WARNING - 4955

[MSURunner]

Just out of curiosity, what weighting factor and shot start pressure are you using? Default, or did you adjust?

Default with friction proofed selected

 

[Calvin45]

I am not going to begin to read this whole thread, but if you were doing all this experimenting w/o a chrono as you went and weren't monitoring signs as you went, then some responsibility is on you.
Too many voices in reloading today, too many shortcuts, and assumptions.
By what I read of your post, or a few posts, is that you reached max efficiency of your platform around 48-49 gr where no more speed was generated by adding powder w/o pressure signs, then bam.
If you were using a chrono, good, if not, buy one. They are a tool in the process.
My post was just my experience with the powder, far from scary, or satisfactory.
Glad you are ok after locking things up.

I was using a chrono

 

[asd9055]

Default with friction proofed selected

Thanks. I usually start like that before a load to get an idea and confirm with loading manuals, and once I have fired cases and velocities I tried to calibrate. I am an amateur with bot QL and GRT, though I have been using QL for over a decade. Most of the times I get good matches. I tend to like GRT better if I have data.

 

[QuietTexan]

I still do not comprehend how 49 and 50 showed zero signs or reluctant extraction before 51 did this. I

Because ejector wipe and primer cratering are both the results of the case pushing against the bolt face. If the case is pushing so hard on the chamber walls the chamber walls are expanding, the signs on the bolt face disappear.

This is why Lapua-sized and larger actions have larger barrel tenon diameters, and why barrel blanks come in not just 1.200", but also 1.250", 1.300", etc, all the way up to 1.500" If the extra metal wasn't needed, people wouldn't pay for it. But the thickness of the chamber walls matter - the larger the case body is the thinner the chamber walls are at any given barrel diameter.

Savage large shank barrel diameter is (IIRC) 1.110". At that outer barrel diameter, a 223 Rem has ~0.367" of metal in the wall. A 308 Win has ~0.320". 300 RUM has ~0.280, and a 338 Lapua has ~0.260" in the wall. A 75000 PSI load in each of those chambers is pushing against different amounts of wall thickness. Same pressure, thinner wall, more movement.

Somewhere in the 65-80k PSI range (depending on action, barrel diameter, tenon diameter, chamber, etc- more pressure when thicker, less when thinner) the chamber walls themselves start expanding and contracting significantly enough to screw with case head signs. You see other things like velocity plateaus at the same time - same theory as you can unintentionally overpressure an AI using a load that was fine for fireforming because the case is expanding so much when forming it sucks in some of the pressure as energy to permanently deform the brass case to the new chamber. The chamber walls themselves do the same thing at much higher pressures.

Sporter barrels work because by the time the thin portion of the barrel is holding back pressure, it's a LOT LESS pressure than peak chamber pressure.

This is usually a big boomer problem when using marginal action and barrel diameters, but you can push anything to this point. Greg at Primal Rights did an entire article on it using a 6.5 Creedmoor and it showed exactly what you saw - pressure signs went away when he went up a again, and the next interval the case went boom.

 

[Calvin45]

Because ejector wipe and primer cratering are both the results of the case pushing against the bolt face. If the case is pushing so hard on the chamber walls the chamber walls are expanding, the signs on the bolt face disappear.

This is why Lapua-sized and larger actions have larger barrel tenon diameters, and why barrel blanks come in not just 1.200", but also 1.250", 1.300", etc, all the way up to 1.500" If the extra metal wasn't needed, people wouldn't pay for it. But the thickness of the chamber walls matter - the larger the case body is the thinner the chamber walls are at any given barrel diameter.

Savage large shank barrel diameter is (IIRC) 1.110". At that outer barrel diameter, a 223 Rem has ~0.367" of metal in the wall. A 308 Win has ~0.320". 300 RUM has ~0.280, and a 338 Lapua has ~0.260" in the wall. A 75000 PSI load in each of those chambers is pushing against different amounts of wall thickness. Same pressure, thinner wall, more movement.

