I had bought a red Nylon Jazz III pick a couple of years ago, somewhere around 2005-2010 that was unused for all of these years because I was primarily using a black Jazz III max grip. The red one was too slippery for me to hold and I didn’t like the dullness in the attack. After Troy’s pick videos, I decided to give the red one a try again and to my surprise I found it very comfortable to play, especially with economy/sweeping movements (which I started doing only since 3 years) and I also liked the tone, because it’s very dynamic with a soft touch. I solved the grip issue by drilling a hole into the pick. I then proceeded to buy a pack of the same type, plus the max grip version and EJ version. To my surprise all of the newer versions sounded way more thin and trebly and also feel quite a bit different to the touch, even the regular red Jazz III. I then examined the “vintage” Jazz III more closely to find out why it sounds so radically different. I noticed that it is made of a much shinier and smoother type of material, and it has a very smooth edge. The newer versions all are made of a different kind of material. (in the picture, the vintage one is the one starting on the left). The newer ones are much duller in looks, a different color red
and the edges are sharper. I doubt that the edges will round off with prolonged play, but I’ll give it a try. They feel like completely different picks to the “vintage” one. Has anyone else noticed something like this?
Many plastics harden with time. Fresh pick should then sound less bright than an old one. If your case is the opposite, and if the material actually did remain the same, they at least changed the molding die. Now it has sharper edges which gives a brighter tone.
Color is so easily manipulated in plastics that you can’t draw any conclusions. Good information could be had with an infrared analyzer. It might tell if the material has remained the same and it is insensitive to visual range (perceived color).
I haven’t experienced what you mention, but I am also a Jazz III player. I jump around between these:
- small black max grip
- small black
- small red max grip
- small red
I’ve noticed that for standard tuning on a 25.5 neck and 10-46 strings I prefer the red Jazz iii. For something with less tension (24.75 in standard tuning 10-46) I prefer the black Jazz iii. I’m just coming to these conclusions now. It used to be that one day I wouldn’t like the black as much, but I’m noticing that it’s related to string tension, and the black feels too stiff with standard scale length and tension. I’m not sure about the max grip, yet. Sometimes the max grip feels good, and sometimes the same pick without max grip feels better and doesn’t slip.
You’re just drilling a hold in the middle of the pick and you find that it helps the grip? I may have to try this.
This is a discursive post, but work posting leaves no time for editing 
I find it definitely helps. A few tips on drilling: the nylon red is a very hard pick. You have to take it slow with drilling, otherwise you can bend the pick by drilling with too much pressure. Also watch out when taking the pick off of the drill. I do that by grabbing the pick with pliers and putting the drill in reverse. If the pick slips from the pliers you could damage the playing edge, making the pick unusable, so hold the pick really tight. If you want the “ideal” hole, you should drill on both sides for a “clean” hole. I don’t do that, I drill them one way through for more grip. Then you get a pretty sharp exit hole. The edges are too sharp for comfort, so I smack the pick with a hammer a few times so the sharp edges get flatter. I play with the side of the exit hole touching my thumb, and the smooth side (where the drill went inwards) touching my index finger. Hope that helps.