Where to mount a red dot sight on a pistol

First topic message reminder :

When mounting a red dot sight to a rail on a pistol, are there any advantages in attaching it more towards the front, or more towards the rear?

Seems to me that the further towards the rear, the better, as it will make the gun feel "lighter".

Maybe it makes no practical difference, but in the photos I see of pistols with red dots, the sight usually is as far towards the rear as possible.

This photo is where I attached my Aimpoint H-2 on a High Standard X-Series.  
To me, it "looked" right, but maybe I'm missing something.

Nothing urgent, the gun seems to work fine as it is now, but if there's a good reason to move it, I'll do so.

......also.....  this rail is the one that came with the gun when I bought the gun from Alan.  But when I wanted to mount my Vortex Venom, it wouldn't fit the rail.  The slots are too narrow, and not deep enough.  I guess I need to order a different rail, or go to work with my file again, as I did years ago on another gun.  Not sure if the rail I have now is "Picatinny" or "Weaver".  My Aimpoint fits fine, but I wanted to try the Vortex Venom.

Here is an insightful article that gives a brief history of the two rail systems if a little superficial.  The Wiki entry is a pretty good detailed review of Picatinny.

Cliff notes:
Picatinny Rails are a mil-spec derivative of the commercial loose standard Weaver "Style" rail.  The need for the Picatinny mil-spec standard came from the lack of a true standard in the Weaver offerings.  Unfortunately if you buy Weaver hardware you risk a mismatch; not that a file couldn't solve the problem.

I endeavored on this post mostly just to educate myself.

@alaronstein the Weaver slot "standard" as best as I can determine is .149" not .140"; depending on who you ask that is both nothing and something....

Mike, 
  I hope that we are dealing with the same picture on the rail. The FIRST Picture is NOT our rail. I will replace it as a courtesy to you BUT, I don't understand how it could have happened.  You have explained my intention and goal with our DESIGN Bases !!! I want them to be TIGHT !!! I don't want them to have the slack that is normal on Weaver Factory Bases !!! That slack leaves the possibility for the ring to NOT be shouldered in the slot on the base. I have zeroed in on what it takes to make the Weaver rings a TIGHT Fit. After 28 years, it appears that the VAST Majority of our customers are VERY Happy. I have ZERO plan to accommodate aftermarket product dimensions. The bases can be modified by users in the VERY small number of cases that might exist. I am also sure the Various manufactures can supply bases for their products.   

 Alan

alaronstein wrote:Mike, 
 The FIRST Picture is NOT our rail. I will replace it as a courtesy to you BUT, I don't understand how it could have happened. 

I had a gun on order for months, if I remember correctly, and you notified me that it was ready...   I immediately bought it. I expected a "victor" but improved.  I would prefer to use the support rings that come with sights, but the stock support rings from Ultradot have always seemed like "junk".  I've always gotten around this by using after market rings, that split apart horizontally, not vertically, so if I remove and re-install my sight, it will always be aligned properly (or close).  With good mounts, the Ultradot sight fits fine on your rail.   Aimpoint H-2 sight also fits perfectly.  I bought another Vortex Venom (small, and light, and excellent), but the locking screw in the middle will not drop down into the rail slots.

No hurry - just let me know when you want me to return it, so you can replace it.  Or, send me a good rail, and I'll do all the work.  Assuming the rail comes off the barrel, all I'll need to send you is the rail...   If there is any doubt, I'll send the rail with the barrel.

Please check that the width of the grooves is at least 0.180" (the standard Weaver Spec). If the groove gap is less than that, maybe the gun will be more accurate, as I think you wrote, but my sights might not fit.  The "screw" on the bottom of the Venom sight, measures 0.159".

I'm not sure why I should care if I get Picatinny or Weaver - I read what you wrote, but both would be good enough for me.  :-)


I don't understand how it could have happened...
Buying "the first" is something I should have been more concerned with.  Quite a few problems with this gun, and all the other problems are fixed.  My fault - I should have waited for you to work out all the "bugs".

I also bought a Victor, at about the same time.  I enjoy all the improvements you've made!

One more thing to add.

Over my life, I've learned that if you buy "the first" of something, you're likely to get something that needs to be corrected.  It's happened to me so many times that I ought to have learned by now.  But in every case so far, and Alan is no exception, if you buy something from a good dealer/manuracturer/whatever, while you DO run the risk lf getting a product with "bugs" or "defects", you know that if that happens, the product will be taken care of.

With Alan - who knows what rail is now on my gun, but I trust he will make it right.

With Nikon they introduced a super DSLR, and I got one of the first of these to show up at B&H camera, but it "died" after a very few photos.  Nikon sent me a replacement, four times, until I got one that was perfect.  

Then I bought my Springfield SA-35 when everyone wanted one, but they couldn't be found without paying hundreds of dollars extra. Stupid me did that - but then it needed three trips back to Springfield until I got one that worked.