Somewhere in the 65-80k PSI range (depending on action, barrel diameter, tenon diameter, chamber, etc- more pressure when thicker, less when thinner) the chamber walls themselves start expanding and contracting significantly enough to screw with case head signs. You see other things like velocity plateaus at the same time - same theory as you can unintentionally overpressure an AI using a load that was fine for fireforming because the case is expanding so much when forming it sucks in some of the pressure as energy to permanently deform the brass case to the new chamber. The chamber walls themselves do the same thing at much higher pressures.

Sporter barrels work because by the time the thin portion of the barrel is holding back pressure, it's a LOT LESS pressure than peak chamber pressure.

This is usually a big boomer problem when using marginal action and barrel diameters, but you can push anything to this point. Greg at Primal Rights did an entire article on it using a 6.5 Creedmoor and it showed exactly what you saw - pressure signs went away when he went up a again, and the next interval the case went boom.

Okay that actually makes some sense. I hadn't thought of it as a matter of the chamber walls themselves stretching and contracting - that's a scary thought.

But I'm not sure I understand primer cratering and pancaking/flattening as well as I thought I did then. Hmmm….

Back to the lab again…

 

[milo-2]

I was using a chrono

I retracted my last comment!
There was an excellent post on here concerning finding and identifying pressures not too far back. Good info in it.

Hey, in haste, I actually mixed powders, not in the cannister, but by topping off my 3 chargemasters I was running to load for a day of shooting. I had normal, mixed and uber hot by adding 4451 to 7977.
It was quite the rodeo trying to figure out why my shots were high till I had to hammer the bolt open.

 

[Calvin45]

I retracted my last comment!
There was an excellent post on here concerning finding and identifying pressures not too far back. Good info in it.

Hey, in haste, I actually mixed powders, not in the cannister, but by topping off my 3 chargemasters I was running to load for a day of shooting. I had normal, mixed and uber hot by adding 4451 to 7977.
It was quite the rodeo trying to figure out why my shots were high till I had to hammer the bolt open.

Laughing only because you're okay so it's okay. That's scary stuff there, it's be one thing if they were similar burn rates.

It's funny, im apparently fast and loose with my load practices regarding ladder increments, but I'm a total paranoid spazz about exactly this issue you mention as someone I know actually blew up an action and suffered some injury to his face and left hand because he just straight up wasn't loading the powder he thought he was

I don't even use dispensers. I'm boring and slow and just load single stage and weight out each charge poured out straight from the canister into the scale. That's one blunder I've always been determined not to make.

Then I go and do this….

 

[asd9055]

Laughing only because you're okay so it's okay. That's scary stuff there, it's be one thing if they were similar burn rates.

It's funny, im apparently fast and loose with my load practices regarding ladder increments, but I'm a total paranoid spazz about exactly this issue you mention as someone I know actually blew up an action and suffered some injury to his face and left hand because he just straight up wasn't loading the powder he thought he was

I don't even use dispensers. I'm boring and slow and just load single stage and weight out each charge poured out straight from the canister into the scale. That's one blunder I've always been determined not to make.

Then I go and do this….

One powder, one set of components in general, for a specific laod at a time on work bench. Learned the hard way from others.
I blew up a barrel and had a bolt locked up in another, because of rushing and not paying attention.

 

[Calvin45]

One powder, one set of components in general, for a specific laod at a time on work bench. Learned the hard way from others.
I blew up a barrel and had a bolt locked up in another, because of rushing and not paying attention.

Most of my mistakes have been made either working in a hurry or trying to do too many things at once.

