I have not read much about diopter sights as compared to one another.  Yes, I did read a review or two about Anschuts, or Walther sights but not compared to anything I would know.  My back round is not 10 meter shooting on a serious competitive level but I do compete when I get a chance.  So I decided I would try to compare some diopter sights to one another and see what others think.  I decided to compare a Williams, this model is more or less used for casual shooting not necessarily competition of serious kind.  Then a Chinese copy of  Gamo diopter, a Tau representation and finally a Hammerli.  I picked these not only due to availability they represent a low to high cost of the sights.

     For comparison I used a tracking criteria.  That means after a sight in I moved the sights 40 clicks up then right then down then left, then up, then left, then down, then right and finally up to the original sight in spot.  This should create a rectangle with all sorts of movement to the sight.  Each group was of five rounds.  But to do it one group will wind up with 10 shots and the original one will have 15 shots passing through it.  I do this to scopes which I want to test as to tracking.  I chose to move 40 clicks because some diopters have a rather small increment of movement.  That has been explained to me by the people at Tau; because if the shooter is good enough he needs to move the impact a fraction to hit the center, he should get only a small fraction of movement.  If you have rather large movement of impact per click you can be on the other side of the 10.  Don’t forget the 10 is only 1 millimeter in diameter.

     The rifle is the new Air Arms S400 MPR (multi purpose rifle) as is sold by NRA, through TGAG..  I made no changes to the rifle itself it is as it came from the box.  Since the rifle comes with the Gamo look alike diopter I used the front sight.  But since I feel the Tau front inserts give cleaner sight picture I used them for all the shooting.  The insert is a clear polymer with a beveled hole in the middle which gives a black circle like the metal ones.  The only thing missing is the wings all the metal ones have.  Therefore I think the sight picture is nice and clean.  Nothing to worry about but the centering of the target in the circle.  Pellets the rifle selected (I did not select the pellets but let the rifle do it after a wide selection of pellets have been shot) was Kovohute (kovo) match ‘R‘.  These are pellets from the Czech Republic 8.3 grains and TGAG sells them for a very nice price.

  
     First up was the Williams sight.  When looking through the diopter it seemed like I was looking through a ghost sight that would normally be on a combat shotgun.  At first it seemed to bother me since I did not have a clear definition of sight.  But like the shotgun it takes some getting used to and the groups were quite respectable.  The main group of 15 shots measured .346 center to center.  I did not think that was bad at all.  It is more then adequate for what the sight is meant to be and that is close to medium hunting replacing the standard sights.  The clicks were defined very clearly no slop between one to the other sight adjustment.  And that includes the windage as well.  There is a screw on the side which tightens the elevation so it can not be moved by accident.  I would rate this sight as excellent but not for 10 meter competition.  In fact I have similar sights on my hunting rifles and one I compete in silhouette.  A sturdy and well made sight.

     Next up was the TAU diopter.  This is my favorite sight of all.  It takes 22 clicks for the elevation knob to make one complete revolution.  This is the sight where one click may not move the shot off the 10 ring but rather only from one side to the other.  Again keep in mind the 10 ring is 1mm in diameter.  The whole sight is made of some tough polymer and very durable.  I can attest to that since I have dropped it before, with no damage to the sight at all.  Two large knobs attach it to any 11mm rail.  The diopter has to be slid into place not dropped over the top of the 11mm rail.  So if the railing is not open in the back this sight may not fit.  However, so far what I seen all the air guns have the back of the rails open in some way or another.  I mounted the Tau so bar back that only one nut was needed to secure it to the MPR.  That kept me from crawling the stock.  Meaning I did not move my head forward as to strain my neck to see through the sight.  The main group of 15 shots at .262 c.t.c was considerably better then the one using the Williams sight.  Also the groups I was able to shoot were smaller one five shot group measured in at .137 c.t.c.   The knobs have + and - as an indicator to move the impact up or down.  It seemed logical to me that + was to move impact higher and minus the opposite.  Windage was similarly marked where + impact moves to the right - the opposite.  The diopter has a small rubber cup which keeps the rear very clean as to reflections and the center is very clear when it comes to the sight picture.  It may be my favorite sight only because I am the most familiar with it but the results are not deniable.

