BULLET COMPARATOR INSERTS Reviews & Ratings

The Sinclair Bullet Comparator inserts are meant to be used with the Sinclair Bullet Comparator and Bump Gage Body. These inserts are stainless steel and machined with a taper and a short straight section to more accurately duplicate the chamber throat. This eliminates the wobble experienced with many comparators which have standard drilled holes. Our design allows you to quickly and accurately measure and compare bullet ogive-to-base as well as loaded round ogive-to-cartridge-base measurements. This measurement gives more consistent results than measuring overall lengths since the meplat (the open tip of the bullet) can very by several thousandths of an inch from bullet to bullet.

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3 Stars

Reviews Summary

The BULLET COMPARATOR INSERTS receive mixed reviews, with many users praising their machining, precision, and superior quality compared to aluminum options. However, some customers report issues with sizing, inaccuracies, and damage upon arrival, leading to dissatisfaction. Overall, while many find them effective and reliable, concerns regarding quality control and fitting persist.

What Reviewers Are Saying

Product Quality

75%

Many reviewers appreciate the precision and machining quality of the inserts, implying they outperform standard aluminum alternatives and are made with durable steel material. However, some noted quality control issues, including dings or defects in the product, which affected usability.

Sizing Issues

40%

A significant portion of reviewers highlighted problems with sizing, particularly that the holes in the inserts may be too large, leading to inconsistent measurements. This has led to frustration among users attempting to achieve accurate readings.

Usability and Accuracy

55%

While many users experienced positive outcomes with precise, repeatable measurements, others found the design problematic. Specifically, the tapered holes sometimes caused difficulties in aligning and measuring the bullets effectively, hindering satisfactory performance.

Comparison with Competitors

60%

Reviewers frequently compared the BULLET COMPARATOR INSERTS to versions made by Hornady, often recommending the Sinclair products for their higher precision. However, some users still prefer Hornady for certain measurements, indicating mixed experiences among different brands.

Customer Support and Returns

25%

A few reviewers expressed dissatisfaction with the customer service regarding returns and exchanges for defective items. This suggests that while the product has merits, the support for resolving issues could be improved.

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Does not work for 6.5CM

Just received the 6.5mm comparator insert. Looks well made and hefty compared to the Hornady version. However the bullet seats too deep and the ogive depth changes by several thousands depending on slight changes in caliper pressure. Very disappointed. Will continue using the Hornady.

by Ken on November 07, 2025

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My Mistake

Purchased these in 6.5mm, 7mm & .308 size. Taper is so great that while you can take a measurement of some arbitrary point it has no value. Had hoped to use to determine bearing surface of bullets. The Hornady inserts have less but still too much taper for my intended purchase purpose. Perhaps with a lathe can cut away useless taper. At present these are of no value to me.

Sinclair International Bullet Comparator

I just plain don't like them. For me they fall extremely low on the bullet ogive. If you are not very careful the bullet will stick in the comparator when measuring your length.

Size Issue Not Corrected

The size issue that others have written has not been corrected. The hole is just too large, period. I am very surprised that this has not been rectified, especially coming from Sinclair. I was issued a return tag and I've asked for a Hornady comparator insert and a credit for the difference. I also ordered a Sinclair 22, a 6mm, and a 30 cal comparator, all of which work satisfactorily.

NOPE!

Hole sizing is incorrect on mine as well. And I'm not seeing an online way for tech support. Product is useless.

Don't buy

The hole in the comparator is that large the base of a bullet goes below the face of the comparator. I had to give it a star rating but in reality it doesn't even qualify for the one star. Advised to return it but International shipping is going to be more than the cost of the 3 comparator inserts.

Buy Hornady instead

Simply does not work. When trying to measure SMK in 52, 69, and 77 gr, the comparator simply slides all the way over the bullet until it reaches the case.