http://www.tannersbrass.com/bullet-choices.aspx

What is the difference between Plated, Full Metal Jacket and Lead Cast Bullets?

(ref: http://www.berrysmfg.com/faq.aspx?q=8&c=1)

1. Plated - Berry's Preferred Plated bullets begin as a swaged lead core. The plating process works through electrolysis. The swaged lead cores are tumbled in an electrically charged cyanide bath containing high-grade copper ingots. The copper clings to the lead and the longer the bullets remain in the bath, the thicker the plating. Our bullets are plated to the correct size and then taken out of the bath.

2. Jacketed - Jacketed bullets start with a copper cup, which is "drawn up" into the form of a jacket. Lead is then infused into the jacket.

3. Cast - Cast bullets are made up of lead that has been poured into a bullet mould. These  come in various hardness levels depending upon the alloy of the lead. All of our cast bullets are lubed and all have the same hardness (about 20 bhu). We distinguish between Hardcast and Cowboy only in that our Cowboy bullets are often used in Cowboy Action Shooting events.

Bullet Comparison

1. Jacketed - Generally are most expensive but can be shot at magnum velocities and require less cleaning than Cast bullets.

2. Plated - Not as expensive as Jacketed and cleaner than lead but you'll want to stay away from magnum velocities when loading plated bullets.

3. Cast - Usually cost the least, but are very "dirty" and often cannot be used in indoor ranges.

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https://www.shootersforum.com/handloading-procedures-practices/80370-plated-vs-full-metal-jacket-bullet.html

Plated is simply electroplated copper on a swaged lead core.
Jacketed is a copper or gilding metal cup swaged around the lead core. There is no way to plate as evenly as a jacket and, in most cases, the plating is so much thinner and more delicate than jacketed. There are some thick plated bullets that get close to the thickness of jacketed, but they have to cost more as the time of plating is much longer. Then, most have to be struck twice to get more consistent exterior dimensions.
If one checks, I doubt that more than a very, very few Bullseye matches have EVER been won with plated bullets. For that accuracy game, cast/swaged lead and jacketed rule.
I find plated bullets to be less accurate than cast lead, swaged lead, or jacketed bullets in any of my guns.
To me, they made some sense several years ago when they had a price between cast and jacketed and the action pistol folks couldn't live with ANY smoke from lead bullets.
Currently, they are priced right with the best from Montana Gold and Precision Delta. Thus, I see them as being a waste of money at the current time.
The only reason I think that plated are still selling well is that the local gun stores carry them--they only carry the "big boy's" jacketed bullets, so the plated look like a good deal. Ordering bulk jacketed over the 'net is a "better" way to buy better bullets.
Buy a case of 124gn JHP from Montana Gold and have fun. They are VERY accurate and run just over 8.5 cents a bullet for one case--they were about 7 cents a bullet 6-12 months ago, but all bullets have been going up in price.