When building a rifle for dangerous game, I always like to include express sights
on the barrel. Let me show you how we put those on. I prefer a quick detachable
scope because there are times, especially in thick bush or in poor light, when open
sights work best. An island style rear base, like this one from New England
custom guns, matched with a banded front ramp from the same company, is a good
place to start. Once the front side ramp is attached the sight beam can be
selected from a variety of inserts after which the rear sight notch can be filed
in. Both the rear and the front sight bases are available for different barrel
contours, but installation requires the final contour to be shaped by the
gunsmith. The leading edge of the rear base should be located about four and a
quarter inches from the front of the recoil lug. The best way I have found to
match the contours is to place a strip of abrasive paper on the barrel so the
dimensions of the wrapped barrel is the same as the bare metal where the rear sight
will be located. Carefully sliding the base back and forth with moderate
pressure will open up the radius to match the barrel contour perfectly. Now I
clean the underside of the sight to remove all the remaining bluing. A bit of
flux is added to the underside of the sight after which I can heat it up using
a propane torch and melt a small layer of solder onto the surface. This process
is called tenting, one wipe with some steel wool finishes
the job. With the barreled action leveled in a vise, I can add a bit of flux to
the barrel, along with the sight. Now I can level the sight on the barrel and
use a spring clamp to hold it in place.
A bit of cold blue added to the barrel around the sight will keep any extra
solder that may run out from sticking.
The barrel and the site are heated until the solder flows securing the site to
the barrel. I then check the site to be sure it hasn't shifted and is still
level, yes. After we're satisfied with this location
the rear sight base will serve as a drilling guide for the fastening screws.
I'm using a #29 drill bit and a stop to prevent drilling into the bore. I
tap the hole remembering to back it off regularly to prevent breaking the tap.
All that's left is to tighten the fastening screw, that looks pretty good.
Now we can install the banded front sight ramp. First I'll disassemble
the sight ramp assembly. The sight is a bit undersized to begin with, the barrel
diameter on a rifle measures about 0.6620, while the inside diameter of our banded
site measures about 0.6470".
Because there isn't much taper in two inches of barrel a standard chucking
reamer will work fine for opening up the band. We're using a three jaw chuck and
some brass shim stock to hold the sight.
I'll slide the sight on the barrel so it's about a quarter-inch from the
muzzle to check it for fit. After removing the sight and cleaning
the contact surfaces with cloth-backed abrasive I can tint them paying special
attention to the underside of the ramp and the inside of the band. After checking
the site for proper fit, I cleaned the barrel surface and flux it along with
the sight. Then I place the ramp back on the barrel check it for level and
outline the sight and cold blue. Now I heat the barrel and sight until the
solder flows. All that's left is to tap in the front sight, that looks nearly perfect.