There are many reasons you might want to install a rear sight on your pistol, in my case I’d previously removed the factory three dot tritium night sights that came standard on my M&P Shield 9mm and in their place installed a Trijicon HD Orange front sight and a custom Burwell read serrated plain (no dots) rear sight in a Hackethorn configuration. Burwell does great work on M&P’s.
What is “a Hackethorn Configuration?” This is an iron sight system named after the man given credit for utilizing a single front tritium sight with a plain rear sight Why? Because three glowing dots in the darkness can get darn confusing and take a lot more time for an experienced shooter to align. New shooters take well to the three tritium dot system mostly because they’re not yet that fast, and they don’t train in the darkness as they should. As you start picking up your speed three glowing dots will slow you down and eventually drive you mad.
Experienced shooters shoot with both eyes open and utilize muscle memory (for lack of a better word, there really is no such thing as muscle memory) as they ‘push out’ their pistol with the sights all but aligned. Experienced shooters point reliably point shoot to longer distances, learn to quickly cover a threat with their front sight, and how to find that front sight dot between the ears of their plain black sight much quicker than trying to align 3 dots. This concept works in daylight also, but the benefits are great in the darkness.
I personally discovered this competing at the higher levels of ISPC Limited Class back in the early 90’s but couldn’t’ convince myself for carry gun purposes until the early part of the new century after doing a lot of reading and talking to people in the industry I trusted.
When I first purchased my M&P Shield there weren’t many rear sights for the Shield yet available and Burwell Gunsmithing had made a few prototype rears for the Shield and I talked them out of one. It was a stout rear sight with large ears I could easily use for one handed racking of the slide if necessary. There was nothing at all wrong with this sight, but I found something that worked better for me.
I’m nearing my mid-50’s and soon I might need reading glasses. But already I’ve noticed it’s more difficult to focus on my front sight and to pick up that front sight between the rear sight ears as quickly as I liked. Working with my M&P 9mm Full Size I changed out my front Tritium HD Orange with a 10-8 Performance front fiber optic sight with a .115 width which is the only fiber optic for my M&P suitable reinforced for actual hard duty use. During all but nighttime use this sight is like magic. I can pick this sight up faster than anything I’ve used before. But, I now must carry this gun with a white light because my tritium is no more. If you’re having trouble focusing on your front sight, try a fiber optic. Amazing difference. You won’t focus any better, but you sure will see it quicker and sooner.
At the same time I replaced my Ameriglo black serrated rear with a 10-8 M&P rear sight with a .156 U notch. U notch sights aren’t new, they’ve been around a long time. Yet, sometimes we forgot the reasons we have different choices until we have a problem. Like not being able to pick up the sights as quickl;y as we’d like. Then we examine why. When drawing with speed you need to pick up that front sight immediately and shortly thereafter center that front sight between the ears of the rear sight. The super bright fiber optic (in any color) front sight certainly helps, and so does having enough light on each side of that front blade. Too much room (light) and you sacrifice accuracy, too little room and you sacrifice speed. Did I tell you I’m nearing my mid-50’s at a pretty fast clip? I need the speed.
The front fiber optic front sight combined with the extra light on each side of that front sight by choosing the .115 front and .156 extra wide rear really helps. But the U notch is like icing on the cake. It gives me light where we don’t expect to see it, on the fore vertical side of the front sight blade. That’s the best I can explain how I got here. Do some reading with the latest top tier instructors and you’ll see this material again.
So, what works with the full size M&P 9mm works on the diminutive M&P 9mm compact Shield? Not exactly. And it’s not the guns, but the way I’ve tasked these pistols. The M&P 9mm Full Size I’ll use in IDPA and steel shooting and I’ll also carry it during the winter during which the added size of an added white light won’t be an issue. The much smaller M&P 9mm compact Shield will be carried during the summer and other times when a tritium front sight will suffice. This means I must keep my Trijicon HD Orange tritium front sight but I can change to the 10-8 Performance .156 U notch rear for sure. Which is what I’ve been trying to get to for the last six paragraphs. Sorry for the verbose explanation.
Let’s get to fitting the rear sight. Can anyone do this? Sure, if you’re used to working with tools, you have some patience, and you won’t hate yourself if you mess up and have to buy another $50 rear sight then maybe this is for you. If you lack patience, fine motor control, and you won’t be able to sleep at night if you trash a sight and must buy another, then let a gunsmith do this for you. You’ll need the basic tools you see below:
A small brass file, a 3/8 “ brass punch, an allen head wrench that fits the set screw of your sight (they usually come with one) a tube of red Lock tight, a strip of 120grit emery cloth, and a sanding block with emery cloth if you have one. You’ll also need an 8 inch double cut #2 Swiss Pattern file. Simple basic tools.
