Pressure Signs, Where do you stop?

[Taylorbok]

Hoping not to start a shit show here.

I am curious where you guys shooting the big boomers stop when it comes to pressure? Flat primers, Ejector mark, case head expansion, ejector swipe, heavy bolt lift.
What is your method for determining where the limit is.

Almost always in this sub peoples pictures of case head show primers flattened completely and typically ejector spot.

I'm doing load workup on a Wildcat and the ejector spot showed up sooner than expected, they are so faint I honestly wouldn't have noticed them except for the sun was straight at my back. That being said the case was definitely not completely formed to the chamber, I had only fired one mild FF load to blow out the taper and move shoulder ahead, then did a pressure ladder test. Primers look reasonable but I wanna knock them out so I can get a better look at them. bolt opened easily every time and fired brass still chambers easily. Tonight I'm going to strip my bolt so I can do a bolt handle drop test on fired brass. Case web don't seem to have expanded at all but I only had shitty calipers on hand, I'll have to wait until I get home to find out for sure.

I know it's more important how consistent it shoots I haven't gotten to group testing yet, hopefully next week.

 

[hafejd30]

I push until my action detonates. Sending pieces of my eye out my ass. Then back off 1/4 grain

Honestly what your seeing seems normal. May even see some marks if your forming brass because there’s more expansion going on in the chamber vs tighter/formed brass. But not positive

Typically I watch for ejector marks, tight bolt lift and flattened primers. The primer cup hardness can determine how early flattening occurs just fyi

 

[Taylorbok]

Honestly what your seeing seems normal. May even see some marks if your forming brass because there’s more expansion going on in the chamber vs tighter/formed brass. But not positive

Typically I watch for ejector marks, tight bolt lift and flattened primers. The primer cup hardness can determine how early flattening occurs just fyi

Yes I know about primer cup hardness.
Part of my issue I guess is usually I see that ejector mark, then another grain or 2 and the primers get really flat and then shortly after that the bolt gets a bit tight. I went another 6 grains past that ejector mark and never saw any more pressure signs and the ejector mark stayed the same.

I may have just answered my own question in regards to it being caused by a bit of excess room on the brass. once I check how this fired brass fits the chamber maybe I will load up one of the now twice fired cases to the charge I'd like to be at and see if it makes another mark.

 

[Dogtown]

Yeah, with big magnums you can often see flattening primers long before ejector marks or heavy bolt lift. If the charge is within a predicted safe zone and I get primer flattening, I'll often continue. It's usually the combination of flat primers plus ejector marks where I'll say "nope, that's too far."

 

[Taylorbok]

Ya I wasn’t concerned about primers more about the ejector mark and not ever seeing any other real pressure signs.

But I realize I’m an idiot, I had taken my ejector out for FF and never put it back in, thinking That’s why it’s making a print so easy. I’ll stuff it back in and report back

 

[TripleBull]

Although I'm no Brian Litz homer, his most recent book's handloading info does correlate to a degree with my experiences. By that, I mean that you need to keep an eye on numerous factors that lead to dangerous pressure and adjust over time. You know the list: the lot of brass, powder or primers you are using, the barrel and its condition, ambient temperature, etc. My natural tendency is to go for the highest muzzle velocity possible, but as you know, changes in the factors mentioned above can move you from a condition the gun can survive to one where it can't. Not long ago, I talked to a kid at our local Sportsman's Whorehouse that was telling me how he knew his load was on the hot side, but he was going to do another ladder and go hotter. I and the (very experienced) salesman advised caution. I saw that same kid a few weeks later with a massively bandaged hand and other bandages on his forehead. He was shopping for a new gun, duh.

Bottom line, I prep some rounds to a node lower than the hottest good node seen in an OCW. I'm willing to go hotter in the winter. But I'm old and soft and don't want to blow my fingers off and don't want to throw my beloved rifles in the trash heap. My main focus is on developing consistent processes to get low extreme spread, consistent concentricity, etc., and to only handload when my head is in the right space where I can focus and do it right. If you compete, you may not have that luxury.

