I've been casting 25 cal bullets for years but only had a .258 lube sizer as a choice. I use the ideal 257388 & lyman 257464 for my 250 savage rifles. Both are .260 from the mold. I now see that buffaloarms has custom sizing dies, one that is .259 and another that is .260.

I'm tempted to get the .259, this would match the conventional wisdom of going .002 over .257 and only slightly reduce the diameter of the as cast by .001. Or would it be better to get the .260 and basically just lube the bullet using the sizer?

How do your .258 sized bullets currently shoot?

I'll get a good group sometimes but not consistently. Could just be my aging eyes and the peep sights I'm using. This is a group from about two weeks ago, it's at 50 yards not 100, this was the 257388, the next is from last year and is the 257464. I'm more concerned about deforming the bullets with the sizing process.


I carefully sort all the bullets by weight, etc.

Have you slugged your bore to see what your groove diameter is? If you haven't, that should be step one.

Only after you have slugged your bore and have definitive results of your rifle's groove diameter should you decide what diameter sizer to buy.

Good advice, but instead I would do a pound cast or a Cerrosafe casting of the neck/throat area and size my bullets to a RCH (.0005") under throat diameter, regardless of what groove diameter is. Then guarantee that the bullet diameter/case neck relationship jives, seating is straight, and seat the bullet out to another whisker shy of engraving in the lands (or if it's soft enough right into the lands a hair). Having the nose of the bullet match the angle of the leade is a benefit, and/or a nice bore-riding shape.

Looks like you're on the right track judging from those targets, but something is wonky and causing fliers. Loaded ammo not consistently straight, shaving lead on some rounds, ill fitting/lopsided gas checks on a third of them, or ??

first change I would try is water dropping them, then size the same day, let them set a week or so before loading.

I bet that will help a bunch on the flyers.

I'd change one thing at a time.

I don't think you need a different sizer. I would try a diff size as a last option from what I see.

Thanks all.

I could see where the gas check could be a problem. I notice when the spur is cut it leaves a rough surface that could cause the gas check to be uneven at the base. I'm going to try and file/shave the base flat before sizing this next time.

The 257388 is a spitzer bullet design and the 257464 is a Loverin so no real bore riding area. I'm using Lyman #2 hardness and I measure it with a Saeco hardness tester.

Have not tried water dropping, and I just cast a lot this last weekend, something to try next time.