Marking the surface of a bullet mold???

[Agarbers]

I recently bought a Lyman mold 311 284 on an online auction. I didn't read the description fully and it came with dimples in the mold cavity. It appears the previous owner used a center punch to put two small dimples in one cavity and one dimple in the other. When I saw that I freaked out and re-read the auction description and found where the seller disclosed this and said the user did it to identify which cavity a bullet came from. Is this a common thing? It seems like it would lessen accuracy. A would appreciate any thoughts on this.

[country gent]

It used to be more common to see. Most marked one cavity on a 2 cavity mould so bullets could be shoot separate from each cavity. Most were marked on the nose. Some used a small center punch, others a letter stamp that was symmetrical like 0 x 8 I. When done right there was little to no difference in the 2 bullets from the marking. It was meant to nullify any variation in cavities by keeping them segregated

[pworley1]

I put the dimple in the lube groove.

[MT Gianni]

It is no longer a common thing as few shooters are as concerned about accuracy combined with more molds are made with cavities with close tolerances. Shooters would use one cavity for matches and align the bullets with the dimple in the same place in the chamber. Therefore the dimple must be visible in the finished product. Done that way there is no detriment to accuracy, probably an improvement.
Cast with it and take 10 rds to the range. Shoot 5 marked and 5 unmarked or double dimpled after you measure the first round of 5. I will wager the second 5 will fit in the same group as the first. It almost takes a bench gun to see the difference.

[Agarbers]

Thanks, everyone. I feel better.

[beagle]

Another marking method you'll see is a slight stoned place where the cavity halves come together. Usually on one cavity, Again, this was done to be able to separate bullets from different cavities. When sorting, the small flashing was scratched off with a thumb nail and no harm was done as to appearance or accuracy./beagle

[Dragonheart]

If you powder coat, the powder may flow into and possibly fill and cover the dimples, depending on where they are.

[kevin c]

That's a neat bit of casting lore that I never would have guessed.

It's truly impressive the depth of experience to be found here. I note that, among themselves, the responders to the OP have over 30,000 posts and 50 years on line here.