Any opinion on how interchangeable / standardized the internals are across different platforms? Used to shooting them, but not working / swapping parts... don't want to start fitting metal if it needs recoated after?
What about within the same manufacturer?
I'd need to know more specifically what parts you are thinking of but there are many that do usually 'drop-in' and could be good enough but not necessarily give you optimum performance. Triggers and thumb safeties typically all have to be fitted by design. Many barrels labeled as drop-in usually still need some tweaking. While many parts such as extractors, hammers, sears, disconnectors, slide releases if they are not oversized usually drop in just fine that extractor typically still needs tuned and those action parts still need worked over if you want a good trigger pull etc (Harrison Design makes excellent kits though that usually don't need any tweaking and are what I use exclusively). I can only remember maybe two magazine releases and mainspring housings that had to be filed a little to work/fit properly (this doesn't count for cosmetic blending etc). If you just want them to fit most parts don't require any major refinishing. The part that would often require refinishing of the part and frame is a fitted beavertail. Fitting parts for function and aesthetic appeal usually requires refinishing. For instance most replacement extractors will sit proud of the slide so I want to file down and blend that to the back of the slide, same with ejectors. Thumb safeties after I fit them need a lot of external contouring so the edges of the safety correspond with the curves of the frame etc.
OK. Listen closely please. This is a lesson I learned long before sharing on Ingo was possible.
We all want to save a nickel and dime here and there. It is the way of things and I get it.
But "Anything involving the operation of a firearm should be respected. If you have the skills and the "Proper tools" then yes, have at it.
If not then either walk the path to learning and acquiring said tools (Yes a serious expense) or pair up with a competent smith. The ramifications can be serious.
Question....what are you considering.
Grips and guide rod/plungers etc. no worry's for the most part.
Anything related to the ignition controls are an absolute unless you really are aware of how they work and fit into the gun.
The 1911 is an old warrior. It has been mfg. by countless company's over time. The specs are all over the place due to this fact. If you buy some after market parts they are over sized because you have to fit them to the gun in front of you. Safety's especially and are most critical in fitment.
As much as it kills me to say this the Glock wins in this area as far as I can tell. Parts swap out easier frame to frame as they are made in the same place by the same people. Not sure about after market parts as I do not mess with Tupper ware but those who do have this advantage.
Be aware. Be cautious. A finely tuned 1911 is pure gun sex. An ill fitted turd is dangerous.
This. But to Polymer guns having fatter tolerances there still is room to build an unsafe Stryker/Hammer situation, just not as often. Witnessed a delayed Stryker release (4sec) last summer. Gunsmith Wannabee with a Dremel. Like CM says, very important are the fire controls.
Holy heck... this is why people should be mandated to know how to do basic safety testing before they are allowed to purchase a Dremel. Don't get me wrong we have done some homemade smithing before, but I always safety-tested the heck out of it. That's nuts.
Dsarge made good points as to Mag releases and such. Frame to frame they usually fit. Mainspring housings are usually close. Ejectors etc. But even they can need some attention.
My Concerns are towards anything Ignition or Safety.
Valid concerns but safety issues usually arise from operator error and not usually from swapping the parts themselves. Safeties are pretty straightforward either you don't over file it when fitting to the sear or you do in which case unless you have a welder you ruined the part (it may however work with a different gun/sear combo, you never know). When you swap out fire control parts you usually upgrade to quality parts like Wilson, Brown, Baer, EGW, Harrison, C&S etc. I've used them all either as sets or even mix-matched and never ended up with what I would describe as anything unsafe. The spec's on these parts are held pretty tight but something like a too long or too short disco or sear can cause problems. All good quality hammers have plenty of meat on the hammer hooks for starting out. The problem usually starts from people trying to do a trigger job that don't know how to do it. Cutting the hooks too short and improper sear engagement can cause problems. The biggest problem is usually a really light mainspring in conjunction with a sear spring set too light this can cause hammer follow. If you are doing the proper function checks though prior to shooting you discover this quickly and make adjustments. Once your gun has passed the function tests and you've checked for things like sear bump when you go to the range only start out with two rounds and then work your way up from there.