Fitting sights is all about patience. Depending on the manufacturer, the manufacturing run, your pistol, you’ll need to remove more or less material from the sight base. THE SIGHT BASE IS THE ONLY PLACE YOU WILL REMOVE MATERIAL. Notice the picture below, three rear sights for the Smith and Wesson M&P. Each sight fits the same. One I only needed to smooth the finish, another I had to remove most but not all of the finish, and the other all the finish and even more metal.. So don’t try to match your new rear sight with what’s been removed from your old rear sight.
KNOW YOUR GUN MODEL. Sometimes the manufacturers hide things under the rear sight. In the case of the M&P you can see the plunger safety block spring cap, and under the cap the spring. If you don’t know they’re there, you’ll launch them into a new frontier never to be seen again. Make sure you cup your hand over this area when removing the rear sight.
To remove the old sight first find the right size allen head wrench. Don’t’ try to just spin it off. Instead slowly work it back and forth, if it has Lock tight securing it this is how you get it off. Otherwise you’ll strip out the screw. Also by knowing your gun you’ll know which direction to remove the sight. In the case of the M&P you remove the sight from the left to right (right being the side the plunger spring is on). Using the brass punch put it on the dovetail base and tap it off with the brass mallet.
LIST OF CAUTIONS:
CAUTION: ALWAYS UNLOAD YOUR FIREARM BEFORE CLEANING OR ANY TYPE OF MAINTENANCE.
CAUTION: NEVER hit steel against steel with hammers. It could cause the hammer to fragment.
CAUTION: Using steel punches will certainly not only remove the finish on your sight, but if you hit it hard enough it will ruin the sight.
CAUTION: ALWAYS use a thick leather pad between your vise jaws and your slide when working on the sights.
But before you do, take a silver Sharpie and make two witness marks. One on the front of the slide right in the center of the sigh notch, and the other on top of the slide set screw. Now, using the brass punch drift out the old sight taking care to trap the safety plunger spring and spring cap.
Using a toothbrush size stainless brush, brush out any residue. Now, put the new 10-8 Performance Sight in the dovetail from the right and see where it stops. You want the leading edge of the sight to go in almost half way across the dovetail. Keeping the file stationary and flat on your bench, move the rear sight across the file taking care to apply even pressure. If you don’t maintain even pressure you’ll end up with more material taken off one side than the other and you’ll soon need a new sight.
CAREFULLY remove metal bit by bit. Try five strokes, test fit, five more strokes, test fit. It might seem like you’ve been filing a long time, but be patient. Once you notice the sight slipping into the dovetail just a bit further than before you’ll need to slow down and maybe it will be time to switch to the emery cloth on the sanding block, finally ending in the strip of emery cloth to smooth out the bottom.
ONLY REMOVE MATERIAL FROM THE BOTTOM OF THE SIGHT DOVETAIL. I’ve said this twice because some people look a tit and can’t help but file the forward and tailing edges. But this isn’t how it works.
The hard part is over. The fitting takes the most time and had the most potential for catastrophe. Take your time, take breaks if you need them. Remove just enough material so the leading edge of the sight dovetail reaches halfway into the dovetail proper.
If your pistol has hidden springs and caps under the sight then you’ll need a sight installation tool like you see on my M&P below. With the slide protected by the leather pad tight in the vise jaws push the sight over as far as it will go. If you fitted the rear sight properly it should go halfway across.
Once there, remove the sight installation tool and apply a single drop of red Locktite. Using your brass mallet tap the sight until it is perfectly centered in the dovetail. Once the sight is on so far you’ll need to go to the brass punch. Ideally it should align with your witness marks and have equal space on each side of the dovetail Give priority to the space on each side of the details over the witness marks. It may be helpful to clamp a straight piece of steel (a file works) to once side of the slide and measure with a veneer caliber. Move the straitght piece of metal to the other side and measure. You can easily center the sight by going back and forth several times until centered.
You will probably find brass marks on your sight, the slide, and anywhere else you hit. No problem, use a soft bronze brush or even a tooth brush and scrub them right off. If on a Glock, M&P,. or any nitrite coated firearm I’ll just use a stainless steel brush until the assembly looks like new.
Finally apply a single drop of red Locktite to the set screw and snug it into the sight. The press fit of the sight gives the rear sight about 80% of its “staying put” power so make sure you don’t remove too much. The set screw at most provides 20%.
The first time you do this plan on a good two hours. The more material you’ll need to remove, the more time it takes and the more chance for error there is. This is simple in concept, but it does help if you have experience with tools and even more if you have experience doing this. I’ve probably installed a few hundred rear sights or more, and occasionally I still mess one up. You can only try and then try again if you must.
Now, sit back and admire your work. Look at the sight picture while dry firing and you’ll notice significant improvements. Notice all the extra light on the bottom of the notch?