Pressure sign/load development question

[jphares44]

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!!

 

[BackofBeyond]

Curious, what primers are you using? Some primers (Winchester) are much softer than others (CCI.) I’ve run into false early pressure signs because of flattened primers, but never ejector smear.

Also, was this first firing on these brass?

 

[jphares44]

Indeed, it was the first firing of this brass. I started this project with 100 pieces of new Peterson brass, so all of this data to this point is based on new brass. Also, CCI 250 primers.

 

[RealMuddyboots]

New brass should be fireformed first before pushing the loads. Start with moderate load to fireform, shoot, push shoulder back 0.002-0.003 and load for performance. Prob seeing new brass "false pressure" ejector swipe from fireforming at stiff load. Grab some cheap bullets, use primers that are not your load primers. Accuracy irrrlevant.

 

[jphares44]

New brass should be fireformed first before pushing the loads. Start with moderate load to fireform, shoot, push shoulder back 0.002-0.003 and load for performance. Prob seeing new brass "false pressure" ejector swipe from fireforming at stiff load. Grab some cheap bullets, use primers that are not your load primers. Accuracy irrrlevant.

That's an excellent suggestion that makes sense to me. I appreciate the feedback!

 

[RealMuddyboots]

Petersen is tough brass and is as good as it gets.

 

[jphares44]

Petersen is tough brass and is as good as it gets.

It sure seems nice. It was between that and ADG. I was surprised to find Lapua doesn't make 7mm Rem Mag brass, but my understanding has been Peterson and ADG are at least in the same ballpark, if not just as good. Thanks again!

 

[Robert N]

Personally, I wouldn’t worry about the slight ejector marks. As others have noted, brass does a bit of fire-forming on the first shots.

My personal take, I’d load 20 rounds at 63.0 grains and then go fire for effect. If you’re getting sub 1/2” accuracy, I’d pretty call it right then and there and be done with load testing.

PS: pressure signs that worry me: massively cratered primers…needing a hammer to open the action…that one “sound” (a super hot load just plain sounded different)…yeah, that’s pretty telling.

 

[Addicting]

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.

 

[jphares44]

Personally, I wouldn’t worry about the slight ejector marks. As others have noted, brass does a bit of fire-forming on the first shots.

My personal take, I’d load 20 rounds at 63.0 grains and then go fire for effect. If you’re getting sub 1/2” accuracy, I’d pretty call it right then and there and be done with load testing.

PS: pressure signs that worry me: massively cratered primers…needing a hammer to open the action…that one “sound” (a super hot load just plain sounded different)…yeah, that’s pretty telling.

Thanks, another good take! Yeah, the primers looked good, and one thing I failed to mention was that there wasn't the slightest sign of a "heavy" bolt lift or anything. It sounds like what I experienced as far as a faint ejector mark/swipe may be common with new brass. I would have been a little disappointed if I had to go backwards, especially since the powder charges on either side of groups under 1/2 minute produced groups that were quite larger. I won't be going out and winning any matches, but I'm happy with 1/2 minute or less in a hunting gun. Especially if I can be confident in the load under varying conditions.

 

[jphares44]

Group size is not indicative of a node. You can no 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.

Thanks, I certainly need to get some velocity numbers...that data will start to tell a story, I'm sure. And, being an average shooter at best, I definitely throw my fair share of shots. I don't doubt the rifle is more capable than I am, LOL!

 

[winmag]

I bet the ejector recess on the bolt face is a sharp 90 degree angle, giving you false ejector marks. That compounded with new brass which isn’t firm formed.

Post a photo of a fired case head?

If the bolt lift and primers are fine then I wouldn’t worry about it.

 

[jphares44]

I bet the ejector recess on the bolt face is a sharp 90 degree angle, giving you false ejector marks. That compounded with new brass which isn’t firm formed.

Post a photo of a fired case head?

If the bolt lift and primers are fine then I wouldn’t worry about it.

Thanks, and a picture would be good. I'll post one as soon as I can!

 

[jphares44]

Sort of hard to get good pics, but here are examples of the 3 worst cases showing ejector marks/swipe. This might end up being laughable for some, but as a beginner reloader sometimes it's hard to tell what is common and what is getting near the "danger zone". Maybe I don't have a trained eye yet for noticing primer issues, but these look ok to me. And again, no heavy bolt lifts on any load so far.

Thanks again to all for your input so far!

 

[MThuntr]

To me those look pretty hot and not just a faint ejector mark. I'm experiencing similar with a hot load using Peterson in my 300win.

You can get some curious pressure signs with new brass especially if your chamber is on the "long" end of SAAMI as the brass tries to flow. Personally if you're planning to load the rest with your chosen load without fireforming then I'd double back with a chrono and looking at the 62.4 load. Peterson brass tends to have smaller internal volume than some of the others and I wonder if you're getting some good velocities with that load.

Or you could size the now oncefired brass and restart your load development. This would be ideal but can burn up components. It will help prevent you chasing numbers and give you a better baseline.

You could also double back using a ladder method to search for single shot nodes...statistically it's not great info but for a hunting rig I bet it'll suffice

 

[winmag]

I’d call that an ejector mark not a slight ejector mark. But I don’t see any swipe.

Primer looks cratered but not blown out flat all the way to edges.

I’d interpret all that (along with no bolt lift issues) as being the very top end of useable pressure. Plenty of match shooters shoot that hot and hotter but I’d back off for a hunting load. You can’t risk getting your action locked up when you need to get a second bullet into an animal.

 

[The Hedgehog]

Sorry to highjack - but does anybody think this is in the danger zone?

 

[winmag]

Sorry to highjack - but does anybody think this is in the danger zone?

View attachment 270253

That’s about the ejector marks I’m getting in my current hunting load in 28 Nosler with ADG brass. I can see an ejector mark in perfect light, can’t feel it with your fingernail, no swipe, no primer crater. I’m using Retumbo which isn’t temperature sensitive so I’m not worried about what might happen in hot temps.

I’m sure some will say any ejector mark at all is too high, but come on, live a little…

 

[jphares44]

@Mthuntr & @winmag - thanks. I think deep down I knew they were a little hot and just didn't want it to be true when I saw the group sizes shrinking. It's' funny, I'm looking at the case now in my hand and looking at the picture, and the picture might make it look a little worse...but I agree with both of your assessments. I'll put the chrono on and start getting some velocity numbers. And there might be some potential in that 62.4 load. Unfortunately, the two trips I've made to the range to test these loads, someone has beaten me to renting the one chrono they have.

@Greenhorn - hope you get the feedback you need!

 

[MThuntr]

Sorry to highjack - but does anybody think this is in the danger zone?

I'd say you're right there at what would be max. Ejector, some swipe, flattened primer. Not knowing the load I'd say that's as hot as I'd go with. That being said the 300WSM I had expressed that characteristic on nearly every load that wasn't below a mild load. I basically had an expensive 30-06