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marcopolo · 08-05-2003, 04:16 PM

A little dity on pistol cases that I found ...

Pistol brass gets no respect from most of the manufacturers of reloading tools (Redding excepted) and often does not even get respect from the shooter community itself. The consequence of this is the fact that there are no neck turning tools available that can uniform revolver brass. This is probably the result of years and years of pistol brass being used in revolvers where the manufacturing tolerances were - shall we say - "generous". So it really didn’t matter if the brass wasn’t uniform, because the gun it was being shot in was as loose as a goose. However, things are changing, and when it comes to the modern revolvers and autoloaders it’s a whole different world out there. Consequently, it can make a difference if bullets are seated off center because of poor case wall tolerances.

I then measured the case walls of the same 25 cases from each brand and found that the case wall variance from one side to the other for IMI brass was only a maximum of a .001 of an inch. Additionally, 80% of the IMI cases had exactly the same variance in their wall dimensions. This means that the case walls were indeed, very consistent.

For Starline, the maximum case wall variance was .004 of an inch. 72% of those cases had the same variances. Not as consistent as IMI.

Now trimming. This is a very important operation for pistol brass. In many brands of brass , case length can vary significantly. The result is that when a bullet is seated in the case and crimped, the variable length of the cases will determine the amount, or "hardness" of the crimp being applied. Additionally, it will also determine where in the bullet’s cannalure the crimp takes place (low, middle, high, or maybe even out of the cannalure). The amount of crimp and placement of the crimp, in turn, can affect the consistency of the powder’s ignition, and cause velocity changes from shot to shot. Bottom line - we want all the cases to be the same length to avoid these variations.

"Speciality tools from Redding Reloading
make a difference in quality."

Besides trimming, Rick also uniforms his primer pockets and primer flash holes to achieve the most uniform ignition. In fact, Rick says he can prepare 100 cases in 10 minutes (primer pockets).

I use a RCBS power case trimmer just like Rick .

So how accurate do you want your handloads ? It is the difference between spraying a target or creating bughole groups .

08-05-2003, 04:16 PM	#24 (permalink)
marcopolo I am the anomaly. Location: Motown	A little dity on pistol cases that I found ... Pistol brass gets no respect from most of the manufacturers of reloading tools (Redding excepted) and often does not even get respect from the shooter community itself. The consequence of this is the fact that there are no neck turning tools available that can uniform revolver brass. This is probably the result of years and years of pistol brass being used in revolvers where the manufacturing tolerances were - shall we say - "generous". So it really didn’t matter if the brass wasn’t uniform, because the gun it was being shot in was as loose as a goose. However, things are changing, and when it comes to the modern revolvers and autoloaders it’s a whole different world out there. Consequently, it can make a difference if bullets are seated off center because of poor case wall tolerances. I then measured the case walls of the same 25 cases from each brand and found that the case wall variance from one side to the other for IMI brass was only a maximum of a .001 of an inch. Additionally, 80% of the IMI cases had exactly the same variance in their wall dimensions. This means that the case walls were indeed, very consistent. For Starline, the maximum case wall variance was .004 of an inch. 72% of those cases had the same variances. Not as consistent as IMI. Now trimming. This is a very important operation for pistol brass. In many brands of brass , case length can vary significantly. The result is that when a bullet is seated in the case and crimped, the variable length of the cases will determine the amount, or "hardness" of the crimp being applied. Additionally, it will also determine where in the bullet’s cannalure the crimp takes place (low, middle, high, or maybe even out of the cannalure). The amount of crimp and placement of the crimp, in turn, can affect the consistency of the powder’s ignition, and cause velocity changes from shot to shot. Bottom line - we want all the cases to be the same length to avoid these variations. "Speciality tools from Redding Reloading make a difference in quality." Besides trimming, Rick also uniforms his primer pockets and primer flash holes to achieve the most uniform ignition. In fact, Rick says he can prepare 100 cases in 10 minutes (primer pockets). I use a RCBS power case trimmer just like Rick . So how accurate do you want your handloads ? It is the difference between spraying a target or creating bughole groups . __________________ Those who can't laugh at themselves leave the job to others.