Installing a M1
Carbine Rear Sight on a Ruger® Mini Thirty®
by Roy
Seifert
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Disclaimer: This
article is for entertainment only and is not to be used in lieu of a
qualified gunsmith. Please
defer all firearms work to a qualified gunsmith.
Any loads mentioned in this article are my loads for my
guns and have been carefully worked up using established guidelines and
special tools. The
author assumes no responsibility or liability for use of these loads,
or use or misuse of this article.
Please note that I am not a
professional gunsmith, just a shooting enthusiast and hobbyist, as well
as a tinkerer. This
article explains work that I performed to my guns without the
assistance of a qualified gunsmith.
Some procedures described in this
article require special tools and cannot/should not be performed
without them.
Warning: Disassembling
and tinkering with your firearm may void the warranty.
I claim no responsibility for use
or misuse of this article. Again,
this article is for entertainment purposes only!
Tools
and firearms are the trademark/service mark or registered trademark of
their respective manufacturers. Click on any
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Introduction
I have a Ruger Mini Thirty® in my collection which chambers 7.62 x 39 ammo.
The rear sight of this rifle is adjustable for windage and elevation, but
it is not click adjustable. In
addition, this sight folds down if a scope is mounted to the receiver.
Although this sight is fully functional, I have never really liked the
looks of it. I have always liked the
looks of a military-style rear sight, so I decided to replace the folding rear
sight with a military-style rear sight.
Adjustable M1/M1A-style rear sights for the Ruger® Mini’s are available
on the Internet anywhere from $40 - $80 and up.
This seemed a bit pricey to me.
M1
Carbine Sight
I found that I could purchase a complete rear sight assembly for a .30 M1
Carbine for $25.00 from
Gun Parts Corporation. This rear
sight assembly is adjustable for both windage and elevation, and attaches to the
receiver via a dovetail. The
dovetail for the M1 Carbine is larger than the dovetail on the Mini Thirty®, but
that should be easy to correct.
Anyone can add aftermarket parts to a firearm, but to modify, adapt or improve
something to make it work is true gunsmithing. I purchased this sight in
2009, but as of the date of this article the price has gone up to $54.
The
original Ruger® rear sight and mount consists of three parts; the rear sight
assembly itself, windage lock, and windage lock screw.
The base of the sight assembly is a dovetail that fits into a
half-dovetail slot cut into the top rear of the receiver.
The windage lock provides the front half of the dovetail slot into which
the sight base sets. The windage
lock screw provides tension on the windage lock, which holds the sight in place.
The width of the original sight base dovetail is 0.376”.
The width of the M1 Carbine sight base dovetail is 0.470”.
Both are a 60-degree dovetail.
Milling the Sight
I decided to mill 0.094” off the rear of the carbine sight dovetail and re-cut
the 60-degree edge so it fit with the original Mini Thirty® parts.
I did this because the base was too wide to accommodate the width of the
windage lock screw head and the small pad on the front of the elevation
adjustment base. This was the best
solution since I didn’t have to modify the receiver
I
disassembled the M1 carbine sight and placed the base upside down in the
machinist vise on my mill. Then I
took a 3/16” square end bit and milled off 0.094” from the rear of the sight
base dovetail. This pilot cut
prevents the dovetail bit from loading up.
Then I
took a 60-degree sight dovetail cutter and cut the final dovetail.
Notice the flat edge of the base from the pilot milling.
After performing the dovetail cut I cold-blued the exposed metal.
I cleaned and oiled the sight base and tried it for fit.
It fit into the dovetail perfectly, and the windage lock held it tightly
in place.
Assembly
I reassembled the sight and used acetone to clean the top of the receiver where
the new sight sets, and cleaned the base of the new sight.
I put a few drops of Loctite 609 onto the base of the sight, centered the
sight in the dovetail, and tightened the windage lock screw.
Loctite 609 is designed to be used where two metal parts fit together.
I frequently use it on sight bases to prevent the sight from moving.
It takes about 24 hours to fully cure.
Unlike glue or epoxy, the sight can be removed later.
I now
have a rear sight click adjustable for both windage and elevation.
Because I didn’t modify the receiver, I can replace the original parts if
necessary.
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