Cast Boolit Size variations

[hdog]

In loading some rounds to fire form some brass, I seated the boolits to touch lands and bolt face. I made a dummy round and used a Hornady comparator to measure OAL by loading into the magazine and then forcing the boolit into the case by closing the bolt. I then measured to the ogive to get the ideal length. After loading about 25 rounds I decided to measure the loaded rounds and found the variations shown in the left column of the attachment. I was surprised and thought the seating die had moved. I then measured some castings that had not been sized and found the variations in the right column. I, being fairly new to casting, am wondering what may cause this.

161658

[Tatume]

The variation in your loaded cartridge lengths is much greater than the variation in your bullet lengths. This indicates that the bullets are not being seated uniformly. Without seeing your reloading gear I can't say what is causing this, but one place to look is lube buildup in your seating die. Another might be variation in your bullet diameters, if you are using a seating stem that is hollow and impinges on the ogive. You could try using a flat seating stem.

Take care, Tom

[JSnover]

… one place to look is lube buildup in your seating die.

Take care, Tom
Exactly what happened to me.
Watch for lube building up on the noses, from there it will migrate up and plug your die. You can wipe it out with a q-tip and/or drill a small vent hole in the stem and the plug, right up through the center.

[Yodogsandman]

I had a similar problem. My boolit would get hung up on the step in the seating die that crimps the case mouth. I too had a wide variation in O.A.L.'s. I bought another seating die and used sandpaper on a split dowel, chucked in a drill to open up that area to better fit the larger boolit nose diameter. I used a super hard C-H die, I'd suggest using a Lee.

You could try both adjusting the seating die up higher and the seater stem down to try to overcome it.

[hdog]

Thanks for all of the suggestions. I will look into each one. My dies are RCBS, and I am using a hollow taper seating stem.