Test Gun: Colt 1911 Government, Defender.
Barrel length: 5 and 3 inches.
Ammunition: Underwood .45 ACP 185gr +P Bonded JHP.
Test media: 10% Clear Ballistics Gel.
Distance: 10 feet.
Chronograph: Caldwell Ballistic Precision Chronograph G2.
Five shot velocity average: 1162fps
Gel Temperature 70 degrees.
*Note* This test was conducted with Clear Ballistics Gel. Clear Ballistics is a synthetic gel and does not correlate with Organic gelatin like Vyse Ballistics gelatin.
Today we try out Underwoods’s .45 ACP +P using the Speer 185gr Gold Dot bullet. This will be the first in three of Underwood’s .45 ACP using the Gold Dot bullet. Later we will try out the 200gr and 230gr, both at +P pressure.
This load had a bit of recoil and muzzle jump. Much more then I would have thought. In fact, it was enough that I would not consider this load based on this alone. I also had three failures to feed. All of them were from the bullet moving forward in the magazine and engaging the slide stop.
I got a five-shot velocity average of 1162fps with a high of 1191fps and a low of 1103fps. This gave an extreme spread of 88fps. Underwood claims 1200fps.
Starting with the full-size government model into bare gel I got a velocity of 1200fps. The bullet penetrated to 11.25 inches and expanded to .86 inches. The recovered weight was 184.25 grains. The second round’s velocity was 1173fps and it also penetrated to 11.25 inches. It’ recovered weight was 184 grains and it expanded to .82 inches.
Shooting the gel-covered with heavy clothing the first round’s velocity was not recorded. It penetrated to 14.75 inches and expanded to .66 inches. It’s recovered weight was 185.5 grains. Round number two’s velocity was 1154fps and its penetration was 13.25 inches. The recovered diameter was .68 inches and the weight was 183.5 grains.
Using the 3-inch Defender the first round in bare gel had a velocity of 883fps. I thought it must have been a bad reading from the chrony but after extracting the bullet it showed much less expansion at .71 inches. You can see that the bullet expanded but did not fold back as is normally the case with this bullet. The recovered weight was 184.5 grains and it penetrated to 12 inches. The second bullet hit the block at 994fps and penetrated to 13.25 inches. The recovered weight was 183.5 and the diameter was .72 inches. Although the recovered expansion was only .01 different, you can see that at some point during it’s trivial through the block the expansion was greater as seen by the peddles folding back
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