45 ACP OVER ALL LENGTH DATA, MIXED WCC8X BRASS, OREGON TRAIL 200 SWC BULLETS
EACH ROUND LOADED BY ITSELF, NO OTHER BRASS IN SHELL HOLDER
( 1.2341 - 1.2332 = .0009 ), AVG= 1.2339, DDEL= .0002, # ITEMS= 10
SIZE, POWDER CHARGE, AND SEAT, NO CRIMP DIE IN FOURTH POSITION
( 1.2382 - 1.2360 = .0022 ), AVG= 1.2369, DDEL= .0005, # ITEMS= 10
SIZE, POWDER CHARGE, SEAT AND CRIMP ON EACH HANDLE STROKE
( 1.2400 - 1.2379 = .0021 ), AVG= 1.2387, DDEL= .0006, # ITEMS= 10
The above indicates that doing each round by itself with no other operations will result in the least amount of press "spring" as shown by the shortest average round over all length. DDEL is the average amount that each round deviated from the over all length average and is also the smallest with this method. The amount of bullet jump from the casing to the leade of the barrel is thus the most consistent using this method. The second group of data comes from using all the dies except the crimp die so the sizing, powder charging, and bullet seating were done at the same time which caused the press to "spring" .0030 more then the single operation method. The variation in round over all length also was 2.5 times more when three operations were being done at the same time. The third group of data represents the use of all four positions of the 550B's turret at the same time thus putting the greatest strain on the press. It shows an increase in over all length of .0048 inch over the single operation data, and it also had three times the amount of variation as the single operation method.
Conclusions -
A. Depth seating is more consistent using single stage presses or single operations
on progressive presses. While this doesn't utilize the speed capabilities of the 550B
it does make the most consistent ammo, and should equal that of most single stage
presses.
B. Mixed brass tends to "spring" a press more on some rounds than others resulting
in less consistent over all length on a progressive press.
C. Adjusting seating depth for a batch of ammo should take this phenomena into
account when using a progressive press, especially when seating bullets near maximum
over all length. Using the brass from above it would be necessary to set the seating
about .0047 short of the desired length so when all operations are being done the
press will spring a little and produce the correct over all length. Each caliber and
head stamp of brass will probably require a slightly different offset value which is
best determined by some simple tests.
THE FOLLOWING 10 CASINGS WERE RANGE BRASS SIZED FIRST WITH RCBS DIES AND THEN
REPEATEDLY FIRED AND RELOADED WITH DILLON DIES USING A HARDBALL SIMULATOR
LOAD(MINIMAL). N DESIGNATES A NICKEL PLATED CASE AND DL IS THE DELTA LENGTH
