Do these primers show signs of high pressure?

They do to me. My 700 BDL had primers like that once with a 'warm' load, never went that high again as extraction was almost impossible

They look flat to me...... So yes

The row on the right, the 4 th case down, shows a little flow into the firing pin hole. May not mean anything at all. More load info is needed, bullet, amount of powder, make of magnum primers, brass.

Reading primers is a poor method of detecting over pressures. Flat primers could simply mean too much headspace.
Was the bolt sticky? Do you own a chronograph?

Primers are (now) notoriously ill-favored as pressure indicators -- too many variables.

On the other hand, I see absolutely no hint of any brass flow in the case headstamp
of your singleton picture. Everything's/the lettering's still sharp. That's Test "1", and you're
not past ~74-75,000psi

Reload THAT case five times and if no primer pocket looseness develops, that's Test "2"
and you're probably Good2Go at ~55,000 - 60,000psi.

Short of being pierced primers tell you nothing.

Just about every variable imaginable has a greater effect on primer appearance than pressure making such appearance guesses just that guesses.

Is your brass stretching/thinning excessive?

Are you using published well vetted load data?

Are your velocities matching or slower than the manual specifies?

If the answer to those questions is yes my reply is "don't worry about what the primers look like"

You ask for help identifying pressure signs, but you give this for load info!

I shot about 40 rounds, and none of them were close to max (50% were in the middle of the chart, the rest inched up to 3/4s of the way up the chart in groups of 4). The powder is H1000.

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Did it occur to you that the Exact details of the load may be as much help if not more help than your pictures?? "50% in the middle of the chart", what the heck does that mean?

I'm in they look alright to me camp.
I'm also in agreement primers are not the way to tell if there's too much pressure in a load.

MORE INFORMATION IS NEEDED!

You told us which powder and it's a 7mm Rem Mag but you didn't tell us what weight bullet and which primers you're using. With most bullets in the 7mm RM the powder charges are large and should be set off by a Magnum primer. If you're not using a magnum primer you should be, IMO of course.

Please give us more information so we can give you a better informed opinion.

You ask for help identifying pressure signs, but you give this for load info!

Did it occur to you that the Exact details of the load may be as much help if not more help than your pictures?? "50% in the middle of the chart", what the heck does that mean?

Did it occur to you that the original question was " Do these primers show signs of high pressure"... nothing more, nothing less. If you would like more information about the load you should simply ask for it, period.

Did it occur to you that the original question was " Do these primers show signs of high pressure"... nothing more, nothing less. If you would like more information about the load you should simply ask for it, period.

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It did! And reading primers is A kin to reading tea leaves ! Especially when most if not all pertinent data is omitted.

Here is the additional data requested. Primers are Win LR Mag. The first 20 rounds were loaded with 62.7gr of H1000. Average velocity 2675, which is a hair under the published data in my book (Hornady) for that load. I never got above 2760 with any of the loads.

Max for that bullet in my book is 68.5gr of H1000, at 3000 fps. Hope that helps.

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Nope, not a lot of help without the bullet and bullet weight.

I'm with the "look ok to me group". I started loading back in the 1960's when we did use primers for a pressure sign and we didn't have anywhere near the equipment available that some do now..

From the numbers he's using that come right out of the Hornady manual he's using a 162gr Hornady bullet.

I would not expect to achieve the velocities listed in the manual because they are generated under lab conditions and usually with a longer test barrel.

From the velocities you are reporting it seems like you probably are not generation the high pressures you originally asked about. Why are you increasing your powder charge if you are worried about pressure? You are speaking about pressure and velocity but you never mentioned accuracy. Just because a load manual tells you you can use xx amount of powder doesn't mean you are required to. Most times the max charge does not deliver the best accuracy and the best accuracy is what you should be trying to achieve. I would not sacrifice accuracy for a slight increase in velocity. That game animal will be no deader if you hit it with a 162gr bullet @2700 fps or @2725 fps!!!

No magic formulas. Reading primers for pressure was disproven with the advent of modern testing equipment, measuring chamber pressure over the entire firing cycle instead of the older method that only measured the maximum pressure reached. What is used by reloaders is the result of the improved testing, comparing published load data with the results obtained by velocity reading and accuracy. It still involves some guesswork, but with the newer data available the estimation is based on far superior data than reading primers.

