Dovetail Sights and Measurements

The dovetail notch is simply a cut in the firearm that sets perpendicular to the bore and allows the sight to be fitted to the firearm. The notch is widest at the base and this is the sight degree. The degree allows the wedge to stay in place. Dovetail sights and their dimensions are very interesting. They are not that difficult to cut and it isn’t difficult to install dovetail sights, but attention to detail is needed.

When you have to cut a dovetail you must dress up the cut, burrs, and parting lines as you finish the job. The final cut must be polished and beveled properly. It isn’t just about the dimensions of the sight but also about the angle. The job isn’t something that is learned quickly, but with care a credible piece of work may be done every time. Most dovetail sights are manufactured oversize with the base flared. This requires some fitting to be done even if the pistol is originally cut for a dovetail.

These are radioactive tritium insert types. These are good sights. The Bomar cut was once standard. Most modern 1911 handguns are supplied with dovetailed sights. The Kimber, Novak, and EGW are common types. Rifles are quite different. The old 3/8 inch dovetail was standard with the front sight 1.5 inches from the muzzle almost all of the time. Dovetail pistol sights are another matter.

GI slides or gunsmith slides such as those from Caspian that are supplied without sights or cuts require cutting to our dimensions. Rear dimensions vary in width, from the LPA found on the EAA Witness at 0.450 wide to the Bomar on an older Colt at 0.350. Any custom project demands deciding which sight will be mounted on the handgun prior to any cutting. Quality cutters can be obtained from Brownells, Numrich Arms, Novak’s Gunshop, and

Top Bottom similar reputable sources. The cutters are numbered and the proper dimensions are listed by the maker for cutting the slide and installing dovetail sights. As an example, here are several useful cutters listed with Numrich Arms parts numbers: 080 621 300, 60 x 300; 080 621 330, 60 x 330; 080 621 359, 60 x 359. American Gunsmith Reader Services 1.

Two punches to the slide kept the sight tight. While not elegant, it worked. The front sight is factory while the rear is an aftermarket unit the author fitted some time ago. The Glock dovetailed rear sight is rather pinched in dimension. If you were to cut a Glock-size dovetail it need not be so pinched and straight would work well. The Glock dovetail is 0.250 by 0.79 deep with a 74 degree angle. It would not be difficult to machine your own high visibility rear sight for the Glock.

Cutters aid in machining a different dimension dovetail into slides such as a standard GI, modern Rock Island Armory, or Springfield Mil- Spec. The cut must clean and exact with the cut squared on the slide. After the cut, the sight is installed.

It isn’t an easy fit and must be filed a bit to properly install the sight into Dovetail Sight Measurements Part Dimensions Angle Width Depth Heinie 60 degrees 0.300 0.060 Wilson Combat 60 degrees 0.300 0.070 Government Model 60 degrees 0.300 0.070 Officers Model 65 degrees 0.330 0.060 EGW 65 degrees 0.330 0.070 Novak 65 degrees 0.330 0.060, 0.070, 0.075 Kimber/XS 65 degrees 0.330 0.075 the dovetail slot. I usually lubricate the slot well and then tap from left to right. This works for me.

Dovetail Repair When a dovetail is damaged it isn’t difficult to repair, providing it hasn’t been completely wrecked. When the old sight in the dovetail proves difficult to remove, the slot may be too tight. If the new sight moves too easily then you need to address the fit. The procedure is simple enough. Perhaps the simplest is also usually the most effective. By using a small hammer and a flat tip brass punch the dovetail may be peened.

Hammer the punch lightly into several places inside the dovetail and slot, raising an area in the dovetail. A sharp prick-type punch raises divots in the bottom of the dovetail slot. After the punch work, the sight is inserted from left to right. The divots in the bottom of the dovetail slot will result in a tightened slot and should yield a good fit. Another approach is punching up a divot on the bottom of the sight itself instead of working the dovetail slot over.

Note, sights are usually made of softer material than the hardened slide, so this isn’t ideal but it can work. For those that find a dovetail slot that is truly troughed out, a small shim may be placed in the bottom of the dovetail under the sight itself. Never attempt to hammer or bend the dovetail inwards on itself as this simply damages the dovetail. Another fix that works sometimes is to fill the dovetail with Loctite. This works if the dovetail is a fairly tight fit with the sight.

The Loctite will not harden for some time, making it possible to move the sight about and adjust it in place before the Loctite hardens. When the slide recoils there are dynamic forces and cyclic loads in force. The sight may take a beating but Loctite accomplishes an excellent bond and may be used if the sight doesn’t need to be adjusted for windage later. AG