TriStar Cobra Force Shotgun Review
Part 6 - Range Testing
July 10, 2011

TriStar Cobra Force Shotgun Review

In this part of the review, I'm going to discuss the feel and point-ability of the TriStar Cobra Force Shotgun and do some basic "out of the box" range testing.  What I mean by "out of the box" is that I'm not going to shoot the shotgun thousands of rounds to demonstrate any aspects related to the life of the shotgun.  Instead, I'm going to focus on showing shot patterns with several different loads of ammo and at a couple of distances that I would consider to be home defense distances.  Although during my range testing,  I will cycle enough rounds through the shotgun to get an idea of basic reliability.


Feel / Ergonomics

Overall I really like the feel / ergonomics of the TriStar Cobra Force Shotgun.  The forend has a slim comfortable profile and the pistol grip has a rubbery texture that gives you a really secure grip.  The shotgun shoulders well and the tall sights give you a heads-up sighting posture.  The shotgun seems solid, but there is some rattle with the forend like you would expect on any pump shotgun.  One of my favorite parts of this shotgun is the location of the action bar (bolt) release lever on the right forward side of the trigger guard.  This allows you to keep your hand on the pistol grip while pressing up on the lever with the tip of your trigger finger to release the action.  This is shown in the photo below.

Figure 1
TriStar Cobra Force Shotgun Review


Point-ability

Point-ability of a gun is directly related to both the weight, center of gravity, and mass moment of inertia of the gun.  To help simplify the inertia measurement, I'm going to make an assumption that the weight distribution of this shotgun would be comparable to other shotguns with similar geometry and features (i.e. stock, barrel length, capacity, etc.).  By making this assumption, it allows me to treat the incremental weight distribution as a single mass.  This allows me to focus on two easily measured features (the weight and center of gravity of the shotgun) to get an idea of point-ability (inertia).  The physics majors will probably give me some grief on this, but I'm going to keep it in simple terms and say that the mass moment of inertia is just the weight of the gun times the distance from the end of the butt pad squared ( inertia = weight x distance2 ).  Using the end of the butt pad to make the distance measurement allows me to take into account a fairly realistic swing point as you swing the gun up/down or left/right when aiming.

In Part 3 of this review, I showed the weight of the shotgun empty to be 7.178 pounds.  After putting the shotgun on a balance pivot point and moving the location of the pivot under the shotgun until the shotgun was in balance, I was able to measure the distance from the end of the butt pad to the pivot (center of gravity) and found that to be 20.90".  When loaded with 6 shells of 2 ¾" 00 buckshot, it weighed in at 7.698 pounds with a pivot point 21.32" from the end of the butt stock.  From this, I calculated the moment of inertia for an unloaded and loaded shotgun to be as follows.

  • Unloaded: 7.178 x 20.902 = 3135 lbs-in2
  • Loaded:  7.698 x 21.322 = 3499 lbs-in2

Basically, the smaller the inertia, the better for point-ability.  When loaded, the inertia of the shotgun increased by 12%.  What does all this mean?  Until I have a chance to compile more data on other similar guns, it is hard to give a good comparative number of point-ability (like you can with weight and length).  What I can say is that the point-ability characteristics of this shotgun are very similar to a Remington 870 Tactical Express shotgun. This link will take you to my Tactical & Home Defense Pump Shotguns page to see other data as it becomes available so you can form your own opinion.

You should also keep in mind that anything you put on your shotgun will have an impact on your point-ability.  For example, if you mount a light on the forend, this extra mass located that far from your shoulder becomes more resistance to you being able to quickly move the shotgun when aiming.

 


Range Testing

For the range testing, I decided to use several different loads of ammunition and I also wanted to get a feel for what the pattern may be at a couple of different distances for some tactical loads.  The ammo I selected to shoot is shown below.

Figure 2
TriStar Cobra Force Shotgun Review 

For range testing a tactical / home defense shotgun, I always like to start out at the 50 yard range shooting Slugs.  Since a slug is a single projectile, this gives me the best opportunity to figure out or adjust the sights along with an idea on how the shotgun will perform shooting slugs.  The photo below shows my setup at the bench.  You may also notice that I moved the rear sight to the front of the receiver mounted rail.  This configuration seems to work better with my bifocal glasses.  I trade off a shortened sight radius for actually being able to see the rear sight.

Figure 3
TriStar Cobra Force Shotgun Review

I placed a single target (the one in the middle of the photo below) out at 54 yards (actual distance between the muzzle and target).  After my first shot, it was clear that I was high because I didn't hit the target and there was a big dust cloud in the bank above the target.  Next I adjusted the sights all the way down and aimed again at the center of the target.  I was still high with no contact with the target.  Next I aimed at the bottom of the large circle.  Again I was still high and off the paper.

