Pressure sign/load development question

[ImBillT]

I've had ejector marks that looked like they were polished onto the brass. No other signs. I don't think ejector marks are the most reliable signs of pressure. mtmuley

If you get a rub when you load and unload a case, then you should probably bump your shoulder a tad. On the other hand, if brass pushes into the ejector hole or slot, and is shaved off when you open the bolt, then you’ve stressed the brass beyond the elastic region and entered the plastic region of its stress/strain curve. The brass will harden, and move the boundary of the elastic region somewhat into what was before the plastic region. You have still permanently deformed the brass. It’s a reliable sign that you’re on the edge of what the brass can handle. If you’re barely over the edge(@Greenhorn ’s primer looked fine) it’s possible that the same charge won’t cause new ejector marks. If it continues to cause new ejector marks with each firing, loose primer pockets are coming soon(although the magnum diameter case head may kick that can down the road more than I’m sure of, as I’ve never loaded for magnums, or used SRP brass in anything but a 222/223).

If gas is going to leak out of a case anywhere but the case mouth, I want to be behind a Remington 700 with a Remington style extractor. If I get any pressure signs when shooting a Mauser or Sako, or Remington with Sako extractor, I back off immediately. Perhaps I’m being over cautious.

 

[cahunter805]

I’ve got about 150 through it. Groups have all been consistently very good with handloads. Best group when i initially tried 4 different powder charges was a half grain less, so I’ll be fine moving back. 3000fps +/- is plenty. I’m hoping to get a lot of firings out of that brass. Will back the powder down a few tenths and do some shooting with this muzzlebrake I just put on and see how that goes.

I’m betting you will get plenty of firings from the brass.

When I start with a new barrel my process is load a modified ladder/OCW test and find the node. Once I find the node I will load up 40-50 rounds and start shooting steel and verify drops.
Once the barrel has settled I will fine tune if needed and then load a bunch of rounds.

 

[Carl]

In regards to ADG brass, it seems really tough and you'd have to be pretty terrible to it for it to be toast by 3x from traditional issues like losing primer pockets, split necks, impending case head separation, etc. The thing I'd be more concerned about with 6.5prc is stretching the web from hot loads early on and then having sticky extraction going forward.

Have you seen what Alex Wheeler has posted (a few places, maybe LRH, definitely LRO, maybe Accurate Shooter) about ADG brass and the PRC's?

No personal experience (I used Hornady due to availability while I had a 6.5 PRC barrel) but he found they ran tight in the web and after a few firings the only solution to avoid clickers was to open up the chamber in the web area. Apparently actually cracked some extra tight dies he made attempting to get the base sized sufficiently.

This isn't to say there's quality issues, all reports I've heard are of great quality brass, but apparently the chamber dimensions can be tricky.


Only tangentially related, I've had chambers in Dashers that were too loose (Shilen) and too tight (older PVA), neither were fun. Shilen replaced the barrel, I didn't give PVA the chance. I'm also sitting on 900 pieces of Alpha's first pitch at Dasher brass, which is too tight after one firing, and I may never mess with it again despite the investment. Chamber/brass/die dimensions matter for long term happiness.

 

[Carl]

I wonder if using the supposedly stronger brass encourages loaders to push the limits more than using "standard" brass? You could be over SAAMI and not even know it. mtmuley

I think this happens a ton with harder magnum brass or 308 case head size brass with small primers.

 

[Wind Gypsy]

Have you seen what Alex Wheeler has posted (a few places, maybe LRH, definitely LRO, maybe Accurate Shooter) about ADG brass and the PRC's?

No personal experience (I used Hornady due to availability while I had a 6.5 PRC barrel) but he found they ran tight in the web and after a few firings the only solution to avoid clickers was to open up the chamber in the web area. Apparently actually cracked some extra tight dies he made attempting to get the base sized sufficiently.

This isn't to say there's quality issues, all reports I've heard are of great quality brass, but apparently the chamber dimensions can be tricky.


Only tangentially related, I've had chambers in Dashers that were too loose (Shilen) and too tight (older PVA), neither were fun. Shilen replaced the barrel, I didn't give PVA the chance. I'm also sitting on 900 pieces of Alpha's first pitch at Dasher brass, which is too tight after one firing, and I may never mess with it again despite the investment. Chamber/brass/die dimensions matter for long term happiness.

Yeah, I have read Alex's thoughts on the PRC clickers multiple times to make sure I'm not misunderstanding. That's part of why I'd be cautious with warmer loads in a standard SAAMI PRC chamber because it seems like once the web is stretched to make things sticky there is no recovering with that brass/chamber regardless of how much you can resize the base of the case. If things did get sticky in future firings for @Greenhorn it seems he may be able to mitigate by running one of Alex's spec'd reamers in his barrel.

Sucks on the Alpha Dasher brass deal! I remember seeing those complaints with first run dasher and GT brass.

