Workbook

LESSON 201: REMOVING AND INSTALLING THE BARREL

(Revised 01-15-01)

To install a barrel on your receiver, you may first have to remove the old barrel, or in the case of

some kits, such as the StG-58, you may have to remove the remnants of a demilitarized receiver from

your new barrel. There is not enough receiver stub to lock up well either in a bench vise or a barrel

wrench. Do not mess with it. You may be enthralled with fondling a small piece of history for a

while, but it wears off quickly. These Austrian barrels are on VERY tight and but can be cut off

easily.

Secure the barrel in the vise with the left side of the receiver facing up. Take a small sharpened

punch and prick the breech through the slot where the cocking handle goes. Make sure your tiny

mark is exactly centered in the slot. This "witness mark" will assist you in getting the barrel aligned

in your new receiver. Get yourself a hacksaw with a

bimetal blade, teeth pointing toward you so they cut on

the pull stroke for greater control. You will notice a

dimple inside the cocking slide channel. This is the

thinnest part of the receiver. Take the hacksaw and cut

parallel to the slot right on top of this. You can use a

cut-off wheel on a rotary tool as well, being careful not

to let the wheel bind and then skip out of the slot and

into your finger. Feeling in your jaw, the vibration of a

cutting wheel grinding to a halt in your knuckle, is

unpleasant. I know this. For doing assembly-line

receiver stub removal, I use a reciprocating saw with a

short and fine DeWalt blade. It works just like the

hacksaw method, but is very easy to screw up and I

don't recommend it for the novice.

You should cut until you see a slight change of color -- you'll see the tops of the barrel threads poking

through. Even out your groove, being careful not to gouge the barrel when you are working at the

front end of the receiver. When you finish, move the blade inside the cocking slide channel and cut

toward the chamber, cutting all the way through the receiver. Stop when you are a few thousandths

of an inch short of touching the breech face. Take a cold chisel (not a woodcarving one) and stick it

between the top and bottom part of the cocking slide channel and smash it with a hammer. A few

vigorous blows will split the receiver right along the groove you have cut and the receiver will spin

off the barrel by hand. If you cut too deeply and actually cut into the threading, don't worry, just

polish out the gouge – it doesn't show and won't hurt the barrel.

To remove a barrel from an intact receiver, secure it in the vise. Either use a correct receiver fixture,

fabricate a block from wood, or shim. More on this later. Do not have any part of the vise jaws

touching the receiver where it joins the barrel. You should have nothing on the barrel except the

front sight assembly and handguard retainers. Remove the carrying handle and gas tube.

If you are going to discard the old barrel you may use a pipe wrench with a 12" or longer handle.

Remember, pipe wrench only grips in one direction. Grab the barrel with the wrench as close to the

receiver as possible. You can gain significant mechanical advantage by adding a hollow pipe

("cheater bar") to the end of the wrench, extending its length. Sometimes a hard rap with a hammer

will free a barrel easier than steady force. Applying heat from a MAPP Gas torch will melt any dried

grease that may be gluing the threads tight. Keep the flame moving around the joint. Under no

circumstances should you use anything but air to cool it off afterwards. Quenching will make the

metal more brittle. After the oil has burned away and any smoking stops, you should have slight