 

[acudaowner]

I found a speed I liked then ran with that so most of the time I never have to worry about pressure signs as there are none even if I go a little faster I am not seeing any signs and probibaly never will ( cross my fingers ) my choosen speeds are 2640's to 2750 ish my actual fastest speeds are 2750= 2880 for the ranges I have to shoot from I have no need for anything faster

 

[roostercogburn98]

I push until my action detonates. Sending pieces of my eye out my ass. Then back off 1/4 grain

Everyone knows it’s gets worse before it gets better. Keep going up a few grains after you KBOOM

 

[rustyinbend]

Frankly ... any or all of the above, is where I back off. I want my cases to live long and prosper, and that quest for another 25 ft/sec of velocity just isn't worth it. That said, my first and best indicator to back off is usually a heavy bolt during ejection.

 

[badassgunworks]

Pressure is only properly measured threw a change in bolt lift. Every action and chamber is different. So when you notice a change in bolt lift. Your at the limits. Now ejector marks are not a way of measuring pressure. Granted if you have heavy enough pressures you can get ejector marks. But ejector marks can show up when the is no pressure issues from surface hardness of brass of ejector issues dirty or stuck or to long. Flat primers is a poor way of measuring pressure primers can be flat due to soft brass( like norma junk brass ). Worn out brass or headspacing issues . It is not a good method of measuring pressures . Creators in primer is NOT a good method eather as that can be caused by poorly designed firing pen and or weak firing pen springs.

 

[cameljockey230]

If your working on a wildcat and getting ejector swipes early it's sometimes caused by the brass fit in the chamber.
On a wildcat the takes away body taper or changes the shoulder location and or angle you want the casehead pinned as hard as possible into the boltface.
If you have a loose fit the firing pin pushes the brass forward into the chamber when you pull the trigger and once it builds pressure it forces the casehead against the boltface giving you premature ejector swipes.
You can use a mandrel to create a false shoulder on your case necks to help pin the brass against the boltface.

As to your question.
If opening the gun after firing it is disrupting your shooting in any way back down the load.

 

[Taylorbok]

Pressure is only properly measured threw a change in bolt lift. Every action and chamber is different. So when you notice a change in bolt lift. Your at the limits. Now ejector marks are not a way of measuring pressure. Granted if you have heavy enough pressures you can get ejector marks. But ejector marks can show up when the is no pressure issues from surface hardness of brass of ejector issues dirty or stuck or to long. Flat primers is a poor way of measuring pressure primers can be flat due to soft brass( like norma junk brass ). Worn out brass or headspacing issues . It is not a good method of measuring pressures . Creators in primer is NOT a good method eather as that can be caused by poorly designed firing pen and or weak firing pen springs.

Ya I never saw a change in bolt lift. I stripped the bolt and the fired case from highest charge I tested the bolt closed with one finger. It was a few charges down before the bolt would drop closed on it's own. I'm really not worried about the primers I was more confused that stiff bolt never showed up. I thought I'd be able to find pressure but I ran out of case capacity. I did achieve the velocity I was hoping for but case is completely full with N570, I have some N565 I am contemplating trying.

If your working on a wildcat and getting ejector swipes early it's sometimes caused by the brass fit in the chamber.
On a wildcat the takes away body taper or changes the shoulder location and or angle you want the casehead pinned as hard as possible into the boltface.
If you have a loose fit the firing pin pushes the brass forward into the chamber when you pull the trigger and once it builds pressure it forces the casehead against the boltface giving you premature ejector swipes.
You can use a mandrel to create a false shoulder on your case necks to help pin the brass against the boltface.

As to your question.
If opening the gun after firing it is disrupting your shooting in any way back down the load.

It's not a swipe just the imprint of the hole.
I had to create a false shoulder for the first firing. I tried to jam the bullet but it wasn't holding it against the BF hard enough. I believe the firing pin was moving the case forward, pushing the bullet back into the case and was stretching cases at the web, the false shoulder solved my issues.
This was the second firing but the brass wasn't fully formed after first firing, 2x fired brass measures .003" longer than once fired which isn't huge.

