Strike Models Big Guns Cannon 2011

A couple of months ago Stephen from Strike Models sent me a new variant of the negative pressure cannon I reviewed after NABGO last summer. This time the cannon was in good working order so I was able to spend a good chunk of a day experimenting with it in the live fire cabinet. This review is shorter than the previous review because I don't really see a need to document a complete tear down of the cannon - it is basically the same cannon with a few small tweaks. However, I will describe what I liked, what I didn't, and include a few pictures to illustrate new points.

I also briefly introduce the new adjustable regulator that Strike Models plans to offer in 2012.

Introduction

If you have not read my review from last summer I recommend you start there. The cannons is more-or-less the same cannon so many of the points I made still apply. This cannon is a negative pressure cannon so it is a little different beast than most Big Gunners are used to. I discuss some of the differences in my previous review.

The cannon being reviewed is a 3/16" tripple cannon. For MABG Members who have missed one of the meetings the Strike Models cannon has been shown it is very close to the same size as the cannons in Nassau.

What Has Changed

Better Fasteners

The first problem I encountered with the previous design was a retaining pin was missing and the cannon blew apart in my hand when pressurize. Had I ever seen a retaining pin there I might have noticed it was missing. However, it fell out prior to me receiving it so I didn't know to look for it. Strike Models has correct this by using better retaining pins at both ends of the cannons

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Use of MEV-2 Exhaust Port to Fire

In my previous review I recommended Strike Models modify their recommended plumbing setup to use a Clippard MEV-2 exhaust port to fire the cannon. We have had great success with these over the years. The new cannon was using the MEV-2. This change will make these cannons very nearly a bolt in replacement for many traditional Big Guns cannons.

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Stronger and Better Supported Magazine Cover

I was not able to adequately test the previous cannons because the magazine cover arrived shattered. I was not the first person to test the cannon one of the previous testers must have over-tightened the screws for the covers. Strike Models has switched to PETG plastic for the covers and added brass spacers.

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This solution should work but is not what I recommended. I would have rather they moved the screws alongside the magazine walls so that the head of the screw (or better yet - a nut!) would press the cover against the magazine wall. This would have eliminated the need for the spacers altogether. This is the approach I use and it works great.

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However, the brass spacers should prevent people from over-tightening the covers.

Alignment Hole

The new cannon has an alignment hole under the center of rotation... sorry I didn't get a picture of it. Unfortunately it is not threaded so you can not use it to help fasten the cannon. Actually, there are no threaded attachment points besides the inlets for the CO2.

Upper Works Tear Down

Below is a series of pictures showing the dis-assembly of the upper-works. I didn't photograph the barrels as they are the standard arrangement most Big Gunners use: bend tubing fastened with hose clamps. (Click on the thumbnails to enlarge)

One thing that is worth pointing out: notice that the screws go into the spacers but do not hold them to the cannon. This is a nice touch. It means you can remove the cover without disassembing the entire upper-works. (as shown)

Here are a couple of pictures of the breech

Recommended Improvements to Upper-works

I recommend making the breech housing tall enough that the magazine cover will sit directly on top of it. The screws for holding the breech in place can then also hold the cover down (if the riser holes are more accurately sized). Currently the cover only secured by the two screws in the front. The assembly screws for the breach are actually under the cover.

There is still a hole for a third assumbly scew but it was not used (presumably a spacer would not fit where it was located?).

I have a small concern that when a servo is hot-glued or servo-taped to the cover the lack of fasteners in the back will cause problems. PETG is pretty tough - so maybe not. However, the space is dead anyway why not use it? Additionally, if you look at the above right picture you can see that the cover does not actually rest of the magazine walls. So a fair bit of CO2 can very easily leak out (but more on that later)

Finally, I recommend that the top of the risers be either flared (best) or highly textured. Experience has shown that the vinyl tubing gets slick over time and hose clamps by themselves are not quite enough to insure a firm hold.

Finally, I strongly recommend having two slots for rotation belts... I think every boat I have owned had at least one cannon which needed two belts around it.

How Well Does It Work?

So how well does it work? The cannon works quite well. I found that the cannon fed and fired reliably. I did not have any misfires or jams. I fired scores of rounds through the cannon and never once had a problem with it.

I did test this cannon with the Combro Chronoscope I bought recently. I have been told that the Australian battle group limits muzzle velocity to 165 fps. Apparently the WWCC used to limit 3/16" cannons to a muzzle velocity of 205 fps. I have not had time to precisely compare muzzle velocity against foam penetration but I did find that by 215 fps the cannon was very overpowered when testing against foam.

I don't know what the target speed should be but I will tell you what I found. First of all, the cannons hit a lot harder if the magazine cover was sealed up... on the order of 30fps faster. So the claims that this style of breech are self sealing are not quite the whole story... yes the shot doesn't fire back into the body of the magazine... but a lot of CO2 is getting back into the magazine. Anyway, here were the results I found:

• 80 psi resulted in 134-143 fps sealed or 104-124 fps if not (depending on amount of ammo in magazine)
• 100 psi resulted in 164-172 fps (all sealed)
• 120 psi resulted in 188-201 fps (all sealed)
• 140 psi resulted in 215-221 fps (all sealed)

I strongly recommend that Strike Models improve the fit of the magazine cover and increase the accumulator length to shave 20 psi off the numbers. I suspect that 190 fps is about right for cannon strength when tested against foam. If these cannons could hit that hard at 100 psi people would be able to use MAR-1 regulators to adjust the power of cannons as needed.

Sneak Preview of New Adjustable Regulator

I am not going to write a full review of the regulator as there were some problems in testing. However, here are some pictures of the prototype:

My recommended changes for this are

• replace the easily stripped on-off set screw with a knob or better yet just get rid of it and replace it with one of those resettable blow-off valves. The regulators we have used for decades don't have an on off valve... yeah it would be nice to have but only if it is not a point of failure.
• the pressure gauge is also pretty useless... a small 0-3000 psi gauge is not very helpful when I need to be able to tell the difference between 100 and 120 psi. If a better alternative is not available then I would still rather have a resettable blow off valve - hey, an on/off valve and a resettable blow off would be really sweet... I already have a pressure gauge.