John,
Yep I use a gas-check on every bullet that can accept one!
No matter what the speed.

Rule 303, no problem sending you some bullets, PM your address across and I'll get some going.
The heavier bullets do quite well out of the Taylor, but you need to "get up them" a bit more, my barrel is a 15" twist, and with the 445 grain CBE, they don't keyhole, but must be on the edge of stability, as they don't shoot as well as everything else.

Neale, LBT stands for "Lead Bullet Technology" a company owned by Veral Smith in Idaho, he makes bullet moulds, top punches, a really good book on getting real speed out of cast bullets, and a very nice lead hardness tester. His bullet designs are supposed to be very good on game, especially his WFN (wide flat nose) designs. Mainly makes aluminium moulds, they are made using a tracer lathe.

NEI stands for North East Industrial, a mould maker, now in Texas. The company was founded by Walt Melander, a very knowledgable cast bullet designer and mould maker. He has now passed on, and his son-in-law and daughter now own and run the business. He makes mainly aluminium moulds, cherry cut, in lots of odd calibres and designs.

CBE stands for "Cast Bullet Engineering", an Australian company in Sydney, owned and run by Jim Allison. Makes brass moulds in heaps of calibres and types. Where I got my Bore Gun mould from. Moulds are made using a cherry, makes top punches to suit using the same cherry for an exact match.

I normally fill all the lube grooves up with lube, just because they are there, but if I had to seat a bullet with lube grooves exposed, and I was carrying them in the paddock, then I would not lube the exposed ones, as it might pick up dust or dirt and potentially scratch the barrel. For the range, I'm not worried about a lube groove or two being exposed.
If I'm getting a nice moist "lube star" on the muzzle of the rifle, then the lube is about right, and doing it's job properly.

Regards,
DC