Bullet comparator explanation needed.

[little_scrapper]

I read the thread "Hand loading for Long range 1: brass case prep". In that thread he says he is using a Sinclair bullet comparator to measure the datum line on the shoulder.

So if there is no bullet to rest on; the outer larger diameter will contact the case on the datum line? Also is the Hornady bullet comparator the same thing as the Sinclair?

 

[1J04]

Your title is asking for "Bullet Comparator" explanation, but you're referring to "Case Headspace Comparator" in your post.

Hornady has both Headspace Comparator for measuring off the Datum to gauge how far you are setting shoulder back

And a Bullet Comparator to measure off the Ogive to give you your CBTO.

If you're loading long Bullets you may very well find the extended Comparator Body to be of use. Sinclair makes one.

Some VLD Bullets will bottom out on the Meplat in the shorter Comparator Body.



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So you can buy yet another piece of equipment


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Or you can just strip your Bolt and find your lands like this. I find this methodology to be sufficient for my needs. Got enough reloading tools laying around. Don't need no more.


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[little_scrapper]

Yes. It sounds like I want/need a Headspace gage for measuring the datum to determine bump; and I want the bullet comparator for measuring cartridge length from head to Ogive. Also, if I want to sort bullets by bearing surface I need a second bullet comparator.

 

[1J04]

Look at what I posted for you. One set of gauges is for measuring cases off the Datum, the other comparator is for measuring Bullets off the Ogive. Sinclair and Hornady, basically same same. That doesn't matter. What matters is understanding there are seperate comaparators. One for Cases, One for Bullets.

 

[abn31c]

Do these come in mil or moa or both?

 

[Tucker301]

Is this still available?

 

[1J04]

Do these come in mil or moa or both?

YES

 

[1J04]

Is this still available?

NO

 

[cornhusker86]

Do these come in mil or moa or both?

Damn metric system...

 

[lash]

Go back to @1J04’s post and take a minute to read and understand what all is there.

Okay, now. Notice that there is a comparator body and there are inserts for that competitor body. Together they make up a comparator. For either rough base too give comparisons and for relative headspace comparisons.

Got it? They compare one measurement on a loaded round to the same measurement point on the next, based on your developed load measurements.

As to which brand is better, if that’s really what you are asking, choose one and don’t look back.

 

[little_scrapper]

Watched it and I get it now. Thought the bullet comparator was being used dual purpose. Glad I asked.

I have everything in the cart except still trying to figure out what to actually order for the head space bushing.

My cart:
Hornady C1000 OAL Gage Straight
308 Win Modified Case
Hornady Comparator body and base anvil
308 win insert

Need to find the head space "bushing". Thanks for the help.

 

[lash]

 

[little_scrapper]

Thanks again for enduring my immense noobishness. Got the 400 in the cart. Looked it up and went and measured a few of my fired M118LR's.

L_S

 

[Threadcutter308]

Do these come in mil or moa or both?

asshole........ ???

 

[1J04]

@little_scrapper If you have someone to Mentor you in your area who really knows what they're doing, that would be very helpful for you. I don't explain things on the net to good, so thanks @lash for helping me AND him. Read, read, read and watch as many videos as you can. There are several ways to skin this cat and get you the same results. You can buy your C1000 OAL gauge and a modified case, or you can just follow the video I provided. Both get the job done.

Learn the basics inside and out. Then you can jump down the rabbit hole for the full effect. Take your time, think things thru, and don't try and cut any corners. You need to know what you're doing and why. Stay safe, have fun, don't ever stop asking questions..........

 

[QuickNDirty]

I really enjoyed reading Lyman's 49th. I went from noob to pro in a couple of days. Real page turner, that one.

 

[Threadcutter308]

@little_scrapper If you have someone to Mentor you in your area who really knows what they're doing, that would be very helpful for you. I don't explain things on the net to good, so thanks @lash for helping me AND him. Read, read, read and watch as many videos as you can. There are several ways to skin this cat and get you the same results. You can buy your C1000 OAL gauge and a modified case, or you can just follow the video I provided. Both get the job done.

