Helo the campfire:
After forty something years of reloading for rifles, shotguns, and pistol/revolver, I had a senior moment. I could not deside if the classic pressure signs of over pressure were universal, or gun specific? In oter words, given two guns, one of which is tight and strong, the other one more typical hunting type, would the over pressure signs show up in each gun at the same pressure, or would one show pressure signs at a ower presure due to its secific chamber, action, barrelect. This does suspose that both are safe as far as head space, lock up, throat. I am not taking about the safety of a particular gun with hot loads, just when the signs show up.
I hope that I have made my question at least clearer than thin mud.
Judge Sharpe

Yes, I'd say two different guns can vary as to where their "maximum" is reached. You just have to work up the loads and watch each for signs along the way.

While we are talking about signs of over-pressure a thought came to mind. For years I've heard/read about the "flattened" primer being a sign of over-pressure. I always thoroughly exam my cases after shooting and casually look at the bottom of the case immediately after firing at the range. This habit comes from a shot fired many years ago that felt quite strong for the load, "I thought", I had in the case. Needless to say, all the pressure of said round was looking for a new home upon ignition of powder and not all was finding it's new abode out the end of the barrel. Looking back on that incident made me wonder. What "exactly" does a flattened primer look like? The primer on every damn rifle I've ever shot flattens them to some extent. Just how flat is FLAT? Another thought just came to mind. Maybe the guy who know what "Is, Is!" could tell me. Thanks and good shooting! Mike

quote:

I could not deside if the classic pressure signs of over pressure were universal, or gun specific?

The can be Universal if the Pressure is extremely high. Or it can be firearm specific depending on the specific dimensions of the chamber and bore as described below.

quote:

In oter words, given two guns, one of which is tight and strong, the other one more typical hunting type, would the over pressure signs show up in each gun at the same pressure, or would one show pressure signs at a ower presure due to its secific chamber, action, barrelect. This does suspose that both are safe as far as head space, lock up, throat. I am not taking about the safety of a particular gun with hot loads, just when the signs show up.
I hope that I have made my question at least clearer than thin mud.

Hey Judge, Your question seems clear enough to me, but perhaps that is because I look into a lot of mud.

You have basically 5 situations:

1. A SAAMI Minimum chamber and a Minimum dimension bore.
2. A SAAMI Minimum chamber and a Maximum dimension bore.
3. A SAAMI Maximum chamber and a Minimum dimension bore.
4. A SAAMI Maximum chamber and a Maximum dimension bore.
5. Somewhere in between all the above dimensions.

1. You will get “Pressure Indications†the quickest. Here the chamber has “less†room for case expansion and there will be “more†drag on the bullet.

You will reach MAX Pressure the quickest with this situation. You might not be able to reach the same SAFE MAX Velocity levels seem in other rifles of this Caliber, but the opportunity for top-notch precision accuracy is usually excellent. These are typically referred to as “Slow Riflesâ€.

Pressure for both 2., 3., and 5. fall between the extremes of 1. & 4.

2. You can get a bit more Velocity than normal for a specific amount of Powder and usually can not Safely exceed typical Manual Loads. Accuracy is usually acceptable for the vast majority of folks.

3. You need to add a bit more powder to achieve the Velocities shown in Manuals, but accuracy can be excellent. Here a Powder typically considered slightly “slow†for the specific Cartridge allows you to get High Velocity at SAFE Pressures with excellent accuracy.

4. You will get Pressure Indications the slowest. Here the chamber has “more†room for case expansion and there will be “less†drag on the bullet.

You will reach MAX Pressure the slowest with this situation. You should be able to easily exceed the SAFE MAX Velocity levels seem in other rifles of this Caliber. Accuracy is typically OK, but not excellent. These is typically referred to as a “Fast Rifleâ€.

VERY MUCH gun-specific!

Very gun specific. For example, let's take primer pocket expansion. If you fire a tight fitting case in a benchrest (i.e. sub minimum) chamber, in a square, perfect action, you can run the pressure well above red-line, and the primer pocket expansion will be minimal to none.

Run that same load in a "sloppy" chamber, and the primer pocket will go to he## in a hurry.

The same with case head expansion. If the chamber/bolt tightly supports the case, it will not permanently expand much.

A lot of benchrest guys run their PPC's well into the 70,000 PSI range, to the point they have to have minimal sized firing pin holes to prevent pierce primers. Their cases last up to 20 firings. But, everything is tight-tight-tight.

Don't try that at home, folks...... JMO, Dutch.

Thanks It makes better sense now. I don't expect to go over max (well maybe a little sometimes) but it is good to know what to look for. Although for the most part my firearms are old, they are tight and sound. I do not have a problem putting more or less "hot " loads in anything except the Mod. 3 Smith and Wesson in .44 Americam. Mainly because I can not find shells for it. If I own it I want to shoot it.
God bless
Judge Sharpe Protector of widows and orphans.