with CANNON PI base
Made by Scot Pace at Reloadableshells.com
Review by GROG Copyright 2016 3LC Productions
Recently, Scot Pace at Reloadableshells.com provided a few of his newest 40MM rounds in the “CANNON” line. These employ a newly designed triple 28ga barrel design, and the newest high power base of the “CANNON” design. The powder chamber is a stainless design capable of taking 23 grains of Bullseye smokeless pistol powder. This is the ONLY powder I tested in this casing to perform properly. Bullseye has the fast burning and power needed to power the high/low system. Scot also provides plastic wads, cork plugs, copper burst discs to reload these casings properly. With the space available, and the power needed, Bullseye is simply the best choice. When loading, I place the flechettes or shot in the wad, place the wads in the barrels, then seat them to the bottom of the barrels, then add a cork wad to keep everything in place.
For testing, I decided to use five common payloads, 1” flechette darts, 1.5” flechette darts, #4 buckshot, OO buckshot (both in frangible form) and #7 lead shot… and for targets, my new plastic military style human shaped targets.
The first round of testing I loaded half with 15 grains, and half with 20 grains. I had 5 casings to work with, so I loaded them with the payloads listed above. I used the mil surplus copper primers as used in the M781 blanks for reliable ignition. Performance varied, but it was obvious that the 20 grain loads performed much better. It was also noted that the base of the casing needed to be slightly reworked, to spread out the recoil of that load to a more wide area. The base of the casings were being malformed, so Scot went back to the drawing board and redesigned the stainless powder cup/primer holder to be both wider, and accommodate more powder. These rounds were going to simply be more powerful.
RESULTS OF PRIMARY TESTING:
CASING POWDER LOAD TYPE PROJECTILE VENT PLUG Muzzle Energy
1 15G BULLSEYE FLECHETTES 1” 6HOLE 448.1 FTLBS
2 15G BULLSEYE #4 OOB FRANGABLE 6HOLE 289.5 FTLBS
3 20G BULLSEYE FLECHETTES 1.5” 1 HOLE 638.6 FTLBS
4 20G BULLSEYE #4 OOB FRANGABLE 1 HOLE 289.4 FTLBS
5 15G BULLSEYE 15 OOB PELLETS LEAD 6HOLE 585.2 FTLBS
FOR COMPARISON I LOADED THREE 37MM CANNON ROUNDS AND GOT THE FOLLOWING:
1 15G BULLSEYE #4 FRANGIBLE BUCK 6HOLE 261.6 FTLBS
2 15G BULLSEYE OOB LEAD BUCKSHOT 6HOLE 560.9 FTLBS
3 15G BULLSEYE 1” FLECHETTES 6HOLE 621.1 FTLBS
The tri-barrel rounds were loaded using the plastic wads provided by Scot, with no metal backers for the flechette darts. In the second loading below, I will use metal backer plates for the darts so they didn’t stick in the wads. It is important to note that the flechettes I use are military surplus, as loaded into the flechette arty rounds, with thin strings holding the darts together, one up, one down, and so on. I roll the darts until the wads are full, then cut the strings there. They are then loaded into the barrels, and topped with the included cork wadding. For testing purposes, I did not seal the bases with any nitro lacquer as I would if I was going to store the rounds long term. (vent hole, primer, vent plug threads) Nor did I use blue loctiteTM on the threads of the casing and barrel for the same reason. Latex paint on top of the cork wads was also not done. If I were going to store these rounds loaded, I would do the previous three steps to waterproof the casings, using a thin cork on the top of the barrels to seal them, with a thin layer of latex paint.
It seems the best performing loads were the heavier lead buckshot, or the flechette darts. More testing to follow. Frangible shot is so lightweight, it is hard to maintain muzzle energy with them. They still do damage when they hit targets though.
I will note that the recoil on just 23 grains is substantial in the high/low pressure system, and we are maximizing them out at this power level, so if you decide to “up the ante” on your own… be prepared to buy a new launcher and perhaps a new shoulder. These things are kicking hard with just 23, and I see no reason to go further.
In the first round of testing I determined that 20+ grains are needed to propel the payloads with good power and penetration in loads meant to be lethal, so I loaded the second round of test casings up with 21 grains, 22 grains, and 23 grains, using only lighter flechette loads and heavy lead shot, no frangible stuff this time, which seemed to work best last time. I fired the test rounds from 25 yards, with the chrono set up 5’ from the muzzle.
Scot also included two different styles of vent hole plugs, one the standard 6 hole, and the other a single larger hole. The copper vent plugs are the standard ones sold with the casings. I prefer the 5 or 6 hole vent plugs, but either will work. The newer tri-barrels have a steel screw added to the center of the barrel portion, on are smoothbore 28 gauge, so buying replacement wads is simple and cheap. You can also select wads that work best with your payloads.
New base design:
The tri-barrel design can also hold a number of different projectiles, gas powder, rubber or wood projectiles for less lethal applications. Each person or department should test projectiles for intended applications prior to loading and using against personnel.
Maintenance and cleaning of the tri-barrel design is simple and easy. Using 28ga shotgun brushes, mops and patches, and some Hoppes #9 and q-tips, one can properly clean the tri-barrel in little time. When the powder residue is removed, use Rem oil wipes on the threads, and outer surfaces of the round. I also pass them through the barrels to give those a light coat of oil. Do not get oil into the high pressure chamber or primer pocket. I use stick-on plastic labels to label the barrels with the payload, and a sharpie marker to label the bases with the power level. This makes it possible to use differently loaded bases with payloads for different ranges.