Learn the basics inside and out. Then you can jump down the rabbit hole for the full effect. Take your time, think things thru, and don't try and cut any corners. You need to know what you're doing and why. Stay safe, have fun, don't ever stop asking questions..........

You actually sound like kind of a nice guy.....

 

[Threadcutter308]

I really enjoyed reading Lyman's 49th. I went from noob to pro in a couple of days. Real page turner, that one.

Uh huh..... ??

 

[abn31c]

You actually sound like kind of a nice guy.....

He must be high, again

 

[Threadcutter308]

He must be high, again

I would be, given the circumstances. Fuckin’ propane bottle in my nightmares........damn straight ?

He’s a good egg, doesn’t deserve the shit & abuse. But........it’s low hanging fruit.........gotta take the shot ...... ? ??

 

[Threadcutter308]

You actually sound like kind of a nice guy.....

Oh, BTW Lulu, be careful out there.......

 

[little_scrapper]

Thanks 1J04. Trust me I am doing tons of reading, watching and asking. Just like the original question.

In my defense; when I go back and look at both chapter 1 and 3 it looks like same tool pictured. In chapter 1 I don't see a long head space bushing like the Hornady and the link goes to a tool called a bullet comparator. That is what was confusing me.

I work in a development lab and so I am used to working with tight tolerance. At work we say the same thing when training the new guys. We build a ton of one off or first time built hardware. We say there are ten ways to skin a cat, you just need to find one that works.

 

[abn31c]

I would be, given the circumstances. Fuckin’ propane bottle in my nightmares........damn straight ?

He’s a good egg, doesn’t deserve the shit & abuse. But........it’s low hanging fruit.........gotta take the shot ...... ? ??

I'm not here to judge people!?

 

[Threadcutter308]

Thanks 1J04. Trust me I am doing tons of reading, watching and asking. Just like the original question.

In my defense; when I go back and look at both chapter 1 and 3 it looks like same tool pictured. In chapter 1 I don't see a long head space bushing like the Hornady and the link goes to a tool called a bullet comparator. That is what was confusing me.

I work in a development lab and so I am used to working with tight tolerance. At work we say the same thing when training the new guys. We build a ton of one off or first time built hardware. We say there are ten ways to skin a cat, you just need to find one that works.

L/S.........BTW, this is kind of a weird place. You may end up with some shit sandwiches for responses. A word of advice ? There’s a lot of talent and knowledge here, but social graces aren’t one of our strong suits. Continue to ask questions, there will be people (loosely interpreted) that’ll jump your shit and there will be those that’ll help you in a heartbeat. Don’t get butt hurt/take the bait from the “off color” guys and just focus on those that are genuinely interested in helping you.
A thick skin is a definite virtue around here. It’s definitely worth putting up with. Just be a bit patient......

 

[Threadcutter308]

I'm not here to judge people!?

That helps......a lot......

 

[little_scrapper]

L/S.........BTW, this is kind of a weird place. You may end up with some shit sandwiches for responses. A word of advice ? There’s a lot of talent and knowledge here, but social graces aren’t one of our strong suits. Continue to ask questions, there will be people (loosely interpreted) that’ll jump your shit and there will be those that’ll help you in a heartbeat. Don’t get butt hurt/take the bait from the “off color” guys and just focus on those that are genuinely interested in helping you.
A thick skin is a definite virtue around here. It’s definitely worth putting up with. Just be a bit patient......

No worries. Im no snowflake.

 

[1J04]

@Threadcutter308 spot on. Sage advice

Now I'm just waiting for @spife7980 to chime in. That man knows his shit and can explain things extremely well. Huge Asset on here.

 

[1J04]

Here ya go @little_scrapper


https://www.snipershide.com/shooting/threads/wts-full-hornady-bullet-comp-kit-w-anvil-base.6942199/

 

[Lapuapalooza]

Your title is asking for "Bullet Comparator" explanation, but you're referring to "Case Headspace Comparator" in your post.

Hornady has both Headspace Comparator for measuring off the Datum to gauge how far you are setting shoulder back


View attachment 7117822

And a Bullet Comparator to measure off the Ogive to give you your CBTO.

View attachment 7117823

If you're loading long Bullets you may very well find the extended Comparator Body to be of use. Sinclair makes one.


