6.5 Creedmor ejector mark question

[Milo 2.0]

This is 42.7gr, the faint ejector mark is over number 5

I can't tell by your pic, even enlarging it I can't see much, an ejector mark would be closer to the edge if present.

 

[Lapua264]

I can't tell by your pic, even enlarging it I can't see much, an ejector mark would be closer to the edge if present.

Can you see one on 43.4gr pic? It’s between number 6 and letter L

 

[chop house]

Again, the point is that these type of "visible" pressure signs don't always mean overpressure. The key is to look at the bigger picture; i.e. is the load safe according to reloading manuals? Are there multiple different pressures signs at the same time? All of this information has to be considered in context before a reasonable conclusion can be reached.

first, my apologies to the op: i am not wanting to hijack the thread but i have a situation that seems similar, yet not the same. I have, in 6.5 cm, sticky bolt lift and very faint case head swipe with no other visible or measured pressure signs. primer looks ok, chrono data is within reasonable tolerance of crosschecked/published data, datum measurements are consistent. recoil is stout but i have been shooting a lot of pd varmint rounds lately so that may simply be my perception. rifle is a stock 700 26" varmint bbl. brass is vaious headstamp from an earlier project... between 0 and 3 firings.

i did not finish the ladder, as i wanted to recheck/rethink the situation. I have a few candidates including hardened brass, overlength datum, bolt timing, rough chamber, wet chamber. since you are all directly on this topic, i am watching your replies here closely. thx.

 

[Milo 2.0]

This is 43.4 gr, the mark is between 6 and L, was getting 2775 with this load

I see that one, see, my 43.5 not sound advice, I'm kind of lost on pressure at 2725 though, honestly.

 

[Milo 2.0]

This is a 24" barrel?

 

[Lapua264]

This is a 24" barrel?

Yes

 

[Milo 2.0]

Yes

What is your goal with the rifle, speeds, accuracy, etc... ? You could always find a diff powder if more speed is the goal.

 

[Lapua264]

What is your goal with the rifle, speeds, accuracy, etc... ? You could always find a diff powder if more speed is the goal.

The goal is to use it for prs matches. Of course accuracy is paramount but I like to be in the mid 2700s if I can. interestingly enough I always had good luck with accuracy at those velocities with various calibers. I might try reloder16, people are giving it good reviews plus it’s temp insensitive like h4350.

 

[Bc'z]

first, my apologies to the op: i am not wanting to hijack the thread but i have a situation that seems similar, yet not the same. I have, in 6.5 cm, sticky bolt lift and very faint case head swipe with no other visible or measured pressure signs. primer looks ok, chrono data is within reasonable tolerance of crosschecked/published data, datum measurements are consistent. recoil is stout but i have been shooting a lot of pd varmint rounds lately so that may simply be my perception. rifle is a stock 700 26" varmint bbl. brass is vaious headstamp from an earlier project... between 0 and 3 firings.

i did not finish the ladder, as i wanted to recheck/rethink the situation. I have a few candidates including hardened brass, overlength datum, bolt timing, rough chamber, wet chamber. since you are all directly on this topic, i am watching your replies here closely. thx.

Start by separating by headstamp, different brass can have different volume. Same as new versus 2 or 3 times fired, different voloume.
Check some of your brass n see if it chambers easy, if not bump shoulders back

 

[243winxb]

CAUTION: The following post includes loading info beyond currently published standards for this cartridge. USE AT YOUR OWN RISK. Neither the writer, Accurateshooter, nor the staff, assume any liability for any damage or injury resulting from use of this information.

Can you see one on 43.4gr pic? It’s between number 6 and letter L

I see something that looks like a shadow.

modulus of elasticity- 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.

If your brass is hard, it will take 76,000 PSI to form a mark from the ejector hole. This psi is way over the maximum working pressure of 63,000 for the cartridge.

