40MM
CANNON PI
By
GROG Copyright 2016 3LC Productions

Scot Pace at Reloadableshells.com has
improved on the design of the 40MM CANNON base by adding a stainless steel high
pressure chamber. This, the latest and most likely the last version of this
reloadable round has a powder chamber capable of holding 20-23 grains of
Bullseye Pistol Powder. This power, added to the reliability of the system
makes the 40mm CANNON the best reloadable 40mm casing on the market, hands
down. The design is lightweight, strong, and capable of being reloaded a
multitude of times. Scot uses the best materials and has spent much of his time
and effort in bringing this reloadable munition to the 40mm community. Since
this munition came out, I only use these in my own weapons systems, and have
loaded up several for my own use in personal protection. I would never bet my
life on crap, nor would I recommend something if I myself did not personally
believe in the product. Since I had a hand in the design, and improvements, I
know of what I speak.
The recoil of the new CANNON round is
substantial when loaded to full capacity. One thing that makes this reloadable
munition stand out from all others is the capability of changing bases, thereby
changing power if the need arises. For a LE or Corrections department, you
could have several barrel portions loaded with different payloads, ready for
use at one time. You could use basically three loadings in bases, low, medium,
and high, and decide at the time of need, which to use. Say you had the ability
to choose from rubber baton, rubber stingball, OC powder muzzle blast
dispersion, CS, door breaching, wooden baton, frangible buckshot, lead
buckshot, steel flechette… then you had the ability to tailor the loadings to
achieve the desired effect right there, at the incident. Grab a pre-loaded
barrel, screw on the power you desire, and let loose. This as opposed to
staring at a bag full of costly, one shot and done, different rounds, loaded
with what the factory thinks fits all situations… Personally, I’d choose the
round that gives you “on the fly” options. I’d also choose the munition that
allows you to train as you fight. With the exact payloads, loaded to the exact
specifications YOU need for the situations that YOU are going to deal with.
Responding to a prison riot in a large open area with multiple bad guys? Rubber
buck, medium power base, and you are ready to go. Responding to a single cell
with one or two bad guys in an enclosed space? Rubber baton with low power
base. Being attacked by North Koreans or zombies? Steel flechettes with a high
power base. With these rounds, you have OPTIONS that YOU control.
Are these rounds more expensive than other
40mm ammo? Up front, yes, they are. BUT… factor in the number of times you will
reload them, for the cost of the payload (which YOU choose and can buy
cheaply), the cost of a primer, and 5-23 grains of Bullseye per round… and
things turn around pretty quickly. Imagine having to buy a brand new $35-50+
round for every possible occasion or use. Now add to that the cost of buying
“training” ammunition that is loaded the same as your duty ammo. For the minor
costs outlined above, and a little time in cleaning and reloading, you can have
so much more. Once you fire one, these munitions sell themselves.
Case in point. My local Sheriff qualifies
retired LEOs in our area for the 50 state LE concealed carry. During one of
these qualifications, I brought my LMT 40mm and a few CANNON rounds loaded with
high power bases and flechettes. I let him fire a few, and after looking at the
range targets, decided not only to invest in the munitions, but buy his
department 40mm launchers to fire them. This from one range session with a
couple rounds fired.
Anyone with experience in the 40mm field
will appreciate and fall in love with this round. It makes your launcher not
only a signal device, or a thing for launching explosive grenades, but a truly
versatile weapons system.

Reloading the CANNON bases is a very
simple thing. You will need a few tools, a reloading powder scale, and burst
discs, and some sealant if you wish to store your rounds long term or in wet
conditions. Reloading the base consists of the following steps:
1. Remove the base from the
barrel section by unscrewing.
2. Remove the vent plug from the
top of the base.
3. Remove the expended copper
burst disc and discard.
4. Knock out the expended
primer.
5. If desired, you can use Hoppes #9 and a q-tip to remove any fouling from the
stainless high pressure chamber, the vent plug, and the primer pocket. I
usually do this after every 5 or so firings, but I fire mine a lot and do not
store them.
6. Replace the primer with a
Remington #2 small pistol primer or similar soft primer. Do not use magnum
primers.
7. Measure out your powder
charge. 3-7 grains is a low power loading used for baton, rubber buck, or
similar less lethal munitions. Experiment to get the results YOU want. 7-15
grains, medium power, 15-23 grains high power.
8. Replace the copper burst
disc.
9. Screw on the vent plug. I
usually use a wrench or socket and only tighten it until it stops. No need to
torque it like a car lug nut… The harder you tighten it, the harder it will be
to remove…
10. Reload and replace your
barrel, done.
Loading the CANNON with
flechette darts:
First, choose your carrier
(wad). Make sure the wad extends to the top of the darts. I recommend covering
the side slits with tape, to keep darts from popping out and scratching your
barrel. These are string wrapped so no worries. I wrap the darts around a small
wooden dowel, centered as in the photo below.

Ready to load 4 barrel sections:

In the below photo, you can see the
PI bases, flechette roll, and black foam top wads. I cut them using a gasket
cutter set to tightly hold the darts in place. Seat the carrier to the base of
the barrel, then insert a foam wad, to the top of the carrier.

In the photo below, you can see the
interior of the 40MM CANNON PI base. The stainless steel high pressure chamber
holds the primer, and a slightly smaller vent plug than the original design.
This is to restrict the amount of powder one can place in the base. The
interior of the high pressure chamber has a rounded base, to direct the power
toward the ventholes. The burst plate that goes between the powder and
ventholes can be either purchased from Scot, or made using a punch and either
copper or brass sheet metal, .015” thick. Variations in pressure can result
from changing metals, so start testing low (3 grains) and work your loads up
from there.

I can do all the above steps in a few
minutes a round. There is no resizing like in brass reloading. The components
do not expand when fired, so there is no stress on the barrel of your launcher.
There is recoil, so be careful if using high power loads in rail mounted M203
style launcher systems.
Maintaining the CANNON rounds is also
simple. Cleaning the barrel portion can be accomplished with a 10ga or similar
shotgun brush, mop, and patches. Don’t use steel brushes as they will scratch
the surface treatment on the interior of the barrel portion.
If you decide to store your
loaded CANNON munition, I recommend you seal them as in the diagram below:

I was provided with several of
the new CANNON rounds for testing, and loaded them with various loadings of
buckshot, flechette, and shot. Using 20-23 grain Bullseye loads, I was able to
fire the casings provided more than 5 times each with the 20+ grain loadings.
No adverse pressure problems were viewed with the casings. They were measured
after each firing, to check for pressure problems, and the primers were
checked, and no adverse observations were made. The CANNON PI will serve the
reloader very well. It is stronger, safer, and performs better than the first
version. If you liked the first version, or were waiting for improvements to be
finished, now is the time. These work fantastic!
Copyright 2016
3LC Productions