Part 5 - Bullet Seating & Crimping
Warning –
this will only apply to 9mmp loads as it is by far the most reloaded cartridge
in SA. Loads discussed are my own. Do not copy them, do a proper safe load
development.
So in part
1, we resized the case and this caused the case mouth to be a little too small
for seating the bullet. In part 3 we looked at flaring the case mouth too
easily seat the bullet…reread these parts before you continue here.
Now we have
a case that is resized, primed, charged and flared. We need to now seat the
bullet.
Seating the
bullet simply means pressing it into the case to the proper depth. Seating
depth is important for a number of reasons.
·
The cartridge has to fit properly in the chamber
and/or magazine, so it can’t be too long or too short.
·
The bullet is designed to be a certain distance
from the start of the rifling in the barrel. If it presses too far into the
grooves of the rifling, high-pressure conditions can result and feeding
problems will occur.
·
Pressing the bullet too far into the case can
also create high pressures.
According to
SAAMI; 9mmp has a max COL of 29.69mm, others state a minimum of 27mm and
maximum of 29mm….I have always worked with this. Yes it is possible to go
longer or shorter but only do this once you have sufficient experience.
Cartridge
Overall Length or COL is the length of the completed round from the bottom of
the “rim” to the tip of the bullet.
How do you
determine a COL that will work for you? Start at the magazine, does the
cartridge fit and feed without issues from the magazine? Then does the
cartridge fit in your chamber. Remove your barrel and drop the cartridge in to
check if it fits. It should fall in freely and be able to spin in the barrel.
When
developing a load I always suggest starting with a COL of 29mm for round nose
bullets and 28.5mm for flat nose bullets. If they fit in your mag and feed
without problems do not decrease the COL. You can later decrease the COL if you
need to tweak your load…more on this in our final chapter.
Let’s setup
your Lee Bullet Seating Die…
·
Set the lock ring as far up on the die as it
will go. The seating adjustment knob needs to be turned as far out as it can.
·
Make sure you have the correct shell holder
installed if you are using a single stage or turret press, same goes for a
progressive press…and make sure that your sizing die is already set. Raise the
ram/carrier to the top of the stroke. Keep pressure on the ram/carrier.
·
Turn the die in until it makes firm contact with
the ram/carrier.
·
Now turn the die out 3 full turns. – Do not skip
this part!
·
If you do not have a Factory Crimp Die, you can
now turn the die back in for crimp. A ¼ turn is normally enough…Coated Bullets do
not over crimp!
·
If you are using a Factory Crimp Die, do not
turn the die in for crimp. Leave it at 3 full turns out. Setup explained a bit
further…
·
Finger tighten the lock ring.
Now to
adjust the seating depth of your bullet you need to turn the adjustment knob
in. You will also use this knob to decrease or increase the depth simply by
turning it in or out. An easy way to start is to take a round that you know the
length of…this is where a Vernier comes in use, do not try and measure with
anything else!
Insert the
round into the die; turn the adjustment knob down until you can feel the
seating plug making contact with the bullet. The die should now be set at that
length…finer adjustments might be needed later.
If you are
using a live round, take the necessary care!
Crimping the
case mouth to remove the flare.
Remember in
part 1 we discussed the design of the 9mmp; it has a tapered case. We now need
to remove the flare from the case mouth to secure the bullet. This is called a
taper crimp and is either done with the Lee Bullet Seating Die or a separate
Factory Crimp Die or Taper Crimp Die.
Taper
Crimping is easy and not as involved as a roll crimp as needed for revolver
ammo. You are basically only removing
the flare and ensuring you do not have set back. The biggest issue that it can
cause is that you could set too much crimp. Too much crimp can cause the peak
pressure in the cartridge to jump too high too quick.
What is
bullet set back? If the bullet is not secured in the case, the action of a semi
auto pistol can cause the bullet to be pushed back deeper in the case. Remember
that a bullet set to deep can increase pressure.
Also if you
do not remove the flare you can have feeding issues. A 9mmp “headspaces” on the
case mouth, if the case mouth is not correct the cartridge will get stuck in
the chamber.
After you
have set your crimp ( Factory Crimp Die Setup explained below), you need to
test it.
Load a dummy
round, no primer or powder.
Measure the COL.
Now take the round and press it as hard as you can into a piece of wood.
Measure again and check if the length is the same? If it shortened you probably
need more crimp. If not load about 5 dummy rounds, load them in your
magazine. Make sure you do this next bit
as safe as possible…follow those 4 rules!
Lock you
slide back, insert mag and slide lock release the slide…you need the force of
the recoil spring for this test! Eject the dummy round. Do this with all 5 and
measure again. If the rounds did not Set Back; you have enough crimp.
Grab your
Vernier and set it to inches. Measure the case mouth, it should measure at
.380inch for a perfect taper crimp.
To check for
too much crimp, grab your Kinetic Hammer or Bullet Puller – yes you do need
one! Pull the bullets and check for a crimp mark on the bullet. If there is no
mark your crimp is fine…if there is a mark you have too much crimp. For coated bullets make sure that the coating
is fine and has not been damaged.
Now Lee also
has a Factory Crimp Die, that you could separate the bullet seating and
crimping operation. Not only does it give a more uniform crimp but it also
sizes the case again. This post sizing operation is especially helpful on a
progressive setup. If you made a mistake like not sizing the case properly by
short stroking the press, chances are this die will sort that out.
To setup the
FCD follow these steps:
·
Set the lock ring as far up on the die as it
will go.
·
Make sure you have the correct shell holder
installed if you are using a single stage or turret press, same goes for a
progressive press and make sure your sizing die is set. Raise the ram/carrier
to the top of the stroke. Keep pressure on the ram/carrier.
·
Turn the die in until it makes firm contact with
the ram/carrier.
·
On a turret or single stage press turn the die ¼
more in, on a Load Master do not turn the die ¼ more in, you should have set
your sizing die already and determined the top of the carrier movement. The FCD
must be set at the exact same level as your sizing die.
·
Finger tighten the lock ring.
·
Turn out the crimping knob; insert a cartridge
with the bullet seated. Now turn the knob in until you feel it making contact
with the case mouth.
·
Take the cartridge out; now turn the knob down
to set your crimp.
Do not over
crimp, a ¼ turn is usually enough for CMJ’s. For lead Cast or coated bullets
much less crimp is required.
As above,
check your crimp!
You should
now have a perfect reloaded 9mmp. Grab your case gauge or barrel drop to
confirm.
Up next will
be our final remarks and we will have a look at load development.
