Range Report Personal Ballistic Card, whats your thoughts???

[NAVYJACKDOC]

I currently use a shooters log I've assembled through impact Data Books.com and wanted some very specific Ballistic cards. So I decided to create my own custom ballistic card for my book. The ammo that this card is built around is the POF (Pakistani Ordnance Factory) 762x51 NATO round. 147gr (1990 build date). I'm using a NF NSX F1 Scope on my POF P308 AR10. I wanted a card with 1/10th MIL adjustment increments per 25 yds along with a quick reaction BDC on the MLR2.0 reticule as well.

Any additional input for my Data card would be appreciated. It's designed around a 100 Yd zero w/ 800 Yd max range. LOS:0, Windage:0, VZR:6".

Once I have the final card, I'll have it printed out in a 8.5"x5.5" and Laminate it for my log.

Am I missing anything for a short range yard?
Thanks.

DocJr

 

[roggom]

Doc, card looks good. I would add the bullet BC somewhere, the temp and elevation the data was calc'd for. Since you established that Red = mil and Green = inches, no need to write the abbreviations in. Also take the Mil down to tenth. You cant dial .01 so you can either round or drop it completely.

With the extra room add a wind column in 5 or whichever increment you want. I like to use the BC of the bullet as an increment, so if your bullet has a BC of .400 the increments are of 4 mph full value, then a quick dirty hold is 100 = .1mil, 200 = .2 mil etc up to 600 which is .7 mil. Your software will spit out the values, but it should be close.

 

[NAVYJACKDOC]

Doc, card looks good. I would add the bullet BC somewhere, the temp and elevation the data was calc'd for. Since you established that Red = mil and Green = inches, no need to write the abbreviations in. Also take the Mil down to tenth. You cant dial .01 so you can either round or drop it completely.

With the extra room add a wind column in 5 or whichever increment you want. I like to use the BC of the bullet as an increment, so if your bullet has a BC of .400 the increments are of 4 mph full value, then a quick dirty hold is 100 = .1mil, 200 = .2 mil etc up to 600 which is .7 mil. Your software will spit out the values, but it should be close.

That's great input! Thx Senior Chief. I'll dial it in more and post up. I was thinking of doing a duel sided card that has the 100 Yd zero then on the back side, same setup, but with the BDC designed around a true "MPBR" maximum point blank range. 6" KZ, and the ranges and optimum zero for that design.


Jr

 

[roggom]

YW, Yes, and considering you have numbers for drops on the right side, you can extrapolate rather quickly what the range should be at the half mil increments. So you can remove the left set of numbers and replace with mil calc'd ranges for an 18" target. That is equiv to deer shoulder to brisket and other useful items (some signs, rims, also C7 to L5 ).

 

[NAVYJACKDOC]

I like those suggestions, thank you Senior!

 

[roggom]

Your welcome, happy and safe shooting shipmate.

 

[riffraff]

roggom knows better than I would, but here is my DOPE chart based on Density Altitudes (0', 2k', etc)...it also has columns for wind correction (mils and inches columns) and for moving targets at 4mph...just use fractions of the 4mph figure for walking (3mph), jog (5mph), or run (7mph)....all of this designed for quick use in local competitions....ymmv depending on the type of shooting you intend to do with it, and others are welcome to throw rocks...there is a wealth of info and experience on this site.

Also, to use this kind of card, you MUST use a very temperature stable powder (Hodgdons) to keep the muzzle velocity constant...this allows you to use Density Altitude as the only variable, while muzzle velocity stays constant.

another thread:


http://www.snipershide.com/shooting...s/233180-ballistic-card-density-altitude.html

 

[NAVYJACKDOC]

roggom knows better than I would, but here is my DOPE chart based on Density Altitudes (0', 2k', etc)...it also has columns for wind correction (mils and inches columns) and for moving targets at 4mph...just use fractions of the 4mph figure for walking (3mph), jog (5mph), or run (7mph)....all of this designed for quick use in local competitions....ymmv depending on the type of shooting you intend to do with it, and others are welcome to throw rocks...there is a wealth of info and experience on this site.

Also, to use this kind of card, you MUST use a very temperature stable powder (Hodgdons) to keep the muzzle velocity constant...this allows you to use Density Altitude as the only variable, while muzzle velocity stays constant.

another thread:


http://www.snipershide.com/shooting...s/233180-ballistic-card-density-altitude.html

Those are slick as well. I like the 1/10th MIL adjustment but as Senior said earlier, no need to put in the 100th value, with what you have is sufficient. Can you explain the very last 3 columns...

 

[riffraff]

Sure.... Lets look at the 600 yard numbers. The last three columns are 1.0, 23, and 2.5 .....the 1.0 is the wind correction in mils, so for a 10 mph direct crosswind it is a 1.0 mil correction to the left or right. The number 23 is the number of inches of drift for that 10 mph wind, so a left to right crosswind would blow the bullet 23 inches to the right. The number 2.5 is the amount of lead that you would hold for a target moving at 4mph (a brisk walk). As always, if the winds are less or more than 10 mph, then just use a percentage of the number... e.g. for a 5 mph direct crosswind, use 50% of 1.0 mils, giving you a .5 mill correction factor.

All of these can be calculated in JBM Ballistics online.

Many shooters/spotters only call out the misses in mil values, so many guys would not include the 'inches' column on their card. I only include it to give me a visual picture of just how much the wind can move your bullet....but it is not an essential column.

Some would say that a 10 mph crosswind on a cold/dense air day moves the bullet farther than on a hot day, but IMHO the winds are always an estimate, so a medium temperature value is always a good starting point.

Notice that out to 600 yards the different density altitude columns don't change a ton.... but the big question for your data is that the powder in your rounds may give you big fluctuations in your muzzle velocity compared to my hand-loaded Hodgdon powder when you go from a 30*F day to a 90*F day..... maybe a 70 fps difference! If so, you would need to make a separate card for each 10*F or 20*F of outside temperature in order to adjust for the increasing muzzle velocity as temperature increases.

After 600 yards the density altitude makes a huge difference in the DOPE data, so having a Kestrel or using a calculator becomes essential.... http://www.pilotfriend.com/calcs/calculators/density.htm

Hope this makes sense...just my .02 cents worth. Many are more experienced than me and can point out flaws in my approach.

 

[NAVYJACKDOC]

Riffraff, that's excellent info and totally makes sense to me. I was assuming that, of the last 3 columns, the 1st was MIL adjust and the 2nd was INCH movement (Im a visual guy too) but wasn't sure of the 3rd column, but now I get it, moving target 4mph....

As for ballistic calculations, the JBM setup is the one I'm implementing. I like it, very accurate with many variables for input.

I see what you're saying regarding the inconsistent velocities with the powder in this round and temp changes.