Figure 4
TriStar Cobra Force Shotgun Review

With my next shot, I aimed about 6-8 inches below the paper target and that gave me the shot on the right below.  I repeated this and got the shot on the left below.  Since it was clear that the rear sight was too high and I had fully adjusted it all the way down and since I was having to aim off the target to hit the target, I decided to forgo any more slug testing.  Next I switched to shooting the Winchester 8 shot just to cycle some ammo through the shotgun and get a feel for the action.  I pumped about half of a box of shot into the kudzu area on the right and the shotgun functioned without issue.

Figure 5 - Slugs at 54 Yards
TriStar Cobra Force Shotgun Review

Once I was able to retrieve my target at the 50 yard range, I moved to the pistol range.  Here I wanted to see how the shotgun performed with several potential tactical / home defense loads.  I setup targets at 7 yards and 21 yards.  Since I knew the sights were shooting high, I aimed at the center of the 7 yard targets and at the bottom of the circle for the 21 yard targets.  Also keep in mind that I'm showing an example of the pattern for different loads at two different distances.  If you really want to understand the pattern of your shotgun, plan to shoot multiple shots and take the average.

Figure 6 - Pistol Range
TriStar Cobra Force Shotgun Review

The photos below show the results of the Hornady Critical Defense 00 Buckshot at 7 and 21 yards.  I'm impressed with how well the Hornady Critical Defense load stays together at the 21 yard distance. 8 out of 8 pellets were within a 12" circle.

Figure 7 - Hornady 2¾" 00 Buckshot 7 Yards             Figure 8 - Hornady 2¾" 00 Buckshot 21 Yards
TriStar Cobra Force Shotgun Review   TriStar Cobra Force Shotgun Review

The photos below show the Hornady Varmint Express #4 Buckshot at 7 and 21 yards.  Again, this is a tight pattern for the Hornady load with 18 of 24 pellets in the black 12" circle.

Figure 9 - Hornady 2¾" #4 Buckshot 7 Yards           Figure 10 - Hornady 2¾" #4 Buckshot 21 Yards
TriStar Cobra Force Shotgun Review   TriStar Cobra Force Shotgun Review

The photos below show the Winchester 3" 00 Buckshot at 7 and 21 yards.  One thing you will immediately notice is how much larger the group is at 7 yards.  At 21 yards, it looks like 9 of the 15 pellets were within an ~20" circle.  Perhaps more pellets were within this circle, but since they were off the target area, I couldn't tell which were new holes  in the card board and which were old.

Figure 11 - Winchester 3" 00 Buckshot 7 Yards          Figure 12 - Winchester 3" 00 Buckshot 21 Yards    
TriStar Cobra Force Shotgun Review   TriStar Cobra Force Shotgun Review

I finished up my range testing by putting another box of 8 shot through the shotgun.  After shooting another full load (5+1) with the spring loaded forward assist, I removed the spring and tried the Cobra Force Shotgun in the standard pump action mode.  I cycled another 6 shots through the shotgun paying close attention to how the shells ejected.  Generally, the shells seem to flip out of the shotgun as opposed to flying out of the shotgun.  Next I tried to fast pump the shotgun to get an idea on the overall speed of the action.  While doing this I had two shells that were not fully lifted in place by the carrier.  To correct this, each time I backed off on the forward pressure to allow the carrier to fully lift the shell in place and then chambered the round.  After decreasing the pump action speed a little for the remainder of the shells, I got a feel for the speed of the action and it functioned without issue.

One thing I found while loading the shotgun is that you shouldn't press the carrier all the way up to slide a shell into the magazine tube. It seems that the edge of the shell may catch on the top of the magazine tube ramp.  Instead, train yourself to feel when the bottom edge of the shell passes the bottom lip of the magazine tube and then push the shell in the tube.  Once I got the hang of this, feeding shells into the magazine tube became natural.

When I got the shotgun back home for a cleaning, I found that my time at the range had loosened the front sight.  I was able to take a 1.5mm hex wrench and retighten the set screw in the end of the sight.  I took some basic measurements and found that the rear sight (adjusted all the way down) was about 1.60" above the centerline of the barrel and the front sight was about 1.20".  The top of the rail was about 1.10" above the barrel centerline.  This leads me to think you would be better off removing the rear sight and learning to use a sight picture using the rail and front sight only.

 

Thoughts

The TriStar Cobra Force Shotgun has some attractive features and turned some heads while at the range.  I found it to be fun to shoot with the spring loaded forward assist.  When fast pumping the shotgun, it seemed like I was able to get ahead of the mechanisms, but when pumping at a normal rate, it functioned without issue.  The rear sight is too high and I would probably remove it and figure out a sight picture without the sight or put some type of optic on this shotgun.

You can view the other parts of this review by using the links below or feel free to add a comment on the "Reader's Comments" page.


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