Being basically a revolver shooter I have never thought
too much about problems that may arise in reloading for the autoloading
handguns. I spent quite a few years learning the tricks of reloading in order to
get the most accuracy from a revolver. It wasn't until I began playing with a
9mm Colt Combat Commander though, that I gave any serious thought about
reloading for the autoloading pistol. As I was to find out, reloading a 9mm so
that it will fire and function is one thing, but getting the most accuracy out
of it can be another altogether.
My first step was to read through the reloading manuals. I
have some that go back as far as 1939, but basically all they give is the
reloading process and a listing of loads with different bullets and powders.
There was not much information on "why" some of the autoloaders just
do not shoot as accurately as they should. It was not until I read the new SPEER
RELOADING MANUAL #12 that I ran across any real information on "why".
While the Speer Manual has the standard reloading information, it also has a
special section dealing specifically with the 9mm and it's special needs.
Begining on page 432, this handy section contains information that can only be
found otherwise through trial and error. While most of the information is stuff
we handloaders SHOULD be aware of, I found it helpful and a good point from
which to work. Reading through all the manuals by the way, was interesting and
did give me some insights. For instance, in Speer Reloading Manual #11 I found
that with 9mm handloads of 28,000 CUP (Coppper Units of Pressure), should you
seat the bullet only .030" deeper into the cartridge case, the pressures
jump to 62,000 CUP!! Enough to wreck a good gun. I got the idea from this that
the 9mm can be touchy to reload and that careful attention to detail (such as
over-all loaded length) is very important.
Another thing that I found was while the 9mm cases are
supposed to be a certain length, there can be large variations, even when the
cases are from the same manufacturer. Cases should be sorted according to
headstamp before reloading. I also found that among the guns firing the 9mm
cartridge there can be variations in bore diameters. It is helpful when you are
searching for accuracy to have bullets that fit the bore. The bore diameters can
surprise you. While the 9mm bore is supposed to be .355" I found many guns
have barrel diameters of .356" or larger. Some are as large as .358",
especially among European-built guns.
After cleaning my empty cases I sorted them all according
the headstamps. Before sizing , neck expanding, and priming the cases I decided
to check them for over-all length (OAL). To my surprise I found that the cases
varied by as much as .020" in length. Using six different brands and
checking ten of each, I found cartridge cases ran from .7355" in length to
.755" for the long ones. This large variation can means that some cases are
not headspacing on the case mouth as supposed, but rather are headspacing on the
extractor. This could account for sloppy accuracy in itself.
While checking the case lengths I decided to weigh the
water capacity of some of them and found the cases I checked to vary as much as
3.1 gr. weight of water. While gunpowder is much lighter and would not vary that
much, it still shows the internal variations from cartridge to cartridge.
After reading and checking dimensions I began to theorize
that I might be able to increase the accuracy of the 9mm - at least in my pistol
- by carefully measuring the cartridge cases and with precise loading. To test
the the theory I choose two bullets to use, the Speer 115 gr. and the Speer 147
gr. Gold Dot hollowpoints. I decided to use only CCI #500 primers and Speer
cases for reloading. For powders I choose two old-timers, Hercules Bullseye and
Unique. To keep variables at a minimum I chose arbitrarily an over-all loaded
length of 1.130". I loaded 10 at this length and function-fired them. They
worked through the action smoothly and gave no problems. What I was seeking was
a length that functioned without any hang-ups. While experimenting with OAL of
the loaded cartridge CAN increase accuracy sometimes, at this point my only goal
was to see if my idea about case lengths was valid.
The powder charge selected was in the recommended range in
the reloading manuals. I did not chronograph any of them. All I wanted was a
load that would be safe and would function in the firearm. I was not out to see
how fast they would go, but rather, could I make any difference in the accuracy
by checking the length of the cartridge cases. Reloading was done with
once-fired cases. I loaded enough to fire 6 five-shot groups with each group of
cartridges. For a greater statistical average a minimum of 10 5-shot
groups should have been used, but at the time I was short on bullets and figured
30 shots would give a good indication.
