Reading pressure. Great article about it

[Echo Charlie]

Reading pressure is a required skill that all shooters must have. Reloaders more.
I often see posts on several forums talking about "reading pressure" and consider them too much "light" for the purpose and regarding the danger involved.
Also see at the range many shooters using handloads that cause unsafe pressure and they just reply "No, I'm using the maximum charge indicated by the powder manufacturer".
The best article I found about this subject is a bit long buy very interesting and with nice photos to illustrate the examples given.
Link bellow.
Just let me reinforce it mentioning that we must use magnification to properly read pressure on the spent cases (or the cell phone camera).
Happy and safe reloading!

https://www.primalrights.com/library/articles/understanding-pressure

 

[ShtrRdy]

I wonder why he didn't include bolt lift in pressure indications?

 

[ar10ar15man]

sorry i pass on all by primal rights

 

[ar10ar15man]

because by then it is too late.

I wonder why he didn't include bolt lift in pressure indications?

 

[CVCOBRA1]

I wonder why he didn't include bolt lift in pressure indications?

Didn't read it did you?
"Heavy Bolt Lift" is what they called it.....

 

[Rich Coyle]

I use very old Spear loading manuals. Is that safe enough?

 

[Randy Tidwell]

I agree with most of the authors report.

The part I don't agree with is lubing cases!

I routinely coat my ppc cases with Kroil oil priot to shooting them, no ill affects. I have done comparisons shooting in a tunnel with dry cases against cases lightly coated, the groups are smaller and rounder.

A load that is hot enough to go over the edge when any sort of lube gets on the case, should never be shot.

I witnessed a 270 blow sky high when it was fired with a round that had been sitting in the sun on a hot summer day. It was loaded with BLC-2, distroyed the rifle.

 

[Dry Heat?]

Yet it's perfectly safe to stick a Factory Load that the factories say is as hot as anything we can load and pull the trigger without regard. Never understood that reasoning. Having said that I've always loaded up from a lesser charge and worked up. A slightly sticky bolt lift is one of the first signs to back off a tad bit on your fuel. Of course if you need to wrestle your bolt open, you've already ignored flattened or cratered Primers and excessive case head expansion. But in my experience a STICKY Bolt Lift is one of the first signs of excess pressure.

 

[Randy Tidwell]

I have been reloading rifle ammo for over 50 years, Shotgun shells longer.

I am constantly amazed at some of the practices by some that call themselves reloaders! That is one of the reasons I rarely go to a public range.

I got into a heated debate with a couple guys on another web blogg site that thought it was perfectly fine to advise a guy to fire his rifle with a stuck case in the chamber.

Apparently the guy was shooting a Marlin 30-30 and had to force the action closed on his reload, then thought better of it. Tried to open the action, couldn't extract the live round. Loaded the rifle up and took it home. Posted a note asking how to get the round out.

These guys told him the 30-30 round did not have enough pressure to damage his Marlin, just shoot it..... HUH?

On their advice, he took it back to the range and pulled the trigger...OMG

How many safety issues to see in this chain of events?

I still have all my fingers and plan on keeping them.

 

[gator378]

Reading pressure is a required skill that all shooters must have. Reloaders more.
I often see posts on several forums talking about "reading pressure" and consider them too much "light" for the purpose and regarding the danger involved.
Also see at the range many shooters using handloads that cause unsafe pressure and they just reply "No, I'm using the maximum charge indicated by the powder manufacturer".
The best article I found about this subject is a bit long buy very interesting and with nice photos to illustrate the examples given.
Link bellow.
Just let me reinforce it mentioning that we must use magnification to properly read pressure on the spent cases (or the cell phone camera).
Happy and safe reloading!/when you have to use a rubber mallet to open the bolt probably need to back off a grain or two.

https://www.primalrights.com/library/articles/understanding-pressure

/////////////////////////////////////////////w

 

[crkckr]

I will relate a story that happened at Angeles National Forest range in CA near to life time ago (it seems, anyway!). About 4 tables from me a guy suddenly jumped up and was dancing around holding his hand. They hustled him off to the office and a few minutes later an ambulance picked him up and off they went to the hospital. The rangemaster came out and said the guy had blown his thumb off at the middle joint and would we form a line and walk down range to see if we could find it... maybe they could sew it back on. We didn't find anything, it was probably vaporized when the barrel split and let all the gas out right under his thumb. After things had settled down a bit I went and talked to his partner and looked at the rifle. It was an old mil-surp Mauser that had been sporterized. But next to the rifle were a dozen or more pieces of brass with every classic pressure sign you can think of - split necks, cratered primers, and there was even a block of wood he'd been using to bash the bolt open! The barrel had a split about 2" long, just below the wood and about 6" from the receiver (it was a stepped barrel and it split just where the diameter was the same for the remainder of it's length). Looking at the brass, I asked his buddy (who had a similar rifle) why in the world he continued shooting the thing with all these obvious pressure signs. "Well, it was shooting so good and the ammo was ok in my rifle..."
So, there were, way back when, 2 different barrel diameters for the 8mm... .318 and .323. The old, old barrels were .318. He was shooting relatively modern .323 mil-surp ammo thru it. I just shook my head a went back to my bench. I did look thru my spotting scope at his targets and he had a 6" or so group! I looked back at my own target where I had 4 groups under .5" and could only shake my head!
So in that respect, the artical is right, everyone needs to be able to read pressure signs, even if you don't reload.
Cheers,
crkckr

 

[Mikecr]

Keep in mind that actual pressure, pressure problems, and issues manifesting with increasing pressure, can be separate individual matters.

For example; difficult extraction can happen with a relatively low pressure load due to a poorly timed action/bolt. Flattening large rifle primers can be a result of excess head spacing. Cratering due to firing pin clearance. Big near web expansion is often the direct result of excess chamber clearance and/or weak breech support. A wet chamber could show up as an issue (or not) regardless of pressure. Case design itself amplifies or suppresses potential issues at every pressure level.

Personally, I work up until I hit a 'problem' for me,, stop and log it.
My standards for this may be different than yours. For example, I don't FL size, ever, so a problem for me would be a growth point requiring FL sizing to recover.
I'm watching with a chronograph, and QuickLoad to consider my potential pressures. But honestly, if it's not a problem, it's not a problem -regardless of apparent pressure.

I take care of most issues when I choose a cartridge/bullet, fill out a reamer print for it, and decide on an action that will put enough barrel steel around it. QuickLoad what-ifs helped me know what powder will fill the case, and reach desired velocities without going over pressure.

 

[ar10ar15man]

(mikecr is a guy to listen to)

 

[PBR driver]

I wonder why he didn't include bolt lift in pressure indications?

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!