Pressure sign/load development question

[The Hedgehog]

I had none of those signs previously. I made a change from 210M to 210 primer, and used some older different lot of blemished bullets, same Base to ogive, same powder charge, same new brass, and same, just mandreled case before loading. Velocity kicked up from 2980 to 3060 avg.

 

[MThuntr]

I had none of those signs previously. I made a change from 210M to 210 primer, and used some older different lot of blemished bullets, same Base to ogive, same powder charge, same new brass, and same, just mandreled case before loading. Velocity kicked up from 2980 to 3060 avg.

hmm those should be same primer compound however changing lots could make for change in burn characteristics.

I've heard (but never had) some blemished bullets may have variations in weight that throw them out of "spec". Have you tossed a few on a scale?

 

[The Hedgehog]

hmm those should be same primer however changing lots could make for change in burn characteristics.

I've heard (but never had) some blemished bullets may have variations in weight that throw them out of "spec". Have you tossed a few on a scale?

Yes, they were fairly consistent in weight, but the Base to Ogive measurement was slightly longer when seated so I adjusted my seater and pushed them all in a few thousandths. I'd assumed that would have had the opposite affect. I'm just assuming very very old lot of the bullets that are a tiny bit different.

 

[Drake4]

New barrel, it's fairly common to have that increase in velocity after 100-200 rounds.

 

[Don Fischer]

Those primer's don't show me any pressure at all. The ejector marks would make me look for other signs . Sticky bolt get's my attention right away. I always back off a sticky bolt. Case head expansion should not be ignored but, I've never fired a new case that had no case head expansion. So while I watch for it, so long as the head doesn't exceed spect's I don't worry much. One other thing I don't care for is primer pocket expansion. At the end of a shooting session I take a look at the indicators and make a guess as what to do. Two key poitns for me would be a sticky bolt and really flat primer's, yours are not something that would bother me.

 

[Brian in Montana]

I wouldn't worry too much about it. If you're shooting groups less than .4" groups you're surely doing something right. Most of my most accurate loads tend to be pretty hot, showing flattened primers and the like.

I'd recommend you get some velocity data. From my experience, loads that are near the pressure max are also a somewhat unstable and usually show some pretty large spikes or drops in muzzle velocity. When brass is really getting stressed, it's more obvious than just an ejector mark. Like others mention, the ejector mark you're seeing might be more from new brass expanding in the chamber, not necessarily from the load being over pressure. You made an exceedingly wise decision to start with Peterson brass in a magnum.

 

[Alpine01]

Group size is not indicative of a node. You can not remove yourself from the equation and that will give you false info. We all throw one once in a while.

A node is velocity flat spot over a range of grains.

That being said different lots of powder vary significantly sometimes. The lot they used is not the lot you are using. A swipe mark is the brass expanding too much at the case head, It’s over pressure.

I would shoot it over a chronograph and see what speed you’re at. Then compare that to different load data to see more of the picture.

Agree with addicting. You are over pressure. Really need velocity data. I am at the same stage loading my 7mm Rem Mag with new Peterson brass. I am loading both 150gr CX and 160gr Partitions. CX's are consistently grouping between 0.46 and 0.48 MOA out to 300-yds with H4831 sc at 3150 fps. I saw similar pressure signs at a 0.5 gr higher load as I was trying to find that over-pressure point. Was seeing similar results and marginally higher velocities but the signs were there to back off. Partitions are still a work in progress but I am near my velocity goal and just now getting under 1 MOA.

 

[mtmuley]

A chronograph will tell the story. mtmuley

 

[Wind Gypsy]

Belted magnums vary so much in case capacity between brass manufacturers that using generic published load data without knowing the difference in case capacities can easily lead one astray. Agree with the others - with tough cases like peterson a chrono can paint the picture of high pressures that the brass may not be telling you.

Somewhat unrelated, I wouldn't put too much trust in the results of single 3 shot groups as indicator of a given load. Hornady has been sharing some great info related to typical variance in group sizes that answered a lot of doubt and questions i've had from results over the years. Their data suggests a rifle/ammo combo is typically prone to shoot 3 shot groups ranging from 60-70% larger and smaller than the average 3 shot group size. So if your average 3 shot group size is 0.5", that combo will likely also shoot groups as small as 0.15" and groups as large as .85". Looking at your group sizes (nice shooting BTW), I would bet it's going to shoot just fine with most any reasonable charge.



I'd recommend watching this video from them before you waste time like I and many others have burning up components and barrels doing meaningless tweaks chasing the magic load that doesn't exist.

 

[Mallardsx2]

Factory 300wsm 150 grain silver tip loads have primers flatter than a pancake…..

 

[Wind Gypsy]

I had none of those signs previously. I made a change from 210M to 210 primer, and used some older different lot of blemished bullets, same Base to ogive, same powder charge, same new brass, and same, just mandreled case before loading. Velocity kicked up from 2980 to 3060 avg.

