.500 Linebaugh Primer Test
Note:
This article is for information purposes only. Anyone who uses any
reloading data contained herein does so at their own risk. The Author
& Leverguns.Com will not be held liable for any problems such a person
may encounter. The Author states that these loads were safe in his gun
and his gun only.
This small article will not cover the origin of the John Linebaugh’s
.500, as that has been covered very well by others. If interested in the
background, I recommend Taffin Tests: The .500 Linebaugh
by John Taffin.
One of the first things a shooter will discover
about the .500L is a dearth of clean-burning light-to-medium loads that bulk
well. In 454s, WC680 (a military surplus powder similar to AA1680) is utilized
volume-to-volume with WC820 (a military surplus powder similar to 296/110) for a
reduced load (usually about 2-300fps less). This allows a high load density for
the powder, preventing the possibility of a double charge. Personally, I just
wasn’t comfortable using a faster powder at something like 30% load density –
particularly since all my ammo is loaded on a Dillon 550.
However, the
next discovery was that the cavernous .500L case did not lend itself to the same
volume-to-volume relationship between WC820/WC680 that worked so well in the
454s. Thirty grains of WC680 behind the excellent 440gr Cast
Performance bullet did not burn well at all – worse yet, variation in the
recoil impulse shot-to-shot was noticed, which indicated LARGE extreme spreads.
Back to the drawing board.
Quickload was queried, and it calculated the
above-mentioned load of 30grs WC680 beneath the 440gr CP bullet crimped in the
groove from my 4&5/8” barrel should yield 68% case fill and 877fps. The
crimp bears mentioning, as a good heavy crimp is necessary for any heavy bullet
load, especially with slower powders. The Dillon is set up with a modified
powder funnel (.005” reduction in diameter) so as to not over expand the case.
Dies are Hornady with seating/crimping done in separate steps.
Since the
.500L originated from .348 Winchester rifle brass, investigating the primer
pockets of the Buffalo Bore Ammunition .500L brass
seemed logical – YES, they will accept rifle primers without problems. Now to
find out if the custom Ruger 5-shot could overcome the harder rifle primer cups.
Inventorying the reloading area for primers yielded six different manufacturers
represented in large pistol flavor and eight in large rifle. Utilizing new,
never fired BBA brass, 30grs of WC680 entombed beneath a 440gr bullet, changing
nothing except primers, I proceeded with the test. Five shot string data below,
with the following definitions: Avg. = average velocity, Std. Dev. = standard
deviation, E.S. = extreme spread, and Avg. Exp. = average case expansion. Case
expansion, measured just above the rim, is Ken Water’s method of comparing
pressures of various loads in the same gun. Barrel and chambers were swabbed
with several patches between each string.
PISTOL PRIMER DATA
CCI 300
Large Pistol Standard
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
804.2 |
.5464 |
| 2 |
775.0 |
.5461 |
| 3 |
795.4 |
.5465 |
| 4 |
803.8 |
.5465 |
| 5 |
808.1 |
.5466 | |
Calculated Data
| Avg. Fps |
797.3 |
| Std. Dev. |
13.3 |
| E.S. |
33.1 |
| Avg. Exp. |
.5464 | |
This one was the surprise of the pistol primer
group with the lowest E.S. of the pistol primers. Still dirty, though.
|
CCI 350
Large Pistol Magnum
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
862.0 |
.5468 |
| 2 |
892.8 |
.5469 |
| 3 |
920.1 |
.5472 |
| 4 |
901.7 |
.5472 |
| 5 |
898.3 |
.5470 | |
Calculated Data
| Avg. Fps |
895.0 |
| Std. Dev. |
21.1 |
| E.S. |
58.1 |
| Avg. Exp. |
.5470 | |
The most commonly used primer in the .500L. Turned
in the highest velocity and second best E.S. Cleanest load in this group.
