What does "safe" mean?

Snyper708 said:

By the time you begin to see visible pressure signs, you've already exceeded safe limits.

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Often I read this type of statement. What does "safe" mean here? A primer will come out of the case? The case will start to flow? The action will lock up?

Rich Coyle said:

What does "safe" mean here?

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In this context it means above SAMMI maximum pressure for the cartridge.
You normally won't see any "signs" with a load that doesn't exceed those limits.

its a statement that can mean what ever you want at that time. without any type of measuring device you cant know what the pressure is.
example.
lapua brass will not show signs as quick
top quality action and barrel compared to prefit barrels.
I use my quickload as my best guess on pressure

Rich Coyle said:

Often I read this type of statement. What does "safe" mean here? A primer will come out of the case? The case will start to flow? The action will lock up?

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Safe from what ?
To some it means everything but Catastrophic failure of the firearm.

To others it means that they may blow primers and trash cases after only one or two shots, but the rifle can handle it because of the built in safety factor.

It should mean that it is within SAMME pressures and will give many years of service without stressing the weapon and the components. and allow for the occasional screw up because of the built in safety factor.

So to me it has at least 3 different meanings to most people. and we must choose which one we will use


J E CUSTOM

I consider pressure 'signs', pressure 'problems', and 'unsafe' pressures, as separate and different, because they present as a local abstract. Often, one without the others.
Depends on the design/build/reloading/conditions.

I see 'unsafe' as a 'problem' that diminishes safe operation of the firearm.
When I blew a muzzle break off the end of the barrel, and noticing that the barrel near the chamber had expanded to stock contact, I considered safe operation as diminished. This was not due to design/build/reloading, but to the condition of firing with a bore sighter still in the muzzle..

Unless you have a pressure trace system or some other means of measuring actual chamber pressures we are guessing at what pressure we are running. Personally if its reliable, accurate, and case life within reason I dont care if Im running 75k psi. If the brass takes it Im gonna do it. I read about how Ackley cases "hide" pressure signs, well ya, thats why we love them!

Alex Wheeler said:

Unless you have a pressure trace system or some other means of measuring actual chamber pressures we are guessing at what pressure we are running. Personally if its reliable, accurate, and case life within reason I dont care if Im running 75k psi. If the brass takes it Im gonna do it. I read about how Ackley cases "hide" pressure signs, well ya, thats why we love them!

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But yet just a few weeks ago you had the audacity to publicly chastise me for making comments that are borderline transcriptions of yours, calling me "dangerous", simply because one of my rifles had an overpressure moment and blew a primer. Enjoying being a hypocrite?

I went home and pulled bullets and checked powder charges, and everything else was in-check. Did you read the new thread about the guy having to chop up his .300RUM for similar unknown pressure issues? It's called "how to blowup a rifle"...

**** happens when you're playing with controlled explosions. You mess with it enough, eventually something is going to have a pressure spike with unknown causes.

When we talk about safe pressure, what is it? Why is one pressure level safe for one cartridge but not another? Take the 270 Win for example, safe is below the max pressure of 65K PSI, but the 30-06, (the parent cartidge of the 270), safe is below 58K PSI. Belted magnums??? I am even more confused 60K PSI??. I thought it was a magnum LOL.. I get the "old military mauser" line of BS, so we load a very nicely designed cartridge down to neutered status.. What gives??? Safe for me is following proven reloading info that has been proven safe for your rifle.. BTW velocity is the most reliable indication of pressure. Thats why any reloader worth their salt has one and uses it in load development.. Higher than usual velocity... higher than acceptable pressure, and in some cartridges it can go up exponentially fast. Just my $.02

This thread reminds me of an overload I made from listening to the "experts" when I was a new loader. This was about 1978. I had a new Klienguenther K14 with the "Stelite insert". I wanted a light load for practicing offhand. I read in a magazine one could use pistol powder topped with cream-of-wheat under a light weight bullet. I followed his instructions. I weighed the c-o-w and added that to the weight of the bullet.

On the first shot I could not open the bolt. I smacked it with a rubber hammer and it opened. I measured a few of the unfired belts of the 7 Rem Mag and averaged them. Then I measured the belt on the "light" load. The belt expanded .170"! You read that right. The gunsmith told me the chamber was bulged but the action was fine. I installed a Douglas Premium Airgauge 28" 7-.300 Weatherby and used it for about ten years. It was outrageously accurate compared to what I was used to. When that barrel was shot out I rebarreled it to .375-8 Rem Mag, also 28" barrel. It is even more accurate.

I don't know of any standard, that applies to YOUR BARREL, that would have SAAMI max(with their barrels) as maximum safe pressure for YOUR BARREL (or theirs for that matter).
Also ak7an, do you know of a formula that converts MV to pressure peak?

Mikecr said:

I don't know of any standard, that applies to YOUR BARREL, that would have SAAMI max(with their barrels) as maximum safe pressure for YOUR BARREL (or theirs for that matter).
Also ak7an, do you know of a formula that converts MV to pressure peak?

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I think he's referring to using the chrono to detect for extremes in velocity, showing pressure spikes.

MudRunner2005 said:

But yet just a few weeks ago you had the audacity to publicly chastise me for making comments that are borderline transcriptions of yours, calling me "dangerous", simply because one of my rifles had an overpressure moment and blew a primer. Enjoying being a hypocrite?

I went home and pulled bullets and checked powder charges, and everything else was in-check. Did you read the new thread about the guy having to chop up his .300RUM for similar unknown pressure issues? It's called "how to blowup a rifle"...

**** happens when you're playing with controlled explosions. You mess with it enough, eventually something is going to have a pressure spike with unknown causes.

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There was nothing safe or reliable about what you bragged about. Proper reloading techniques and working up slowly watching for pressure signs would have prevented your problems. Never have I over pressured a case to the point of the primer falling out, then claim that I backed off .5 grain and run them there. Does that seem like good advice? The biggest reason I thought you should not give advise is not because of one accident but the fact you though a case head separation supported in the chamber was caused from pressure. But there was a very good reason for your over pressure, even if its unknown to you. Tens of thousandths of rounds are fired over saami spec every year in competition, over pressures are not normal or even common.

MudRunner2005 said:

I think he's referring to using the chrono to detect for extremes in velocity, showing pressure spikes.

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Yup, that is what I was getting at. Your load manual says ##.# of XYZ super powder gives 3000 FPS in a 24 in barrel. You load yours to the same charge and go shoot, but it chrono's 3200 out of your rifle. Safe??? you bet it is, cuz the manual said it was. I am afraid a lot of load development goes that way.. The problem is the one that does with out a chrongraph has no clue he is over MAX pressure, but then maybe he does, cuz his primer told him so. He has that secret formula for reading primers for pressure spikes .. I am exaggerating a bit in good fun.. but I still don't get the whole safe for one but not for another deal..
Take care
Ed

If some one is working up to pressure say .5 gn.s at a time theres a lot of signs before it becomes dangerous. Primers are not the best because they vary in thickness. Ejector marks are usually your first real good sign, after that you will start to feel some increased resistance one the bolt lift. Thats when you need to stop. Velocity is a poor judge because powder lots vary, and bore dimensions cause large swings in velocity. I have seen more than one guy smacking his bolt handle to open the rifle and continuing to shoot.