Ejector mark.

[farmer7]

Just fired off a few rounds and one of the shots in the middle of the string of 10 had an ejector mark. Just curious why???

 

Its a relatively light load of RS62 with 123gr Amax and BR2 primers. Brass is on its second firing and during load development I had been 1.7 grains higher up the charge scale with no pressure signs at all but accuracy wasn't quite as good.

 

Velocity was perhaps 9-10 fps higher than average for that particular shot but Quickload only has me at around 51k psi. Accuracy was also fine. Any ideas???

 

I was wondering about carbon fouling in the throat but accuracy hasnt dropped off at all. Cleaning wise I only use patches and Wipe-out and the Accelerator.

 

 

Also found a few of these in my RS62! (The long "worms" not Amax!)

 

[jcampbellsmith]

Are you sure it's not an ejector mark from the first firing? Regards JCS

[Brillo]

I had a similar experience when developing loads using H4895. I started low and saw the same extractor marks straight away. When I got to higher charges the ejector marks disappeared.

The proposed reason for this is that when the powder ignites the case expands and grips the chamber. If the load is light this grip takes a Nano second longer and pushes the case against the bolt face and hence the ejector plunger. I suggest a higher powder charge would prove the point with your rifle.

 

HTH

[baldie]

Are the case necks sooty ?

 

If so, the case isn't obturating properly, and will cause this, as Brillo mentioned above. The primers are showing no signs of even remotely spreading, and this is a more common sign of early pressure.

 

Up the load.

 

I would be more concerned about the powder. If I found crap like that in a tub, it would go on the compost heap. That is never going to burn reliably.

[The Gun Pimp]

Dave, maybe one case had a little re-sizing lube on it and it didn't grip the chamber as well as it should - putting additional load on the boltface.

[bradders]

Are the case necks sooty ?

 

If so, the case isn't obturating properly, and will cause this, as Brillo mentioned above. The primers are showing no signs of even remotely spreading, and this is a more common sign of early pressure.

 

Up the load.

 

I would be more concerned about the powder. If I found crap like that in a tub, it would go on the compost heap. That is never going to burn reliably.

My powder goes from jug to measure, and then to case.

I certainly don't spend time looking at it......that is really anal :-)

[farmer7]

Are you sure it's not an ejector mark from the first firing? Regards JCS

No definitely on this time around. I was checking after the first firing as I was working up loads for a few different bullets.

 

Are the case necks sooty ?

 

If so, the case isn't obturating properly, and will cause this, as Brillo mentioned above. The primers are showing no signs of even remotely spreading, and this is a more common sign of early pressure.

 

Up the load.

 

I would be more concerned about the powder. If I found crap like that in a tub, it would go on the compost heap. That is never going to burn reliably.

Not particularly sooty. At the moment its shooting sub 1/2moa for 5 shots for an average of 2880fps, if I up the load the groups were opening up to 3/4 moa.

 

As for the powder that was left behind in my chargemaster! Never seen it before.

 

Dave, maybe one case had a little re-sizing lube on it and it didn't grip the chamber as well as it should - putting additional load on the boltface.

Wasn't lube as I hadnt full length sized them. Just neck sized after fireforming.

 

My powder goes from jug to measure, and then to case.

I certainly don't spend time looking at it......that is really anal :-)

No Mark I dont go through my powder grain by grain either!! Was left behind in my chargemaster, along with one other bit!

[gbal]

One little worm in a batch of several thousand kilos is six sigma standards in practice (roughly,no manufacture can be perfect all the time). Not even Swiss.

As said,since it won't meter into cases,anyhow,not much of an issue,unless you have half a tin of spaghetti left in the hopper. (contact retailer).

Real men would add it to their 5 weetabix,to promote vigour and all that... :-)

(but not recommended-too anal).

g