Can thumb safety affect trigger pull?

[darwin-t]

Can an improperly fitted thumb safety cause the trigger pull to increase?
I have tried an ambi from one of my 1911s on a different pistol and it seemed to me that the trigger pull was heavier, but I do't have a trigger pull scale to check it.

If so, what part of the safety would affect it?

Thanks

[1911Tuner]

Yes it can. The thumb safety lug has three points on it. One blocks the sear by contacting the rectangular pad on the sear when the safety is in the "safe" position.
When it's off-safe, the opposite pad can sometimes make light contact in certain pistols with certain thumb safeties. It's usually a matter of tolerance stacking.

You can determine what is causing it by assembling the gun without the grip safety. That willallow you to look into the area and see where the bug is, and stoning to create a little clearance on the contact area of the lug's point. Don't remove any from the one that blocks the sear. Be sure to correctly identify the one that's causing the problem.