Zeroing a C-More

[Jeff686]

I made a couple of these graphs after reading this thread. I really like visual representation of data, and thought this would help people pick the dot size and zero distance that is best for them. As noted in the spreadsheet, I created the data for a Hornady HAP 121gr .355 bullet at 1470 fps. That's a little hot, at about 177 pf. I'll make a new one, if requested, using a different bullet and/or velocity. I need the BC, bullet weight, and velocity. I had to guess at the dot height above the barrel, so if you want a custom graph, measure that too. Also, this chart assumes that you zero at the CENTER of the dot. I can adjust that too, but haven't bothered yet.

Can everyone understand the graph's meaning, or should I provide further description?

Edited October 3, 2008 by Jeff686

[HSMITH]

Jeff, that is killer!! 115 JHP Zero at 1530fps with a dot height of 1.1" above the bore center would be cool to see if it isn't too much trouble.....

[Jeff686]

For HSSMITH. I used a BC of .118 that I found for a 115gr JHP bullet. It wasn't Zero, but it must be close.

EDIT: with higher res graph

EDIT2: thought there was a missing trace, but with this BC/Velocity the 25yd zero and 50yd zero are almost identical.

Edited October 3, 2008 by Jeff686

[uscbigdawg]

Good to know my 25 yard zero still works well.

Rich

[jasmap]

I made a couple of these graphs after reading this thread. I really like visual representation of data, and thought this would help people pick the dot size and zero distance that is best for them. As noted in the spreadsheet, I created the data for a Hornady HAP 121gr .355 bullet at 1470 fps. That's a little hot, at about 177 pf. I'll make a new one, if requested, using a different bullet and/or velocity. I need the BC, bullet weight, and velocity. I had to guess at the dot height above the barrel, so if you want a custom graph, measure that too. Also, this chart assumes that you zero at the CENTER of the dot. I can adjust that too, but haven't bothered yet.

Can everyone understand the graph's meaning, or should I provide further description?

Wow Jeff. Thank you!

[Flatland Shooter]

Can everyone understand the graph's meaning, or should I provide further description?

Excellent presentation Jeff!

Now for all us techno-weenies out there, what program did you use for the graphics?

Thanks.

Bill

[Jeff686]

Can everyone understand the graph's meaning, or should I provide further description?

Excellent presentation Jeff!

Now for all us techno-weenies out there, what program did you use for the graphics?

Thanks.

Bill

Hi Bill,

I used an online ballistics calculator for the data in the curves, then just made some tables and graphs using Excel 2007.

I'll upload the spreadsheets on Monday, if you want a copy.

[Flatland Shooter]

Hi Bill,

I used an online ballistics calculator for the data in the curves, then just made some tables and graphs using Excel 2007.

I'll upload the spreadsheets on Monday, if you want a copy.

Jeff,

Looks like I finally have justification to upgrade my old Excel (Small Office 2002). If convenient, I would like copies of the file.

Thanks.

Bill

[fasteddy]

Jeff,

can you do mine please..here is the details..Bullet frontier CMJ 124grain RN .356, chronoed HI -1425 LO- 1387 PF 168 to 174 my Cmore dot 8MOA then I measured the height from the bore center to the Cmore dot about +/- 2.3 to 2.4inches.

Thanks

[Jeff686]

Hi Bill,

I used an online ballistics calculator for the data in the curves, then just made some tables and graphs using Excel 2007.

I'll upload the spreadsheets on Monday, if you want a copy.

Jeff,

Looks like I finally have justification to upgrade my old Excel (Small Office 2002). If convenient, I would like copies of the file.

Thanks.

Bill

You can do the same thing in 2002. I'll save a copy in 2002 format. I'm not sure how it will look, the colors might be off. You just have to know your way around Excel graphing features.

[HSMITH]

Awesome, thanks Jeff!!!

[Jeff686]

Jeff,

can you do mine please..here is the details..Bullet frontier CMJ 124grain RN .356, chronoed HI -1425 LO- 1387 PF 168 to 174 my Cmore dot 8MOA then I measured the height from the bore center to the Cmore dot about +/- 2.3 to 2.4inches.

