I messed with this when running a p35 yesterday. For me the administrative benefit of riding and therefore running the safety outweighed the advantages to shooting performance it might provide. In other words it's really important to me to ride the safety -- down when intending to shoot and up when not intending to shoot.
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I played around with this at the range last week. I found my performance is dramatically better with the thumb curled down. I always shot thumb flagged previously but here we are. Learn something new every day lol
I work with both 1911 and Glock. I ride my safety on the Kimber and on the Glock I do the Nyeti wide thumb wrap with the strong thumb when using both hands. Support hand is thumbs forward wedge grip. On both guns when shooting one handed I notice a more consistent press with less sight disturbance if I lock my thumb to my middle finger.
pat
After doing a mountain of SHO and WHO shooting last week at Rogers (I shot many of the freestyle drills SHO or WHO just for the extra practice where I needed it most), I found yet another instance of what we think we do, isn't necessarily what we actually do. Despite what I say above, I found myself doing a lot of the one-handed shooting with my thumb in a fairly relaxed, ill-defined position (straight forward, neither up nor down.) It worked ok. My subjective feeling, which I do not really trust, was that I had better control of the trigger from less general tension, which was the overriding need in that context. I know other people get more mileage on that with the thumb up or down. Will have to test it with some Bill Drill type stuff and see if it makes a difference for me there.
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Don't know if you noticed, but instructor Adam shot his SHO demos with his thumb pointing forward but held under tension.
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Latest post: The Rogers Shooting School Experience (15 Jul 2014)
Technical excellence supports tactical preparedness
Lord of the Food Court
http://www.gabewhitetraining.com
Mike Seeklander teaches thumb flagged up. His reasoning being to maintain even pressure along the back strap of the gun. He also teaches to maintain vertical orientation of the gun when shooting one had, as opposed to canting slightly inboard.
I have always shot with my thumb up slightly when shooting SHO or WHO. I used to cant the gun slightly inboard, but am moving away from that.