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Discussion Starter · #1 ·
Does anyone happen to know the ballistic coefficient of 7.62 M80 Ball ammo? Reason Im asking is we're taking the M24 to the range today but we are low on M118 Match so were saving it and shooting our MG ammo to do some timed engagements. Since we dont usually shoot this ammo we are making some ballistic charts using the Sierra software. We have all the info for a custom bullet on the software, except for the coefficient.

I appreciate any help, till then Ill find the closest round I can to the M80 (147gr FMJ) and use that. Thanks
 

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Good morning,

I have both the SD and BC value for the M80 from an old Access 97 program called Baltraj. It only uses the G1 drag models, as opposed to varying the drag model as a function of velocity, so it may or may not be precise enough to the ranges you may shoot.

BC = 0.393
SD = 0.224

Warmest regards,
Rob

(If it's not too much trouble, let us know if you note any discrepancies.....however it may not be noticeable depending on how much precision was used when the M80 was loaded...that's just standard issue ammo, isn't it?) Have a good day.


Does anyone happen to know the ballistic coefficient of 7.62 M80 Ball ammo? Reason Im asking is we're taking the M24 to the range today but we are low on M118 Match so were saving it and shooting our MG ammo to do some timed engagements. Since we dont usually shoot this ammo we are making some ballistic charts using the Sierra software. We have all the info for a custom bullet on the software, except for the coefficient.

I appreciate any help, till then Ill find the closest round I can to the M80 (147gr FMJ) and use that. Thanks
 

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From KAC's Bulletflight L2, Military G1 database, I've got:

BC1: .393 @ 2800fps
BC2: .383 @ 2456fps
BC3: .378 @ 2010fps
BC4: .370 @ 1786fps
 

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Discussion Starter · #4 ·
Thank you very much.

That should be close enough for today. We can only take it out to 300m on the range were going to. I havent compared M80 and M118 together but my Sgt said out of the M24 its not too bad, at least out to 200m or so since thats as far as he has been able to shoot the M80.

I imagine at further distances its a huge difference. The M80 is a 147gr at 2800 fps (text book) and the 118 Match is a 173gr at 2600 fps (text book) However the M80 velocity is out of a 240B.

And yes the M80 is standard issue MG ammo so I doubt it will shoot that well. Ill try to get some pics of the targets today and let you know how it shoots. Thanks again
 

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Discussion Starter · #6 ·
Well I didnt get any pictures of the targets. The M80 ammo shot like crap to say the least. It could have been partly our fault but neither one of us could get it to group as good as we had liked.

Our first set up was at 100m just to confirm zero. We got it back on target just fine but it was shooting groups averaging about 1 3/4" or so. We didnt even bother measuring haha. Not trying to make excuses but after talking about it, there were alot of things working against us not counting possible shooter error. We were shooting MG ammo which is a far cry from the match ammo that its designed for. And as with most weapons in the Army's inventory, only God knows how many shots have been through it and how it has/has not been taken care of prior to us getting the rifle. So nothing really points to tight groups here.

As far as the coefficient, that really helped alot today. We plugged in that plus all the other info to include environmental factors and came up with a chart thanks to the Sierra software. It was pretty accurate as far as we could tell. Had a slight tail wind that wasnt figured into the chart but that didnt affect us much.

After the initial zero we backed up to approx 250m (as far as we could on this range) and were able to consistently hit silhouettes on rapid fire strings from various supported positions and timed fires. Me being a lefty it still sometimes feels akward to shoot a right hand bolt, especially with any speed. But its all good.

All in all it was a good day I suppose. Still didnt shoot as well as we wanted to but maybe they will get us some more M118 Match so we can put it to good use. If only we could use hand loads haha. Thanks again for the responses, maybe this info will help end the lives of some terrorists soon GI1
 
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