Case signs alone from that pic aren’t that out of the ordinary from what I’ve seen with moderate ADG SAUM loads with 210Ms, maybe a little flatter on the primer but that’s not that uncommon with 210s imo. Velocity seems high though if it’s a 140+ class bullet in a 21” tube. How was bolt lift?

 

[The Hedgehog]

Case signs alone from that pic aren’t that out of the ordinary from what I’ve seen with moderate ADG SAUM loads with 210Ms, maybe a little flatter on the primer but that’s not that uncommon with 210s imo. Velocity seems high though if it’s a 140+ class bullet in a 21” tube. How was bolt lift?

Bolt lift not sticky at all. Velocity was the surprise, 139 scenar with 56.5 grains of RL26. bullet .01" off lands. Only other difference was I was shooting through chrono 18 yards away, instead of 6 yards. Don't think that would matter?

 

[Wind Gypsy]

Bolt lift not sticky at all. Velocity was the surprise, 139 scenar with 56.5 grains of RL26. bullet .01" off lands. Only other difference was I was shooting through chrono 18 yards away, instead of 6 yards. Don't think that would matter?

Bullet probably loses about 30 fps in the first 18 yards. I never did fully trust my ProChrony optical 100%. Not positive but I’d think if it isn’t perfectly square you might get slightly off readings too?

I won’t say it isn’t safe because I don’t know but I’d be shocked if 3090 fps with a 139 scenar in a 21” PRC isn’t clearly above saami max pressure. I tend to back things off even if there aren’t obvious pressure signs when I start seeing velocities that indicate a warm load like that. Not saying everyone should but it makes me feel better about it.

The other thing is that hotter loads are more likely to get the web of the brass expanding to the point it may become prone to clickers a lot earlier in its life. And it sucks to have expensive brass get sticky on bolt lift already on firing #3.

 

[Deleted member 16014]

Belted magnums vary so much in case capacity between brass manufacturers that using generic published load data without knowing the difference in case capacities can easily lead one astray. Agree with the others - with tough cases like peterson a chrono can paint the picture of high pressures that the brass may not be telling you.

Somewhat unrelated, I wouldn't put too much trust in the results of single 3 shot groups as indicator of a given load. Hornady has been sharing some great info related to typical variance in group sizes that answered a lot of doubt and questions i've had from results over the years. Their data suggests a rifle/ammo combo is typically prone to shoot 3 shot groups ranging from 60-70% larger and smaller than the average 3 shot group size. So if your average 3 shot group size is 0.5", that combo will likely also shoot groups as small as 0.15" and groups as large as .85". Looking at your group sizes (nice shooting BTW), I would bet it's going to shoot just fine with most any reasonable charge.

View attachment 270369

I'd recommend watching this video from them before you waste time like I and many others have burning up components and barrels doing meaningless tweaks chasing the magic load that doesn't exist.

This video is worth watching (or listening to, it's on spotify) with an open mind, I will be doing so again before I do load development for another rifle in the future. At first blush I think it would be easy to find depressing compared to what we're "used to" as recreational shooters, but it's really not. It answered and explained a few questions that always linger for me.

They do a good job of balancing the technical information with practical application for match shooters and hunters.

 

[Drake4]

Bolt lift not sticky at all. Velocity was the surprise, 139 scenar with 56.5 grains of RL26. bullet .01" off lands. Only other difference was I was shooting through chrono 18 yards away, instead of 6 yards. Don't think that would matter?

You're good. I wouldn't worry about minor ejector marks if you're not showing any other pressure signs. I'm the same caliber, bullet, powder with a 2" longer barrel and getting 3,165fps w/ no pressure.
I'd attribute your velocity increase to the barrel...fairly common to see up to 100fps increase after 100 rounds or so. I bet @Carl would have some good experience with that.

 

[Wind Gypsy]

This video is worth watching (or listening to, it's on spotify) with an open mind, I will be doing so again before I do load development for another rifle in the future. At first blush I think it would be easy to find depressing compared to what we're "used to" as recreational shooters, but it's really not. It answered and explained a few questions that always linger for me.

They do a good job of balancing the technical information with practical application for match shooters and hunters.

There’s a part 2 that goes further into how they’d do load development.

 

[BackofBeyond]

There’s a part 2 that goes further into how they’d do load development.

And very much worth the time to listen to.

 

[MS 9x56]

I would drop back to 62.4 and call it good.

 

[Carl]

You're good. I wouldn't worry about minor ejector marks if you're not showing any other pressure signs. I'm the same caliber, bullet, powder with a 2" longer barrel and getting 3,165fps w/ no pressure.
I'd attribute your velocity increase to the barrel...fairly common to see up to 100fps increase after 100 rounds or so. I bet @Carl would have some good experience with that.