Thanks

Yep, but not till Monday...

[fasteddy]

Jeff,

Ill wait, and thank you in advance!

Fasteddy

[Jeff686]

For Fasteddy...

8moa only.

[fasteddy]

For Fasteddy...

8moa only.

Jeff686

Thats awesome! now, I can relate what the ideal zero I am looking around.

Many Thanks.

[Jeff686]

Attempting to upload excel spreadsheets. XLS files are not allowed, had to zip them up.

One is in Office 2007 (original).

One is in Office 2003 (compatibility mode, with unknown status of graphs).

dot_window.zip

[Flatland Shooter]

Attempting to upload excel spreadsheets. XLS files are not allowed, had to zip them up.

One is in Office 2007 (original).

One is in Office 2003 (compatibility mode, with unknown status of graphs).

Good evening Jeff,

Downloaded the Office 2003 version and it looks wicked.

Thanks so much.

Bill

Edited to add: On the conversion to Excel 2003, the range changed from 0 to 100 yards to 0 to 20 yards. I haven't quite figured it out but should be an easy fix.

Edited October 10, 2008 by Flatland Shooter

[Firstcut]

I like the zero at 17yds.

[bwit]

Not me, I like the 25 yard zero as it's easy to zero at the range then for a 25 to 50 yd shot it's right on [or close enough]. You just have to remember you are 1 1/4 inches low at about 6 feet.

[HSMITH]

Mine hits inside the 6 moa dot now from 10 yards to almost 50. 3 yards center upper A aim gets you an A, as does the same aiming point at 50 yards. Details available in a couple weeks.

[Benjamin Arendt]

Mine hits inside the 6 moa dot now from 10 yards to almost 50. 3 yards center upper A aim gets you an A, as does the same aiming point at 50 yards. Details available in a couple weeks.

+1 for that. The same for me and my zero with 6MOA dot. I was at a match last weekend with some 3meter targets it worked very well for me there..

DVC Benjamin

[kgunz11]

If you guys would just use the Quinn mount it would get you dot closer to your center of bore and trajectory would be less of an issue.

This is way easier than discerning the proper battle range zero for a rifle when hold over/under to maximum effective range and point blank analysis is concerned. Now THAT debate would make Einsteins head hurt!

I zero the dot @ 15 yards and confirm impact at 30 and 3.

[joecichlid]

Jeff, VERY cool!! Thanks for going through all of the trouble. I saved to help out as I test some loads over the next few weeks.

Joe W.

[Gregory_k]

If you guys would just use the Quinn mount it would get you dot closer to your center of bore and trajectory would be less of an issue.

This is way easier than discerning the proper battle range zero for a rifle when hold over/under to maximum effective range and point blank analysis is concerned. Now THAT debate would make Einsteins head hurt!

I zero the dot @ 15 yards and confirm impact at 30 and 3.

That is what I like about the Barry mount. Low mounted dot.

[2alpha]

Zero your gun for the hardest shots you will have to make. That is not usually the 3 yd head shot thru the port!!!

Reminds me of an Area match I was shooting when my dot went TU on me and I borrowed a friends gun for the next stage. He failed to tell me he had sighted the Cmore railway on top of a weigand frame mount for the 3 yd head shots with no shoots under on the stage. This stage started out with PPs at 25 and 35, after several shots thankfully staying within the berm but very high I figured it out and aimed under the popper and finally took them down and got to move down to those real hard 3yd head shots. Between his built in flinch, super high mounted dot, and 3 yd zero I think it was shooting 2 ft high at 35!! Always bring a back up gun and have it in your bag with you on stage!!

The other point is the longer range you set your gun up for the more accurate your zero is. You can't completely depend on charts because they are assuming a perfect zero. So zero at close range if you just have to but check it at longer distances because it could easily look fine but shoot 2 or 3 inches off windage wise at the longer distance when you NEED to be right on. But I'm forgetting that USPSA is a 15 yd max game now.