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Bullet comparators compared?? Reviews please

DngBat7

Silver $$ Contributor
So my reloading ocd is now in the market for a comparator. I have noticed the plain and simple ones, which I have. It’s ok. So I have noticed a few that have got my attention. First I saw the Darrell Holland gold standard comparator that kind of has the setup like a Wilson trimmer. Reviewers swear by them. Sierra uses it at their factory. So I can but assume it’s pretty good. The. I saw the sortezz. Honestly, it looks pretty sick devise with the app. Then I also saw the bob green with the gauge? Opinions very welcome buy those who know these items. Catch is, not having tried these, I want the one where the bullet is stable and the ogive is supported “if that sounds right”. I can never get a proper measurement because the bullet is always moving around and never seats right in the comparator. I need honest reviews
 
comparitors are noting more than holes in a piece of metal to provide a positive stop for measuring. The Sinclair nut or the Hornady unit with your calipers or micrometer does the same thing a lot cheaper. I have to admit the Holland unit is sexy if you want a new expensive toy and I am sure it would work just as well as the nut or the Hornady. If you want to really save money and have a drill, just drill a hole in a nut slightly smaller than the caliber and use your calipers.

I have used .45 ACP and 9MM cases to measure shoulder setback before I broke down and spent $15 for a store bought case comparitor.

https://www.sinclairintl.com/reload...insert-style-bullet-comparator-prod34014.aspx

https://www.brownells.com/reloading...r-hex-style-bullet-comparators-prod83792.aspx

https://www.midwayusa.com/product/1...ad-bullet-comparator-basic-set-with-6-inserts

get one of these and use the money you save on components for practice ammo
 
The optional base on the hornady seems to help get the bullet perpendicular for a good measurement. Otherwise I found myself having to spin it a bit to get a minimum reading. I need to polish the ogive hole a little, its a little sharp and can put a ring on the bullet.
 
I always like to hold the comparitor up to a light and spin it like Fliers, the light lets you know if the bullet/case is sitting squarely. For the scoring issue take a case chamfer tool and spin it backwards in the datum to burnish the edge
 
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comparitors are noting more than holes in a piece of metal to provide a positive stop for measuring. The Sinclair nut or the Hornady unit with your calipers or micrometer does the same thing a lot cheaper.

Comparators (and several other tools we use) are merely reference tools giving us a number that we can use in relation to other areas of dimension. Very rarely will two comparators from the same company, let alone different manufactures, give you the exact same readings. That is why using the measurements from another shooters information is futile. The exception, for me, is another shooter's jump. Jump is the relationship of a bullet's ogive, measured with a comparator, to the lands, also/hopefully measured with the same comparator. And, I do know that ogives can vary but knowing that a bullet will shoot well at a known jump, or a number that's reasonably close, is helpful is starting load development.

I'm in the camp that it doesn't take a lot of expensive tools to accomplish a task. Just use the same tool when taking measurements to keep things apples-to-apples.
 
Comparators (and several other tools we use) are merely reference tools giving us a number that we can use in relation to other areas of dimension.

I just used the .22 caliber insert on my Hornady to help me get the bullet seating depth on my new 6mm, it worked fine, any hole smaller than the caliber of the bullet will work. It wasn't that long ago I was using 9mm and 45ACP cases to adjust my FL sizing dies with.

That Holland rig does looks like it would be the trick for bullet comparison however. It doesn't look complicated and I have 3 dial indicators and a decent wood working shop I am going to try and put together a home grown version tomorrow
 
Try to make sure that your comparator insert and seating stem contact the bullet ogive at the same place the lands do. Will make things a lot easier.
 
If I bore my .22 Hornady comparator to .240 for a 6mm, is that taking the same measurement as a BGC? I admit I can be dense, I don’t understand what’s special about that comparator.
How about copying the Hornady comparator with a gizzy?
 
So my reloading ocd is now ......

Sinclair and Hornady tools makes no sense ,those hole dimensions
are not the same as the rifle bore so you must forget it.


