Question regarding temperature sensitivity

[DrRansom]

Hi,

Earlier in the year I had done OCW work to obtain a optimal load:

Stock 5R Rem w/PMII
Berger 175gr OTM
Lapua Brass, CCI BR primers
H4895
COAL @ mag length - a few hundredths

With some work, found a node around 42.8-43.0gr H4895. With the 175gr OTMs, I could probably slide the bullet out a little more, but I prefer mag feeding, so haven't messed with that. Most of the work was done in PA, and the last few sessions have been in the 20-30*F range. During the initial workups, I had stopped around 43.6gr because of light pressure signs. There may have been a few very light signs at 43.4, but light enough that I couldn't tell if it was just me.

So in preparation for not having to work today, I loaded 10 each of 42.8, 42.9, and 43.0 to see if I couldn't narrow that sweet spot down and increase consistency a bit...and when I hit the range (50*F and clear, in the Socialist Republic of Taxachusetts), I started seeing pressure signs almost immediately. They weren't consistent; an occasional light, one or two clear, but scattered throughout all 30.

This was firstly very frustrating, as this had been considerable time invested, second because the 42.9 came out good (ES ~20, SD 7, 10-shot group of .75"), and third because even though I know that no powder is truly temperature insensitive, I hadn't expected H4895 to be this reactive...and I thought I had more headroom.

Anyway, my question is: is this level of variability expected for this powder, or could it have been something else that I did?

Auxiliary question: I've borrowed a Dillon D-Terminator scale while I get my own, do you guys think they suck? Because I've tried everything with this one, and I don't think it would even work good as a boat anchor.

Thanks.

 

[turbo54]

Re: Question regarding temperature sensitivity

No experience with the Dillon scale. In general, I hold Dillon in high regard. Did you use the same scale for both reloading sessions?

If so, I highly doubt the scale is the issue.

For that matter, I highly doubt the 20-30°F temp increase was your problem.

In my experience, the #1 cause of "unexpected pressure" is a lubricated chamber/brass.

Are you certain your brass and chamber are bone-dry, clean, and free of any kind of grease, wax, sizing lube, gun oil, bore solvent etc etc??

Otherwise, I might suspect your seating depth changed a little.

 

[DrRansom]

Re: Question regarding temperature sensitivity

Thanks for your response.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">No experience with the Dillon scale. In general, I hold Dillon in high regard. Did you use the same scale for both reloading sessions?

If so, I highly doubt the scale is the issue.</div></div>

Yes, used the same scale for all reloading throughout the work. One of the reasons I don't trust it is that it will often "walk" while you're watching it. I have this huge OCD routine now where I weigh, rezero, reweigh, just so I can have some semblence of consistency with it...

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">For that matter, I highly doubt the 20-30°F temp increase was your problem.

In my experience, the #1 cause of "unexpected pressure" is a lubricated chamber/brass.

Are you certain your brass and chamber are bone-dry, clean, and free of any kind of grease, wax, sizing lube, gun oil, bore solvent etc etc??

Otherwise, I might suspect your seating depth changed a little. </div></div>

I hadn't cleaned the chamber, bore, etc. within the last 50-70 rounds, and I have been cleaning the cases with an ultrasonic (drying for days prior to loading), then neck sizing with a Lee collet, so the brass hadn't been in contact with any of those things.

I'm using a Redding competition seater, and I don't think that the micrometer has been moved - but I can recheck.

Also, I should note that this is the third firing of this Lapua brass, if that's pertinent.

Thanks again.

 

[X-fan]

Re: Question regarding temperature sensitivity

Aside from what Turbo mentioned, in my experience if you can see pressure with Lapua brass it is all there.

I have a fall back position where it comes to pressure...Pressure is like a random pile of old dog crap:
If it looks like it, feels like it, smells like it, and and tastes like it...You might not want to step in it.

You know your load ES and SD, but what is your current MV?
I have money says its up.

Then again I've had way...too much Scotch tonight!

 

[Oneteam]

Re: Question regarding temperature sensitivity

If pressure is up, so is velocity, out a few over a chrony. Does your brass chamber easily or take a little effort? If it has stretched enough, you may need to set the shoulder back a touch.

 

[DrRansom]

Re: Question regarding temperature sensitivity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: X-fan</div><div class="ubbcode-body">You know your load ES and SD, but what is your current MV?