FROM ONE FIRING TO THE NEXT. ALL FLASH HOLES WERE REAMED TO .0825.
CORBON 82.3 GR WITH 4.55/BE/230 RNL LOAD
CORBON .8875 .8856 .8852 .8846 .8837 .8830 .8816 .8802 .8798 .8791
CORBON DL= -.0019 -.0004 -.0006 -.0009 -.0007 -.0014 -.0014 -.0004 -.0007
CORBON TOT SHRINK = -.0084 AVG SHRINK = -.0009 AVG LAST 7 = -.00087
FC96 81.3 GR WITH 4.55/BE/230 RNL LOAD
FC96 .8812 .8792 .8786 .8773 .8750 .8733 .8725 .8717 .8706 .8702
FC96 DL= -.0020 -.0006 -.0013 -.0023 -.0017 -.0008 -.0008 -.0011 -.0004
FC96 TOT SHRINK = -.0110 AVG SHRINK = -.0012 AVG LAST 7 = -.00120
FED 82.2 GR WITH 4.55/BE/230 RNL LOAD
FED .8835 .8801 .8787 .8781 .8773 .8764 .8740 .8728 .8718 .8698
FED DL= -.0034 -.0014 -.0006 -.0008 -.0009 -.0024 -.0012 -.0010 -.0020
FED TOT SHRINK = -.0137 AVG SHRINK = -.0015 AVG LAST 7 = -.00127
FED N 82.9 GR WITH 4.55/BE/230 RNL LOAD
FED N .8832 .8804 .8802 .8796 .8772 .8763 .8759 .8732 .8728 .8723
FED N DL= -.0028 -.0002 -.0006 -.0024 -.0009 -.0004 -.0027 -.0004 -.0005
FED N TOT SHRINK = -.0109 AVG SHRINK = -.0012 AVG LAST 7 = -.00113
PMC 90.3 GR WITH 4.55/BE/230 RNL LOAD
PMC .8883 .8876 .8875 .8861 .8858 .8853 .8843 .8840 .8830 .8819
PMC DL= -.0007 -.0001 -.0014 -.0003 -.0005 -.0010 -.0003 -.0010 -.0011
PMC TOT SHRINK = -.0064 AVG SHRINK = -.0007 AVG LAST 7 = -.00080
RP N 83.8 GR WITH 4.55/BE/230 RNL LOAD
RP N .8854 .8853 .8813 .8810 .8790 .8784 .8768 .8760 .8741 .8732
RP N DL= -.0001 -.0040 -.0003 -.0020 -.0006 -.0016 -.0008 -.0019 -.0009
RP N TOT SHRINK = -.0122 AVG SHRINK = -.0014 AVG LAST 7 = -.00116
RP N+P 84.2 GR WITH 4.55/BE/230 RNL LOAD
RP N+P .8844 .8826 .8797 .8795 .8803 .8772 .8759 .8761 .8750 .8723
RP N+P DL= -.0018 -.0029 -.0002 .0008 -.0031 -.0013 .0002 -.0011 -.0027
RP N+P TOT SHRINK = -.0121 AVG SHRINK = -.0013 AVG LAST 7 = -.00106
*--* N 84.2 GR WITH 4.55/BE/230 RNL LOAD
*--* N .8940 .8919 .8902 .8897 .8891 .8878 .8869 .8869 .8856 .8854
*--* N DL= -.0021 -.0017 -.0005 -.0006 -.0013 -.0009 .0000 -.0013 -.0002
*--* N TOT SHRINK = -.0086 AVG SHRINK = -.0010 AVG LAST 7 = -.00069
WCC97 87.7 GR WITH 4.55/BE/230 RNL LOAD
WCC97 .8863 .8857 .8839 .8827 .8826 .8801 .8794 .8784 .8777 .8754
WCC97 DL= -.0006 -.0018 -.0012 -.0001 -.0025 -.0007 -.0010 -.0007 -.0023
WCC97 TOT SHRINK = -.0109 AVG SHRINK = -.0012 AVG LAST 7 = -.00121
WW 89.6 GR WITH 4.55/BE/230 RNL LOAD
WW .8853 .8850 .8833 .8821 .8811 .8800 .8791 .8770 .8750 .8753
WW DL= -.0003 -.0017 -.0012 -.0010 -.0011 -.0009 -.0021 -.0020 .0003
WW TOT SHRINK = -.0100 AVG SHRINK = -.0011 AVG LAST 7 = -.00114
SAME AS ABOVE BUT WITH A LIGHT TARGET LOAD, JUST POWERFUL ENOUGH TO FUNCTION
AN M1911 WAD GUN WITH A STANDARD 16# SPRING, IRON SIGHTS.
CORBON 80.4 GR WITH 3.7/BE/200 OT SWC LOAD
CORBON .8923 .8924 .8917 .8917 .8914 .8911 .8919 .8911 .8904 .8910
