Questions about lube groove on mould

[Kermit2]

I just purchased a used Lyman 429421 single cavity mould. It's in excellent condition and seems to cast nice boolits. I also have a Lyman 429421 that I purchased new a couple of months ago. I've noted that the older single cavity mould has a lube groove that has a rounded contour while the lube grooves on the new double cavity mould have a square contour.

Is one type of lube groove superior to the other, and provide better protection or lubrication? While lubing bullets cast with the older mould with the rounded lube groove it seemed to be a little more difficult to get the groove to completely fill with lube on the first try and often had to put the boolit through the sizer a second time to fill the groove with the lube. Is this my imagination or has anyone else noted that? Also, does the square contour lube groove hold more lube than the rounded one? Your input and experiences will be appreciated. Thank you!

[462]

Elmer Keith designed the 429421 with a square lube groove, and got upset when it was changed to round. The square groove holds more lube, the rounded one will probably drop easier.

My mould is an older, two-cavity, square groove version. I've no experience with the round version. I have no idea if one is better in any way than the other.

[GaryN]

Maybe you just need to adjust your sizer die to allow the bullet to go a hair deeper. Also pump up the pressure a little more. All mine are square lube grooves so I'm just guessing.

[GP100man]

The square 1 holds more lube , but in handgun length barrels either will hold sufficient lube.

When ya get to the longer barrels is when more lube will be required .

Sounds as if ya need a little heat on ya sizer , really according to the type of lube ya using , some lubes will move without heat but tend to "shear" or be more crumbly , that`s when heat comes to play.

[rintinglen]

I have a 4 cavity 429-421 with round lube groove which replaced a two cavity with square groove. I much prefer casting the round groove, they come out of the mold much easier. The old Ideal used to give me fits pounding on the hinge trying to get the boolits to drop out. I couldn't tell any difference between them shooting wise.

[cajun shooter]

I find that the square edge lube grooves are much better for holding the extra lube that is needed for rifles as has been posted. They also work better if you are shooting real black powder.

[mroliver77]

When we did some group buys on Kieth type boolits there were arguments about this. I prefer the round groove as they drop easier from the mold. I lost and my 454423 has the square groove. It can be very persnickety about letting go. The reason given by the square groove crowd was lube capacity. Well back in the day it might have been an issue. Todays lubes provide plenty of protection with the reduced capacity of the round groove. Heck, with Felix lube I can shoot the Lee tumble lube boolit designed for the 7.62x39 in my M1A with complete satisfaction!
Jay

[MtGun44]

Good info. I have had good luck with the rounded groove versions, and never noticed
any dropping issues with the flat bottomed versions. I prefer the flat bottomed, more
lube is good and for historical reasons, too.

In any case - a great design. Basically, Lyman has gone back too the original Keith
designs in the last few years with 429421 and 358429, both and current production has
the original flat bottomed design. Not certain about 452424, or even certain that they
still catalog that one. Also, Lyman molds have really drifted over the decades, but seem
to be a lot closer to the original intent these days than in decades gone by. Some are
unhappy with their QC, but others have gotten good molds.

Bill

[casterofboolits]

Good info. I have had good luck with the rounded groove versions, and never noticed
any dropping issues with the flat bottomed versions. I prefer the flat bottomed, more
lube is good and for historical reasons, too.

In any case - a great design. Basically, Lyman has gone back too the original Keith
designs in the last few years with 429421 and 358429, both and current production has
the original flat bottomed design. Not certain about 452424, or even certain that they
still catalog that one. Also, Lyman molds have really drifted over the decades, but seem
to be a lot closer to the original intent these days than in decades gone by. Some are
unhappy with their QC, but others have gotten good molds.

Bill

I have two each of the round and square grease groove Lyman four cavity 429421 moulds. all at lest 25 years old. I got the same accuracy with both grease groove types.