6 Dasher Pressure Signs...is this what you call "cratering"?

[Senor_Barney]

This is the first time I've loaded for 6 Dasher and first experience with any of these components below.

For those shooting 6 Dasher, or just those more knowledgeable than myself, can you please educate me on the tell-tale pressure signs to look for?

I should know, but unfortunately don't...

I did 80 rounds of barrel break in using the below load

Load Data

• 32.6gr Varget
• CCI 450
• 107gr SMKs
• Alpha Dasher OCD Brass
• 0.005 Jump
• MV 2915
• SD 7
• Lone Peak Fuzion

Below are pictures of the primers on a handful...all seem to show "cratering" but honestly I wouldn't know what that looks like.

I've never been shown cratering in person before and I don't know if this is how it is supposed to look.

I didn't feel like there was anything else abnormal with the operation of the rifle during all 80 rounds.

What do these pictures tell me and what charge and velocity "should" I be targeting with Varget and these components?

 

[straightshooter1]

This is the first time I've loaded for 6 Dasher and first experience with any of these components below.

For those shooting 6 Dasher, or just those more knowledgeable than myself, can you please educate me on the tell-tale pressure signs to look for?

I should know, but unfortunately don't...

I did 80 rounds of barrel break in using the below load

Load Data

• 32.6gr Varget
• CCI 450
• 107gr SMKs
• Alpha Dasher OCD Brass
• 0.005 Jump
• MV 2915
• SD 7
• Lone Peak Fuzion

Below are pictures of the primers on a handful...all seem to show "cratering" but honestly I wouldn't know what that looks like.

I've never been shown cratering in person before and I don't know if this is how it is supposed to look.

I didn't feel like there was anything else abnormal with the operation of the rifle during all 80 rounds.

What do these pictures tell me and what charge and velocity "should" I be targeting with Varget and these components?

View attachment 7828699View attachment 7828700

Yes, that's what cratering looks like. However, primers can look like that if the firing pin hole in the bolt fact is a little too large where the pressure less than max can push primer material into the space around the firing pin. The primers don't look particularly flat, but I do see ejector pin imprints and a little bit of swipe on several of the case bases, which definitely indicates overpressure. So, putting it all together over all (including what looks like cratering), it looks to me like you're right at max pressure.

If you didn't feel any stiff bolt lift, much more pressure and you probably will. And that can happen with this load if you fire this load in higher ambient temperatures.

 

[918v]

Check your neck clearance

 

[Supersubes]

If this was fired with virgin brass, you're over pressure based on the case head markings, as straightshooter pointed out. The same load on the once fired brass will be even worse.

What receiver are you using? Many factory actions including remington 700’s do that even at normal pressure, due to pin fit in the bolt face. That is “cratering”.

 

[spife7980]

Don’t go just by primers. 32+ is over pressure though, just look at the imprints on the case head.

Understanding Pressure :: Primal Rights, Inc

Reading pressure is a required skill that all shooters must have. Whether you are shooting factory ammunition or your own handloads, you absolutely must be able to detect and interpret pressure signs on your fired brass.

www.primalrights.com

 

[Senor_Barney]

Don’t go just by primers. 32+ is over pressure though, just look at the imprints on the case head.

Understanding Pressure :: Primal Rights, Inc

Reading pressure is a required skill that all shooters must have. Whether you are shooting factory ammunition or your own handloads, you absolutely must be able to detect and interpret pressure signs on your fired brass.

www.primalrights.com

Thanks for this article.

OMG....feel like such a loser...sigh. Scary how bad things could have gotten it I don't know what I am doing. The good and bad about the Hide in is the information can sometimes be conflicting.

Why did I break in at 32.6gr varget? Well, this thread right here on Hide showed most if not all members that provided load data in the >32gr range.

6mm Dasher

Wondering if anyone can help me on freebore and OAL measurements and seating depth on dasher. I’ve been through all 6 pages here and some others and I see a lot of “.010 jump” and such but not many base to ogive figures. I’m new to dasher but not to reloading by any means. I’m measuring for...

www.snipershide.com

Then of course there was this gem from Google image search.

 

[spife7980]

Thanks for this article.

OMG....feel like such a loser...sigh. Scary how bad things could have gotten it I don't know what I am doing. The good and bad about the Hide in is the information can sometimes be conflicting.

Why did I break in at 32.6gr varget? Well, this thread right here on Hide showed most if not all members that provided load data in the >32gr range.

6mm Dasher

Wondering if anyone can help me on freebore and OAL measurements and seating depth on dasher. I’ve been through all 6 pages here and some others and I see a lot of “.010 jump” and such but not many base to ogive figures. I’m new to dasher but not to reloading by any means. I’m measuring for...

www.snipershide.com

Then of course there was this gem from Google image search.


