What is a choked barrel (...and why do we care?)

by Harley Ayre

Most shooters know what a choke does for a shotgun barrel. It constricts the shot column just before it leaves the muzzle, resulting in a tighter pattern downrange. A choked rifle barrel does the same thing, but not for the same reason.

What is a choked rifle barrel?
A choked barrel is a constriction in the bore size near the muzzle. Instead of a screw-in device or an add-on appliance, the rifle bore is made that way. The bore actually gets smaller. It is always a small amount - usually less than one-thousandth of an inch. Both the bore and the lands close in by an equal amount. This is done gradually to not disturb the bullet, or, in our case, the pellet.

Choked barrels are not new
Barrelmakers were choking barrels in the 19th century. Harry Pope, the most famous barrelmaker who ever lived, sometimes bored his choke along the entire length of the bore! I doubt anyone is still doing something like that, but isn't it fascinating that anyone would? Remember, he then had to lap (polish) the bore and then rifle it! Most barrelmakers lap AFTER rifling, but Pope did it both before and after! That's why a gun with a Pope barrel commands the price of a new luxury car today.

What does a choke do?
A choke assures the uniformity of the bullet/pellet at the most critical point in its internal travel - just before it leaves the muzzle. It actually swages (squeezes) the projectile slightly smaller, ensuring that all of them leave the bore a uniform size. This is the reason that it does very little good to run pellets through a sizing die. The barrel itself IS it's own sizing die!

The choke doesn't even have to be uniform!
It's true. The Weihrauch company builds a lot of spring-piston air rifles. They do not choke their barrels, but they do swage in dovetails to hold the front sight base. The upsetting of the outside of the barrel carries through to the bore, which becomes slightly choked. It may not sound like much, but let's look at what it does.

A little knowledge is a dangerous thing!
Back in the 1990s, when the internet chat forums were getting started, some people posted that the optimum length for a spring rifle barrel is 9-12 inches. After that, the pellet no longer accelerates. That's actually true, but what that fact did was start a rash of barrel-bobbing. Unfortunately, the barrel-cutters didn't get any MORE velocity, but they did manage to remove their chokes. So, they got less accuracy. If you shop for used spring air rifles, beware of "carbines" that are homemade!

Keepa you hands off!
Now don't run out and start damaging all your barrels in an attempt to choke them. If you have quality guns Like Falcons and AirForce rifles, the barrels are already choked correctly. If you push a pellet from the breech to the muzzle, you will actually feel the choke as it resists the pellet's passage. However, now you have another reason to not clean a barrel from the muzzle unless there is no other way.