View attachment 7117827


Some VLD Bullets will bottom out on the Meplat in the shorter Comparator Body.



<iframe width="560" height="315" src="" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>


<iframe width="560" height="315" src="" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>


So you can buy yet another piece of equipment


<iframe width="560" height="315" src="" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>



Or you can just strip your Bolt and find your lands like this. I find this methodology to be sufficient for my needs. Got enough reloading tools laying around. Don't need no more.


<iframe width="560" height="315" src="" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

No wonder you sound so smart. You done got yourself that YouTube my kids are always tellin me about. I have 2 questions...
1.) if you already measured your datum, why do you need to measure your bullet too? Don’t you already know your shooting a .308.... duh!!!!
2.) if you already have your YouTube, then where would I find my metube? ???

 

[1J04]

No wonder you sound so smart. You done got yourself that YouTube my kids are always tellin me about. I have 2 questions...
1.) if you already measured your datum, why do you need to measure your bullet too? Don’t you already know your shooting a .308.... duh!!!!
2.) if you already have your YouTube, then where would I find my metube? ???

Wrong Section.

 

[Lapuapalooza]

Wrong Section.

This section? Is this the one??

This has been going on too much lately. Someone asks a question that some feel isn't worth it and the feeding frenzy commences. Well it stops now. This is the first and final warning. We see it and you will get a 3 day ban the first time. Happens again and you are gone for 3 months.

You guys who spend more time in the Bear Pit or Maggie's Drawers posting stupid pictures than shooting or posting on shooting got it? It's done.


If there are problems then that is what Mod alerts are for. Asking a question that someone feels is stupid isn't a problem. Asking a question that has been asked before isn't either. Anyone new or old member causing problems deliberately should be brought up to the mods. Too long has this place run like the wild west. The Mods are here for a reason. If there is a problem then alert us.

Read the forum rules if you are unclear as to what is right and wrong to be posted around here. Lowlight is the man who wrote them and it's his word that will be followed and not what some members think.

I have another question...

If even a blind squirrel finds a nut, how come he can never find the other one? ????

 

[little_scrapper]

Thanks for the link 1J04 I already ordered the whole pack. Was like $90 shipped.

829-200-308 308 Winchester Modified Case	(In Stock)	$7.99	$7.99	1		$7.99
749-000-519 30 Caliber Bullet Comparator Insert	(In Stock)	$6.19	$6.19	1		$6.19
749-012-107 Hornady Lock N Load Anvil Base	(In Stock)	$15.29	$15.29	1		$15.29
749-002-627 Hornady Lock-N-Load Bullet Comparator Body	(In Stock)	$15.49	$15.49	1		$15.49
829-200-000 Lock-N-Load OAL Gauge (Straight)	(In Stock)	$37.99	$32.99	1		$32.99
100-031-835 0.400" Headspace Bushing	(In Stock)	$9.99	$9.99	1		$9.99

SUBTOTAL

$87.94

 

[Mike Casselton]

Make sure you compare the datum line on your modified case vs a fired/unsized case from your rifle.
Many times they don't match up and since the modded case works off the shoulder but is measured total length, they can give false results.
That doesn't mean they are junk, quite the contrary. You just have to know the limitation of the tool or make your own modded case from your fired cases.

 

[little_scrapper]

Yes. Need to measure datum on 5 or 10 fired cases to get an average. Then measure OAL from Ogive because meplats can vary quite a bit while the Ogive is very consistant. Got my Press mounted last night. Will be ordering supplies soon. Off to read more load development threads and start loading to magazine length.

 

[IowaGeologist]

Alright guys, going to feel a little stupid on this one but at this point I really don't give a shit and would just like to know. Been reloading for a few years now, and often use my Hornady Bullet Comparator to give me 0.000-0.020" (often 0.010") jump depending on what shoots best for that particular bullet. I know how to use the tool and can get consistent case base to ogive reloads which allows me to play with seating depth.

