Shotgun Barrel/Bore confusion: the confusing world of chokes, barrels, bores, & such!

[stud40111]

Hi everyone. I was looking into the subject of "slugs" for shotguns and when reading the details of which slugs are appropriate for which types of shotguns, I realized that I know next to nothing about the various types of barrels, bores, and such. As such, I have a few questions that I hope everyone can answer for me.

1) What is considered a "smooth bore" barrel? Is any barrel that is not rifled considered "smooth"? If not, then what is the criteria for determining this?

2) What is "cylinder bore"? Does it mean that this is a non-rifled barrel that also lacks a "choke"? And what does it mean if something has a "cylinder choke"? Furthermore, what is meant by "improved cylinder bore"?

3) What is a "choke" exactly and why is it that shotguns with shorter barrel lengths, e.g. home defense types, seldom have one? I understand that a "choke" is something found in a shotgun barrel and that it helps with accuracy but I am not quite sure why, almost without exception, shorter barreled shotguns lack them (I used to think that it was because they were unnecessary for those shotguns' intended purposes, however, once I was thinking of buying a full sized Remington 870 and then getting the barrel cut down o 18.5 or 20 inches and the gunsmith was telling me that in that case the chokes would be removed and I don't understand why).

If anyone could answer the questions above, I would appreciate it.

Thanks in advance.

[RobW]

Howdy,

1. If it isn't rifled, it's a smoothbore.
2. Cylinder bore indicates that the barrel is unchoked (typically). There are variances in terminology and constriction for each designation between manufacturers.
3. A shotgun choke is a restriction (a reduction in size) at the muzzle end that is designed to improve the pattern at longer ranges. In general, the tighter the choke the tighter the pattern, but there is a point of diminishing returns.

Short barreled "home defense" type shotguns are unchoked because:
a. the intended use (short range) doesn't require a tight choke
b. cylinder bored barrels are easier to make (cheaper)

[knight0334]

1. A smoothbore lacks rifling. However there are "rifled smoothbores". On a rifle or handgun, the rifling is cut into the bore - the bore is the smaller diameter. On a "rifled smoothbore", the bore is the larger diameter and the rifling is raised from that.

2. A cylinder choke means it lacks a choke. Its bore diameter is the same pretty much the length of the barrel. An improved cylinder has a slight constriction. Modified, improved modified, full, extra full, turkey, etc have tighter constrictions.

3. A choke is when at the end of the barrel the inside diameter is smaller to squeeze the shot together to make a tighter shot column. That tighter shot column will help keep the pattern tight(keep pellets from spreading). Some chokes are fixed, meaning the barrel is bored that way. Some chokes are interchange able by the use of a tube that you screw into the muzzle.


If you cut down any barrel you will remove the choke whether it is fixed or interchangeable. You would end up having a "cylinder" choke.

[stud40111]

....


If you cut down any barrel you will remove the choke whether it is fixed or interchangeable. You would end up having a "cylinder" choke.

But if the choke is removed, why would it be called a "cylinder" choke?

Regardless, thank you to both respondents for your replies.

[knight0334]

But if the choke is removed, why would it be called a "cylinder" choke?

Regardless, thank you to both respondents for your replies.

Because it is practice to do so.

With shotguns there is an understand that there is a choke, whether it be tightly constricted or no constriction. Calling it a "cylinder choke" makes note that there is no constriction. There are even looser constrictions like a blunderbuss where the muzzle is flared out to purposely induce spreading(although the flaring's main purpose was for ease of loading).

[stud40111]

Because it is practice to do so.

With shotguns there is an understand that there is a choke, whether it be tightly constricted or no constriction. ...

So then in this case, strictly speaking, there is no choke, correct?

[knight0334]

So then in this case, strictly speaking, there is no choke, correct?

Correct.

Lopping off the end of the barrel should effectively remove any choke. ...unless the manufacturer bored the tube with a long tapered choke.

If the bore diameter is .729" to .732" once it's cut, you effectively have no choke.

[Pete D.]

a blunderbuss where the muzzle is flared out to purposely induce spreading(although the flaring's main purpose was for ease of loading).

The second part of that - ease of loading - is the point of the belled muzzle. Actual bore is "cylinder". The bell has no real effect on making the pattern wider.
My blunderbuss, in fact, delivers a slightly tighter pattern at ten yards than the "book" says it should.

Pete


















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