Solid or lube groove?

[Huskerguy]

I am powder coating all of my bullets and looking at a new mould for 9mm. I picked up an NOE for 38/357 a while back and it works great. Now I am seeing more moulds with no lube grooves. What are the advantages or disadvantages either way?

As a side note, my 9's at this time are all CZ's.

[bmortell]

I did a thread like this a while back, some things are.

for me atleast regular lube groves fully obturate out flat when fired in some calibers, because there's nothing in them to resist. so I consider that less than optimal

also lube groves are just making it less mass efficient for length, look at a 44 keith boolit for example its basically a 38cal lead with driving bands sticking out. so your stuck with more outside or inside the case then you could have.

personally I think ordering with tumble lube groves are best for PC, because it provides a little bit of displacement room when sizing and when being squeezed by rifling, but not more than needed. plus its most likely the easiest design to stick powder too.

when I order for PC in mind I order TL grove that drops at a diameter where I could tumble lube and shoot straight from the mold if I really wanted but not so big to where your sizing down allot after PC'ing. then if your ordering with gas check shank I order .001 smaller but I guess that depends how it normally fits for you.

[Froogal]

I am a traditionalist I guess. I want the lube grooves and the traditional type of lube.

[Petander]

also lube groves are just making it less mass efficient for length, look at a 44 keith boolit for example its basically a 38cal lead with driving bands sticking out. so your stuck with more outside or inside the case then you could have.

Exactly. A thin bullet core. And lots of wasted powder space.

NLG bullets are also very easy to cast,bullets dropping from mold like rain.

https://i.postimg.cc/PqSdxjjR/IMG-20191125-001242-358.jpg

[kevin c]

I've got both styles in 9mm, all get HiTek coated. I've never learned to use traditional lubes.

I don't know what other folks have found, but my current favorite design has a lube groove. At the same cast weight and sized to the same diameter as other grooveless designs I have, it makes the same velocity as the other boolits with less of the same powder (loaded to the same internal case volume). Maybe there's a difference in friction from the reduced bearing surface. I'm not sure since it doesn't seem to apply to the other lube grooved designs I have.