Then again I've had way...too much Scotch tonight! </div></div>

Checking through my logbook...

2/11/12, 32* light snow
42.8gr - avg: 2638
43.0gr - avg: 2640
43.2gr - avg: 2666

3/10/12, 30* clear
42.8gr - avg: 2643
43.0gr - avg: 2679
43.2gr - avg: 2676(?,down)

3/17/2012, 53*
42.8gr - avg: 2618
42.9gr - avg: 2638
43.0gr - avg: 2671

Hrm. I guess it could just be that I was right at the top of my headroom...?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneteam</div><div class="ubbcode-body">If pressure is up, so is velocity, out a few over a chrony. Does your brass chamber easily or take a little effort? If it has stretched enough, you may need to set the shoulder back a touch. </div></div>

These were all over the chrony, however the prior data were smaller, 5-round groups. My brother had also mentioned that it may be time to bump the shoulders back, although I would have thought that if the cases were expanding, pressure might go down instead of up? Do I have that backwards?

Thanks again, fellas.

 

[X-fan]

Re: Question regarding temperature sensitivity

Excessive headspace can create a false ejector mark when the cartridge case head slams against the bolt face.
Your snug headspace will do none of that.

Your velocity/pressure is up at the top of the scale, yet given the velocity I am surprised you are seeing ejector marks. The thing is you CAN see ejector marks and that is all that matters...Tight chamber, low capacity brass, tight bore..Who knows why?
Ejector marks are the result of enough pressure to push all the way through the thick (and very strong Lapua case head)....Give or take 70,000+psi.

Maybe try Varget?

My head hurts today

 

[BuzzBoss915]

Re: Question regarding temperature sensitivity

I am not sure how it ties in to temperature sensitivity, but bumping the shoulder is never a bad idea.

What does the term "headroom" mean? You used it a couple times and lost me completely? Whatever, a three quarter inch ten shot group tells me you don't have much of a problem. BB

edit: after seeing the above post: I reviewed the Dr's posts and saw no mention of extractor marks on the case head?

 

[DrRansom]

Re: Question regarding temperature sensitivity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: X-fan</div><div class="ubbcode-body">Your velocity/pressure is up at the top of the scale, yet given the velocity I am surprised you are seeing ejector marks. The thing is you CAN see ejector marks and that is all that matters...Tight chamber, low capacity brass, tight bore..Who knows why?
Ejector marks are the result of enough pressure to push all the way through the thick (and very strong Lapua case head)....Give or take 70,000+psi.

Maybe try Varget?</div></div>

Great point, and I suppose it's best to keep safety first. Tough to let that node go, though...

I had tried Varget earlier and didn't have much luck consistency-wise, but maybe since it's warmer now, that could change too. Maybe I'll give Reloader15/AR-Comp/MR2000 a shot too.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">I am not sure how it ties in to temperature sensitivity, but bumping the shoulder is never a bad idea.

What does the term "headroom" mean? You used it a couple times and lost me completely? Whatever, a three quarter inch ten shot group tells me you don't have much of a problem. BB</div></div>

Sorry, by 'headroom' I meant that I thought that since my node fell about .5 grain of powder lower than where I had previously seen pressure sign, I had plenty of "room" for temperature to rise (and pressure to rise with it) without having to worry. Apparently I was wrong.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">edit: after seeing the above post: I reviewed the Dr's posts and saw no mention of extractor marks on the case head? </div></div>

I didn't mention it, but he seems to have guessed correctly. My current definition of pressure sign is ejector marks and "sticky" bolt lift.

 

[DrRansom]

Re: Question regarding temperature sensitivity

Incidentally, I gotta stop multi-quoting people or they're never gonna let me use the classifieds here.

 

[BuzzBoss915]

Re: Question regarding temperature sensitivity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DrRansom</div><div class="ubbcode-body">

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">edit: after seeing the above post: I reviewed the Dr's posts and saw no mention of extractor marks on the case head? </div></div>

I didn't mention it, but he seems to have guessed correctly. My current definition of pressure sign is ejector marks and "sticky" bolt lift. </div></div>

(having previously stated)
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> During the initial workups, I had stopped around 43.6gr because of light pressure signs. There may have been a few very light signs at 43.4, but light enough that I couldn't tell if it was just me. </div></div>

Okay, for me the above comment does not convey sticky bolt and ejector marks on the case head. Those are pretty severe signs, not "a few light signs", and Xfan is a clairvoyant to have determined what you meant by what was written.