   Next was the Chinese copy of the Gamo Diopter.  This is almost identical to the Gamo, and yes it does say “made in China.”  Complete revolution of the knobs takes 10 clicks.  But they are rather large.  And they seem to feel rather strange.  I could hear the spring which holds the ball indent.  This tells me the hole drilled for the spring is too large and the spring could bind.  However, that did not happed but I just could not get used to it.   I would use them only as sight in but if I was consistently to one side of the 10 by a millimeter I would be afraid to move the sight by one click since I would be off the mark.  In fact after I finished testing all four sights I overlaid the targets and the Chinese diopter was wider then the rest.  Even the Williams had much finer adjustments, which surprised me.  The main group of 15 shots measured .407 c.t.c. it was oblong telling me it may not return to original zero.  The smallest 5 shot group was .162 c.t.c. and that tells me the sight at least stays in one spot when moved.  Couple more things I did not care for.  One when the sight sits on the MPR one has to be careful how the bolt is cocked.  If you are too ambitious cocking the rifle you could get one heck of a scratch on your right hand.  The diopter has rather sharp corners.  I can imagine the scratch could be large enough to distract a shooter from task at hand.  Two was the sight center hole for some reason was not giving me a clear picture.  OK, granted I am not the youngest shooter to use the sight but the others did not present the same challenge.  I even tried to clean the center and it did not seem to matter what I did.  This diopter also has a rubber cup for the rear.  In fact this cup was the largest and the deepest of the sights I tested.   The best part of this sight by far is that it comes with the MPR as standard equipment as it comes from T.G.A.G.

    
     I saved the most expensive for last a Hammerli diopter.  Sort of a squarish proposition but very well build.  Most of the sight is some sort of steel or iron with the adjustment knobs of polymer.  It takes 10 clicks to move the knob one revolution but as large as that seems and even looks it does not move the sight any more then the Tau which has the most adjustments.  They are clearly marked, and as comes from TGAG it comes with a front sight.  An all steel sight with one insert.  One thing that took me a while to get used to is the adjustment is backward.  The elevation is marked at T and H.  And to move them you move the sight from where you want it.  It seems to be a typical German system, I just did not realize that the Swiss used it also.  You will need some alen wrenches to secure the sight on the rifle but not a big deal.  Oh, by the way the alen wrenches are metric.  The sight provides probably the best sight picture of them all.  The sight is a rather long tunnel with a screw in eye cup.  It does not overhang to the back of the receiver so you cant gash your hand over any edges.  Not that there are any to begin with.  The smallest five shot group measured .166 c.t.c. and the 15 shot group was .318.  I am not sure why I did not shoot better with this sight then the Tau.  Other then the familiarity with the TAU and I have a habit of resting my glasses on the eye cup making a more of a steady hold.  With this sight that is impossible,  but still the sight picture I would rate as the best of all the diopters.

     As you could have guessed the Hammerli brings the highest price at $295.00, second was Tau at $135.00.  These prices I obtained from TGAG and I don’t think that includes S & H please check on that.  The MPR rifle has the diopter included with it.  A very similar sight from Gamo is about $115.00.  And the Williams I found at Brownells for about $81.50, I am not sure I was looking at the one with the large windage and elevation knobs.

       
     So there you have it a non expert look at diopter sights.  One question I am not sure I answered and that is “would I use them for hunting?”  Answer;  you bet, but only with an appropriate front sight insert.  And that would be most likely a post.  In fact I seen several different posts some very pointy to squarish with different widths and even a ball at the very tip. I like the 3 millimeter wide one for hunting, easy to see.

 

Thanks
Rada