Troubled Lyman 457406 mold

[Don1357]

I finally got to cast with the mold I bought a while back. After cleaning it I noticed the one side has corrosion marks that are texturing one side of the boolit. On the picture it probably looks worse than in person but it should give you the gist of it.

In addition the first band is .460 the second a smidgen shy of .459, and by the time you get to the 4th one .455.

Thoughts?

[EDIT]

For the record it is dropping +/- 2 grains around 500gn, using CWW + 5% tin. I didn't mean to make it that rich but I screwed the math...

252543

252544

252545

[Gewehr-Guy]

That little bit of pitting should not hurt that bullet one bit. I have a rather rare Lyman 311403 in a 4-cavity, which has been bead blasted before I acquired it because of a lot of fine pitting. One cavity had some pits on the nose at the parting line, that caused little lumps of lead on the nose the size of grains of sugar. When I shot them I never noticed them to create flyers, but I was shooting them with open sights, maybe with a scope I would have noticed a difference. Later I filled the pits with Liquid Steel with the tip of a toothpick, and that stayed in the pits for many bullets, need to do it again.

[LIMPINGJ]

The base is what steers so I cull for perfect bases. Defects on the nose don’t seem to open groups at normal hunting ranges.

[Don1357]

The base is what steers so I cull for perfect bases. Defects on the nose don’t seem to open groups at normal hunting ranges.

That's the thing I wanted this guys to play at long range shooting with open sights. For hunting (which I haven't done yet) I was planning on using a RCBS 457-405 FNGC

[country gent]

try them and see how they do in your rifle. Taking the taper out and getting each band right is going to be a big job. As to the roughness on the nose. What is the nose dia as cast? This may determine ehat options you have. If its not affecting bullet release from the mould I would test them before going farther. toothpaste or auto rubbing compound on just the nose and turned by hand in a tapping type motion back and forth in partial rotation segments thru a full rotation or 2 may clean it up some. Nose dia will determine what can be done

[Don1357]

The nose ahead of the seating band is 452~454.

[Bird]

Where are you measuring the bands? At 90 deg to the parting line, or 10 degrees off the parting lines?
My Rcbs mold was doing a similar thing.Larger bands at the top of the bullet and almost 4 thou smaller at the base. The bullet measured .458'' at 90 deg to the parting lines at all bands, but measured .4565 at 10 deg off the parting line one side and .4595 at 10 deg on the other side.
The mold was out of alignment, and I could not adjust it to my satisfaction, so I sent in to the manufacturer for adjustment. It came back perfect with linotype bullets at .460'' diameter on the top band, and a nice even diameter of .4595 on the lowest band.
Measure your bullets in the 3 different places and see what you have. Those single cavity 400 and 500 grain molds, with plain clip on wheel weights, need a bit more heat in the alloy and molds for a good fill out, 780 to 800 deg. With your alloy and 5% tin they should fill out well at normal temps ,725 to 740 ish.
If your mold is in good alignment, then you will need to find the temperature sweet spot for it. casting the larger bullets, can be a bit finicky.