Have a look on "Whidden Gunwerks" and you find the right tool
you looking for :
https://www.whiddengunworks.com/multi-purpose-overall-length-gauge/
accordingly your caliber you choice the proper bore dimension size bushing
and you're able to work accurate ,the previous mentioned are toys and not tools :(:(
The caliber bore dimensions you can find by Bruxbarrels :
(for .22 caliber take bushing size .219 ,for .30 caliber take size .300 )
 

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Sinclair and Hornady tools makes no sense ,those hole dimensions
are not the same as the rifle bore so you must forget it.

Actually you have it backwards, the hole in the datum must be smaller than the caliber or major diameter for the tool to work. Since it is a comparitor it does not matter how much smaller just as long as it is large enough to stabilize the bullet in. It can be .001 smaller or .10 or .050 below. I don't have a 6 mm insert so I use the .22 caliber insert with my 6CM. For comparison purposes it works fine.

if the datum holes were the same diameter as the major diameter of the bullet they would fall through. You might want to review what a ogive is in reloading terms

oh and yes I know a datum is a number not a physical object but I speak hillbilly, English is my second language


http://www.mssblog.com/2016/06/10/bullet-basics/
 
If I bore my .22 Hornady comparator to .240 for a 6mm, is that taking the same measurement as a BGC?
No. What's missing in this thread is declaration of WHAT comparison to discuss. There are different kinds.
The BGC rests on two datums at once.
#1 a bullet inserted to stop at a datum near land contact
#2 an indicator with a seating stem (like Wilson's) rests against the bullet nose forward of #1
The measure here is the distance between the two datums, and is showing ogive radius variance.
The value in this 'comparison' from bullet to bullet is in matching them -so that all other measures off ogives are qualified (to any matched standard).

Now with qualified ogives, it does not really matter where on bullet noses where you set datums.
The Sinclair 'nut' cursed as inadequate, is totally fine. Yes it does not represent land contact datum, but neither does any other tool unless it's cut to same throat angle as your chamber.
Do full seating testing, measure (with ANY tool) your best CBTO, and always use THAT tool to recreate the condition.

Just keep in mind that until you've qualified ogive radius, none of what you're measuring from a bullet nose is qualified. I don't know if Erik knows this, but ogive radius is the base from which to begin discussion w/resp to CBTO.
 
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Try to make sure that your comparator insert and seating stem contact the bullet ogive at the same place the lands do. Will make things a lot easier.

Although I fully agree with that recommendation, I am trying to figure out how that would be accomplished. Unless you purchase an identical seating stem and/or die combination and build a comparator around/with it.
 
Understand that bore diameter is not usually the land contact point on bullet noses. The contact datum varies, sometimes considerably, due to nose shape and throat angle. And it's very complicated to calculate.
Also, a seating stem should never press any where near land contact for most bullets. This would lead to a great deal of wedging, and variance of it, while pushing bullets into varying seating forces. That's why proper seating stems are not so high up on noses.
 
Has anybody tried the sorteez? I would love to mix the digital capabilities of that with the Holland. To much money at the end of the day tho
 
Understand that bore diameter is not usually the land contact point on bullet noses. The contact datum varies, sometimes considerably, due to nose shape and throat angle. And it's very complicated to calculate.
Also, a seating stem should never press any where near land contact for most bullets. This would lead to a great deal of wedging, and variance of it, while pushing bullets into varying seating forces. That's why proper seating stems are not so high up on noses.

I have a Wilson 6mm inline seater that I use for my DTAC RBT Hbn coated bullets. I have multiple seating stems that I ordered and modified to contact the bullet ogive at different places above the bearing surface. The closer to the tip the more variance I see in finished bullet base to ogive measurements as expected. The closer I get to the place the lands contact the ogive the better that measurement becomes without any loss in concentricity. I am also using a 21st Century hydro press to keep an eye on seating force so I don't really think that having a seating stem contact the ogive at the same place the lands contact the ogive is a problem as long as you are using a high quality seater, low neck tension, lubed or coated bullets, proper seating stem profile and keeping an eye on seating force.
 

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