150 grain Sierra in a .357 Magnum

[JGalt]

I found two vintage 100-count boxes of Sierra 150 grain .38 caliber (0.357") hollow cavity bullets at a flea market for pretty cheap a few weeks ago, and worked up a load for my 6" barreled Ruger GP100. The bullets were made in the 1970's and they're an uncommon weight, so not much published handloading data could be found for them.

Looking at the powder I had on hand, I first worked up a load with Hodgdon H-110 and Winchester magnum primers, resulting in an average velocity of 1332 fps. Not happy with the accuracy, I next worked up a load with the magnum primers and Alliant Blue Dot powder, resulting in an average velocity of 1467 fps, which was a little hot. At that velocity, the primers started flattening out a little, and the accuracy wasn't what I wanted.

The next thing I did was to use standard small pistol primers instead of the magnum primers, and worked up the load to a comfortable ~1360 fps. That gave me a good compromise between power and accuracy, so I went with it. The final load I used was 10.5 grains of Alliant Blue Dot powder, Winchester WSP small pistol primers, an overall length of 1.570”, and a good crimp.

Like I said, the pistol I used to work up the load is a 6" barreled Ruger GP100. The cases showed no signs of over-pressure, such as cracking or splitting, and the primers showed no signs of flattening out or piercing.

A six-shot group fired at 25 yards gave me the following velocities in fps, measured by a Caldwell Ballistic Precision chronograph placed 10' in front of the muzzle:

1367
1379
1363
1355
1359
1340

This was an average of 1360 fps and the standard deviation of those six rounds came out to 11.856, which isn't too bad of a spread. Six rounds at 25 yards fired from sandbags under my wrists resulted in the following group:

The next thing I did was c-clamp six pieces of 1/8" tempered Masonite to see how that round would penetrate. I fired one round from 10' away and this was the result:

Comparing this load to commercially-available ammunition, only two companies offer this weight bullet in a .357 magnum. A company named "Grizzly Ammunition" has a 150 grain @ 1400 fps, and PMC Ammunition @ 1200 fps. The optimum velocity for a 150 grain .357 magnum bullet is about 1350 fps, which is why I chose that.

Incidentally, I did find published data after the fact, in a 1995 Nosler bullet reloading guide. It showed a 150 grain soft point using 9.8 grains to produce 1302 fps, 10.3 grains @ 1397 fps, and 10.8 grains @ 1492 fps. That's pretty darned close to my 10.5 grains for an average of 1360 fps, considering all the variables involved.

 

[toobfreak]

I found two vintage 100-count boxes of Sierra 150 grain .38 caliber (0.357") hollow cavity bullets at a flea market for pretty cheap a few weeks ago, and worked up a load for my 6" barreled Ruger GP100. The bullets were made in the 1970's and they're an uncommon weight, so not much published handloading data could be found for them.

That is odd, I just lost a couple of boxes of old Sierra 150 grain hollow cavities at a flea market a few wees ago!

This was an average of 1360 fps and the standard deviation of those six rounds came out to 11.856, which isn't too bad of a spread.

Especially considering who loaded them.



Seriously, nice test and documentation JG, and good read.

 

[JGalt]

Now for a real test: I have a five gallon bucket full of fine sand that I use for clearing weapons. I put a cloth over the top to keep from splattering sand all over the place and fired one round to check for three things:

1. The bullet properly expanded

2. That the copper jacket didn't strip off

3. That the bullet didn't fragment into a bunch of pieces.

Here is a picture of the result:

At the muzzle, this round had a calculated 616 foot pounds of energy, and drops off to 472 ft-lb at 50 yards. For comparison, a 158 grain FMJ Blazer 38 Special +P traveling at 850 fps has 253 ft-lb of muzzle energy, a 147 grain JHP Blazer 9mm at 950 fps has 295 ft-lb of muzzle energy, a Federal 180 grain JHP 44 magnum traveling at 1160 fps has 896 ft-lb of muzzle energy, and a 185 grain FMJ Winchester 45 ACP with a muzzle velocity of 910 fps has 340 ft-lb of muzzle energy.