First choice of pistol primers. |
Federal 150
Large Pistol Standard
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
641.3 |
.5432 |
| 2 |
744.9 |
.5447 |
| 3 |
715.5 |
.5446 |
| 4 |
759.6 |
.5461 |
| 5 |
642.5 |
.5435 | |
Calculated Data
| Avg. Fps |
700.8 |
| Std. Dev. |
56.0 |
| E.S. |
118.3 |
| Avg. Exp. |
.5444 | |
DO NOT TRY THIS
ONE. Worst performer of the lot. Unable to ignite the powder
consistantly. Terrible extreme spread, velocity variation apparent in
recoil. Cases wedged in chambers by unburnt powder, necessitating brass
rod for ejection. |
Federal 155
Large Pistol Magnum
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
846.2 |
.5464 |
| 2 |
789.3 |
.5462 |
| 3 |
774.0 |
.5459 |
| 4 |
823.0 |
.5464 |
| 5 |
785.4 |
.5460 | |
Calculated Data
| Avg. Fps |
803.6 |
| Std. Dev. |
30.0 |
| E.S. |
72.2 |
| Avg. Exp. |
.5462 | |
Ok, but the CCI 350 and Remington 2 ˝ outclass it
in both E.S. and cleanliness. |
Remington 2 & 1/2
Large Pistol Standard
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
848.8 |
.5462 |
| 2 |
875.5 |
.5467 |
| 3 |
850.6 |
.5464 |
| 4 |
829.4 |
.5460 |
| 5 |
840.6 |
.5462 | |
Calculated Data
| Avg. Fps |
849.0 |
| Std. Dev. |
17.0 |
| E.S. |
46.1 |
| Avg. Exp. |
.5463 | |
Quite respectable – my second choice of the pistol
primers. Relatively clean burning, very comparable to the CCI 350.
|
Winchester Large Pistol
Std/Mag
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
787.2 |
.5465 |
| 2 |
736.3 |
.5449 |
| 3 |
835.9 |
.5467 |
| 4 |
703.9 |
.5443 |
| 5 |
724.5 |
.5448 | |
Calculated Data
| Avg. Fps |
757.6 |
| Std. Dev. |
53.5 |
| E.S. |
132.0 |
| Avg. Exp. |
.5454 | |
Poor showing, but it did eject ok. Velocity
variation was noticeable in recoil variation. |
RIFLE PRIMER DATA
CCI #34
Large Rifle Milspec
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
895.8 |
.5464 |
| 2 |
897.5 |
.5464 |
| 3 |
883.6 |
.5462 |
| 4 |
998.5 |
.5466 |
| 5 |
954.4 |
.5466 | |
Calculated Data
| Avg. Fps |
926.0 |
| Std. Dev. |
49.0 |
| E.S. |
114.9 |
| Avg. Exp. |
.5464 | |
CCI is not kidding when they say these primers are
tough! Two required a second strike to ignite, the only primer in this
series to defeat the Bisley's stock mainspring. Large E.S. probably
attributable to marginal firing pin hits. Unusable, obviously - unless you
want to check your flinch. |
CCI 200
Large Rifle Standard
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
904.0 |
.5470 |
| 2 |
889.4 |
.5469 |
| 3 |
876.7 |
.5468 |
| 4 |
842.1 |
.5463 |
| 5 |
848.6 |
.5464 | |
Calculated Data
| Avg. Fps |
872.2 |
| Std. Dev. |
26.4 |
| E.S. |
61.9 |
| Avg. Exp. |
.5467 | |
Decent performance, but notice the primer strikes.
Not a good enough performer to risk a FTF. CCI primers are hard. No
wonder they work so well in the 454C. |
CCI 250
Large Rifle Magnum
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
890.3 |
.5463 |
| 2 |
895.0 |
.5468 |
| 3 |
881.1 |
.5462 |
| 4 |
893.7 |
.5466 |
| 5 |
892.0 |
.5464 | |
Calculated Data
| Avg. Fps |
890.4 |
| Std. Dev. |
5.5 |
| E.S. |
13.9 |
| Avg. Exp. |
.5465 | |
Whee-doggie! Now that IS what we are looking for!
