehead is driven back violently against the boltface. the ejector mark shows up on the casehead, even when presure is not excessive. After fireforming, when I had my dies set for minimum shoulder bump, the symptom dissapeared. If you have a stoney point type tool for measuring the lenght to datum line on the shoulder, you can check the measurements for yourself (new case versus fired case with primer removed).

You may want to resize a case, load it and try it again with a few of the same loads that caused the initial symptoms. And I removed the marks from the end of the casees. I put a piece of 400 grit emory cloth over a small piece of granite left over from a kitchen re-mod and worked the casehead over it in a figure 8 motion with only slight downward pressure. This will "square up" the casehead so the case isn't slanted on the shellholder.....
Elkbane

 

[fredhorace77]

Not to tell you what to do but i agree with previous post by sleepygator...When i comes to reloading if you dont use a chronograph you might as well not reload. Put a chrono to use in your arsenal and it will teach you so many things.

 

[243winxb]

You may want to read his other post below. http://forum.accurateshooter.com/index.php?topic=3789663.0

 

[fredhorace77]

hmm..ty for some reason i never saw that post...just the current description he gave

 

[eddywitay]

I have A Olher 35P but I was just wondering about the ejector marks the velocity's where around what the book said give or take all the brass from the lowest load to over max had the same marks that is why I was wondering If some thing else was wrong besides pressure as for Elkbane's question the brass is brand new Nosler and I have a Sinclair bump gage so I will measure the shoulder on a fired case and a new case and see what I have and one other thing is this brass ok to use again because this stuff is not cheap I hope It is not junk thanks..

 

[Benjerman08]

quick answer......not

 

[eddywitay]

I bought this gun off a friend and he gave me some hand loaded amp with IT and I was looking at the case heads and they all have an ejector mark on them maybe there is something going on with the bolt

 

[243winxb]

High pressure signs would be IMO.- The ejector mark is raised, flowing into the hole.-Primer cratering, flowing back into the firing pin hole,but can be a Remington bolt with chamfered firing pin tunnel. -Gas leaking around the primer.-Loose primer pocket in 5 firings or less..-Web has expanded more that .001", some say .0001" is too much. -Hard bolt lift.- When workingl up, increasing the powder change, look for an orderly progression of muzzle velocity vs. charge weight. If muzzle velocity stops going up or actually goes down, or if it goes up too much, you have a problem. I would want to see more than 1 of these signs. Velocity is a poor way to measure pressure, but will give you useful info. Cartridge Brass-
Material is 70 copper/30 zinc with trace amounts of lead & iron , called C26000. Material starts to yield at 15,000 PSI when soft (annealed), and 63,000 PSI when hard.
Material yields, but continues to get stronger up to 47,000 PSI when soft, and 76,000 PSI when work hardened. Look at photos in these albums. some show very high pressures.
www.photobucket.com/joe1944usa