I've never used Underwood on account of the fact that it's expensive ammo which has a tendency of being loaded very hot, sometimes in excess of SAAMI Specs, and in some cases uses exotic projectiles of unusual shape.

Semiautomatic Pistols can be finicky in terms of reliability once you step outside of the ordinary in terms of ammunition. Ammunition that is loaded hot or with unusual projectiles tends to be less reliable.
In addition, this is why I never buy SD ammo in large quantities, no matter how low the sale price may be until I have confirmed that it functions reliably in my firearms.

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Shooting Comfort is bilateral.