That brings me to the title of this thread - "Where to mount a red dot sight on a pistol?"  

I've discovered a few things, but while they work for me, I'm not sure that is the best answer.

For me, the further forwards the sight is, the heavier the gun feels in my hand.
The more I move it back, the lighter the gun "feels".
The lighter the gun "feels", the more steady I can hold it, for the longest time.

Also, on my 22 Pistols, the "longer" the sight is the more I can keep it steady.  Which is why when I replaced my Expensive Aimpoint H-2 with a lighter 1" Ultradot (as suggested by Dave), I could shoot it better.


But, to be honest, I tried one other "trick" at the same time a using the Ultradot.  Brian Zins made that video where he suggest we look at the TARGET, not the DOT.  Surprisingly, doing it Brian's way was easier for me.  My perhaps silly explanation is that when I'm paying attention to the dot, I'm bothered by how much it wiggles and wobbles.  When I pay attention to the target instead, and turn down the dot brightness, everything is easier for me.

Maybe someone who understands these things better than I do, can do abetter job of suggestion the best way to use a red dot sight.

This was interesting to try to trace. 

The 0.18" figure for slot width in a Weaver rail is quoted in many places on the internet, but based on the wording all instances appear to ultimately originate from a Brownells article at http://www.brownells.com/.aspx/lid=10724/guntechdetail/Picatinny_Rails__Weaver_Rails__What_s_The_Difference, or perhaps at https://bulletin.accurateshooter.com/2009/02/tech-tip-picatinny-vs-weaver-rail-specifications/; with the first link dead and no attribution on the second one it's not clear what the true origin is. This is also cited and repeated in the Wikipedia article for Weaver rails, which is probably the proximate source that most of the places repeating this figure got it from.

This however does not appear to have ever been a published standard from Weaver. As far as I can tell, Weaver never formally specified this, so unlike Picatinny rails (which do have a standards document) this should probably be considered merely a convention.

I do, however, find many sources that quote the width of the standard Weaver locking bars (to fit the slot) as nominally 0.149"-0.150" or 3.8mm for as long as they've been sold. Now as WSR32 pointed out above earlier there is a discrepancy here with the 0.140" width Mike and Alan have mentioned. I don't have one in hand so I can't confirm whether it's really 0.14" or 0.149", but assuming that discrepancy was just a measurement error or tolerance allowance or mis-remembering somewhere between these posts and quoted sources, I imagine what happened is that the slots on Alan's rails were sized to closely fit the standard Weaver locking bar. That matches up with what Alan says earlier in this thread regarding his die.

With the disclaimer that I don't have specific expertise on the subject, I'd cast a vote here asserting the following:
- that the 0.18" "standard" width of Weaver rail slots has never in fact been standard and appears to have been promulgated across the net from a single Brownell's article which itself did not cite any source or standard
- that the 3.8mm / 0.149" width of Weaver locking bars / locking screws is also merely "standard" in the same manner - i.e. in that Weaver stuck to that size on most everything they sold
- and that therefore Alan's die maker's choice of slot width was reasonable given their justification of deciding to follow one "standard" over another "standard" (the size of the bar over the size of the slot) for sound mechanical reasons.

It appears that there are really two "standards" by convention here - the width of the locking bar as sold by Weaver and the width of the slot on the rail as sold by copycats and Weaver itself. Alan's toolmaker decided to fit to the bar rather than follow the slot width convention, and Vortex decided the opposite (or didn't really think about it, or their toolmakers got fooled by the same "standard" from the aforementioned Brownells article / Wikipedia page). In other words I think both made equally defensible and reasonable decisions, but given that they are not even attempting to match the same number, Alan (and his diemaker) should not be blamed for his rails not fitting a Vortex screw. Especially if you define a "Weaver rail" as "a rail that fits rings sold by Weaver" rather than "a rail with slots 0.18" wide".

I just measured the slots on the Weaver rail that LSP sells for their HS barrels and they are also .140".

I'm wondering if the location of the red dot affects the movement of the red dot. If my wrist is the fulcrum or pivot point & the red dot is directly above my wrist there is maybe less movement than if the red dot mounted further forward. The more forward the more movement. Just my assumption, I may be completely off.

I think it does make a difference.

I try mounting the dot so that its center of gravity is above the grip - I have two of the same gun with different mounts, on my usual gun I can do that and on the other one I'm forced to mount it further forward due to the mount being shorter towards the back. I notice on the latter that the further forward weight distribution pulls the muzzle downwards, which adds a forward rotational strain on my wrist since I'm not used to it, which makes it a bit harder for me to maintain a good hold over long sessions. Perhaps you could get used to it, but I could see an argument where the added muscle usage needed over a more "neutral" hold that has less forward rotational strain on your wrist would make a difference even if the relevant muscles in your hand/wrist were used to the forward center of gravity and stronger.

I think further forward the weight, easier to hold on short term but fatiguing. I find heavier the gun, easier to point until tired