Hornady bullet comparator insert for .355

[bantam9]

Anyone care to share what their OAL is with RMR's new 124 gr FMJ?
I run the 124 gr 9mm Match round nose at 1.150 oal, and they shot great, but this new 124gr FMJ has a different profile. Hornady doesn't make a comparator insert for .355 best I can tell.
I would love to compare length at ogive from these 2 projectiles, and use it as starting point for the new RMR 124gr FMJ, unless others would share their OAL's on the new 124FMJ.

 

[Ruger 15151]

They don't make a comparator for 9mm because it isn't necessary. Maximum / Working OAL will be different in every chamber depending on how short it is "throated" (distance from the end of the chamber where the shell case locates and the barrel riffling. Just use the "Plunk Test" to learn the max OAL for your barrel. Then you need to determine working OAL from there because Maximum OAL doesnt necessarily cycle in every gun.

Here is a helpful link explaining how to determine your max OAL/COL:

https://www.thehighroad.org/index.p...l-with-your-bullet.506678/page-2#post-8864541

You will need to do this with every bullet you use to reload because they all have a different profile. I load at least .010 from the bullet hitting the riffling to allow for variance in shell case lengths. Once you have determined the Maximum/Working OAL, just keep a dummy round so you can set up your dies quickly when you change between bullets weights and profiles. If you have multiple 9mms, most will require a different Maximum / Working AOL. You will have to find the 9mm pistol that requires the shortest and then load that OAL for all the 9mm pistols you have.

Hope that helps! Good luck!

 

[bantam9]

Thanks--Guess I have some work to do!!

 

[wrench459]

You will need to do this with every bullet you use to reload because they all have a different profile. I load at least .010 from the bullet hitting the riffling to allow for variance in shell case lengths. Once you have determined the Maximum/Working OAL, just keep a dummy round so you can set up your dies quickly when you change between bullets weights and profiles. If you have multiple 9mms, most will require a different Maximum / Working AOL

+1
I'll make five dummy rounds at various lengths for each bullet..then save them for future reference.

 

[Ruger 15151]

Here is a link that I thought I would share. Not only is there some great reloading information, but the last pages discuss chamber throating and its effect on OAL.

https://www.thehighroad.org/index.p...s-and-discussions.778197/page-9#post-10644921

 

[PhillySoldier]

Has anyone found an 9mm / .355 comparator or substitute to use yet? I understand whats been said that it most likely isnt needed for pistol but would still like to be able to see the differences from one bullet brand/type to the next. Caliber measuring seems to be utterly useless since even bullets within the same brand/box seem to vary. I just want some consistency when checking the seating of my finished rounds and actually confirm its the bullet and not the seating on the progressive varying from one finished round to the next.

 

[thomas15]

Welcome to The High Road.

Caliber measuring seems to be utterly useless since even bullets within the same brand/box seem to vary.

Some might say that you answered your own question.

 

[PhillySoldier]

Thank you. Yeah thats why I was thinking something measuring from ogive might be more consistent

 

[thomas15]

^^^More to the point, and I say this as an individual that shoots a lot of 9mm in competitions, if your shooting style requires bench rest style rifle precision then probably 9mm is not the best choice.

 

[thomas15]

But...if you insist, my solution to the problem would be to take a smaller (Hornady) comparator insert to a machine shop and have the hole enlarged to meet your requirements.

 

[Dudedog]

Welcome to The High Road.
lots of great people here.


I would find what the longest OAL that will plunk is.
Start maybe .01 or .02 deeper.
If that gives you for example lets say 1.15 (and you not loading MAX loads) I would load some there and also try some a little shorter say maybe 1.13 and possibly 1.11.
I didn't shoot a lot of the new RNs (shooting the new 124 MPRsJHPs) but from past experience most of the time my pistols are happier when I go shorter (within reason).
My guns seemed happiest about 1.13-1.12 with them. (shorter than normal for most RNs) YMMV

 

[jell-dog]

bantam9,
I have found that the
Hornady bullet comparator insert 30
works well for measuring 9mm col at the ogive on most 9mm bullets.
JD
PS
I find my "max COL" with the "plunk" method, then find my "working COL" by checking if dummy rounds will cycle in my pistol.

I set my seating die to 0.010" less than my "working COL" to account for different lengths in range mixed pickup brass.

THEN I use the comparator to see what the ogive to base of cartridge COL is.

Because of the differences in bullet length even in the same box of bullets, your measured cartridge COL may be +/- 0.004".

I have found that when using the 30 comparator the measurement is most times only +/- 0.002" differance at the ogive.

This has given me the confidence to set the seating die to the cartridge OAL I am looking for and not worry about the measured cartridge COL being +/- 0.004", as the 30 comparator measurement is most times only +/- 0.002" differance at the ogive.

Close enough for me!
JD

 

[sparkyv]

They don't make a comparator for 9mm because it isn't necessary. Maximum / Working OAL will be different in every chamber depending on how short it is "throated" (distance from the end of the chamber where the shell case locates and the barrel riffling. Just use the "Plunk Test" to learn the max OAL for your barrel. Then you need to determine working OAL from there because Maximum OAL doesnt necessarily cycle in every gun.