All firing was done from 25 yards using an Outers Pistol Perch. For
the first segment of testing I had four groups of cartridges. Loaded with the
115 gr. Gold bullet and 4.7 gr. of Bullseye, the cases were sorted as follows:
- 30 that were chosen at random and not checked for length
- 30 that were measured but that varied .003" in length
After firing and recording all the groups and their
averages it was determined that the cases of .750" gave the best accuracy
by far.
I then went back to the reloading bench and did the whole
exercise over again, this time using the 147 gr. Gold Dot bullet. Other than
changing the powder charge to 3.9 gr. of Bullseye, the loading was the same.
Over-all loaded length was kept at 1.130" and the CCI #500 primers were
used throughout. Again the cases that were .750" in length gave the best
results, giving groups that averaged half the size of the the groups fired from
cases that were not measured.
I also tried using some cases that were longer than the
.750" length that worked so well. I went up to .755" but accuracy
deteriorated with cases over the preferred length. I guess this gun is just
partial to them.
Using Unique powder I found gave slightly smaller group
averages. For some reason the pistol I was using prefered the slightly slower
powder. I feel sure that by experimenting with over-all loaded length and by
trying other powders or primers, some loads will shoot more accurately than the
ones I recorded. However, each firearm is an individual and testing needs to be
done with each one if you wish to get it to shoot to it's maximum potential.
Note though, that simply by careful attention to details I was able to increase
the useable accuracy of this particular firearm.
After studying the results of my shooting tests I decided
to see if it would hold true with cast bullets. Using what I had learned from
the previous tests, I used only 2 different lots of cases. One lot was cases
picked at random and not measured for length. The other lot was cases of
.750" length. The bullet diameters were .356", more closely fitting
the bore diameter of the Colt Combat Commander. I used four different bullets
during this phase of firing. One was a nice semi-wadcutter from BRP High
Performance Cast bullets which weighed in at 115 gr. I also had 2 bullets from
MT. Baldy Cast Bullets, both of 122 gr weight. One was a flat point (FP) while
the other was a round-nose (RN) design. The last cast bullet was one I cast
myself. In a pointed shape, it was Lyman's version of one of the old original
Luger bullets. Weighing in at 121 gr., the Lyman number for this design is
#356402. Again, testing confirmed that in this gun at least, cases of .750"
length shot the most accurately. As I have stated before, you will have to find
what case length shoots the best in your particular firearm. However, this is a
good starting point.
To summarize, when reloading:
1. sort your cases by headstamp
2. check the over-all length of each case and sort them by
length
3. watch the over-all loaded length of the cartridges
4. monitor your powder charges carefully
5. determine which case length shoots the most accurately
in your firearm
NOTE: ALL OTHER GUIDELINES FOR SAFE RELOADING APPLY ALSO
The 9mm can be a bit frustrating to load for at times, but
your efforts will be rewarded. Do not get in a rush. The 9mm is a high-density
cartridge and a small change can yield large results. Watch the powder charges
and over-all lengths as well as the seating depth of the bullets. Do no try to
hot-rod it. Stay within the bounds of the Manuals.
LOADS WITH THE 115 GR. GOLD DOT BULLET - SPEER CASES USED
THROUGHOUT - ALL LOADED WITH 4.7 GR. BULLSEYE - ALL PRIMERS CCI #500 - ALL
GROUPS FIRED FROM AN OUTERS PISTOL PERCH AT 25 YARDS
| Case length |
Average of 6
5-shot groups |
| random length |
3.9" |
| vary .003" |
4.2" |
| .743" |
5.6" |
| .750" |
2.6" |
LOADS WITH THE 147 GR. GOLD DOT BULLET - SPEER CASES USED
THROUGHOUT - ALL PRIMERS CCI #500 - ALL GROUPS FIRED FROM AN OUTERS PISTOL PERCH
AT 25 YARDS
| Case length |
Average of 6
5-shot groups |
| random length |
5.3" |
| .748" |
4" |
| .750" |
2.5" |