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