Here is a helpful link explaining how to determine your max OAL/COL:

https://www.thehighroad.org/index.p...l-with-your-bullet.506678/page-2#post-8864541

You will need to do this with every bullet you use to reload because they all have a different profile. I load at least .010 from the bullet hitting the riffling to allow for variance in shell case lengths. Once you have determined the Maximum/Working OAL, just keep a dummy round so you can set up your dies quickly when you change between bullets weights and profiles. If you have multiple 9mms, most will require a different Maximum / Working AOL. You will have to find the 9mm pistol that requires the shortest and then load that OAL for all the 9mm pistols you have.

Hope that helps! Good luck!

Ruger 15151 is absolutely correct. BTW, if you do consider using someone else's comparator data, you should be sure that their firearms, gear and setup is identical to yours. Otherwise, they won't be comparable! That's because with a comparator, the cartridge base to ogive length (CBTO) is being measured, not the overall length of the cartridge (COAL). Clear as mud, I'm sure.

 

[jell-dog]

Ruger 15151 is absolutely correct. BTW, if you do consider using someone else's comparator data, you should be sure that their firearms, gear and setup is identical to yours. Otherwise, they won't be comparable! That's because with a comparator, the cartridge base to ogive length (CBTO) is being measured, not the overall length of the cartridge (COAL). Clear as mud, I'm sure.

sparkyv,
You are correct that "That's because with a comparator, the cartridge base to ogive length (CBTO) is being measured, not the overall length of the cartridge (COAL)".

However, I was not suggesting that bantam9 blindly use my comparator data, but to establish for himself that the overall length of the cartridge (COAL) when measured from cartridge base to bullet tip varied by what ever amount (my example was "COL may be +/- 0.004" was only an example) that the comparator would show that the cartridge base to ogive length (CBTO) would be LESS of a difference.

This means that although the overall length of the cartridge (COAL) may be off by (EXAMPLE: +/- 0.004") the cartridge base to ogive length (CBTO) may only be off by (EXAMPLE: +/- 0.002").

If you have correctly followed "finding max coal using your barrel"
https://www.thehighroad.org/index.p...rel-find-a-max-o-a-l-with-your-bullet.506678/
THEN finding your correct WORKING COAL, you will have a safe COAL.

The OGIVE is what binds on the rifling in your barrel when trying to find your CARTRIDGE MAX LENGTH.

You do not need "be sure that their firearms, gear and setup is identical to yours."

When you establish YOUR WORKING COL FOR YOUR GUN, using YOUR firearms, gear and setup, you can then use the comparator to determine YOUR cartridge base to ogive length (CBTO) with YOUR selected COL, using YOUR firearms, gear, setup, brass and bullets.

This gives you a BASE LINE CBTO measurement that you can compare with cartridges that are over/under your YOUR selected COL.

It has been MY experience that the when YOUR DETERMINED overall length of the cartridge (COAL) is off (EXAMPLE: +/- 0.004") that you will find that the cartridge base to ogive length (CBTO) is less than the variance of the COAL.

This difference could be attributed to several factors such as variation of bullet nose length in plated/fmj bullets in the same lot to the coating differences on the nose of a coated lead bullet.

They don't make a comparator for 9mm because it isn't necessary. Maximum / Working OAL will be different in every chamber depending on how short it is "throated" (distance from the end of the chamber where the shell case locates and the barrel riffling. Just use the "Plunk Test" to learn the max OAL for your barrel. Then you need to determine working OAL from there because Maximum OAL doesnt necessarily cycle in every gun.
Here is a helpful link explaining how to determine your max OAL/COL:
https://www.thehighroad.org/index.p...l-with-your-bullet.506678/page-2#post-8864541
You will need to do this with every bullet you use to reload because they all have a different profile. I load at least .010 from the bullet hitting the riffling to allow for variance in shell case lengths. Once you have determined the Maximum/Working OAL, just keep a dummy round so you can set up your dies quickly when you change between bullets weights and profiles. If you have multiple 9mms, most will require a different Maximum / Working AOL. You will have to find the 9mm pistol that requires the shortest and then load that OAL for all the 9mm pistols you have.
Hope that helps! Good luck!

I strongly agree with what Ruger 15151 said in his post!

Anyone care to share what their OAL is with RMR's new 124 gr FMJ?
I run the 124 gr 9mm Match round nose at 1.150 oal, and they shot great, but this new 124gr FMJ has a different profile. Hornady doesn't make a comparator insert for .355 best I can tell.
I would love to compare length at ogive from these 2 projectiles, and use it as starting point for the new RMR 124gr FMJ, unless others would share their OAL's on the new 124FMJ.

The way I read the OP's question is 2 parts:
1)"Anyone care to share what their OAL is with RMR's new 124 gr FMJ?"
ANSWER: IMHO Every gun barrel may need a different OAL so asking for shared COL's may not work in your gun and every bullet will need different OAL to work in your gun barrel.

2)"is there a Hornady comparator insert for .355" (9mm) that I can use to compare "the 124 gr 9msm Match round nose at 1.150 oal, and they shot great, but this new 124gr FMJ has a different profile".
MY ANSWER: IMHO The Hornady comparator insert 30 could do that.

(to quote sparkyv) "Clear as mud, I'm sure".

YOUR MILEAGE MAY VARY
JD

 

[Walkalong]

I tend to run FMY in 9MM at 1.130 to 1.135 AOL. If that plunks in your gun(s) you're good to go. If that OAL is shorter than the OAL in the data you are using adjust accordingly. A small amount makes a big difference in 9MM.

Since you have been using 1.150 OAL try a couple with no powder at that OAL and see if they plunk OK. If they do you are good to start working up your load.

IOW, what folks have been posting.