I'll admit when I did my impatient bone head move here I was trying to get 4 other 243 loads with this bullet and other powders rough tested just to see which one was most worth pursuing further as well as three different 257 wby loads with the 75 grain hammer hunters (which I'll post about elsewhere - easily exceeded 4000 fps)

I was also seizing a rare opportunity to have coffee with my dad for a bit (shooting at his place out in the country) just the two of us, and my fingers were glowing red from cold by the time i had got to this which happened to be my last load. Still waaaaay below freezing up here and there was a nasty wind too. Couldn't feel my hands at this point. Just wanted to get done.

Lesson learned.

 

[milo-2]

One powder, one set of components in general, for a specific laod at a time on work bench. Learned the hard way from others.

In my scenario above, all I had on the bench was 7977, running downstairs to refill the cannister from an 8lb jug is where the disconnect came from. Not color blind, in a hurry and did not pay attn.
I still do the same today, buy in bulk, load from 1lb'rs, BUT< big but, it will never happen again.

 

[asd9055]

In my scenario above, all I had on the bench was 7977, running downstairs to refill the cannister from an 8lb jug is where the disconnect came from. Not color blind, in a hurry and did not pay attn.
I still do the same today, buy in bulk, load from 1lb'rs, BUT< big but, it will never happen again.

Rushing is what got me!

 

[QuietTexan]

Understanding Pressure :: Primal Rights, Inc

Reading pressure is a required skill that all shooters must have. Whether you are shooting factory ammunition or your own handloads, you absolutely must be able to detect and interpret pressure signs on your fired brass.

www.primalrights.com

This is a good example of how cases 4gn apart look very similar unless you get very up close to them, the ejector got worse before fading then the primer finally let loose.

Pressure sign reading is a little bit of voodoo and shows why working up is so important - any given charge weight might not show any/all of the signs, but the progression and even regression of signs matters. I have a pair of lighted magnifying glasses I use to inspect cases when there is no load data, or when loading beyond book.

 

[Blackdirt Cowboy]

Most of my mistakes have been made either working in a hurry or trying to do too many things at once.

I'll admit when I did my impatient bone head move here I was trying to get 4 other 243 loads with this bullet and other powders rough tested just to see which one was most worth pursuing further as well as three different 257 wby loads with the 75 grain hammer hunters (which I'll post about elsewhere - easily exceeded 4000 fps)

I was also seizing a rare opportunity to have coffee with my dad for a bit (shooting at his place out in the country) just the two of us, and my fingers were glowing red from cold by the time i had got to this which happened to be my last load. Still waaaaay below freezing up here and there was a nasty wind too. Couldn't feel my hands at this point. Just wanted to get done.

Lesson learned.

Looking forward the to post on the 257 wby with 75 grain hammers. I'm building a 257 wby now and was planning on loading the 75 grain hammers for a varmint round.

 

[Calvin45]

Looking forward the to post on the 257 wby with 75 grain hammers. I'm building a 257 wby now and was planning on loading the 75 grain hammers for a varmint round.

I'll post more details in a separate thread and won't be doing load refining or real accuracy testing for a while now.

But I can tell you this from four powders tried:


Superformance was entirely unsuitable for this application

H4831 was very useable but won't realize the velocity possible as it's still too slow a burn rate for this application - never thought I'd see 4831 being on the slow side for ANY .257 wby load.

H4350 hit the highest velocity before starting to show pressure signs - just heavy cratering, no stiff bolt or anything like that - nonetheless hit unacceptable pressure indicators at 4277 feet per second

H380 realized almost as high a velocity as 4350 and consistently at 2-3 grains lighter charges. But showed pressure at slightly lower velocities, still way over 4000 fps.

I am not going to proceed further until I also try rl17 as I have a sneaking suspicion it might be the king. However, it is not in my hands yet - I've already paid for it, but need to get to the city to pick it up haha.

If rl17 disappoints it's between h4350 and h380, whichever is most accurate I guess, the difference in velocity between the max of each was not enough to matter to me.

@ButterBean was right…again….

I never would have dared to put h380 in a 257 wby if it weren't for that menace! Oops, I mean, if it weren't for that man!