With no pressure testing equipment, a handloader has to follow published loading data. When there is none, powder may be increased till pressure signs appear. Then reduce the powder charge to where the best accuracy was. The brass that showed pressure signs is now scrap. This method is safer in a Remington 700 type action.

If your action has a major gas leak, the extractor cut in the bolt face is the weak point. Imo.

https://www.thehighroad.org/index.php?media/albums/high-pressure-signs.148/

Good luck. Be safe.

 

[243winxb]

Or use this powder data.https://www.vihtavuori.com/reloading-data/rifle-reloading/?cartridge=95


6,5 CREEDMOOR
Test barrel: 650 mm (25½”), 1 in 9” twist
Primers: Small Rifle
Cases: Lapua, trim-to length 48,50 mm (1.909”)

Note that the listed maximums may be over pressure in your rifle. Brass life may be as short as 3 loadings.

 

[spife7980]

You are getting marks on the 43.4 one, those are fairly clear but I would do all of this on it again once its become fire formed. You found your max for initial firing, load under that this first time. Im going to guess that these are growing a fair amount. Pop the primers out and measure the base to shoulders, base diameter, and shoulder diameters. Im going to guess that they are growing a good amount and its them slamming back thats giving you the marks. They should be larger on the second firing with more volume and you should be able to go a bit higher without the marks. I find a crude load real fast to form brass and then Ill do an actual load work up with it once fired.

 

[Lapua264]

You are getting marks on the 43.4 one, those are fairly clear but I would do all of this on it again once its become fire formed. You found your max for initial firing, load under that this first time. Im going to guess that these are growing a fair amount. Pop the primers out and measure the base to shoulders, base diameter, and shoulder diameters. Im going to guess that they are growing a good amount and its them slamming back thats giving you the marks. They should be larger on the second firing with more volume and you should be able to go a bit higher without the marks. I find a crude load real fast to form brass and then Ill do an actual load work up with it once fired.

I will definitely try that.
How do you keep track of those marks for each firing?

 

[Bc'z]

I will definitely try that.
How do you keep track of those marks for each firing?

I would make a mark with a sharpie on your on old ejector mark. Next firing compare previous mark with new if any.

 

[spife7980]

I will definitely try that.
How do you keep track of those marks for each firing?

You see them before you load the shell, if it comes out with a second in a different spot you know.

 

[260AckImp]

I dont want to hijack a thread but what is everyone's thoughts on this ejector mark?
Im not finding any other pressure signs but this and its frustrating me as this load shoots the best. Its a 260 AI that has a 142 SMK over 48gr of H4831SC loaded long with a COAL of 2.985"
Quickload only predicts 54,500psi and the velocity is 2910fps.
Thanks for any advice

 

[BDman]

I've seen one of these caused by an ejector that sat too proud of the bolt face. The rifle would do it with the mildest of loads. Once the ejector was machined .0015 it solved the issue. JMHO...

 

[243winxb]

thoughts on this ejector mark?

Look at ejector hole edges for a burr. Smooth if found.

Looks like a pressure sign , but on the low side. Some factory rounds in other cartridges will produce it.

Is bullet jammed into rifling? COL seems long? https://www.accurateshooter.com/guns-of-week/gunweek046/ jam = more pressure.

 

[Bill K]

Thanks for response.
Now If I load in increments and let’s say at 42 grains I don’t se the faint ejector mark and at 42.7 it begins to show, does that definitively mean it’s a pressure sign or also not necessarily?
And second, is it common to see pressure signs on the round that is not compressed?

That would indicate your are starting to show pressure signs, back down to where they don't show, find a load that groups and be happy and safe.

 

[260AckImp]

Look at ejector hole edges for a burr. Smooth if found.

Looks like a pressure sign , but on the low side. Some factory rounds in other cartridges will produce it.

Is bullet jammed into rifling? COL seems long? https://www.accurateshooter.com/guns-of-week/gunweek046/ jam = more pressure.

This 260AI has a long throat to suit 140gr bullets. These are being jumped 0.015"