Reading pressure. Great article about it

[ar10ar15man]

just not true
you are saying the factory loads are max loads in all guns

I believe Bolt Lift would feel different to different shooters.
By what method would you judge Bolt Lift with pressures?
A much better method of judging pressure signs is by the use of a 0.0001" Micrometer.
Fire X number of FACTORY LOADS in your chamber, then measure your case expansion to the 0.0001"- take the average expansion of these would be your base line.
As you shoot your handloads starting at the lowest load shown in the manual, measure your fired cases case expansion at the web.
When your handloads develop the same measured case expansion as the factory loads then you have found your MAXIMUM LOAD in YOUR CHAMBER with YOUR COMPONENTS.
Now there are a few exceptions to this rule such as the .30-06 for example.
Ken Waters talks about this method in his "Pet Loads" Volume 1.
This system works well and in my shop this is the method used to keep my customers out of trouble.
I have seen factory loads be over pressured, this may mean your chamber and bore are tighter than the factory test BBL.
Have fun and good luck.
May your firearms shoot well and your brass last a long time!

 

[crkckr]

If you're working up a load as you should, difficult bolt lift would be anything more difficult than normal. On most rifles you can pretty much lift the bolt with one finger... if you have to use your palm and struggle a bit to get bolt open, that would be considered difficult bolt lift! That part is definitely not rocket science and no voodoo is involved! I have experienced this a couple or three times in the past and it has never once just suddenly shown up without other pressure signs showing up first.
Cheers,
crkckr

 

[Mikecr]

Before powder development I use culled cases to do a test for 'MyMax'. I incrementally go up in load, measuring each extracted case at it's webline (widest expansion) with a blade mic. I usually see this diameter go up to a plateau and hold while continuing. At some point there is a yielding step change at this datum. Diameter amplitudes are different with smaller/larger cartridges of course, but the step change from plateau is the point where FL sizing would have to be included in reloading cycles.

That's brass yielding into the chamber's own expansion, where you would hope the brass would spring back more than the chamber(for easy extraction). But once brass reaches yielding it takes smaller force increases to continue that yielding.
You feel that just prior to twisting the head off a bolt, and Ya know it's coming..
Continued use at that MyMax pressure, without counter-sizing, will lead to popping extraction. It can even with sizing, or it could be cleared enough with case lube or with lapping out the breech mouth a bit.

What I've noticed with MY cartridges & chambers, is that this yield point consistently calcs out very near SAAMI max in QuickLoad. Given this, I suspect there is some connection there, at xxKpsi pressure, when max it's actually determined by SAAMI.

 

[Echo Charlie]

When your handloads develop the same measured case expansion as the factory loads then you have found your MAXIMUM LOAD in YOUR CHAMBER with YOUR COMPONENTS.

Let me just reinforce that applies pretty good BUT only when reloading the same cases for the same rifle and specially for the first reload (second shot) because of the brass hardening with shooting and sizing

 

[Rich Coyle]

How about a wildcat?

 

[PBR driver]

Let me just reinforce that applies pretty good BUT only when reloading the same cases for the same rifle and specially for the first reload (second shot) because of the brass hardening with shooting and sizing

Not so, this gives you your maximum in your CHAMBER.
It is independent of the cases used just as long as you stay at the given 0.0001" measurements.
Thinner or lighter cases and thicker or heavier cases will give your maximum loads at a different point but you can use this expansion as gospel in your chamber.
Do not try and over think this test it is really simple.
If you are using a factory fired case that is for example expands to .468" then this is your maximum case expansion.
When your loads achieve this same measurement that is the maximum your reloads should expand in your chamber.
There are some exceptions to this rule such as the .30-06 which you may find in a Winchester 1895, a weaker action so the factories load to safe pressure found in such rifles, you may be able to load to approximately 1/2 a 0.0001" more in your bolt gun.
Factory ammo is loaded for the most part up to the max so the rule of your max still holds true.

 

[ar10ar15man]

again just not true

Not so, this gives you your maximum in your CHAMBER.
It is independent of the cases used just as long as you stay at the given 0.0001" measurements.
Thinner or lighter cases and thicker or heavier cases will give your maximum loads at a different point but you can use this expansion as gospel in your chamber.
Do not try and over think this test it is really simple.
If you are using a factory fired case that is for example expands to .468" then this is your maximum case expansion.
When your loads achieve this same measurement that is the maximum your reloads should expand in your chamber.
There are some exceptions to this rule such as the .30-06 which you may find in a Winchester 1895, a weaker action so the factories load to safe pressure found in such rifles, you may be able to load to approximately 1/2 a 0.0001" more in your bolt gun.
Factory ammo is loaded for the most part up to the max so the rule of your max still holds true.

 

[crkckr]

PBR driver,
Factory ammo is, in most cases, certainly not loaded to any kind of max. It's made to work in as many different firearms as possible. There are some factory loads that may be at the SAAMI max but generally speaking, the only ones that I've personally found have been imported from foreign countries. I have yet to find a factory loading that I have not been able to beat in both velocity and accuracy (ok, yes, once in a while you might find something that shoots really well out of your 295 Whizbang but the cost will probably break the bank... certainly my bank, which is usually on the verge of being out of business anyway!). My loads only have to work in *my* rifles. The odds of my loads working in your rifle are pretty slim. I do, on occasion, buy factory ammo, especially if I get oddball pressure signs too early in the work up process. For instance, I had a .357 that used to flatten the bejeesus out of primers with just about any jacketed bullets. Turns out it flattens nearly every primer, the only exception being super lite target loads or loads with cast bullets. I just got used to seeing it out of that pistol.
Cheers,
crkckr