I know there is a velocity limit for plated bullets, and it seems different depending on the brand, and bullets size/style.
The specific bullet in question is a rainier 9mm 115gr FMJ. Rainier states not to exceed 1500 fps.
Using quickload to run some simulations, for one specific load, out of a 4.9 inch barrel it would be around 1240 fps. So out of a pistol, it's ok. However I also have a PCC with a 16 inch barrel. When I change the barrel length to 16 inches, the velocity increases to 1549 fps. 50 fps past their "limit". According to the simulation, it hits 1500 fps at around 13 inches, then gains the last 40 fps the last 3 inches.
Is 50 fps enough over their limit to worry about?
So I was wondering, what happens when the velocity limit is exceeded, and how much (past the limit) is too much?
I assume the bullet no longer catches the lands and instead of spinning, just pushed through the barrel (kinda like when the threads of a bolt or screw "strip out"). How would you know if this has or is happening? Would you have to check the bore after each shot?

The plating will come off and can lead up the bore. Your accuracy will also be pretty bad if they are pushed too had. You'll start getting keyholing.

Evertime I've tried to use plated bullets, I've gotten really poor accuracy unless I load them super light. I gave up on them on supersonic calibers quite a while ago and I hope to never have to shoot them again.

I'd load them pretty light and see how they do.

They will strip in the rifling.

You know it is happening when you see lead in your bore and you can't hit shit.

I wouldn't drive them over 1200 no matter what the "literature" says, and 1000 would be better.

Just treat them like cast bullets.

I haven't used Rainier bullets, so I didn't comment on this. Maybe their plating is significantly thicker. I don't know. However, this has been my experience with Berry's and Xtreme bullets as well. Berry's standard plated bullets say not to exceed 1,250 fps. I couldn't get decent accuracy until I was well under 1,000 fps. These things really don't like to be driven hard at all.

That's why I ditched them and went back to FMJ's. Plus during normal times you can pick up FMJ's for about the same price.

Well thankfully I only have a box of 100 of these. I was really wanting to be able to use them in my carbine, but if I can not, that is ok. I shoot more 9mm out of the carbine than I shoot my pistols, hence the reason I was wanting to shoot them from the carbine. It likes hotter ammo to cycle fully/properly. Guess I will just load these for the pistols and stick to regular jackets for the carbine.
I also have about 300-350 100 grain 9mm berrys plated bullets I was hoping to be able to use. I guess those are out of the question as well.

The heavier the plating the better it holds up.  I have run the X-Treme 150-gr 30/30 bullets in a .300 BLK load at 1700-ish FPS without issue.  Wouldn’t try for more than that but for a plinking/practice load it is fine.

In pistols I use a lot of plated Bullets.  Again, X-Treme is my favorite.  In .45 ACP or any of the special revolver loadings you have zero worry.  In supersonic pistol loads stick with the plated suppliers that use heavier thicknesses like X-Treme.

But with the rise of coated bullets you can do much of the same.  I use a coated 158-gr now for cheap .300 BLK rounds at the same speeds I ran the X-Treme for under 9 cents a bullet.  Can’t beat that.  I still prefer plated in my semi-auto pistols but am experimenting with coated in 9mm.

Firing properly loaded plated bullets at high velocities does not cause the plating to separate and/or lead the barrels. That is simple internet hype. What causes plated bullets to fail is simply handloader error, i.e. over crimping or worse, roll crimping the loads so that the case cuts through the plating. It's that simple.  Load them correctly and they work fine.  Screw it up and they don't.

The caution the manufactures put on the velocities is purely to limit liability, i.e. the lawyers want it.  I talked to the owner of Rainier bullets a number of years back and he confirmed that the limits are there because they don't control how their bullets are loaded and therefore the lawyers insist that they establish some limits to limit any legal exposure.  Not because the bullets can't take it but because there are idiots reloading them incorrectly. It's also true that like plain lead bullets, they aren't precision bullets made for high velocities.

Further, he stated that if loaded correctly (not cutting through the plating by over crimping or roll crimping) that they can be driven at high velocities without any issues.  They may not be as accurate as precision bullets as they obturate into the rifling more than fmj, but their plating won't peal off if loaded correctly and driven fast.

Like dryflash3, I've fired 10s of thousands of .357Mag, .40s&w, 10mm, 45acp, 45Super, .30 carbine, and even .308 plated bullets at high velocities, the .357Mag over 2,000fps, the 10mm over 1,550fps, the 45 Super over 1,300fps, and both the .30 Carbine and .308 over 2,000fps without a single plating failure.  Zero leading of the barrels.  Further, I've recovered dozens of fired bullets and found the plating intact on every one.  Some bullets are flattened to pancake shape and the plating still hasn't failed.  Why? Because I take care and don't over crimp, that's why.

If you lead your barrel or lose the plating on your bullets, blame the reloader, not the bullet, because you screwed up, not the bullet. That's the real reason that many blame plated bullets.  They screw up loading them but won't take the blame for doing it wrong so they blame the bullet. In fact, most shooters I've listened to claiming that high velocities caused their bullets to lose the plating come from the 'everyone gets a participation trophy' era and have never learned to take responsibility for anything they do.

I have pushed RMR plated up to 1350fps out of my 357 magnum with no ill effects. No barrel leading or accuracy issues, no plating separation I can see on recovered bullets.

I was under the impression you do not crimp 9mm or other straight walled rimless cases that headspace off the rim. You simply remove the bell you made to seat the bullets.

Definitely dogs and cats living together, basically, mass hysteria.

BTW, Speer makes a big thing of the fact that their Gold Dots are 'bonded' rather than plated bullets and are good for any velocity, right?  Do you know what bonding is?  It's another word for 'plating' because when you 'bond' a copper jacket to a lead core, you do it by depositing atoms of the copper on the lead, i.e. plating it.  

So plating is the process of applying a metal coating on another piece of metal (or another conductive surface) through an electro-deposition process, i.e. bonding the copper to the lead. In electroplating, the deposited metal becomes part of the existing product with the plating/coating. i.e. it bonds to it.

So that's what Speer Gold Dots are, they are plated bullets that they advertise as bonded (which is actually another word for plating). Look closely at their bullets.  You can see that they start with a formed lead core, bond the copper to the lead by plating the lead core with copper, and then restrike the completed bullet to form the HP by punching through the plating at the nose.

A Rose by any other name . . . . .

The real reason that you just want to remove the flair in the case mouth when crimping with a taper crimp die like Lee's is that over crimping actually loosens the bullet in the case rather than tightening the bullet up.  The reason for that is that lead doesn't 'spring back' while brass does which creates a loosely held bullet. Over taper crimp it enough and you can pull the bullet out with ease.

Sir:
I'll respectfully disagree with your comments here.  
"Plating" is it is used here is taking a lead core and building up a copper coating over it.
That is how you get the "Extreme" plating.... it is thicker by building up the layers.  
   
That is NOT the same as the process Speer uses.  
They insert a lead core into a copper jacket and fuse them together.
Their jackets are NOT formed in layers and much thicker than any plated bullets.  

https://www.speer.com/performance/gold-dot-performance.html  

Lead base? If so the base could melt and cause leading.

I pushed some Rainier 158 grain plated bullets to almost 1900 fps from my 77/357.   Accuracy sucked, but the bullets held together.    The same load data with Hornady 158 grain XTP bullets were far more accurate.    I tend to keep plated bullets for subsonic stuff and they do quite well in that capacity.