You mean you want to install a beavertail grip safety? IIRC, the Ed Brown beavertail is for a Commander style hammer and will interfere the standard Goldcup hammer, so your in for a new hammer and trigger work if you don't have that already.
Otherwise, no problems. I have one the Ed Brown fixtures and it is pretty hard, so the file slips right over it. I dress the result by draw filing with a chalk loaded fine mill-cut (don't want to trip the word filter with the actual term) file. I just used Oxpho-blue on the exposed steel, as it is covered pretty well by the safety.
After that, the extension from the safety that blocks the trigger had to be filed at the nose on mine until it didn't rub the trigger bow as it engaged. I also had to file a little up under that extension so the trigger bow would slip under it freely when the trigger is pulled. That's something you can file until the safety just engages enough. That way your grip doesn't have to be perfect to release it. I also had to file a little off the bottom of the safety behind the two retaining feet in order for it not to rub on the mainspring housing.
Once you've done all that work and have the safety in place, I think you'll be happy with it. The standard safety always rubs the web between my thumb and index finger until its red. For long shooting sessions the beavertail is much more comfortable.
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