CORBON DL= .0001 -.0007 .0000 -.0003 -.0003 .0008 -.0008 -.0007 .0006
CORBON TOT SHRINK = -.0013 AVG SHRINK = -.0001 AVG LAST 7 = -.00010
FC97 81.4 GR WITH 3.7/BE/200 OT SWC LOAD
FC97 .8853 .8834 .8832 .8836 .8826 .8824 .8826 .8816 .8814 .8820
FC97 DL= -.0019 -.0002 .0004 -.0010 -.0002 .0002 -.0010 -.0002 .0006
FC97 TOT SHRINK = -.0033 AVG SHRINK = -.0004 AVG LAST 7 = -.00017
FED 82.0 GR WITH 3.7/BE/200 OT SWC LOAD
FED .8880 .8857 .8858 .8855 .8853 .8846 .8839 .8841 .8841 .8839
FED DL= -.0023 .0001 -.0003 -.0002 -.0007 -.0007 .0002 .0000 -.0002
FED TOT SHRINK = -.0041 AVG SHRINK = -.0005 AVG LAST 7 = -.00027
FED N 83.3 GR WITH 3.7/BE/200 OT SWC LOAD
FED N .8896 .8887 .8881 .8879 .8881 .8881 .8870 .8870 .8871 .8861
FED N DL= -.0009 -.0006 -.0002 .0002 .0000 -.0011 .0000 .0001 -.0010
FED N TOT SHRINK = -.0035 AVG SHRINK = -.0004 AVG LAST 7 = -.00029
PMC 90.1 GR WITH 3.7/BE/200 OT SWC LOAD
PMC .8918 .8917 .8915 .8906 .8908 .8907 .8901 .8898 .8897 .8902
PMC DL= -.0001 -.0002 -.0009 .0002 -.0001 -.0006 -.0003 -.0001 .0005
PMC TOT SHRINK = -.0016 AVG SHRINK = -.0002 AVG LAST 7 = -.00019
RP N 85.7 GR WITH 3.7/BE/200 OT SWC LOAD
RP N .8845 .8846 .8838 .8847 .8843 .8836 .8833 .8822 .8815 .8819
RP N DL= .0001 -.0008 .0009 -.0004 -.0007 -.0003 -.0011 -.0007 .0004
RP N TOT SHRINK = -.0026 AVG SHRINK = -.0003 AVG LAST 7 = -.00027
RP N+P 85.1 GR WITH 3.7/BE/200 OT SWC LOAD
RP N+P .8848 .8851 .8847 .8848 .8841 .8834 .8828 .8822 .8816 .8814
RP N+P DL= .0003 -.0004 .0001 -.0007 -.0007 -.0006 -.0006 -.0006 -.0002
RP N+P TOT SHRINK = -.0034 AVG SHRINK = -.0004 AVG LAST 7 = -.00047
*--* N 81.5 GR WITH 3.7/BE/200 OT SWC LOAD
*--* N .8923 .8904 .8907 .8894 .8891 .8896 .8888 .8892 .8884 .8885
*--* N DL= -.0019 .0003 -.0013 -.0003 .0005 -.0008 .0004 -.0008 .0001
*--* N TOT SHRINK = -.0038 AVG SHRINK = -.0004 AVG LAST 7 = -.00031
WCC97 87.0 GR WITH 3.7/BE/200 OT SWC LOAD
WCC97 .8880 .8866 .8868 .8861 .8861 .8866 .8859 .8853 .8849 .8848
WCC97 DL= -.0014 .0002 -.0007 .0000 .0005 -.0007 -.0006 -.0004 -.0001
WCC97 TOT SHRINK = -.0032 AVG SHRINK = -.0004 AVG LAST 7 = -.00029
WW 88.1 GR WITH 3.7/BE/200 OT SWC LOAD
WW .8878 .8887 .8869 .8876 .8869 .8868 .8850 .8838 .8851 .8851
WW DL= .0009 -.0018 .0007 -.0007 -.0001 -.0018 -.0012 .0013 .0000
WW TOT SHRINK = -.0027 AVG SHRINK = -.0003 AVG LAST 7 = -.00026
WW N 86.6 GR WITH 3.7/BE/200 OT SWC LOAD
WW N .8906 .8882 .8893 .8883 .8878 .8871 .8879 .8874 .8871 .8871
WW N DL= -.0024 .0011 -.0010 -.0005 -.0007 .0008 -.0005 -.0003 .0000
WW N TOT SHRINK = -.0035 AVG SHRINK = -.0004 AVG LAST 7 = -.00031
SAME AS ABOVE WITH 8 WCC97 CASINGS FROM THE SAME BOX, SIZED THE FIRST TIME
WITH RCBS & DILLON DIES, WITH AND WITHOUT LUBE, FIRED WITH LIGHT TARGET
LOADS, THEN REPEATEDLY RELOADED WITH DILLON DIES AND NO LUBE AND THEN FIRED.
