Why seat and crimp separately?

[REDLINE]

Specifically regarding 10mm Auto;  Why seat and crimp separately?

[cwlongshot]

I just commented in your previous post about your crimping issue...

I mention doing this in two steps... you NEED to first set up the seating AND crimping. You do this SEPARATELY. Make up a dummy case. (NO powder or primer) then you can use it top set up the dies next time to load this bullet.

Generally speaking, semi auto cartridges can be setup to do both at once. When I load a caliber with a roll crimp, I ALWAYS do it in two steps. This allows for a much improved final product. Improved with its look, function and accuracy.

CW

[The_Shadow]

Good info CWLongshot, I do all seating and crimping in seperate steps...WHY?  When doing them together the bullet is still being pushed deeper as the crimp is being applied.  Even the slightest movement of the bullet can catch the jacket or bullet material and make for a springy  reaction of the brass as it catches on the bullet.  Some bullets it is not as much of a problem especially those with cannellures as this sort of provides space for the brass to go.  However on a straight sided non cannellured bullet something has to give, the brass can spring back, deform to loose bullet tension or wrinkle or in the case of plated bullets, the plating can be cut, or bullet can be deformed.  These situations can cause issues like failure to fully feed, bullet set backs, loose bullet tension.   The extra step is well worth the time and the resulting quality to insure positive reliability. 

Also taper crimps don't need to be too tight as to squeeze the bullets too small, this can lead to poor accuracy or tumbling and even leading using cast bullets! 

I purchased a set of die spacer rings many years ago (they are still avalible from Redding) in my efforts I set my taper crimp die for proper taper crimps, and use the die spacer ring to lift that die (that way I don't have to continuously re adjust it), with it lifted I use it to seat all my bullets to the proper COAL.  When all are seated I remove the Spacer ring to return the die for proper taper crimping with only the bullet seater stem being moved back out so as not to change the COAL while the taper crimp is applied.

I used to have the seater/taper crimp set differently when I was doing the 40 S&W's using one or two spacers when I was doing for various steps.  But I picked up a second Seater/Taper Crimp die and use one for 10mm the other for 40S&W now.

[REDLINE]

Good info CWLongshot, I do all seating and crimping in seperate steps...WHY?  When doing them together the bullet is still being pushed deeper as the crimp is being applied.

Hard to believe a true taper crimp would push a bullet deeper.  With a roll crimp common sense tells me that would be inherent.  But with a true taper crimp?

Please know I realize I don't speak from experience.  Think of it as thinking out loud.

[DM1906]

Good info CWLongshot, I do all seating and crimping in seperate steps...WHY?  When doing them together the bullet is still being pushed deeper as the crimp is being applied.

Hard to believe a true taper crimp would push a bullet deeper.  With a roll crimp common sense tells me that would be inherent.  But with a true taper crimp?

Please know I realize I don't speak from experience.  Think of it as thinking out loud.

Crimping doesn't "push a bullet deeper" (roll or taper).  Seating the bullet does.  If you are seating/crimping in one step, the bullet is still being "seated" WHILE the case is being "crimped".  Bullet insertion is still happening until you STOP handle movement.  If you seat and crimp in separate steps, bullets will remain where you left them when seated.  The exception (there's always an exception) is, if it is overly crimped, it will actually cause the COL to lengthen, due to bullet deformation (and a couple other "exceptions", but for later discussion).  That is, until you reach a point where you actually crush the case, and it gets shorter (usually evident by the wrinkles in the case).

[REDLINE]

Good info CWLongshot, I do all seating and crimping in seperate steps...WHY?  When doing them together the bullet is still being pushed deeper as the crimp is being applied.

Hard to believe a true taper crimp would push a bullet deeper.  With a roll crimp common sense tells me that would be inherent.  But with a true taper crimp?

Please know I realize I don't speak from experience.  Think of it as thinking out loud.

Crimping doesn't "push a bullet deeper" (roll or taper).  Seating the bullet does.  If you are seating/crimping in one step, the bullet is still being "seated" WHILE the case is being "crimped".  Bullet insertion is still happening until you STOP handle movement.  If you seat and crimp in separate steps, bullets will remain where you left them when seated.  The exception (there's always an exception) is, if it is overly crimped, it will actually cause the COL to lengthen, due to bullet deformation (and a couple other "exceptions", but for later discussion).  That is, until you reach a point where you actually crush the case, and it gets shorter (usually evident by the wrinkles in the case).

Makes sense to me when you explain it like that.  So I guess with me seating and crimping in the same step I simply have the seating and crimping working in concert to seat the bullet together at the depth I want.  Glad I understand that now.  Now I just wish my seat/crimp die would let me have my finished rounds back without a fight.

[sqlbullet]

With taper crimp you can do it in the same step.  The crimp really isn't a crimp in this case, just smoothing out the bell, which was only there to start the bullet which is done at this step.

But, it is way easier to adjust dies if you split them up.  On single stage I do them together usually because I don't want to pull the handle again.  On progressive I split them up since I usually have a station or two idle anyway on handgun.

[DM1906]

If you are just starting out with all this reloading nonsense, there's NO reason to not slow it down and get the feel for it.  Don't rush.  One step at a time.  There's plenty of time later for warp speed (unless you get in a hurry, and blow yourself up, or worse, like end up on youtube in a very embarrassing video, which can ruin your afterlife, which ain't cool, and you'll be stuck with fat/ugly chicks for all of eternity..........).

[REDLINE]

I promise to do my best not to become a negative statistic.  Though I believe the negative statistics get the most recognition.  Hmmmmm, how much attention do I want, live, mamed, dead...  Maybe if I just lost a partial of a finger.

No doubt I hear what you're saying!  My dad and I are always talking in jest about me blowing up the place, among other thoughts along those lines.  Actually sometimes I think I'm too careful.   What had me most on edge so far was seating the first primer.  Turned out that went really slick, almost too slick.  I didn't like it that I couldn't feel the primer bottom out in the primer pocket, but since they seated just below flush I felt okay with it.  Then sometimes I have to remember to breath when hand weighing powder charges, though that's partially because of how sensitive the Hornady Bench Scale is.  Yeah, I'm taking it slow!

I do take it very seriously, commonly triple thinking about what I'm doing and beyond.   Right now it's all on hold till Hornady gets a new die set out to me.