I finally got to the indoor range today to complete my testing of the 125gr Dardas cast bullet. I checked twenty at random, and they averaged .356" in diameter, .605" in length, and 125.2gr in weight. Dardas claims their alloy runs 18-20 in hardness, and the bullets appear to be very well-made with a blue crayon-type lube. Since they carry two styles in this weight, I should add that I used the bullet with the driving band at the base. No appreciable leading was observed in any of the firearms after testing.
All rounds tested used a 1.140" COL, once-fired Fiocchi brass measuring .750", CCI 500 primers, and a light taper crimp (just enough to eliminate the case flare). Powder weights were selected with an eye towards the desired 1020 fps, and what the Lee Pro Auto Disk's fixed cavities would throw. The target was at 25 yards, the CED Millennium chronograph with IR screens was at 10 feet, and the guns were rested on sandbags. Age has affected my vision to the point that it no longer allows me to honestly test for extreme accuracy, so please understand the lack of group size. The numbers in the table are reported as fps/es/sd. Ten rounds of each load were fired in each gun.
The test firearms were two S&W 547s with 3" and 4" barrels, a Beretta 8000F Cougar with a 3.6" barrel, and a Beretta 92FS with a 4.9" barrel. I was particularly interested in seeing how the different action types and barrel lengths performed with identical loads.
............................8000F (3.6").......547 (3")...........547 (4")..........92FS (4.9")
------------------------------------------------------------------------------
AA #2.......4.0gr.......994/15/5.......1016/21/6........1045/25/7........1058/17/5
VV N320...4.0gr........973/24/8.......1007/30/10......1028/31/10.......1046/38/10
VV N330...4.6gr......1020/18/5.......1059/35/10......1084/30/9.........1098/29/9
VV N340...4.7gr......1017/25/8.......1045/41/11......1054/48/13.......1085/37/10
Unique.....4.3gr.......925/65/23
Unique.....4.7gr.......985/23/13
Observations:
1) I was surprised that all of the loads were faster out of the 3" revolver than the 3.6" semi-auto. Counting the length of the chamber in the Cougar, it's effective barrel length was only slightly shorter than the 3" 547, but I was expecting more velocity loss from the 547's cylinder gap (the 3" has a .007" gap, and the 4" has a .005" gap).
2) Even though I wasn't checking specifically for accuracy, I did notice early in the testing that N330 was significantly more accurate than any of the other powders. I measured its ten shot group at 2.0" out of the 92FS.
3) Since the 547s are pretty rare and I don't want to overstress them, I'm sure that they'll see mostly cast lead bullets in the future. But they're a hoot to shoot, with nice double actions a plus.
4) Any of these powders work well with this cast bullet. No evidence of tumbling showed on the targets.
Comments or suggestions are always appreciated.