So, what we have is a rather unique situation where you develop a load @ 20 degrees and it is apparently pushing the limit. Then, you do some shooting @ 50 degrees and see, "a few light signs"? I guess this is what the big worry is, and rationale for using temperature stable powders?

Never mind that it's completely backwards from the way I like to develop a load, which is; make sure that it's safe in warm weather and (later) find out where it's printing, in cold weather.

I think, if this is how you go about things, and this is how you evaluate things, then you should be using a powder that is approved by Hide membership as temp stable and hope for the best. BB

 

[bricktop]

Re: Question regarding temperature sensitivity

I'll chime in here since I helped him with the work-ups, for better or worse. We did initially start out with a test of 5 shots/load to find the pressure limit, which seemed to be about 43.5-ish grains H4895 with light marks, which was all done around 30F. It doesn't get much over 80F average high temp in PA where we shoot. The bolt has a chamfered firing pin hole (feature?) so primer cratering is pretty much out as a pressure sign since they all do it (and evern this isn't the best sign anyways). So we used velocity, ejector marks, and sticky bolt as signs. None of the velocities are ridiculous I think, since 2647 fps is the listed max. per Hodgdon. Even the 42.8 and 42.9 where signs could be seen at 53F, the velocity is under max.

But I agree, if the pressure signs are there, then something should be done to remedy the situation. H4895 is a bit faster than Varget, so Varget could be tried again. But, we got such bad ES/SD with it before that I think it would be a waste here, unless perhaps we changed the primer as well to the Federal Match or something else. So again the aforementioned powders might be tried next instead. I don't think we wanted to go down another node with H4895.

The Dillon D-Terminator is their new "Super A-OK" Chinese manufactured scale facsimile.

I'm going to speculate that the powder just did not approve of the state it was being used in and decided to misbehave, commit suicide asap in the form of an accelerated burn rate, whatever.

 

[DrRansom]

Re: Question regarding temperature sensitivity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">So, what we have is a rather unique situation where you develop a load @ 20 degrees and it is apparently pushing the limit. Then, you do some shooting @ 50 degrees and see, "a few light signs"? I guess this is what the big worry is, and rationale for using temperature stable powders?</div></div>

As bricktop mentioned, there are no other signs that I am aware of. The CCI BR primers I use crater no matter what. I had assumed that since the 5R's were so common around here, that this might be common knowledge, apologies if that isn't the case.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Never mind that it's completely backwards from the way I like to develop a load, which is; make sure that it's safe in warm weather and (later) find out where it's printing, in cold weather.</div></div>

So if you don't have a load in the winter, you wait until summer to shoot? Besides that, won't a node you found in the summer likely be somewhere else as the temperature shifts? I was under the impression that the changes in pressure/velocity would incur changes in barrel resonance, mucking with your "summer node"...

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I think, if this is how you go about things, and this is how you evaluate things, then you should be using a powder that is approved by Hide membership as temp stable and hope for the best. BB </div></div>

What do you mean, how I go about/evaluate things? Because I decided to work on this in the winter as opposed to waiting until summer...?

 

[BuzzBoss915]

Re: Question regarding temperature sensitivity

No, I was referring to "a few light signs". Even if you have to work up a load under winter conditions, you can take precautions, like keeping the cartridges in an inside pocket, perhaps?

But, your friend has a good suggestion because I think that Varget is less temperature sensitive than 4895?