Problem is, I'm still not sure I understand how the comparator is actually working. My understanding is the ogive is where the tangental/secant curve meets the bearing surface and is the point that the comparator measures. However, I don't see how the compartor is able to stop on a specific point which happens to also be the maximum diameter of the bullet (intersection of bearing surface and curve). Is the comparator actually cut to a opening a few thousandths of an inch smaller than the ogive? Which means you're actually measuring everything somewhat relative to the true ogive? Or am I misunderstanding what the ogive truly is and is often represented as?

Thanks for any feedback, it's appreciated. Any feedback using crayon drawings your kids made for me to figure it out is even better.

 

[spife7980]

Alright guys, going to feel a little stupid on this one but at this point I really don't give a shit and would just like to know. Been reloading for a few years now, and often use my Hornady Bullet Comparator to give me 0.000-0.020" (often 0.010") jump depending on what shoots best for that particular bullet. I know how to use the tool and can get consistent case base to ogive reloads which allows me to play with seating depth.

Problem is, I'm still not sure I understand how the comparator is actually working. My understanding is the ogive is where the tangental/secant curve meets the bearing surface and is the point that the comparator measures. However, I don't see how the compartor is able to stop on a specific point which happens to also be the maximum diameter of the bullet (intersection of bearing surface and curve). Is the comparator actually cut to a opening a few thousandths of an inch smaller than the ogive? Which means you're actually measuring everything somewhat relative to the true ogive? Or am I misunderstanding what the ogive truly is and is often represented as?

Thanks for any feedback, it's appreciated. Any feedback using crayon drawings your kids made for me to figure it out is even better.

Easy to throw your calipers on and see for yourself. Spin them on the bullet and youll see the exact point it hits with your equipment and components.
The "true" ogive is the entire curvature of the bullets nose. The ogive we use for reloading is just where our datum (the comparator) interacts with the bullet down towards the bearing surface, its semi slang. You are correct that its a tad smaller.

This shows a datum (plane) on a case shoulder instead of a bullet but same principle

A bullet is .308"
Your hornady comparator is a .30 hole. But your hole also has a chamfer on the inside edge making it slightly wider for somewhere between .30 and .308 which is actually where your 308 bullet hits on the leade betwen the wide throat and the narrow bore. The chamfer gets it pretty close to the leade in your rifle/where the freebore transitions to the full profile lands.

 

[IowaGeologist]

Easy to throw your calipers on and see for yourself. Spin them on the bullet and youll see the exact point it hits with your equipment and components.
The "true" ogive is the entire curvature of the bullets nose. The ogive we use for reloading is just where our datum (the comparator) interacts with the bullet down towards the bearing surface, its semi slang. You are correct that its a tad smaller.

A bullet is .308"
Your hornady comparator is a .30 hole. But your hole also has a chamfer on the inside edge making it slightly wider for somewhere between .30 and .308 which is actually where your 308 bullet hits on the leade betwen the wide throat and the narrow bore. The chamfer gets it pretty close to the leade in your rifle/where the freebore transitions to the full profile lands.
View attachment 7118103
View attachment 7118098
View attachment 7118100

View attachment 7118104

Very good write-up, helps a ton. Much more clear that the stuff I found after some half assed google searches.

 

[lash]

@spife7980 does not mess around when he helps out.

 

[dttheliman]

Do these come in mil or moa or both?

More importantly what about in common core math - the fundamental principle involves using physical manipulatives as well as pictures to help reloaders visualize numbers and the relationships among numbers. Reloaders then can begin to form mental models of quantitative relationships by first using concrete objects such as two bullets .....

 

[Steel head]

@spife7980 does not mess around when he helps out.

Nope!

 

[1J04]

Told Ya So. ??

Nice Job @spife7980

 

[little_scrapper]

More importantly what about in common core math - the fundamental principle involves using physical manipulatives as well as pictures to help reloaders visualize numbers and the relationships among numbers. Reloaders then can begin to form mental models of quantitative relationships by first using concrete objects such as two bullets .....

Don't forget Ebonics is a core part of common core math.

Ex. Common Core Math question: Is you be hav'un 10 gatz. And Obammy be sayin you got2B givin up 8 uv um. How many gatz do youz be hav'un left?

Ans.: I steel be has ten gatz. Strizaight Up cuzz! I ain givun up shiznatz.

**FLASHING GANG SIGNS** Homeboy be hav'un mad math skilz! Werd!