I had a 300 Norma barrel that was guaranteed to be sticky by 3rd firing with norma brass, 2nd firing on hot loads. Once Lapua and Peterson norma mag brass hit the market a lot of people's brass life and clicker issues were solved but if I recall correctly the ADG NM brass was still a little more prone to getting clickers. I don't have the volume of experience to confirm but anecdotally it seems that while ADG brass consistency in dimensions/weight and primer pocket life is top shelf, they seem more prone to clickers in multiple cartridges.

It's great we have all these options for premium brass manufacturers and modern cartridge design but it seems to be more crucial for people to understand brass, chamber, reamer, die dimensions than it ever did with traditional cartridges.

Even with factory ammo, norma is loading the 6 creed 107 golden target ammo with loaded neck diameters of 0.275" when SAAMI chamber neck diameter is 0.277. Feldkamp told me his SAAMI reamer should end up around 0.2765 so my new barrel with a "SAAMI" chamber might not play nice with the factory ammo i bought.

 

[Drake4]

Have you seen what Alex Wheeler has posted (a few places, maybe LRH, definitely LRO, maybe Accurate Shooter) about ADG brass and the PRC's?

No personal experience (I used Hornady due to availability while I had a 6.5 PRC barrel) but he found they ran tight in the web and after a few firings the only solution to avoid clickers was to open up the chamber in the web area. Apparently actually cracked some extra tight dies he made attempting to get the base sized sufficiently.

This isn't to say there's quality issues, all reports I've heard are of great quality brass, but apparently the chamber dimensions can be tricky.

I had to do this to my chamber.

 

[N2TRKYS]

Yeah, I have read Alex's thoughts on the PRC clickers multiple times to make sure I'm not misunderstanding. That's part of why I'd be cautious with warmer loads in a standard SAAMI PRC chamber because it seems like once the web is stretched to make things sticky there is no recovering with that brass/chamber regardless of how much you can resize the base of the case. If things did get sticky in future firings for @Greenhorn it seems he may be able to mitigate by running one of Alex's spec'd reamers in his barrel.

Sucks on the Alpha Dasher brass deal! I remember seeing those complaints with first run dasher and GT brass.

I had a 300 Norma barrel that was guaranteed to be sticky by 3rd firing with norma brass, 2nd firing on hot loads. Once Lapua and Peterson norma mag brass hit the market a lot of people's brass life and clicker issues were solved but if I recall correctly the ADG NM brass was still a little more prone to getting clickers. I don't have the volume of experience to confirm but anecdotally it seems that while ADG brass consistency in dimensions/weight and primer pocket life is top shelf, they seem more prone to clickers in multiple cartridges.

It's great we have all these options for premium brass manufacturers and modern cartridge design but it seems to be more crucial for people to understand brass, chamber, reamer, die dimensions than it ever did with traditional cartridges.

Even with factory ammo, norma is loading the 6 creed 107 golden target ammo with loaded neck diameters of 0.275" when SAAMI chamber neck diameter is 0.277. Feldkamp told me his SAAMI reamer should end up around 0.2765 so my new barrel with a "SAAMI" chamber might not play nice with the factory ammo i bought.

What are “clickers”?

 

[Carl]

Yeah, I have read Alex's thoughts on the PRC clickers multiple times to make sure I'm not misunderstanding.

I'm not surprised you were savvy.

Sucks on the Alpha Dasher brass deal! I remember seeing those complaints with first run dasher and GT brass.

I know I'm not alone. Have/am considering having a barrel opened up in the web area to see if I can get it to run nice, as I have enough for ~8 barrels worth if I took the Alpha as far as I've taken my Lapua brass. That's what I had done with my old PVA chamber, which showed up small enough it touched the web on unfired Lapua 6BR. I hear the OCD is good to go, and I've considered buying a large lot, but am hesitant for obvious reasons.

I had to do this to my chamber.

Bummer, but at least there's an option someone has figured out.

What are “clickers”?

When fired brass is tight enough in the chamber (most commonly in the web, at the base of the case) that it requires the secondary extraction cam of the action to pop it loose from the chamber. It causes a click or a pop to fully open the bolt. The action IS designed to do this, but guns run much nicer if the bolt opens easily and can be cycled without moving the rifle off target. It is also a spectrum, a light click is barely noticeable unless you're really dialed in, a really bad one can render it basically nonfunctional. People often call this "sticky bolt lift" and it is one potential sign of pressure, but overly tight brass will cause it with completely reasonable pressures.

 

[OntarioHunter]

Try prune juice to relieve pressure signs in load development.

 

[Red-Team 98]

In 7 RM my favorite IMR 4350 has served well with 160gr Nosler Part.

 

[Drake4]

Bummer, but at least there's an option someone has figured out.

I should clarify. I wasn't experiencing this. Only have 2 firings through my ADG brass and things are re-sizing just fine. I used a custom reamer that was not SAMMI spec and had a shorter freebore. My gunsmith was experiencing this on Hornady brass and started researching the topic. He ordered a new reamer with the same custom freebore and .003 larger in the web. He offered to run it through my chamber. I decided to do it before I ever had any clicker issues. It didn't change accuracy, velocity, etc. at all.

 

[Red-Team 98]

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.

