Making a Seater die stem(from scratch) fit bullet well ??

[Shawnba67]

So I may have overthought this to the point of brain frazzle. I am not having much luck making a stem for a seater die that doesnt deform the bullet. Having hard time making an acceptable cone/angle for pressing against the bullet. The idea i havent tried but think might work involves a tiny tiny boring bar which i dont have. my current smallest is like a .200 hole size. Any ideas or advice is appreciated.

 

[boltfluter]

Shawn,

Do you happen to have a 60 deg end mill? It might work in combination with a small drill for nose clearance. Just a thought. I usually purchase the seater stem and build the rest of the die. The one time I did this.

Paul

 

[DaveTooley]

A couple of things I've done in the past. Use a bullet(s) and lap a corresponding contact patch. The other is to use bedding compound to form the cone. If you try this remember to drill out the meplat area after bedding.

 

[liljoe]

Here is the one I made for that purpose.
Joe

 

[NorCalMikie]

Use bedding compound to form the cone.

There's you answer right there. Drill it deep so the bullet tip doesn't touch and release agent on the bullet.

 

[gunsandgunsmithing]

A couple of things I've done in the past. Use a bullet(s) and lap a corresponding contact patch. The other is to use bedding compound to form the cone. If you try this remember to drill out the meplat area after bedding.

This is exactly how I've done it in the past. A little release agent on the bullet and after it cures, pull the bullet and drill out the center meplat area. About as perfect of a fit for that bullet as can be, that way but still works for other bullet styles fine too. For me, it seemed to reduce runout a small amount but I'm a believer that runout is predominantly a sizing issue much more that a seating issue, most always.

 

[Shawnba67]

Shawn,

Do you happen to have a 60 deg end mill? It might work in combination with a small drill for nose clearance. Just a thought. I usually purchase the seater stem and build the rest of the die. The one time I did this.

Paul

I tried a 60 degree center. it puts a nice big ring in the 85gr bthp i was seating!

Thank you very much for the other suggestions. Ive even got some devcon that needs used up soon as well.
Plus after seeing that little boring bar I always forget that broken drill bits I save are just little hss blanks.

 

[alinwa]

You'se guys are making this 'wayyyy too hard

Sons-Ofa-Guns, take a lesson from that Will guy over there on Red Jacket Firearms on The History Channel....... there is ONE tool, ONE answer

step drill


duhhh

 

[laveritt]

First, I drill a proper sized hole in the stem then chuck up a bullet you plan to use, apply lapping compound or valve grinding compound & oil. Then place the stem hole onto bullet with compound & oil mixture applied with the lathe turning. Start off with a fairly fast cutting grit. Go to progressively finer grit until the stem contact area is a copy of the bullet ogive and very SMOOTH. Grind until the stem opening is virtually a knife edge intersecting the outer stem perimeter. My stems prepped this way do not mark the bullets and are a very good fit to the bullet's ogive.

Ensure the initial hole in the stem is sufficiently deep so that the bullet tip never touches, so as to bottom out.

If you have some extra stock, practice on it rather than your stem.