Smith 41 barrel interchange

Just received a Smith 41 I had been wanting for a while and have been waiting on a red dot mount. Was dying to shoot it so took it to the range with a friends 41 who happened to have an extra 7in barrel with irons on it. Figured I could swap barrels for a bit until my scope mount comes. Well, we're a bit baffled as my barrel fits his gun, but his barrels will sit on my rails but the trigger guard feels like it would break something if it were forced. The serial numbers on the guns are both UAK2XXXXX and only 480 digits apart with mine being newer. Havent had time to start taking calipers etc to it yet but any adjustments or things I should be looking for? Not going to try to force them at all.

When my 7” version was taken apart the first time I was afraid the trigger guard might break. Different problem than what you experienced. Some barrels just fit tight. Clark said their barrels are drop in for 90% of M41. The rest require fitting.
After removing the barrel on mine the trigger guard was still stiff. Oiled up the pawl and it slowly improved. Think it is a sign of tight lockup.
The trigger guard is stronger than it looks. After getting it halfway open the first time, it locked up. Almost used a hammer to close. Figured if it snapped S&W could replace.

My old A model, bought used, had the barrel peened for a better fit to the frame. No doubt there are tolerances in play. Whether or not you'd want to swipe a fine file down the sides is up to you. I'd look for burrs to clean up first.

And you can always expand a new barrel to fit the frame if it gets opened up a bit. If it even matters.

well if you want to fit the barrel that is too tight simply file this side of the locking lug on the barrel.. Go Very slowly least you take too much off.. best to use a file with a safe edge on the top so you don't cut the other lug side

WEll the fun continues with this gun, got my rail in so I could mount up a red dot and noticed that the barrel on the rail (as factory, no tweaking yet) has a lot of movement. This gun appeared to be new when I bought it and had no sights or rail on it. Either the first owner got tired of it quickly or didnt want to work thtu its issues. You can definitely feel the barrel move with even a moderate grip. Other 41's I have used dont seem to have any movement, but I didnt specifically look for it either. Anyone have this issue? I think its going back to the factory shortly unless I find a easy solution.