I might take my press to the range and stress test a piece of brass to see how long it can hold up at the charge weight I want to run. That will give me an idea of what's going on.

 

[cameljockey230]

On virgin brass try coating one piece with imperial sizing die wax before chambering it and use a well jammed bullet and a false shoulder as well.
And yes the firing pin strike will definitely push the case onto the bullet.
On the false shoulder I like it so snug that you need to palm the bolt handle closed. If it closes freely you'll need additional fireforming loads.

 

[Taylorbok]

On virgin brass try coating one piece with imperial sizing die wax before chambering it and use a well jammed bullet and a false shoulder as well.
And yes the firing pin strike will definitely push the case onto the bullet.
On the false shoulder I like it so snug that you need to palm the bolt handle closed. If it closes freely you'll need additional fireforming loads.

I was jamming and false shoulder. I've never heard of the sizing wax but that would probably help. I've formed all the brass I was going to for now, I've got another 100 but it's a different lot and was going to save it for just in case. I'll have to fire all these again to get fully formed but that's fine I've got testing, data gathering and practice so I should be able to get that done before Ko2M Canada.

 

[Taylorbok]

I went back to the range to do some load stability testing and noticed some very light bolt click on the highest charge and the ES went to dog shit. I found what seems to be a very stable charge weight window about 4 grains down from that top charge so I am going to play in there. Thanks for your guys help.

 

[TheGerman]

Recoil starts feeling 'off' even though you only stepped up to the next increment.

Also pierced primers are usually right around the 'stop' area where extractor swipes and flattened primers are common.

 

[badassgunworks]

Recoil starts feeling 'off' even though you only stepped up to the next increment.

Also pierced primers are usually right around the 'stop' area where extractor swipes and flattened primers are common.

Sorry but those are all signs of being way into pressure Beyond where you should have stopped

 

[Baron23]

 

[themightytimmah]

Ejector swipes can be really brass dependent too. In my 300, I’d run mild loads in Hornady brass that came out looking like a kaboom was imminent (a perfect imprint of both ejectors) despite easy bolt lift and primers looking perfect.

I switched to Lapua, and at the same MV (load was a little different due to case capacity) there were absolutely no marks whatsoever.

I’m with @badassgunworks. Ejector swipes don’t necessarily scare me but when the bolt gets sticky, I’m out.

 

[raider1v1]

It's a combination for me balanced with performance. If I can run less powder with no signs, I'll do that. I dont need that extra 15fps.

If I see ejector, I'm not super concerned, but primer plus ejector is too much. Any sticky bolt is too much.

Be safe everyone!

 

[Earnhardt]

Taylorbok, What cartridge are you working on, with these pressure signs showing up?

 

[918v]

Here is a thought:

Excessive pressure depends on the case. Some cases can take 70000 PSI. Most can’t. I think it’s best to stick to loads that don’t destroy your brass. If you need more speed get something bigger or get a longer barrel.

 

[TSULLI]

It's a combination for me balanced with performance. If I can run less powder with no signs, I'll do that. I dont need that extra 15fps.

If I see ejector, I'm not super concerned, but primer plus ejector is too much. Any sticky bolt is too much.

Be safe everyone!

This... Primers by themselves don't worry me as some tend to crater way earlier than others due to cup hardness like previously mentioned. Its not until I start seeing primers + something else that I back off.

 

[Taylorbok]

Taylorbok, What cartridge are you working on, with these pressure signs showing up?

375 RUM- Gibbs (Box Monkey Express)

I got the idea from 375 ultra mag thread. I decided to do a 375 Rum with a 40* shoulder, moved ahead .053" and taper reduced to .006" A guy over on that forum had done a similar cartridge several years ago and called it the 375 Box Monkey Express. Initially I tried to seat the bullet hard into...

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