Need balistics info on 7.62 X 39

[Sly Old Fox]

I have an old but very good ballistic program that I've not used for years as it was on a 5.25" . I have now transferred it to a 3.5" and want to run it on an old laptop. Anyway I need

> the BALLISTIC COEFFICIENT (B.C.) of the standard FMJ 123 gr. bullet

> and is the muzzle velocity out of a Tula '53 2,150 FPS?

The recent thread here on sight setting was great. I have my Tula sighted for 200 metres, but with the old program I have, I will be able to produce info for use in checking at various distances in yards.

Many Thanks,

 

[SoBored]

Well SOF, it looks like you might have to do it the hard way and find a Ballistic Coefficient Calculator.

One method uses velocity at two known distances. Problem is, I wouldn't feel very comfortable shooting my SKS over a chrony at much past 50 or 75 yards. If the range is slow, (read as I'm the only one there), I will try to run some 123 FMJ over my chrony at 25 and 75 yards some day. Another problem is the ammo itself has varied powder charges so an average would have to be used.

http://www.beartoothbullets.com/rescources/calculators/BC/index.html

The other method is to measure the hell out of the bullet and run it through something like:

http://www.uslink.com/~tom1/calcbc/calcbc.htm

I haven't looked at this last link much but it might be of some use.

 

[mmattockx]

From the VZ Shorty thread by Clobbersauras:

Now to the interesting stuff. I chrony'd my rifle with surplus Czech ammo against my buddies Non-restricted 858. I fired ten rounds through each rifle. I was very happy with the results!

858 Results: 19inch 7.62x39
AVG Velocity: = 2294fps +/- 21fps

DLASK Conversion results: 12inch 7.62x39
Average Velocity: 2119fps+/- 29fps

So going with 2300fps would be a reasonable guess.

As for the BC, it hardly matters out to 200yds. Hornady lists the G1 BC for their 123gr FMJ bullet as 0.266, which will be more than close enough unless you are trying for first round hits at 500yds.


Mark

 

[Sly Old Fox]

From the VZ Shorty thread by Clobbersauras:


So going with 2300fps would be a reasonable guess.

As for the BC, it hardly matters out to 200yds. Hornady lists the G1 BC for their 123gr FMJ bullet as 0.266, which will be more than close enough unless you are trying for first round hits at 500yds.


Mark

Thanks Mark. The G1 of Hornady for their FMJ of 0.266 will work great.

As I said in the OP, I only want to run some charts using various first Xings and the elevations at 100, 200 & maybe 300, yards and metres.

I have no thoughts of using the program as I did years ago for my Win 70 in .338 with the 225 Hornady bullet, using a 10" diameter of the boiler room for a moose, has a point blank shot right out to 365 or so yards and aldo knew the drops past that if I had previously measured the longer distances for a hold over shot. (apology for the one last sentence.

Now to take the vernier and measure the distance of the front post aboce the more center.

Cheers

Don,