I did not plan on shooting this drill today but I decided to mess with various glasses and found something interesting.
Normally my shooting glasses have some magnification (.75). As a result, I can see the front sight clearly but long distance targets are slightly blurry. Today I decided to try regular shooting glasses to experiment with target focus vs sight focus shooting at distance.
First, I shot a Bill Drill at 25 yrds without the prescription glasses and was surprised by both time and hits. Normally I can shoot the 25 yrd bill drill around 4.5 sec with a couple of Cs if not clean if everything (Grip) goes okay. Without the Rx glasses my first run was 3.75 sec with one very close C. I shot again - 3.98, with one C. So I swapped the glasses and got 4.25 sec with three C's wearing the Rx glasses. After a while I found that I was definitely faster without the Rx glasses and my accuracy was the same or may be even better on this type of open targets.
So I decided to shoot the GM drill. I used to shoot it a lot when I was shooting Production to practice the DA trigger.
USPSA Limited rig: 40SW CZ TSO, DAA holster. No Rx glasses
1st run - 3 Cs. With major scoring - 52 points
2nd - 1 C (the head shot) - 54 points.
I have to admit that the head shot was actually more difficult without the Rx glasses. So for the tight partial targets (Zebra, for example) it may be not worth it.
Today was a sunny day. I am not sure if I would have the same results indoor or under different light conditions but I am going to explore this further.