OKAY. I'm no expert, engineer or theorist. I do stuff to see what happens I observe. So a couple of thoughts, just based on MY experiences.
Some guns fit some people better than others,just like limpwristing with semi-auto handguns do. A better fit for one individual does not mean a better fit for someone else.
Some guns do not like certain people. I have no problem with Glocks if a person chooses to use one, or is required to as it is an issued weapon. Glocks do no like ME. I open two boxes with two new guns, first gun I un-wrap the font sight is off the gun and falls on floor. Second gun is out back being shot. these are brand new guns mind you. The fellow has run a couple of mags. I shoot his new gun about a half a mag...trigger thingy breaks! OK Glocks don't like me and my gunbuddy will not let around one.
Same deal with Shotguns...some shotguns just don't like certain people.
Guns have certain ammo minimum req's, some defy, some are more picky.
Ammo is supposed to made to spec's, Sometimes the ammo gremlin goofs up a lot.
Chambers, Chambers, Chambers. Just like Mother-in-laws, you get all kinds, that behave all kinds of ways. Some are easy to please, some are gonna fuss no matter what...always have that bunch that like to meddle. Chambers have to work with the extractor( like the wifey). If MIL ain't happy wifey ain't happy and no matter what you do they will BOTH work against you.
Some chambers are become more easily dirty with plastic fouling and require more frequent cleaning. Some are not spec'd as long as should. [couple with ammo spec'd too long and problem compounded...]Some are more tight so if ammo is not spec'd as closely as should ( inexpensive priced loads) ...or...not re-sized properly ( one gun chamber is larger and not re-sized to fit the smaller of chambers) we have a problem.
Back to the Inertia dealie. Some guns need to held more tight/solid in order for system to work. So as mentioned before that extra weight with add-ons can effect the ability for gun to run. Or anytime on deviates from original gun other things can be affected.
Binding from too tight of bolts. Too short of bbl affects dwell time, and the weight increase "can affect" dwell time. Opening ports to run a certain ammo will cause another(other ) ammo to not run. If gun is too heavy for a good shoulder/snug fit won't run. Sometimes the more one tries to tweak the more they get into trouble. like no matter what you do you have MIL and wifey mad at you...always be nice to the dog and build a good dog house from get-go.
Lubrication. This Topic irks me to no end. We have way too many "line extensions" on products today. I have no problem with free market ideas, but can I just buy something without having to choose b/t regular/light/ reduced/improved/low fat/no fat/ babypowder or bubblegum scent?
Most folks over-lube - period!
Other bunch improper lube.
Most folks over clean the bores, never clean the chamber, extractor, or action.
Most folks are NOT going to run a bazillion rounds b/t cleaning and lubing as the "lube" states it can do, and recomended by the Mutant Bear Society on Mars.
They gotta mess with the gun, so they can eat off the bore, everytime there is nothing on TV. They never inspect and maintain the critical stuff. They do try all the new stuff that is ordered or store bought. They clean and lube new guns to try new cleaning and lube stuff...on a clean gun that has not been dry-fired...forget the live ammo...the monies went for "lube" instead of ammo or range fees.
The gun will tell you with use and practice and upon inspection at what intervals IT ( the guns) requires PROPER cleaning and lubing.
Make a tool, clean the chamber with 0000 steel wool or Scotchbrite, keep dry and clean, brush extractors and bolt face, and get the cut-out on chamber where extractor fits ( yeah that notch looking dealie) . Pipe cleaners work on ports...some folks don't even need the proper size "port drill " if you will to clean. Get one stuck and whoa boy...pipe cleaners are fine.
