Standard Bullet Weight for Caliber

[Alk8944]

Just a thought for you who shoot light or heavy for caliber bullets in your S&W revolvers. I have seen posts mentioning that the poster has gotten the best accuracy for a specific caliber when loading a standard-for-caliber weight bullet, specifically the .38 Special/158 gr. He opined that maybe This is the weight the cartridge was designed for Without knowing it he hit on a very true fact, the 158 gr. bullet is exactly the weight the .38 Special was designed around. If you look at all the S&W calibers you will find they all have a significant similarity, sectional density and length of the standard-for-caliber bullets have, actually, two similarities that are tied together, these are sectional density and bullet length. So what you will find by making a comparison is that bullets of the same length and profile will all have the same sectional density. They are also fired from barrels having the same rifling twist, which for center-fire revolvers is 18 3/4 inches!

So for the "standard" calibers you will see the following standard-for-caliber bullet weights:

.32 S&W Long, 100 grains +/- **
.38 Special, 158 grains
.44 Special, 246 grains

**As I recall the actual calculation was 115-120 grains for this cartridge, the same as original .32-20 factory ammunition. I don't know where my calculations chart disappeared to!

There are two exceptions, .41 Magnum and .44 Magnum. There is no "standard" cartridge for either of these, and bullet weight was determined more because the 246 grain .44 could not develop the desired velocity with the 246 grain bullet within safe pressures in S&W's and Remington's testing so they adopted the 240 grain. The .41 was sort of a hybrid having two variations with differing required velocities for different purposes.

So, because at least the .32 S&W Long, .38 Special, .357 Magnum and .44 special shoot the same length bullets through barrels having the same rifling twist rate, all will show very similar accuracy results. Except for the .357 they will also show very similar velocities when loaded to similar pressure levels. .357 is the exception that shows that velocity by itself is not a significant factor when it comes to accuracy!

 

[Ivan the Butcher]

Interesting. Thanks, for the info.

Ivan

 

[mikld]

When I start reloading a new to me cartridge, I like to start with the bullet the cartridge was designed for or the "standard bullet"; 38 Spcl., 158 gr., 9mm 124 gr., 44 Spcl. and Magnum 246-250 gr. Once I perfect, get used to reloading a specific cartridge/load I can then go with different weight bullets, 125 gr for 38/357, 115-147 gr for 9mm, 200 gr, up to 300 gr for 44 Spcl./ Magnum...

 

[jmiles1960]

I was at the range last week with my Model 66 and a box of 38 special 158 gr reloads. Actually did some of my best target shooting - much to my surprise. I was thinking - what a perfect bullet and load for the range!

 

[IAM Rand]

I was always under the impression that it was more the twist rate than for a specific cartridge. Now, having said that, I would not be surprised that certain calibers usually have a specific twist.

I addition to twist, I believe that velocity will also have something to do with it AND then you add in how close to the lands/groves. Most of that might be more specific to rifles but, I don't think that this should be discounted for some pistols---->revolvers.

 

[Nevada Ed]

I am a firm believer that matching the barrel twist to the weight and SD of a bullet, correctly
will offer the shooter the best performance in their guns.

Most low SD bullets are ok from 0-100 yards but at 300 yards with rifles,
a higher SD is needed due to gravity, wind, air resistance and elevations.

However, there is always a revolver or pistol that tosses these rules out the window
and shoots the very light or extra heavy bullets better, than the "Standard" bullet.