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Thread: 55gr vs 77gr Data
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September 11th, 2017, 10:51 AM #1
55gr vs 77gr Data
Does anyone have bullet path/drop data they are able to share for a 1 in 7 twist, 16" AR for M193, and Mk262 (and M855 would be awesome too)? Say out to 400-600 yds.
I'm having trouble finding this data on the web so if anyone has recorded data using good statistical analysis that would be awesome. I would do it myself but I'm limited without money to spend on Mk262, a good bench rest, and a range >100yds. But I do have good MS Excel skills .
My goal is to be able to dope a rifle to the different loads to a decent degree of accuracy without physically shooting a statistically significant number of rounds.
A chart would be great but the raw data would be excellent too. Perhaps if we collect more than one data set, I can average that and do some stats to provide to everyone interested in a nice format.
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September 11th, 2017, 11:17 AM #2
Re: 55gr vs 77gr Data
Speer reloading manuals list ballistic tables out to 500 yds you'll need to know the BC and muzzle vel for the loads out of the shorter 16 " barrel . An example :
55 gr fmj with BC of .250 and MV of 3100fps, sight above bore 1.5" ,rifle zeroed at 100 yd
200yd drop 3.3"
300 yd drop 12.8"
400 yd drop 30.9"
500 yd drop 60.7"Last edited by Tim Ault; September 11th, 2017 at 11:29 AM.
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September 11th, 2017, 01:09 PM #3
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September 12th, 2017, 01:15 PM #4
Re: 55gr vs 77gr Data
Take a look at forums based on the AR-15. If the answer isn't found, sign up and ask. Looking for tables based on length of barrel is really looking for tables based on muzzle velocity. People on the forums who chronograph their loads will help folks with questions.
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September 13th, 2017, 06:18 PM #5
Re: 55gr vs 77gr Data
Found this velocity data for different loads and barrel lengths. This combined with Federals online ballistics calculator has me setup.
MK 262 VELOCITY DATA
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7.5" 2053 FPS ... 10.5" 2363 FPS
DIFFERENCE 310 FPS
DIFFERENCE/INCH 103 FPS
10.5" 2363 FPS ... 14.5" 2576 FPS
DIFFERENCE 213 FPS
DIFFERENCE/INCH 53 FPS
14.5" 2576 FPS ... 16" 2669 FPS
DIFFERENCE 93 FPS
DIFFERENCE/INCH 62 FPS
16" 2669 FPS ... 18" 2769 FPS
DIFFERENCE 100 FPS
DIFFERENCE/INCH 50 FPS
18" 2769 FPS ... 20" 2818 FPS
DIFFERENCE 49 FPS
DIFFERENCE/INCH 25 FPS
M855 VELOCITY DATA
__________________________
7.5" 2244 FPS ... 10.5" 2639 FPS
DIFFERENCE 395 FPS
DIFFERENCE/INCH 132 FPS
10.5" 2639 FPS ... 14.5" 2861 FPS
DIFFERENCE 222 FPS
DIFFERENCE/INCH 56 FPS
14.5" 2861 FPS ... 16" 2938 FPS
DIFFERENCE 77 FPS
DIFFERENCE/INCH 51 FPS
16" 2938 FPS ... 18" 3046 FPS
DIFFERENCE 108 FPS
DIFFERENCE/INCH 54 FPS
18" 3046 FPS ... 20" 3061 FPS
DIFFERENCE 15 FPS
DIFFERENCE/INCH 7.5 FPS
XM193 VELOCITY DATA
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7.5" 2364 FPS ... 10.5" 2755 FPS
DIFFERENCE 391 FPS
DIFFERENCE/INCH 130 FPS PER INCH
10.5" 2755 FPS ... 14.5" 2984 FPS
DIFFERENCE 229 FPS
DIFFERENCE/INCH 57 FPS PER INCH
14.5" 2984 FPS ... 16" 3075 FPS
DIFFERENCE 91 FPS
DIFFERENCE/INCH 61 FPS
16" 3075 FPS ... 18" 3245 FPS
DIFFERENCE 170 FPS
DIFFERENCE/INCH 85 FPS
18" 3245 ... 20" 3254 FPS
DIFFERENCE 9 FPS
DIFFERENCE/INCH 4.5 FPS
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September 13th, 2017, 06:35 PM #6
Re: 55gr vs 77gr Data
With some of the basic data/info previously provided by forum members, you can make your own ballistic cards here for free:
http://www.jbmballistics.com/cgi-bin/jbmcard-5.1.cgiLast edited by bamboomaster; September 13th, 2017 at 06:48 PM.
- bamboomaster
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September 14th, 2017, 07:34 AM #7
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September 21st, 2017, 10:11 PM #8Active Member
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Re: 55gr vs 77gr Data
Here is a BUNCH of factory round Chrono data... from my 16" and 20" AR15's
https://www.ar15.com/forums/ar-15/Va...-56/16-676005/
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