@Greenhorn

There's a lot of factors at play regarding X amount of powder producing Y amount of velocity in a given chambering. Variables would include:

Bore size (there is over a .001" variance in acceptable bore size for a given caliber and it makes a significant impact on what load results in what velocity)
Bore condition (copper and powder fouling tighten the bore, a carbon ring in the throat can also spike velocity)
Bullet lot variation (as you mentioned may be an issue)
Throat geometry
Powder lot variation
Powder humidity (which changes the density, lower humidity = more actual powder vs water per grain)
Primer variation (primer to primer or lot to lot)

Beyond that, the consumer grade chronographs I'd trust for a decent absolute velocity are: Labradar, Magnetospeed, Ohler. Full stop. If you aren't using one of those, for me there's too much in question to make much of the velocity data.

****** Caveat - the last year or so I have been using a chronograph minimally and mostly go off drop data, but plan to buy a labradar so I can stop borrowing one. If you know what you're doing you can get away with it in most cases, but I appreciate the data. It also helps you confirm the rare occasion when Berger sends you a dull lot of bullets.




That said...

- R-26 is pretty special at producing high velocity without crazy pressure.

- Slightly higher velocity almost never makes a NOTICEABLE difference in performance.

- Your brass looks like 65k+ psi to my untrained eye, I've shot 1000's similarly in the past but try not to now.

- With an aluminum action like the element, I'd error on the soft side personally.



Regarding the Hornady podcast, Miles Neville thinks the same way I do but has better tools at his disposal than I to put his hypotheses to the test. If you aren't already in contention to win F-class or 1000 yd BR matches, I think you should follow his suggested path, I do.


Edited to add (cause I wrote way to much) I'd back off a skosh personally.

 

[NAHMINT]

Hey all, new reloader here. I have a question regarding pressure signs, specifically when it comes to ejector marks/swipe. A little info to start...

The rifle:
Bergara Wilderness Ridge in 7mm Rem Mag, 24" barrel, 1:9.5 twist

The range:
Indoors, 100 yds., bi-pod and rear bag

The load:
175 gr. Berger Elite Hunter
VT-N560 powder, CCI 250 primers, New Peterson brass, seating 0.20" off the lands

Using the Berger reloading manual, the starting load for this particular powder and bullet is 60.5 gr., with a max load of 63.5 gr.

I loaded 3-shot strings starting at 61 gr. up to 62.2 gr. in 0.4 gr. increments and 62.4 gr. to 63.0 gr. in 0.2 gr. increments. I started to see what I considered a "node" at 62.8 gr. and 63.0 gr., with the group sizes at 0.38" and 0.33".

However, I started to notice the slightest ejector mark (just a little kiss) and slight swipe on the case head from operating the bolt for both of these loads. I do not notice this until I get to that 62.8 gr. mark. Again, it's very slight, but I prefer to stay away from too much pressure for obvious safety reasons...especially when I shoot outdoors in potentially hotter weather, etc. There are no issues with the primers. No flattening/cratering, or anything of that nature with any of these loads.

I've read about "false" pressure signs, especially with new brass, which I am currently using. That said, this information comes from the internet, and considering I'd prefer to stay away from pressure signs altogether, what are people's thoughts on this? I almost hate to back off on powder because it's really starting to group well. Maybe I can go back to that range where I was doing 0.4 gr. increments and do 0.2 or even 0.1 gr. increments and see what happens?

Of note, using this bullet/powder combination, the Berger manual spans a total of 3 gr. from starting to max load (60.5 gr. to 63.5 gr.). Looking at the Hornady manual, for a 175 gr. projectile and using this same power, the total range between starting and max load spans 8 gr. (52.6 gr. to 60.5 gr.). Also, the test rifle used in the Hornady manual (Rem 700, 24" barrel, 1:9 twist) more closely resembles my rifle than that in the Berger manual (26" barrel).

If it helps, here are the results of firing these different powder charges:
61.0 gr. (0.43" group)
61.4 gr. (0.76" group)
61.8 gr. (1.01" group)
62.2 gr. (0.82" group)
62.4 gr. (0.44" group)
62.6 gr. (0.94" group)
62.8 gr. (0.38" group)
63.0 gr. (0.33" group)

I guess my question is...where would you go from here? Should I be concerned with a soft kiss from the ejector? Is there really such a thing as "false" pressure signs with new brass? Is Peterson brass considered "soft" compared to other brands where something like this might happen? It might be hard to provide answers since I haven't put a chrono on it yet and have no velocity numbers, and maybe this isn't a big enough sample size. I was basically looking for raw accuracy to this point. Maybe this is all really stupid to ask about and I'll get a bunch of "welcome to HT" comments. Regardless, curious to hear thoughts or advice you have! Thanks!!

First off, get advice from a trusted reloading friend IF you have concerns.
Any advice you get on the NET should not be taken as a ''matter of fact'' !!
Major reloading manuals are a pretty safe source of info........
be safe.