As far as a chamfered firing pin hole. Okay, maybe you can't go by cratering but you can see flattened primers. Extractor marks on the case head is a really big clue, not a "light sign". And, as far as



<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">What do you mean, how I go about/evaluate things? Because I decided to work on this in the winter as opposed to waiting until summer...?</div></div>

do what you need to do but recognize that by doing such, you need to be aware of what might happen under warmer conditions, and judging by your explanations, the load is <span style="font-style: italic">past</span> borderline unsafe. I would say that 30 degrees is entirely possible in Pennsylvania, as is 50 degrees. Therefore, developing a load at 20 or 30 could present problems under blue bird spring conditions. All that is said without consideration of, this stuff:

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">the changes in pressure/velocity would incur changes in barrel resonance, mucking with your "summer node"...</div></div>

I don't want to say common sense is required, but you need to take some of the variables into consideration, and a "hard bolt lift and ejector marks" are a pretty big deal. What I can say is; okay, don't wait until summer, but understand how these things work, if you don't, or can't. BB

 

[DrRansom]

Re: Question regarding temperature sensitivity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">As far as a chamfered firing pin hole. Okay, maybe you can't go by cratering but you can see flattened primers. Extractor marks on the case head is a really big clue, not a "light sign". </div></div>

Even with the extractor marks, the primers did not flatten in the slightest. They are nice and round.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">do what you need to do but recognize that by doing such, you need to be aware of what might happen under warmer conditions</div></div>

I don't think anyone is debating that point? Did it seem like I was unaware of this? I'm not carrying around cartridges in my pocket just to be safe. That's not indicative of how I'll be shooting them when I'm shooting for distance, so it's not how I'm gonna do my OCW.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I don't want to say common sense is required, but you need to take some of the variables into consideration, and a "hard bolt lift and ejector marks" are a pretty big deal. What I can say is; okay, don't wait until summer, but understand how these things work, if you don't, or can't. BB</div></div>

And which variables am I ignoring here? The only pressure sign I see, ever, with this rifle and cartridge are ejector marks and the occasional sticky (never hard) bolt lift. I had done a workup previously and didn't see any pressure sign _at all_ until a solid .5 grain of powder above where I was at, and I had stopped right there - didn't even finish the 5 round group. In that case, again, no flattened primers, only light ejector marks. And as bricktop said, I was well under max listed velocity.

So back to my original question. should I have expected the powder/pressure combo to shift that much with only a 20* difference? If the answer is yes, fine. Or, if you'd rather continue to preach "common sense" to me, whatever...

 

[BuzzBoss915]

Re: Question regarding temperature sensitivity

Nope, I'm done.
You don't deserve another response. It's obvious we aren't speaking the same language, and you already know everything.
Good luck, Pal. BB

 

[DrRansom]

Re: Question regarding temperature sensitivity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">Nope, I'm done.
You don't deserve another response. It's obvious we aren't speaking the same language, and you already know everything.
Good luck, Pal. BB

</div></div>

Thanks for your help.

Is there anyone who can comment on my actual question?

 

[X-fan]

Re: Question regarding temperature sensitivity

I don't think you guys are doing anything crazy that is for sure.
The velocities you are getting are seemingly safe as well.
Fast batch of powder? Tight bore? Big bullets? Why you have elevated pressure who knows, but there are a lot of possibilities.

A couple of data points for your consideration:

1) Primers.
Primers are a completely unreliable indicator of pressure. I have pressure testing equipment and I can assure you I never know what a primer will look like and I know the exact pressure. They may be flat or show zero pressure signs at 80,000psi.

2) Bolt lift.
Mostly I us either blueprinted Remingtons or custom actions and bolt lift as a pressure sign is much less reliable than primers.

3) Velocity
High velocity always indicates high pressure. Moderate velocity usually indicates the same in pressure, but not always.
Hogdon shows 175gr Sierra over a max load 42.7 grains of H-4895 for a velocity of 2647fps. You guys are using the same velocity benchmark, but have Lapua brass, and a Berger bullet...So what does that mean?
There is no way to 100% know without pressure testing gear.

4)Ejector marks.
A sure sign of pressure. The first signs of which (from what I have seen) start at about 70,000psi.
IMHO once you see this sign you are there....And them some.

Hope that helps.

Buzz....You can call me YODA

 

[BuzzBoss915]

Re: Question regarding temperature sensitivity

In my world, I increase a powder charge and I see flattened primers. Flattened primers mean something to me, without benefit of pressure equipment. It is like night follows day. The same with cratered primers. It may be a poor indicator to a few enlightened individuals, but when I fire a hot load, I see cratering, decrease the amount of powder and I see it less than before.

When I go a little too much towards a max load, occasionally I see a difficult bolt lift. A few tenths less and I do not experience a "hard" "sticky" or "difficult" bolt lift.