WC97-1 RCBS, NO LUBE 1ST TIME, 3.7/BE/200 OT SWC LOAD
WC97-1 .8909 .8909 .8879 .8887 .8886 .8877 .8875 .8868 .8870 .8870
WC97-1 DL= .0000 -.0030 .0008 -.0001 -.0009 -.0002 -.0007 .0002 .0000
WC97-1 TOT SHRINK = -.0039 AVG SHRINK = -.0004 AVG LAST 7 = -.00013
WC97-2 RCBS, NO LUBE 1ST TIME, 3.7/BE/200 OT SWC LOAD
WC97-2 .8902 .8894 .8889 .8888 .8879 .8867 .8868 .8866 .8862 .8870
WC97-2 DL= -.0008 -.0005 -.0001 -.0009 -.0012 .0001 -.0002 -.0004 .0008
WC97-2 TOT SHRINK = -.0032 AVG SHRINK = -.0004 AVG LAST 7 = -.00027
WC97-3 RCBS, LUBED 1ST TIME, 3.7/BE/200 OT SWC LOAD
WC97-3 .8871 .8885 .8881 .8860 .8856 .8862 .8854 .8851 .8844 .8850
WC97-3 DL= .0014 -.0004 -.0021 -.0004 .0006 -.0008 -.0003 -.0007 .0006
WC97-3 TOT SHRINK = -.0021 AVG SHRINK = -.0002 AVG LAST 7 = -.00044
WC97-4 RCBS, LUBED 1ST TIME, 3.7/BE/200 OT SWC LOAD
WC97-4 .8886 .8883 .8877 .8862 .8882 .8863 .8861 .8851 .8841 .8845
WC97-4 DL= -.0003 -.0006 -.0015 .0020 -.0019 -.0002 -.0010 -.0010 .0004
WC97-4 TOT SHRINK = -.0041 AVG SHRINK = -.0005 AVG LAST 7 = -.00046
WC97-5 DILLON, NO LUBE 1ST TIME, 3.7/BE/200 OT SWC LOAD
WC97-5 .8877 .8856 .8851 .8855 .8851 .8852 .8849 .8843 .8830 .8833
WC97-5 DL= -.0021 -.0005 .0004 -.0004 .0001 -.0003 -.0006 -.0013 .0003
WC97-5 TOT SHRINK = -.0044 AVG SHRINK = -.0005 AVG LAST 7 = -.00026
WC97-6 DILLON, NO LUBE 1ST TIME, 3.7/BE/200 OT SWC LOAD
WC97-6 .8907 .8889 .8908 .8880 .8898 .8872 .8876 .8861 .8856 .8856
WC97-6 DL= -.0018 .0019 -.0028 .0018 -.0026 .0004 -.0015 -.0005 .0000
WC97-6 TOT SHRINK = -.0051 AVG SHRINK = -.0006 AVG LAST 7 = -.00074
WC97-7 DILLON, LUBED 1ST TIME, 3.7/BE/200 OT SWC LOAD
WC97-7 .8883 .8874 .8851 .8855 .8840 .8830 .8830 .8833 .8826 .8832
WC97-7 DL= -.0009 -.0023 .0004 -.0015 -.0010 .0000 .0003 -.0007 .0006
WC97-7 TOT SHRINK = -.0051 AVG SHRINK = -.0006 AVG LAST 7 = -.00027
WC97-8 DILLON, LUBED 1ST TIME, 3.7/BE/200 OT SWC LOAD
WC97-8 .8878 .8865 .8865 .8869 .8863 .8856 .8858 .8858 .8857 .8845
WC97-8 DL= -.0013 .0000 .0004 -.0006 -.0007 .0002 .0000 -.0001 -.0012
WC97-8 TOT SHRINK = -.0033 AVG SHRINK = -.0004 AVG LAST 7 = -.00029
Notes and conclusions:
A. Measurements were done with a dial caliper and magnifying glass so I
can't vouch for the last .0001 or .0002.
B. Most of the casings tended to go "bananas"(turn slightly banana shape)
which was probably due the case wall being thicker on one side than the
other. This may have caused a few of the casings to appear to expand a
little. That could also be due to not getting the exact longest side of
the casing when measuring.
C. After firing, some of the casings may have had a case head that wasn't
quite perpendicular to the axis of the casing.
D. Because of the method of measuring used, the fourth decimal place is
probably not exact. For the same reasons, the fifth decimal place is
an example of mathematical heresy but is given since it is an average
and may convey some information.
E. Rarely are two casings identical, and even if they are, fire them once
or twice and they will probably not be the same length.
F. The heavy load seemed to shrink casings about .0011 per firing while
the lighter load shrunk them about 1/3rd to 1/4th as much, about .0003.
G. Shrinkage for any one brand of casing is probably related to the
hardness and thickness of the brass. Dimensions are easy to get but
the hardness is nearly impossible to determine by an ordinary shooter
and probably varies somewhat from case to case.
H. The location of the "bulge" in the casings after firing was closer to
the head when using the heavier loads as you might expect. One of the
Federal casings using the heavy load had the head of the case expand
radially so much that it barely entered an RCBS shellholder. Such
large diameter case rims put more stress onto the extractor and may
lead to their premature failure. If you can barely read the headstamp
on the casing, check the rim diameter.
I. Uniform headspace(or lack thereof) is one of a bunch of reasons why
rifles tend to be considerably more accurate than comparable pistols.
We can trim the cases every time we fire them to get consistency but
at that rate we will very quickly have casings that are really too
short.
J. Do you have any other conclusions or ideas to add here? If so email
Constant Force Products. Thanks.