2 different Lyman 457125 molds

[sse]

I have 2 sets of Lyman 457125 molds.
1 set has round grease grooves as throws 489 gr. of WW
The other has square grease grooves and throws 478 gr. of WW
Starting to load for a Win. 1885 that I just got and while looking at what molds I have for it, I came up with these 2.
Anybody have any thoughts or info on them?
Thanks

[15meter]

I have read that the weight of the boolit cast varied over the life of the cherry used to make the molds. I had not heard of the profile changing dramatically.

I have a couple of 452460 molds that cast considerably different weight boolits. I don't recall the profile being radically different.

May have to dig them out and cast some with both (or 3, don't remember if there's a third mold) just to compare.

I think Elmer Kieth was the one who insisted on square grease grooves. I think he was looking for maximum lube volume.

I always thought square grease grooves made it harder for a boolit to come out of a mold. Rounded grease grooves just seem to drop easier.

Lyman probably changed to the rounded groove to reduce complaints about boolits not dropping and kept the same number for simplicity of inventory.

[Larry Gibson]

With the modern lubes of today [actually the last 65 +/- years with the introduction of the NRA 50/50 lube] the big square lubes aren't needed. Exception being with bullets for BP shooting. I never found the square groove bullets with smokeless or BP lubes to be any better than round grooved bullets. As mentioned, I have found the square grooved bullets to be harder to release from a mould unless the "square" has a slant to it.

Be interesting to see a side by side accuracy test with all else being equal except the bullet groove shape?

[sse]

Yes, the square grooves do not drop out as easy as the round but they seem to be a little more consistent by weight.
I will let you know how the side by side accuracy test goes.
Thanks guys.

[sse]

Well, I just fired a couple of groups. I was planning on 10 shot groups but failing light and it is just too darn cold.
The round groove 6 shot group ( I thought I had missed the paper on first shot) went 3 1/4", nice rounded group.
The square groove 5 shot group went 3 3/4", not as nice but I think under better conditions it might shoot as well as the other.
All loaded the same, 25 gr. 5744 seated out to touch. All cast out of same batch and shot at 150 yards.
A little warmer and 10 shot groups will tell.

[Green Frog]

It has been related that when they wore out a cherry at Lyman, the person who cut the new one would often change the design slightly. In fact, at one time they stamped a code letter on the block to indicate which cherry was used. I don't know what the life cycle of cherries cutting those meehanite blocks would have been, but when patterns were popular and made for over a century, it's a safe bet the cherries wore out and had to be replaced.

I for one will be very interested to see what kind of results sse will get when he does side by side in a controlled manner. I have great respect for Elmer Keith, but I've never seen it written that he showed why his favored square bottom lube grooves were superior to those with round bottoms. There are a lot of truisms out there that just don't stand up to real world testing.

Froggie

[Good Cheer]

Lyman would change designs as time went on. Changing grease groove configurations, sometimes the plug diameters on hollow base molds and sometimes the entire bullet like with #454613. Another thing was that when they found cherries had been inserted a tiny bit too deeply into the blocks then the pile of rejects built up over time. Got some great molds for amazingly cheap prices when they sold off the "factory seconds".