Today was a beautiful day to go to the range, so I decided to bring 3 of my 357 Mags to the range; 2 Model 27s and my Coonan Classic. Plus, I got in a replacement Caldwell Chronograph to replace my defective one I got around Christmas, so I decided to do a little chronographing reloads against some factory ammo. I ended up having a real good time and ran some rounds through all 3 pistols over the chrono.
The ammo I brought to shoot were as follows:
The factory ammo was PMC Bronze, loaded with 158 grain JSP bullets
On my reloads, all used Zero 158 grain JSP bullets. All used CCI 550 small pistol magnum primers. And all were loaded into new, virgin Starline brass. For powder and charges, I used the 3 magnum class powders I have here at the house. I used 11.0 grains of Alliant Blue Dot, which is a mid-to-hot load for BD. I used 16.0 grains of Winchester 296, which is around a mid-load from that powder. The third powder I used was 13.0 grains of Accurate #9, which is a mid-to-hot load for that powder.
The pistols I used are as follows:
Model 27-3 with 5" barrel. This pistol was unfired before today. Build date was some time in late 1985.
Model 27-5 with 6 1/2" barrel. It has had around 270 rounds through it before today's range trip. Build date was around October 1990.
Coonan Classic 5" barrel 1911 style semi auto 357 Magnum. I've had it roughly 1 1/2 years and it has north of 1K rounds through it. I brought it for 2 reasons. 1. It's a hoot to shoot and 2. To compare velocity differences (if any) between vented and non-vented barrels. And you have to remember that the Coonan's barrel includes the chamber in overall length, so you effectively only have around 3 1/2" or so of rifled barrel.
Here is a pic of the 3 pistols on the bench at the range before shooting:
Range conditions today were just beautiful. It was a clear day with 5-10 mph winds. Temps while chronographing were 66-67 degrees and barometric pressure was from 30.15-30.09 inches Mrecury. All in all, a much nicer day than the crud we had all last week.
Testing was 5 shot strings. I was going to do 6 shot strings, but had reading errors on several strings so I dropped a shot out of the strings without errors so all would be measuring 5 shot strings. The Caldwell Chronograph was set up around 20 feet in front of the bench.
Now to results. First up was the 11.0 grain Blue Dot loads. This is what I got with the 3 pistols:
5" Model 27-3
Average velocity - 1343.00 fps
Average energy - 633 ft-lbf
Standard deviation - 23.71
Min velocity - 1318 fps
Max velocity - 1374 fps
Spread - 56
True MV - 1346.05 fps
6 1/2" Model 27-5
Average velocity - 1264.00 fps
Average energy - 560.6 ft-lbf
Standard deviation - 13.38
Min velocity - 1252 fps
Max velocity - 1287 fps
Spread - 35
True MV - 1266.87 fps
Coonan Classic
Average velocity - 1328.60 fps
Average energy - 620 ft-lbf
Standard deviation - 34.77
Min velocity - 1281 fps
Max velocity - 1371 fps
Spread - 90
True MV - 1331.62 fps
Next up were the 16.0 grain WW 296 loads:
5" Model 27-3
Average velocity - 1234.60 fps
Average energy - 535 ft-lbf
Standard deviation - 31.19
Min velocity - 1196 fps
Max velocity - 1276 fps
Spread - 80
True MV - 1237.4 fps
6 1/2" Model 27-5
Average velocity - 1195.80 fps
Average energy - 502.2 ft-lbf
Standard deviation - 38.38
Min velocity - 1146 fps
Max velocity - 1246 fps
Spread - 100
True MV - 1198.52 fps
Coonan Classic
Average velocity - 1282.00 fps
Average energy - 577 ft-lbf
Standard deviation - 24.34
Min velocity - 1261 fps
Max velocity - 1322 fps
Spread - 61
True MV - 1284.91 fps
Next up were the loads with 13.0 grains of Accurate #9:
5" Model 27-3
Average velocity - 1330.60 fps
Average energy - 621.2 ft-lbf
Standard deviation - 10.33
Min velocity - 1316 fps
Max velocity - 1340 fps
Spread - 24
True MV - 1333.62 fps
6 1/2" Model 27-5
Average velocity - 1326.60 fps
Average energy - 617.8 ft-lbf
Standard deviation - 34.13
Min velocity - 1367 fps
Max velocity - 1352 fps
Spread - 85
True MV - 1329.61 fps
Coonan Classic
Average velocity - 1352.60 fps
Average energy - 642.6 ft-lbf
Standard deviation - 52.56
Min velocity - 1259 fps
Max velocity - 1381 fps
Spread - 122
True MV - 1355.67 fps
Finally, we get to the PMC factory ammo:
5" Model 27-3
Average velocity - 1204.60 fps
Average energy - 510.8 ft-lbf
Standard deviation - 81.75
Min velocity - 1133 fps
Max velocity - 1309 fps
Spread - 176
True MV - 1207.34 fps
6 1/2" Model 27-5
Average velocity - 1141.80 fps
Average energy - 457.6 ft-lbf
Standard deviation - 27.43
Min velocity - 1102 fps
Max velocity - 1170 fps
Spread - 68
True MV - 1144.39 fps
Coonan Classic
Average velocity - 1224.80 fps
Average energy - 526.4 ft-lbf
Standard deviation - 17.99
Min velocity - 1206 fps
Max velocity - 1244 fps
Spread - 38
True MV - 1227.58 fps
What did I learn from all this at the range today? First, I'm a bit of a numbers geek and this gave me plenty of numbers to look at.
Next, the Coonan more than holds it's own against the revolvers as far as bullet velocity is concerned. Even though it's effective barrel length is much less than the 2 revolvers, it was neck and neck or better as far as bullet velocity is concerned. 3. Even though the 27-5 has a 1 1/2" longer barrel, it consistently turned in lower velocities than the other 2 pistols. Just goes to show you how velocity can differ from pistol to pistol. 4. Even though the 296 reloads were the lightest of my 3 reloads, they were also the boomiest. And that held true in revolver and semi auto.
I hope you enjoyed reading my short story. I darn sure had a good time getting all these numbers.