Therefore, I do not see why I am being told that .....Hey primers are a poor indicator, sticky bolt-meaningless? Maybe for some peeps, but I pay attention and I stay away from those "meaningless" indicators.

Now, we have ejector marks, usually seen imprinted as a round shiny mark from a Remington 700 action. Here we have something that everybody can agree on. When you see ejector marks, they are never described like this:

"light pressure signs"

And yet; Yoda figures out what OP means by "light pressure signs". He means signs that could blow liquid brass, pierce primers and cause a "sticky" bolt, if not weld the case head to the bolt face.

We have universal agreement on ejector marks. This is a serious situation and something to which a shooter/handloader needs to pay serious and immediate attention!

Listen, my sensitive child. My motivation is pure and my intention is to HELP, not insult. You ask for help and in my own way, I offer HELP but you instead, get offended. For that I am sorry. Also sorry for the long post since that also seems to bug you? Whatever, your attitude could use a little adjustment, Amigo. If my bedside manor also needs work, I will take that under advisement.

Be careful! BB

PS one last comment. Above, the observation/justification was made that you were under published max loads. In my world, regardless of published guidelines; max loads are what is happening with your firearm, NOT what is printed in a manual or on a bottle of propellant. That is a fact, not an opinion. Your rifle will tell you when you have a hot load, not the book.

 

[clmayfield]

Re: Question regarding temperature sensitivity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">In my world, I increase a powder charge and I see flattened primers. Flattened primers mean something to me, without benefit of pressure equipment. It is like night follows day. The same with cratered primers. It may be a poor indicator to a few enlightened individuals, but when I fire a hot load, I see cratering, decrease the amount of powder and I see it less than before.</div></div>

Primers are poor indicators for pressure from rifle to rifle and component to component, but individuals who know their rifles and components well can use them. For instance, I know to ignore certain types of cratering because of the shape of my firing pin, but flattened primers are good indicators for me. Also, when I switch to CCI primers (which have harder cups than Federal), I get fewer signs in the primers... doesn't mean there is less pressure, just fewer indicators.

The big issues with using primers is when there are new shooters who use solely the primers as their indicators. A few weeks ago, someone showed pics of their brass and was noting that there were no pressure signs. The primers looked great, but there were some pretty profound ejector marks. Clearly the load was overpressure.

The key is to know ALL the pressure signs as well as what else the pressure signs might be. For me, ejector marks show up the earliest and are my guide for ceasing to step up the charge in load development. A bolt lift that is a little sticky doesn't bother me much because I headspace my cartridges pretty tightly.

It is important for each shooter to understand the signs as well as the why's and wherefore's of pressure. I have actually started to write a big post on the pressure signs for the Hide. I was hoping for people to contribute graphics so that new shooters can know what to look for.

 

[DrRansom]

Re: Question regarding temperature sensitivity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">Listen, my sensitive child. My motivation is pure and my intention is to HELP, not insult. </div></div>
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">I don't want to say common sense is required</div></div>
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">Nope, I'm done.</div></div>
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">You don't deserve another response. It's obvious we aren't speaking the same language, and you already know everything.
Good luck, Pal. BB</div></div>
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">You ask for help and in my own way, I offer HELP but you instead, get offended.</div></div>
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">Whatever, your attitude could use a little adjustment, Amigo. </div></div>

You're a tool, and you're not helpful. I see you have also shat all over other people's threads in this forum as well. I hope this ridiculous doublespeak is not indicative of what I can expect here at Sniper's Hide.

To all the other posters who actually contributed in this thread, thank you. Sorry for the derail.

 

[DrRansom]

Re: Question regarding temperature sensitivity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Carter Mayfield</div><div class="ubbcode-body">I have actually started to write a big post on the pressure signs for the Hide. I was hoping for people to contribute graphics so that new shooters can know what to look for. </div></div>

I think that would be very helpful, I would find value in such a thread.

Thanks.

 

[BuzzBoss915]

Re: Question regarding temperature sensitivity

That's a good post, Carter Mayfield. Concise and informed and states what I was trying to say with fewer words and more clarity.

I almost never use CCI primers, so I have not seen rounded primers with accompanying ejector marks. I only use CCI in a vintage Colt AR, which gets rare usage. On the rare occasion that I see ejector marks, I also see flattened primers. Well flattened primers.