Cases aren't sooty, reasonably clean burning. This one will be studied
further. Notice the light primer strikes. Again, CCI primers are
hard. More testing is in order to insure reliable ignition.
|
Federal 210
Large Rifle Standard
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
925.2 |
.5465 |
| 2 |
893.7 |
.5463 |
| 3 |
872.6 |
.5459 |
| 4 |
875.7 |
.5461 |
| 5 |
935.6 |
.5466 | |
Calculated Data
| Avg. Fps |
900.6 |
| Std. Dev. |
28.6 |
| E.S. |
63.0 |
| Avg. Exp. |
.5463 | |
This one did worse than expected in the E.S.
department. Still, second highest velocity after discounting the milspec
as unusable |
Federal 215
Large Rifle Magnum
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
976.7 |
.5471 |
| 2 |
964.6 |
.5467 |
| 3 |
980.8 |
.5472 |
| 4 |
971.5 |
.5468 |
| 5 |
993.0 |
.5473 | |
Calculated Data
| Avg. Fps |
977.3 |
| Std. Dev. |
10.7 |
| E.S. |
28.4 |
| Avg. Exp. |
.5470 | |
Interesting. Second lowest E.S. while running away
with the velocity crown for all primers tested. Generally accepted as the
hottest primer available and used in BP cartridge rifles to ignite the
large BP charges. Cleanest burn of all primers tested.
|
Remington 9 & 1/2
Large Rifle Standard
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
863.1 |
.5464 |
| 2 |
861.0 |
.5461 |
| 3 |
902.0 |
.5466 |
| 4 |
851.8 |
.5461 |
| 5 |
871.3 |
.5464 | |
Calculated Data
| Avg. Fps |
869.8 |
| Std. Dev. |
19.3 |
| E.S. |
50.2 |
| Avg. Exp. |
.5463 | |
Another interesting primer that will see more
testing. |
Winchester
Large Rifle Standard
 |
Chronograph Data
| Shot |
Fps |
Exp. |
| 1 |
872.6 |
.5463 |
| 2 |
871.3 |
.5462 |
| 3 |
858.5 |
.5460 |
| 4 |
896.8 |
.5465 |
| 5 |
876.7 |
.5464 | |
Calculated Data
| Avg. Fps |
875.2 |
| Std. Dev. |
13.9 |
| E.S. |
38.3 |
| Avg. Exp. |
.5463 | |
Respectable performance while delivering an average
velocity closest to Quickload's prediction. Neither here nor there, of
course. Another interesting primer that will see more testing.
|
Notice the wide swing in velocity; WC680
is rather slow for the .500L, but will turn in respectable results if close
attention is paid to primer selection. This is true of both pistol and rifle
primers. It must be mentioned that the poor showing of some of the pistol
primers in this test does not mean they will not work as their manufacturer
intended; i.e., in normal pistol cases with faster powders.
The
following day, one hundred rounds of the above load were fired. Fifty rounds
were primed with CCI 250 primers and fifty rounds with the Federal 215 primer.
Disappointingly, there were three failure-to-fires (FTF) with the CCI 250
primers. No doubt the mainspring is not up to the task of igniting the hard CCI
rifle primer. No problems at all with the Federal 215 loads. Both loads put down
the six-inch falling plates from the fifty-yard line with alacrity. No surprise
there as the IPSC Power Factor for the Federal 215 load (440gr @ 977fps) is 430…
No attempt was made to shoot these variations for groups during this
test, preferring to cull a few of the underachievers via the chronograph. Also,
a plain-base 480gr Whitworth mold has been obtained from Mountain Molds
it was expressly designed to displace more internal volume than the Cast
Performance 440gr bullet, so it should prove even better suited to the
reduced load task.
In conclusion, and at this point, WC680 or it's
commercial twin Accurate Arms 1680 appears
to be a viable powder when rifle primers are utilized for the .500L
pending accuracy testing. It certainly fits the requirement of preventing a
possible double charge while providing a light-to-medium practice load.
John Killebrew
Email: John K.
03/06/04
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