View attachment 7828892

I started my forming there as well based on what I had read on the internet (but before that prb article which shocked me). I recognized that my bolt lift was heavy and resisting opening, the case was overpressured and swelled up tight in the chamber above 32 gr. Not what a person whats when they are after a smooth fast working rifle.
You probably arent going to blow up your gun with what youve doing but the primer pockets are going to give out much sooner than you would like to brag about, no 10-20 firings on it to show off on the forums with (I dont think the people in that prb article care about that or brass lasting longer than 5 or so).

I find that 30-32 is the proper operating range for a dasher starting on the bottom end, where ever you find it shoots best in the 2750-2900 range with a 105-115 is all youll ever need. Youll find it to be boringly consistent and accurate. Which is what we want after all, no?

 

[Hoyt7mm]

Realize that alot of that load data and info from PRB is based on Lapua BR brass formed into Dasher. Alpha (Peterson too) has significantly less case capacity, so the same charge will be higher pressure in those brands of brass. There was also a stupid trend to run a Dasher and still make Creedmoor speed.

30.x is a safe starting point with Varget and 105s or similar. Keep velocity below 2900 (for typical barrel lengths) and you should end up with a safe and super consistent load

 

[Supersubes]

Thanks for this article.

OMG....feel like such a loser...sigh. Scary how bad things could have gotten it I don't know what I am doing. The good and bad about the Hide in is the information can sometimes be conflicting.

Why did I break in at 32.6gr varget? Well, this thread right here on Hide showed most if not all members that provided load data in the >32gr range.

6mm Dasher

Wondering if anyone can help me on freebore and OAL measurements and seating depth on dasher. I’ve been through all 6 pages here and some others and I see a lot of “.010 jump” and such but not many base to ogive figures. I’m new to dasher but not to reloading by any means. I’m measuring for...

www.snipershide.com

Then of course there was this gem from Google image search.


View attachment 7828892

You have to assume that data you see on the hide is hot, until you can validate it in your gun . If it seems to good to be true, it probably is.

 

[straightshooter1]

Thanks for this article.

OMG....feel like such a loser...sigh. Scary how bad things could have gotten it I don't know what I am doing. The good and bad about the Hide in is the information can sometimes be conflicting.

Why did I break in at 32.6gr varget? Well, this thread right here on Hide showed most if not all members that provided load data in the >32gr range.

6mm Dasher

Wondering if anyone can help me on freebore and OAL measurements and seating depth on dasher. I’ve been through all 6 pages here and some others and I see a lot of “.010 jump” and such but not many base to ogive figures. I’m new to dasher but not to reloading by any means. I’m measuring for...

www.snipershide.com

Then of course there was this gem from Google image search.


View attachment 7828892

That data for that chart from PRB comes from professional shooters with custom rifles and they typically load are hot, even loads that are well above SAAMI max pressures. On the Hide, from what I've observed over the years, most posted charges are on the high side. That's always an issue for me since such loads are posted without any details about the chambers being used. And, given that different lots of powder can have different burn rates that'll effect pressure too, which can be problematic when trying someone else's load specs.

 

[Barelstroker]

This is the first time I've loaded for 6 Dasher and first experience with any of these components below.

For those shooting 6 Dasher, or just those more knowledgeable than myself, can you please educate me on the tell-tale pressure signs to look for?

I should know, but unfortunately don't...

I did 80 rounds of barrel break in using the below load

Load Data

• 32.6gr Varget
• CCI 450
• 107gr SMKs
• Alpha Dasher OCD Brass
• 0.005 Jump
• MV 2915
• SD 7
• Lone Peak Fuzion

Below are pictures of the primers on a handful...all seem to show "cratering" but honestly I wouldn't know what that looks like.

I've never been shown cratering in person before and I don't know if this is how it is supposed to look.

I didn't feel like there was anything else abnormal with the operation of the rifle during all 80 rounds.

What do these pictures tell me and what charge and velocity "should" I be targeting with Varget and these components?

View attachment 7828699View attachment 7828700

I know a guy with an old Sako chambered in 223 which would crater every primer with no other signs of pressure.
Those photos look to me to lack pressure signs accept for the cratering which as already stated, can have other causes.

 

[Raffy]

The pressure signs are there. Not every case had ejector marks, but enough do that you are right there on pressure. See the areas circled in red here.

 

[Barelstroker]

The pressure signs are there. Not every case had ejector marks, but enough do that you are right there on pressure. Se the areas circled in red here.

I don't take much notice of ejector swipe if the primer corners are still rounded. The primers show little to no pressure signs IMO. I think ejector swipe has more to do with the surface condition of the ejector pin than pressure. I've seen plenty of ejector swipe on cases where I know the load is mild to middling so I've learned to ignore it for the most part.