I see a number of primers in the pics that look as though they are protruding from the pocket. Those to me indicate a possible low pressure situation. And the rest don't really exhibit high pressures in my opinion, but they do look inconsistent in appearance. The rather erratic appearances lead me to believe you may be seeing low pressure signs, rather than high. But in all honesty, I don't rely on primers for pressure evaluation other than using them in addition to other factors. When I work up a load in my 7 mags and have reached the limit, the primers will of course exhibit filled pockets, evidence of top hat expansion, and cratering around the firing pin strike. I'm not seeing any of that going on here.

I don't have a lot of experience with H1000 in the 7 mag, other cartridges, but not a lot with 7 mag.. That said, I'm uncertain if the chrony information you provided us, would be consistent with what's to be expected with H1000 using a mid range load. I know with RL22 I can expect to easily obtain 3000 to 3100 fps range with room to spare, in terms of pressures v.s. velocities with a bullet weight consistent of that which you are using.

Another element that can cause pressure issues is how far you are off the lands. this alone can elevate pressure well beyond acceptable with loads that would normally be acceptable. As well, if you had seated that close to the lands as indicated .003" - .002" without a ton of experience doing so, it is possible to get some significantly closer, or actually into the lands, while others may be considerably further off the lands, thus producing inconsistent primer expansion.

So how was the bolt lift? What were the specifics of the charge? And were you using an accurate method of measuring OAL off the olgive, to obtain those seating depths? And did you measure each charge using a scale?

GS

Rmeju said:

I posted this info in post #11. I have now reposted it in the OP, so it is easier to find.

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Sir, the bullet weight was not in Post #11 until you did and edit and added it later on. I read that post more than once and it was not there. No reason to make things up especially when we are all trying to help you.

Now, please explain to me why you are using such a powerful cartridge for killing paper @100 yards? Such a heavy hitter is even too much for Deer, including Mule Deer IMO. If I were loading a 7mm RM for target shooting I would download the ammo. Many shooters who have a 300 Win Mag do the same and download their ammo to 30-06 power.

I would switch to a Hornady 162gr BTHP Match bullet and use a starting charge of a faster powder like 4350, 4831 or even Hybrid-100V. Sending that bullet out of the barrel @2500 fps will make your range shooting much more pleasant IMO and with the reduced recoil you just might increase your accuracy too... You might even want to shoot a Sierra 150gr MatchKing bullet instead and load even lighter similar to the 280 Remington. Just a few thoughts you might consider.

Light loads of Slow powders have been blamed for more than one KB over the years. According to Hodgdon your loads are below Minimum, not a good place to be with slow powders.

Hodgdon data lists 67gr as Minimum.


http://data.hodgdon.com/cartridge_load.asp

steve4102 said:

Light loads of Slow powders have been blamed for more than one KB over the years. According to Hodgdon your loads are below Minimum, not a good place to be with slow powders.

Hodgdon data lists 67gr as Minimum.

Code:

 162 GR. HDY SPBT 	Hodgdon 	H1000 	.284" 	3.290" 	67.0 	2800 	45,400 CUP 	70.0 	2905 	49,600 CUP

http://data.hodgdon.com/cartridge_load.asp

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While I agree with your post Hornady's load data is very different than that supplied by Hodgdon. Hornady #9 with their 162gr A-Max bullet lists a charge range of 56.8gr to 68.5gr H1000 in the 7mm Rem Mag. It's amazing how very different some of the data out there is. I wish someone could enlighten me as to how both data sources are safe??? With just over a 10gr difference in minimum load that's a little hard to understand, no? (at least the high side is not so different)

ArchAngelCD said:

I'm in they look alright to me camp.
I'm also in agreement primers are not the way to tell if there's too much pressure in a load.

MORE INFORMATION IS NEEDED!

You told us which powder and it's a 7mm Rem Mag but you didn't tell us what weight bullet and which primers you're using. With most bullets in the 7mm RM the powder charges are large and should be set off by a Magnum primer. If you're not using a magnum primer you should be, IMO of course.

Please give us more information so we can give you a better informed opinion.

Click to expand...

Same here. Although primers are a poor indicator of pressure, I get real concerned when a flattened primer looks to be milled into it's pocket.

I agree with HangF. I realize this is a 7mm mag. Primers may look like that due to this cartridge. If it were a 308 with primers looking like that, I would look for other case stretching issues.