Yes a slight difference in primers will make a change as well as outdoor Temperature

 

[millerkiller77]

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.

Are you fireforming all new brass regardless of brand? (ADG, LAPUA, PETERSON) and in standard calibers or just wildcats?

 

[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.

@SEII

 

[Don Fischer]

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!!

Ya know the only pressure sign I might over look, might, is a flat primer. I've noticed what a lot of people think is flat doesn't mean a thing. Bolt opening hard does! I also pay attention to the ejector mark. But your the one firing the rifle and I think you should decide for yourself what different pressure signs actually mean. I despise loose primer pockets, primer pocket is loose the case head had to expand and I'm not big on that. Talked to a guy in Penn a number of years ago and his advice about that was ignore it and glue in the primer. He said more than I'd want to hear right there and I have never done it. Doesn't mean it won't work just means I'm not willing to try that! As for the flat primer, it has to be flat all the way across the pocket and if it is then most likely the case head has expanded! Your fooling with a lot of pressure, try stuff but pay attention to pressure signs.

 

[Don Fischer]

Just a little more. Been reloading about 58 yrs now and one thing I have come to understand is to not experiment to far before saying enough. Look at the case and look for pressure indications then you decide if your willing to risk more! The guy that say your alright and go up some more is not the guy that will be shooting your ammo! Something I don't know what anyone has is a way to actually measure pressure, use extreme caution. I have exceeded max loads in manuals at different time's with no problem and have noticed what I'd call more pressure at other times. Your the one pulling the trigger, what do you think? Keep in mind there are other powders you could use that will probably equal what you are getting right now and there are lower loads that will probably get the job done just as well. Experimenting is a good thing I think but you had better be ready for the end result if you screw it up. That's the down side of it!

 

[3006Sprng]

Ya know the only pressure sign I might over look, might, is a flat primer. I've noticed what a lot of people think is flat doesn't mean a thing. Bolt opening hard does! I also pay attention to the ejector mark. But your the one firing the rifle and I think you should decide for yourself what different pressure signs actually mean. I despise loose primer pockets, primer pocket is loose the case head had to expand and I'm not big on that. Talked to a guy in Penn a number of years ago and his advice about that was ignore it and glue in the primer. He said more than I'd want to hear right there and I have never done it. Doesn't mean it won't work just means I'm not willing to try that! As for the flat primer, it has to be flat all the way across the pocket and if it is then most likely the case head has expanded! Your fooling with a lot of pressure, try stuff but pay attention to pressure signs.

I agree with this regarding primers and flattening only. Primers alone are tricky to judge (unless you blow hole in them or pop them right out).

I have definitely seen different brands of primers flatten to different degrees while being way under max loads/pressure. Doesn't mean ignore it, just be cognizant of all pressure variables.

 

[Don Fischer]

Should have said something sooner. This is a 7nn rem mag and a problem you just might run into that will drive you nuts is case head separation. Problem with some belted mag case's is they headspace on the belt and as a result some have sloppy chambers! Easy way to avoid than is to use the fl die to partial resize from the start. You'll find that in short order the case won't chamber again without fl sizing and that is where you set the dies to partial size the case. The case get's blown out to fill the chamber and headspaces on the shoulder doing away with the sloppy case. Once you get a fired case that won't chamber mty, the case has filled the chamber and to get it to fit at this point you need to partial resize. Little at a time partial size until the case feeds well and you no longer feel the shoulder rubbing trying to load the just resized case. At that point the case now fits a chamber that was sloppy even though headspace on the belt may be right and you'll end the possibility of case head separation! Had the problem with a 7mm rem mag years ago and wrote someone about it and that is what I was told. Tried it and it worked. Originally I was separating case heads with about three loadings. Something to watch for with belted magnum case's!

 

[Alpine01]

Should have said something sooner. This is a 7nn rem mag and a problem you just might run into that will drive you nuts is case head separation. Problem with some belted mag case's is they headspace on the belt and as a result some have sloppy chambers! Easy way to avoid than is to use the fl die to partial resize from the start. You'll find that in short order the case won't chamber again without fl sizing and that is where you set the dies to partial size the case. The case get's blown out to fill the chamber and headspaces on the shoulder doing away with the sloppy case. Once you get a fired case that won't chamber mty, the case has filled the chamber and to get it to fit at this point you need to partial resize. Little at a time partial size until the case feeds well and you no longer feel the shoulder rubbing trying to load the just resized case. At that point the case now fits a chamber that was sloppy even though headspace on the belt may be right and you'll end the possibility of case head separation! Had the problem with a 7mm rem mag years ago and wrote someone about it and that is what I was told. Tried it and it worked. Originally I was separating case heads with about three loadings. Something to watch for with belted magnum case's!

Interesting. I am relatively new to reloading and most of what I have done is with the 7mm RM. I full length resize after every firing. I also just recently got a die from Reloading Technologies that resizes the brass outer diameter just above the belt that alleviates the potential for a secondary belt to develop from FL sizing. I am going into my fourth round of resizing so will be curious to see if this helps/hurts the case head separation issue you experienced.