So, what I was trying to say, that when we see/read that primers are a poor indicator; that may be so, but in my experience, (poor though they may be), I always pay attention to flattened (210M) primers, my choice for over a dozen different chamberings. BB

 

[BuzzBoss915]

Re: Question regarding temperature sensitivity

Dr Randsom, I'm thinking you are a young man? Right? Immature, obviously.

TOOL? Name calling? Listen jerk, I'm old enough to be your grandfather and can probably kick your ass if you give me any more lip. (just kidding)

Seriously. You get way too excited, junior. Calm down! That post with all the quotes took some effort, congratulations; you are obviously a keyboard commando and a firearms novice.

Quit worrying about the Forum, it will survive.

I promise, I am done. BB

 

[X-fan]

Re: Question regarding temperature sensitivity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Carter Mayfield</div><div class="ubbcode-body">
Primers are poor indicators for pressure from rifle to rifle and component to component, but individuals who know their rifles and components well can use them. For instance, I know to ignore certain types of cratering because of the shape of my firing pin, but flattened primers are good indicators for me. Also, when I switch to CCI primers (which have harder cups than Federal), I get fewer signs in the primers... doesn't mean there is less pressure, just fewer indicators.

The big issues with using primers is when there are new shooters who use solely the primers as their indicators. A few weeks ago, someone showed pics of their brass and was noting that there were no pressure signs. The primers looked great, but there were some pretty profound ejector marks. Clearly the load was overpressure.

The key is to know ALL the pressure signs as well as what else the pressure signs might be. For me, ejector marks show up the earliest and are my guide for ceasing to step up the charge in load development. A bolt lift that is a little sticky doesn't bother me much because I headspace my cartridges pretty tightly.

It is important for each shooter to understand the signs as well as the why's and wherefore's of pressure. I have actually started to write a big post on the pressure signs for the Hide. I was hoping for people to contribute graphics so that new shooters can know what to look for. </div></div>

Carter,
I totally agree and valid points for the experienced reloader for sure.

Please remember my points above are directed toward the (less experienced) OP and not meant for the guys that have been there done that for years. My thought here is it is better to discuss pressure in absolutes while highlighting serious pressure indicators. This in an effort to help create clarity for the less experienced out of a potentially confusing assortment of indicators.

What we don't want is the inexperienced guy wondering if his pressure is safe when he is 100fps over book max and the cases look perfect.

I admit a more rounded approach is in order.
A well thought out and detailed pressure sequence in a package as you suggest would be most helpful.
I think it wise to prioritize the warning signs of what we know to indicate serious pressure and then tie together the bigger picture established reloaders use as data points.
Graphics will help a lot.

 

[DrRansom]

Re: Question regarding temperature sensitivity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">In my experience, the #1 cause of "unexpected pressure" is a lubricated chamber/brass.

Are you certain your brass and chamber are bone-dry, clean, and free of any kind of grease, wax, sizing lube, gun oil, bore solvent etc etc??</div></div>

I doubt you'll be surprised, but I think you nailed it with this.

I hadn't cleaned the rifle anywhere near before this sitting, so didn't really think about it - but later, during another session, I had cleaned it and got some oil in the bolt - and when shooting a known safe load, got an extractor mark, it was like Miss Cleo was speaking to me from beyond - I remembered that I had had to clean the oil off of the headstamp before inspecting the cases during the session described in the OP.

What a frustrating experience. I stripped the chamber and bolt, hit it with the mineral spirits, cleaned the firing pin assembly, etc., and it was much better - for a few rounds. Now I have to disassemble and figure out where the damn oil is pooling up at...

In any case, thanks again for your help.

 

[DrRansom]

Re: Question regarding temperature sensitivity

Speaking of which, do you guys clean your chambers with acetone and leave it dry, like bone dry? Is there no reason to fear rust?

I think I might try a shotgun bore mop for my range bag if this happens again. What do you all use?

 

[Aimsmall55]

Re: Question regarding temperature sensitivity

I always shoot about 5 rounds and then clean while the bore is still hot. It's a hell of a lot easier to remove copper. Then when I'm done shoot 2 or3 rounds just to get all the chemicals out. I'm scared to say much more bc I see that this has been a "cut throat" as far as postings go and I don't like being yelled at. Just kidding