Howdy folks,
Lets take a closer look at something that’s often misunderstood in the shotgun world: chokes — and more specifically, how to actually know what choke you’re running.
A lot of shooters rely on visual cues or notch markings on choke tubes (one notch, three notches, etc.) to determine whether a choke is full, modified, improved cylinder, and so on. The assumption is simple: fewer notches means tighter choke. But that assumption doesn’t always hold up.
Using common tools like calipers can introduce serious measurement errors. The contact points on calipers are often too wide to sit properly inside a choke or bore, which can lead to readings that make a choke appear far tighter (or looser) than it really is.
Measuring the bore properly:
To get accurate results, Stanley uses a specialized bore-measuring tool with ball bearings and a dial indicator. This type of tool makes very small contact points inside the bore, allowing for a much more reliable reading.
By measuring:
In the video, a choke that appeared to be nearly a full choke when measured with calipers turned out to have only about 0.004" of constriction — meaning it would realistically perform more like an improved cylinder.
On the flip side, another choke marked as “full” measured with roughly 0.043" of constriction, which puts it well into extra-full or turkey choke territory, despite what the marking suggested.
Choke markings are a reference, not a guarantee.
Actual shotgun performance depends on many variables, including:
Even shells that seem nearly identical on paper — from different manufacturers — can produce noticeably different patterns in the same shotgun.
If you enjoy this kind of practical, measurement-based content, let us know in the comments of the Youtube video linked above.
Thanks for reading, and as always,
True North Arms
Lets take a closer look at something that’s often misunderstood in the shotgun world: chokes — and more specifically, how to actually know what choke you’re running.
A lot of shooters rely on visual cues or notch markings on choke tubes (one notch, three notches, etc.) to determine whether a choke is full, modified, improved cylinder, and so on. The assumption is simple: fewer notches means tighter choke. But that assumption doesn’t always hold up.
Why markings can be misleading:
Shotgun chokes are often marked according to a manufacturer’s standard, but those markings don’t always reflect the true constriction. Two chokes that look different — or even measure differently with basic tools — can perform very similarly once properly measured.Using common tools like calipers can introduce serious measurement errors. The contact points on calipers are often too wide to sit properly inside a choke or bore, which can lead to readings that make a choke appear far tighter (or looser) than it really is.
Measuring the bore properly:
To get accurate results, Stanley uses a specialized bore-measuring tool with ball bearings and a dial indicator. This type of tool makes very small contact points inside the bore, allowing for a much more reliable reading.
By measuring:
- the actual bore diameter of the shotgun
- and then the true inside diameter of the choke
In the video, a choke that appeared to be nearly a full choke when measured with calipers turned out to have only about 0.004" of constriction — meaning it would realistically perform more like an improved cylinder.
On the flip side, another choke marked as “full” measured with roughly 0.043" of constriction, which puts it well into extra-full or turkey choke territory, despite what the marking suggested.
Why performance matters more than labels:
The takeaway here is simple:Choke markings are a reference, not a guarantee.
Actual shotgun performance depends on many variables, including:
- Bore diameter
- Barrel length and finish
- Choke geometry and alignment
- Ammunition type and wad design
- Environmental factors like temperature
Even shells that seem nearly identical on paper — from different manufacturers — can produce noticeably different patterns in the same shotgun.
Final thoughts
If you want consistent results, don’t rely solely on notch markings or assumptions. Measure when possible, take notes, and most importantly, test your setup on a pattern board. Every shotgun is a little different, and finding what your gun likes is part of the process.If you enjoy this kind of practical, measurement-based content, let us know in the comments of the Youtube video linked above.
Thanks for reading, and as always,
True North Arms
