Pressure sign/load development question

[antelopedundee]

@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.

From what I've read Reloder 26 works best with the heavier/heaviest bullets for a given caliber. For .264 that might be 140 grains and higher.

 

[antelopedundee]

Anyone ever experience a difference in felt recoil from an over pressure load? Sometimes I can fire one and just know that something seems different.

 

[Jbotto]

I think I’d be cruising the used side of things for a Leupold 4x, a VX1, or VX2 that fits the bill. They are still out there. If you come across a Redfield Revolution too, I wouldn’t shy away at the right price. I believe they were just a rebranded VX1

 

[MS 9x56]

Not so much over pressure but for sure on heavier bullets.

 

[antelopedundee]

I think I’d be cruising the used side of things for a Leupold 4x, a VX1, or VX2 that fits the bill. They are still out there. If you come across a Redfield Revolution too, I wouldn’t shy away at the right price. I believe they were just a rebranded VX1

Does Leupold still make the Redfield line?

 

[Jbotto]

Does Leupold still make the Redfield line?

Not sure but I don’t think so. I’ve heard that Revolution line got dropped and they only kept the Revenge line.

 

[Jbotto]

I think I’d be cruising the used side of things for a Leupold 4x, a VX1, or VX2 that fits the bill. They are still out there. If you come across a Redfield Revolution too, I wouldn’t shy away at the right price. I believe they were just a rebranded VX1

Sorry about this post. I swear I typed this on the $200 scope thread this morning but couldn’t find it later on. Somehow my phone switched threads on me. My apologies for off topic post.

 

[ImBillT]

I don’t consider any pressure sign to be “false” if it was cause by the pressure and not some other phenomenon.

Winchester primers are the softest. They will absolutely flatten under less pressure than other brands. CCI and Federal are both very hard and wil handle substantial pressure. Does that mean the Winchester is showing a “false” pressure sign? No. If you keep going you’ll pierce a primer and get a face full of gas. If you want to increase pressure you can switch to a harder primer.

Norma, Hornady and Remington are pretty soft brass. RWS and some others fall in the middle, and Winchester and Lapua are very hard. I have not shot some of the new high end domestic brass and can’t say anything about them. 100% you’ll get ejector marks on Norma or Remington brass with lower powder charges than with Lapua or Winchester. Is it false? No. You keep going up and you’ll loose primer pockets and potentially even get a face full of gas and a case that won’t extract. There is variation from lot to lot, and from cartridge to cartridge. I ran into some Norma 6.5-284 that was very hard, but it was also not the quality that Norma usually produces. I’m sure someone will disagree with my general positioning of the brands, but they are in line with my experience.

Brass does get harder with use, and this is more pronounced with softer brass. It’s entirely possible that after 2-4 firings you will be able to load a little more powder before getting ejector swipe than you can on the first 1-2 firings.

There’s a reason every manual ever printed said not to go directly to max. Different barrels, different components, and different powder lots can all lead to different pressures at the same powder charge. Just because Berger reached a certain pressure level before it violated the SAMMI spec doesn’t mean that you will be able to go that high.

 

[ImBillT]

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

View attachment 270253

“Danger Zone” and “I would most likely back off” are two different things. It also depends on what gun I’m behind. A Remington 700 with standard Remington extractor is generally very safe, and I’ve been behind one during more adventurous reloading, as well as two casehead separations. Something with a Sako or M-16 style extractor, regardless of who made it(Sako, Howa, Christensen, Bergara, modified Remington), and I would be much more careful. When I load for Mausers I’m extra careful of any pressure signs, and really want to settle on a load before I ever reach a pressure sign. They vent into the magazine well, and that can do all sorts of exciting things that I don’t want to be a part of. I assume CZs and Winchester Model 70s are similar.

If I was shooting that in a Remington 700 I would only be concerned with how primer pockets were holding up, and that would only be because I wanted to reload the brass a fair number of times. As long as the pockets were tight, I wouldn’t care about ejector marks.

The primers look reasonable. I assume the brass is a tad on the soft side.

 

[cahunter805]

The primer looks good and the ejector mark is very faint IMO.
Is that new brass or once fired?
I don’t really worry about ejector marks especially if the load shoots great. Brass is cheap if you get a few firings from them.

 

[mtmuley]

“Danger Zone” and I would most likely back off are two different things. It also depends on gun I’m behind. A Remington 700 with standard Remington extractor is generally very safe, and I’ve been behind one during more adventurous reloading, as well as two casehead separations. Something with a Sako or M-16 style extractor, regardless of who made it(Sako, Howa, Christensen, Bergara, modified Remington), and I would be much more careful. When I load for Mausers I’m extra careful of any pressure signs, and really want to settle on a load before I ever reach a pressure sign. They vent into the magazine well, and that can do all sorts of exciting things that I don’t want to be a part of. I assume CZs and Winchester Model 70s are similar.

