By Jim
A lot of people think that you can't properly shorten a barrel to a handier length without using a lathe to crown the muzzle. But I'm here to show you that with proper hand tools you can. The crown is an important part of the barrel, because the bullet needs to release properly from one shot to the next. The bullet can be tipped to one side or another by the hot gasses and pressure behind it as it leaves the muzzle, resulting in poor shot placement.
This is only going to work on bolt action or pump action rifles. A semiautomatic rifle that uses gas pressure to cycle the action has different requirements. Simply shortening the barrel will cause malfunctions.
I begin by measuring the length of the barrel from the closed bolt face to where the new muzzle needs to be, and then cut the barrel to that new length.
Next, I clean the muzzle up with a belt grinder. This takes a lot of work out of the next step.
The barrel is clamped in a padded vise with the muzzle facing up.
A 90* cutter is prepped with the appropriate brass pilot to fit the bore. A lot of cutting oil is used to keep the teeth from building up metal shavings and to prevent tool chatter.
Smooth and steady turning of the 90* cutter ensures the face of the muzzle is square with the bore.
The brass pilot and handle is transferred to the 79* cutter and the process is repeated. This cutter makes an 11* recess to set the crown back from the edge of the muzzle to protect it from getting nicks or dings.
A radius cutter is spun in a drill to break the sharp edge of the outside diameter of the barrel. The entire thing is then polished to smooth out any machining marks.
Cold bluing chemicals are used to match the new crown to the original finish of the barrel.
Then it's off to the milling machine or drill press to drill and tap holes to replace the front sight base.
The front sight base is installed on the barrel. A finalized check let's you know if everything's OK.
And this is the barrel of a Remington 7600 pump action rifle shortened to a more manageable length. It's now a 16.5" carbine.
On a slightly different note, be aware of shortening the barrel of a semi automatic rifle. Doing so might mean that you have to open up the gas port to get the rifle to function properly. The dwell time on a shorter barrel (the amount of time the bullet passes the gas port until it leaves the muzzle) might not allow the gun to build up enough pressure to cycle the action. Increasing the gas port slightly allows more pressure to work the action. Simply cutting the barrel short often leads to malfunctions in semi auto firearms. The balance between the port pressure and operating pressure has to be maintained.
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