 

[Raffy]

I agree. I have a rifle that will show ejector swipe on every case head. However my circled area on the cases was trying to indicate the semicircular imprint or "stamp" of the ejector hole. Not swipe, more an imprinted stamp

 

[Barelstroker]

I agree. I have a rifle that will show ejector swipe on every case head. However my circled area on the cases was trying to indicate the semicircular imprint or "stamp" of the ejector hole. Not swipe, more an imprinted stamp

I did have a look at the pics. To me it's all the same thing. There's probably a tiny lip of a 10th or 2 where the ejector pin rubs the edge of the hole.
The only thing I can think of is that the headspace is a bit much & the case is slamming back to the bolt face. The primer could be backing out a little which causes a deep F-pin indentation & the cratered edge is formed when the primer smashes back to the bolt face & is extruded by chamber pressure at the primer.
I notice a Hodge podge of flattened & rounded primers with the same factory ammo &, after measuring cases & velocities, I've put it down to the quite considerable differences I've measured in base to datum measurements prior to firing the factory ammo.
My overall take on the pics is that you don't have pressure issues. In 100% of my experience with high pressure loads, the primer is always flat as a fart, no exceptions.

 

[Raffy]

Interesting observations. In both my 7 saum and 6 creedmoor if I fire one off and feel stiff bolt lift you can rest assured that when the head of the case is examined the semicircular imprint will be seen. When I experience heavy bolt lift it is 100 percent of the time corresponding to the imprinting just like the case heads circled above. I associate that sign with pressure. I could see how it could happen with excessive headspace as you described above though.

 

[Barelstroker]

Interesting observations. In both my 7 saum and 6 creedmoor if I fire one off and feel stiff bolt lift you can rest assured that when the head of the case is examined the semicircular imprint will be seen. When I experience heavy bolt lift it is 100 percent of the time corresponding to the imprinting just like the case heads circled above. I associate that sign with pressure. I could see how it could happen with excessive headspace as you described above though.

I can't be sure about every case as I don't have 7 saum or 6 Creedmoor but, the 1st sign I always see before any others is the primer flattening to some degree.
While we're on the subject, I gather you may have heard about measuring the case head diameter to determine a high or overpressure powder charge. There's a great article on the "Pressure Trace" web site that should be mandatory reading for any hand loader.

https://www.shootingsoftware.com/ftp/dbramwell%20july%2019%2004.pdf

Here's a nice little article which explains the perverse nature of SD & how to interpret data samples.

https://www.shootingsoftware.com/ftp/Perverse%20Nature%20of%20SD.pdf

 

[Barelstroker]

I can't be sure about every case as I don't have 7 saum or 6 Creedmoor but, the 1st sign I always see before any others is the primer flattening to some degree.
While we're on the subject, I gather you may have heard about measuring the case head diameter to determine a high or overpressure powder charge. There's a great article on the "Pressure Trace" web site that should be mandatory reading for any hand loader.

https://www.shootingsoftware.com/ftp/dbramwell%20july%2019%2004.pdf

Here's a nice little article which explains the perverse nature of SD & how to interpret data samples.

https://www.shootingsoftware.com/ftp/Perverse%20Nature%20of%20SD.pdf

On the subject of stiff bolt lift. The reason isn't necessarily high pressure or that the case is jammed "base to datum" in the chamber either.
I can get slightly stiff bolt lift, measure the "Base to Datum" (BTD) of the case then, resize the case with the identical BTD measurement & the bolt closes on the case with no interference at all. The majority of my heavier bolt lifts is almost always due to case expansion just above the solid web & not tight BTD in the chamber.

 

[Raffy]

Thanks for the articles. Very worthy reading material. Flattened primers are definitely one sign I look for as well. Cratering can be caused by other things, although pressure is one of those. My 6CM could use a bolt bushing treatment as I see similar looking cratered primers frequently.

A constellation of findings is certainly the red flag for pressure. Some are lacking. Although, to address the OP's question, if I were to see those signs at the range with heavy bolt lift, my ears would begin to perk up a bit and if primers were flattened in addition to the above I would defitinely reassess my load.

 

[Hetzer]

A "base" run through QuickLoad shows what 32.6 Varget to be near max pressure. That's with the default settings.

 

[supercorndogs]

That data for that chart from PRB comes from professional shooters with custom rifles and they typically load are hot, even loads that are well above SAAMI max pressures. On the Hide, from what I've observed over the years, most posted charges are on the high side. That's always an issue for me since such loads are posted without any details about the chambers being used. And, given that different lots of powder can have different burn rates that'll effect pressure too, which can be problematic when trying someone else's load specs.

That would be oil the guys trying to skip the work and copy someone else load. It is against basic reloading safety procedures to try someone else load with out working up to it.

 

[superde]

View attachment 7828892

That was from 4 years ago? We all used to go for speed. At that time almost everyone shooting Dasher was launching Berger 105's at 2960-3000 fps with 32.5 of Varget and CCI 450's (Lapua Brass). Now almost everyone has slowed it down and realized that we didn't need to go that fast. 6 BR's, 6 BRA's and 6 Dashers in the 2800-2850 fps range with 105-110 grain bullets is the norm. I think (IIRC) Morgan King told me last year he was running 2725 fps out of his gun.