If I was shooting that in a Remington 700 I would only be concerned with how primer pockets were holding up, and that would only be because I wanted to reload the brass a fair number of times. As long as the pockets were tight, I wouldn’t care about ejector marks.

The primers look reasonable. I assume the brass is a tad on the soft side.

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

 

[Wind Gypsy]

The primer looks good and the ejector mark is very faint IMO.
Is that new brass or once fired?
I don’t really worry about ejector marks especially if the load shoots great. Brass is cheap if you get a few firings from them.

Generally I agree with not being too concerned with the primer/ejector marks on Greenhorns brass. It's just the velocity (if accurate) that would put me on alert. Still possible that I'm over cautious and not giving RL26 enough credit too. Published hornady max data is inline with his velocities.

ADG 6.5 PRC brass is like $1.80/ea. Might just be how it coincided with barrel break in/speed up but i've noticed higher pressures on second firing with ADG SAUM brass and noted the same with other cartridges too. So if you only get 3 firings on 1.80/ea brass, your first and second firings behave differently and your third has sticky bolt lift, I'd be pretty unhappy with that experience with a precision rifle and expensive components.

 

[mtmuley]

Generally I agree with not being too concerned with the primer/ejector marks on Greenhorns brass. It's just the velocity (if accurate) that would put me on alert. Still possible that I'm over cautious and not giving RL26 enough credit too. Published hornady max data is inline with his velocities.

ADG 6.5 PRC brass is like $1.80/ea. Might just be how it coincided with barrel break in/speed up but i've noticed higher pressures on second firing with ADG SAUM brass and noted the same with other cartridges too. So if you only get 3 firings on 1.80/ea brass, your first and second firings behave differently and your third has sticky bolt lift, I'd be pretty unhappy with that experience with a precision rifle and expensive components.

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

 

[cahunter805]

Generally I agree with not being too concerned with the primer/ejector marks on Greenhorns brass. It's just the velocity (if accurate) that would put me on alert. Still possible that I'm over cautious and not giving RL26 enough credit too. Published hornady max data is inline with his velocities.

ADG 6.5 PRC brass is like $1.80/ea. Might just be how it coincided with barrel break in/speed up but i've noticed higher pressures on second firing with ADG SAUM brass and noted the same with other cartridges too. So if you only get 3 firings on 1.80/ea brass, your first and second firings behave differently and your third has sticky bolt lift, I'd be pretty unhappy with that experience with a precision rifle and expensive components.

Most barrels will settle/speed up at around 120-200 rounds.
I would also be upset with only 3 firings on ADG brass. 7-8 firings I would be ok with.
Do you anneal your brass regularly.

Greenhorn- how many rounds down the barrel? Did the group size change at all or POI change?

 

[The Hedgehog]

Most barrels will settle/speed up at around 120-200 rounds.
I would also be upset with only 3 firings on ADG brass. 7-8 firings I would be ok with.
Do you anneal your brass regularly.

Greenhorn- how many rounds down the barrel? Did the group size change at all or POI change?

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.

 

[Deleted member 20812]

Might just be how it coincided with barrel break in/speed up but i've noticed higher pressures on second firing with ADG SAUM brass and noted the same with other cartridges too.

I’ve experienced this as well.

 

[Deleted member 20812]

I would also be upset with only 3 firings on ADG brass.

I’m seeing a couple of split necks on Peterson brass in my .300 Win at five loadings.

 

[Wind Gypsy]

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

That definitely happens a lot.

Most barrels will settle/speed up at around 120-200 rounds.
I would also be upset with only 3 firings on ADG brass. 7-8 firings I would be ok with.
Do you anneal your brass regularly.

Greenhorn- how many rounds down the barrel? Did the group size change at all or POI change?

Looks like barrel speed up might be a factor here too.

I typically anneal my brass every few firings. Might go 4x on virgin brass before annealing depending on circumstances. 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.

 

[Deleted member 20812]

Annealing is such a rabbit hole, possibly more contentious than politics…

 

[ImBillT]

Most barrels will settle/speed up at around 120-200 rounds.
I would also be upset with only 3 firings on ADG brass. 7-8 firings I would be ok with.
Do you anneal your brass regularly.

Greenhorn- how many rounds down the barrel? Did the group size change at all or POI change?

Annealing brass won’t save primer pockets. If the case head is deforming(ejector marks) your primer pockets are at risk of getting loose over time. More material around a primer pocket mitigate these effects, so magnum cases, and standard cases that have small primer pockets can tolerate more case head deformation without loosing primer pockets. Also, the case head will harden with use, so it possible for a load that left an ejector mark to stop causing that much deformation after a few firings.

You can try loading a single case 4-10 times with the same load and see if ejector marks stop occurring, it the primer pocket gets loose, and if the case web starts springing back too much out of the sizer causing insufficient clearance in the chamber even after sizing.