Accuracy One Seating Depth Comparator Review

Looking for a faster, easier, and more accurate way to measure bullet positions on your loaded rounds? Check out the Accuracy One Seating Depth Comparator. This unique tool provides a shoulder-to-ogive measurement instead of the traditional cartridge base-to-ogive measurement. The Accuracy One Comparator just might work for you. This unique tool allows a very rapid and secure measurement that provides a precise determination of the bullet seating depth in the case.

Accuracy One Seating Depth Comparator

Product Review by F-Class John
You probably check your loaded ammo by measuring cartridge base to ogive, but have you ever considered there may be a better way? Curt at Accuracy One has considered the question, and after exhaustive research and testing he created the Accuracy One Seating Depth Comparator. As opposed to looking for a base to ogive measurement, this tool measures from the shoulder to ogive, which is arguably the more repeatable number when it comes to accuracy.

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As Curt explains, “Well, when you fire a chambered cartridge, the strike from the firing pin first pushes the cartridge forward until it bottoms against the shoulder. The primer is then ignited. What this means is that your seated bullet depth consistency can more accurately be gauged using the dimension from shoulder to ogive. Using this dimension, you effectively eliminate any small variances in your sized case length from the equation”. As a result, it made sense that when he was designing the measurement tool his goal was to create a universal insert that allowed a user a quick, easy, accurate and repeatable process that measures from mid-shoulder to ogive.

The comparator fits cartridges from .22 to .30 Caliber with 0.400″ and larger shoulder diameters. The tool fits so many bullet sizes because of the specific taper that Curt developed. This ensures that any caliber in that range makes good contact along the ogive. As I used this tool and talked to people about it, I kept getting skeptical comments with people asking how it could measure the ogive on that many calibers accurately. I had to remind them that the ogive is not a single point on the bullet but in fact the entire curve from the tip of the bullet to the point it straightens out. As a result, it’s only important that the tool you use is consistent in what point along the ogive it measures and that’s where the Accuracy One Seating Depth Comparator shines. According to Curt, he went through countless iterations on his design until he was able to accurately and repeatably measure all those calibers (.22 to .30).

How to Use the Accuracy One Seating Depth Comparator
Using the comparator is simple. There are alternative methods. The easiest way is to simply zero the indicator, insert a loaded round, note the measurement and compare any future rounds against it for variation. An alternative to this is a method I use. I insert a loaded round and then zero the indicator. This allows you to see the exact variation without mental math (and frankly it’s faster this way). I also use this method to sort loaded rounds for matches in order from shortest to longest ensuring that rounds that measure the same are fired together.

Bonus Option — Measuring Length to Lands with Tool
Another great use for this Accuracy One comparator is to take my initial depth to lands. This helps ensure my seating depth was properly set. Using a case with very light neck tension, I load a bullet, and with a stripped bolt I load and close it. Then I can remove the round and take a measurement, zero the indicator and make a note of it in my book. After that the comparator will remember the new zero until it’s zeroed again and if that happens by accident, I can always reference the number that my round measured and pull on the indicator stem until that number is found and then zero it again. I found this entire process fast, easy and repeatable as I loaded rounds and needed to check for any seating depth variance.

Tool Pricing:
Seating Depth Comparator without Indicator: $65.00
Seating Depth Comparator with Indicator: $115.00
Gauge Stand: $47.00

Purchase Options
You can buy the tool with or without an Digital Indicator. Accuracy One also makes a Primer Depth Gauge. Both Accuracy One tools employ the same digital indicator. This helps save money as you can order the comparator alone if you already have one (either from another Accuracy Tool or another tool).

The Accuracy One Seating Depth Comparator is essentially the same size as the Accuracy One Primer Depth Gauge, so you can even utilize Accuracy One’s primer gauge storage case. There is also an optional stand that I HIGHLY RECOMMEND as it can hold either the seating depth OR primer gauge, making for amazingly simple one-handed operation while you’re loading.

CONCLUSION — Tool Is Precise, Repeatable, and Fast
Overall, this tool left me feeling confident in my depth setting and I found it quick and easy compared to past methods. At the end of the day there are several ways to skin the proverbial cat when it comes to measuring seating depth. But if you’re looking for what just might be the most accurate, consistent and speediest method, give the Accuracy One Seating Depth Comparator a try.