Marlin 1894 Cowboy .357

[Brad]

What brand seater?

 

[waco]

Open the seating die up about two thousandths and the problem should go away.

400 grit wet/dry sandpaper with some oil on a wooden dowel and a drill?

 

[waco]

What brand seater?

An OLD RCBS

 

[Will]

I recently purchased a hornady cowboy seater for 44 and it also works really good.

I love the RCBS cowboy dies though. I know for sure that I have no problems with .360” bullets in the RCBS cowboy dies. That’s what I use for loading my 357 maximum.

 

[Brad]

Can you “slug” the seater die? Maybe dive a bullet in to a variety of depths and see if Ian and his intuition are right? The case mouth folding in too soo will certainly cause damage like you see.

 

[waco]

Can you “slug” the seater die?

I can try.

 

[Ian]

Can you “slug” the seater die? Maybe dive a bullet in to a variety of depths and see if Ian and his intuition are right? The case mouth folding in too soo will certainly cause damage like you see.

Yep, all he has to do is start a flared case with a bullet in it into the seating die and pull it back out to see what's happening. Go a little deeper each time and I bet by halfway in the case mouth has closed up on the bullet.

 

[Brad]

Take measurements as you go. Diameter and depth. That gives an idea of the true dimensions of the die insides and most important, does it have any internal taper.

 

[waco]

pull the bullet each time as I go into the die or measure the outside of the case?

 

[Brad]

Measure the diameter of the flare as you go. Does it get smaller in diameter and the case mouth closes as you go? Case mouth closing before bullet is full depth is not good for bullet bearing surfaces.

 

[waco]

The case mouth is closing before it even gets to the grease groove.

 

[Brad]

At what point does the case mouth contact the bearing surface?

Did you chamfer the inside of the case mouths?

 

[waco]

Case mouth after sizing brass is .373"
After running into flare/powder die it's .388"
After running it into the seat die(no bullet) it's .384"

 

[waco]

Did you chamfer the inside of the case mouths?

No. I use my Dillon as intended. Pull brass from tumbler and run through machine start to finish.
I have NEVER chamfered a pistol case in my life.

 

[Ian]

He said no chamfer. Good idea to always chamfer cast bullet brass if any kind of crimp is used because the bullet gets ripped up upon case exit if you don't.

 

[Ian]

No. I use my Dillon as intended. Pull brass from tumbler and run through machine start to finish.
I have NEVER chamfered a pistol case in my life.

That philosophy is "intended" for jax bullets. You're loading cast.

 

[Brad]

Got a tubing mic? Can you get an accurate case

That philosophy is "intended" for jax bullets. You're loading cast.

And unless you trim it is a once and done thing.

 

[Brad]

Case mouth after sizing brass is .373"
After running into flare/powder die it's .388"
After running it into the seat die(no bullet) it's .384"

Got a tubing mic? What does case wall measure? Wonder if mouth of case is touching bullet before crimping.

A light chamfer does reduce the tendency to scrap as we remove that sharp inside corner.

 

[waco]

Yeah I have a ball mic. Problem is it’s mixed headstamp brass. It’s going to be all over the place.

 

[Brad]

Get a measure on mouth thickness then seat a bullet and see what it measures at the mouth. We then know if that case has the inside of the mouth touching the bullet.
Might not mean much for other cases but sometimes we gotta make some generalizations?