Testing Bullet Pull

by JimT, Texas, Saturday, April 01, 2023, 11:35 (538 days ago)

I was talking with Mic McPherson about the old H&R and how anemic most loads were, especially with .38 and 9mm bullets of .358" and .356" diameter. Mic told me that he believed it was because they fit so loosely in the cartridge that the primer was driving the bullets out of the cartridge before the powder fully ignited. I knew the bullets fit pretty loose because even with a heavy crimp you can spin the bullets in the case.

SO ... I decided to run a little test. A chronograph session would be ideal but ... Not being able to chronograph easily I decided to load up 2 different loads and fire the old H&R .38 S&W into a 2x4 and measure the difference in penetration.

I took 2 cartridges and sized them in the .38 S&W sizing die.

I took 2 cartridges and sized them in a 9mm sizing die.

I flared just the mouth of the cases sized in the 9mm die.

I used the .38 S&W neck expanding die normally for the cases sized in the .38 S&W die.

Not trusting the strength of the old H&R I used the Bear Creek 124 gr. round nose 9mm bullet sized .356". They will slide all the way into a case that is sized in the .38 S&W die. I slightly pinched the case mouth to keep the bullets from dropping onto the powder charge. Even with a heavy crimp you can spin the bullets in the cartridge.

With the cartridges sized in the 9mm sizing die I loaded one with 12 grains of 3Fg Goex black powder. That is a completely full case, compressed.
The other case I loaded with 3.0 gr. of Bullseye.
Both cases were clearly marked.

With the cartridges sized in the .38 S&W sizing die I loaded one with 12 gr. of 3Fg Goex black powder. Again a completely full case, compressed.
The other case was loaded with 3.0 gr. of Bullseye.
Again, both cases were clearly marked.

I fired all 4 rounds into a 2x4, spacing about a foot between the shots. I then measured the depth of penetration of each using a Browne and Sharpe dial caliper.

12.0 gr. Goex Black Powder
case sized in the .38 S&W die penetrated .540" to the base of the bullet
case sized in 9mm die penetrated 1.07" and broke the rear side of the 2x4

3.0 gr. of Bullseye
case sized in the .38 S&W die penetrated 1.109" to the base of the bullet
case sized in the 9mm die penetrated 1.487" and would have exited if it had not turned sideways

Recoil was noticeably more with the tighter sized loads

Take-Away: Bullet Pull Does Matter!

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Ele era velho.
Ele era corajoso.
Ele era feio.