Core seating and why?

[buck1]

Forgive my newbeeness!
I cant get my head around this.
on the one step 44/40 dies we are just lightly seating a pre cast core and swaging as is. ETG is droping under sized cores in his case jackets and swaging great boolits. SO...
except for weight, why do we need a tightly seated core. On the surface it seems a correct wt undersized core would be the ticket. Just drop in and swage.
Is it just to regulate the cores lead volume?
Thanks....Buck
:swagemine: :cbpour:

[Daywalker]

Good question Buck1!

In my case, I am having to stretch the 40 S&W case to a diameter of .451. I have to use the core seat die to swage it up to .451 diameter then I can swage to the final product. I believe, and this is my belief, the swaging die, it is forming the ogive and placing a hp into the bullet. So therefore, the lead has somewhere to go and not stretching my case to the fullest. It takes alot of pressure to get that 40 case to .451 diameter. The 40 and the 44's, do not require as much to stretch that 40 case.

As stated, this is just my personal belief and have nothing to back that up. I am only like months into swaging and have not learned the terms or anything. I am hoping that my observation may be correct. Hopefully one of the more professionals at this could confirm this or correct me as well..

[BT Sniper]

Drop in and swage would be the ultimate goal. Core seater does the job when a pretty good bump in size is needed. Core seat die also needed to notch the jackets with :). In a more traditional use of the core seat die with conventional jackets the core seat base punch can have a bleed hole for excess weight/lead to bleed off in attempt for mor uniform bullets. This technique does not work to well when using brass cases for jackets though.

Enjoy the simplisity of the one step and go do more shooting!

Swage On!

BT

[MIBULLETS]

The main reason is to get the core to completely fill out the inside of the jacket for the best uniformity, meaning no air spaces at all. In the dies BT is using and making, you can put more force on the bullet in the nose or point forming die and may be coming close to this, but for normal rifle bullets, you need the core seating step.

[bohica2xo]

Core seating is necessary if you are moving the brass a lot - like making .452's from 40 or 9mm brass.

The core seat allows spreading the force between operations if you are stretching the case a long way. It also provides more force to expand the case head.

B.

[buck1]

Ok I think Im on board,
The core seat die takes the bulk of the swaging force to reach full dia, then the swaging die takes the "bumped up" core/ jacket to the next step of finishing the full or nearly full sized core in to a boolit compleete with nose and hp etc. ?
Too much for one operation I guess?....Thanks guys..............Buck

[bohica2xo]

Not "too much", but "much easier".

The force required to do the whole job at once when you are expanding the rim on the case is very high.

By doing this in two steps, the work is spread over two press strokes. It also give a step that is suited to things like notched jackets.

B.

[Hickory]

Forgive my newbeeness!
why do we need a tightly seated core. On the surface it seems a correct wt undersized core would be the ticket. Just drop in and swage.


It would be like building a car engine and not tighting up the bolts,
They need to tight or else the will fly apart.