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Posted: 5/24/2011 2:52:36 PM EDT
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Looking for trajectory table or chart for Prvi Partizan 223 Match HPBT 75 gr.
I am zeroed at 100 yds. I'm specifically lookiing for bullit drop in inches from 100 to 200 yds... and 100 to 300 yds. Thanks guys! |
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PRVI advertises a muzzle velocity of 2723 fps with that load - I assume out of a 20" barrel, and I assume you are also using a 20" barrel.
PRVI does not advertise a BC for the bullet so I am assuming .395 - at the low end of 75 gr .223 bullets (but the difference will be pretty minimal anyway). Sight height is also important and I am again assuming you have a 2.5" sight height (distance from top of front post or center of reticle to the center of the bore - pretty common for an AR-15. With those assumptions in mind along with standard atmosphere, sea level elevation and a 100 yard zero you get: 25 yd = -1.4' 50 yd = -.6" 75 yd = -0.1 100 yd = 0.0 125 yd = -.02 150 yd = -.08 175 yd = -1.7 200 yd = -3.1 225 yd = -4.8 250 yd = -7.0 275 yd = -9.7 300 yd = -12.8 325 yd = -16.4 350 yd = -20.6 375 yd = -25.3 400 yd = -30.6 425 yd = -36.5 450 yd = -43.1 475 yd = -50.3 500 yd = -58.2 525 yd = -66.9 550 yd = -76.4 575 yd = -86.7 600 yd = -97.9 It's worth noting that with a 5" vital zone (+/- 5" from point of aim), the optimum point blank zero distance is 285 yards. If you do that it changes the trajectory substantially: 25 yd = -0.5' 50 yd = 1.3" 75 yd = 2.7" 100 yd = 3.8" 125 yd = 4.6" 150 yd = 4.9' 175 yd = 5.0" 200 yd = 4.6" 225 yd = 3.8" 250 yd = 2.5" 275 yd = 0.8" 285 yd = 0.0 300 yd = -1.4" 325 yd = -4.0" 333 yd = -4.9" 350 yd = -7.3" 375 yd = -11.0" 400 yd = -15.4" 425 yd = -20.3" 450 yd = -25.9" 475 yd = -32.2' 500 yd = -39.2 525 yd = -46.9 550 yd = -55.4 575 yd = -64.8 600 yd = -75.0 With a 100 yard zero you can basically hold dead on out to 150 yards and be very close to point of aim. However, beyond that you have some pretty significant hold over to contend with. If you zero for 285 yards, you just hold under the target 4" from 100-225 yards and not be more than 1' off POA. You can then hold basically dead on from 225-300 yards and not be more than about +/- 4' off POA. Or you can make it even simpler and just hold dead on out to 333 yards and never be more than +/- 5" off point of aim. Past 333 yards, you then also have less drop to correct for with the longer zero, so even with adjustable turrets on a scope you save some adjustment - about 3 MOA or 23" at 600 yards. |
| Checkmate; using a scope, it's common to sight in at 100 and then use the ranging lines on the reticle to hold over for 200, 300, 400, 500 and 600, although scopes are calibrated for generic .223, not 75 gr.. With iron sights or a red dot, you may want to consider a 50 yd zero that will be about 2.0" high at 100 and back around zero at 200. You'll need a chart like the one provided above but tailored for your exact equipment in order to know what you're doing. |
Not to hijack this tread, but on the same subject, does any one know an effective way to obtain the BC for many standard bullets? I've emailed my current ammo's customer service in an attempt to obtain the BC so that I can work on some firing solutions, but with no response. Is there a chart that will give even an approximate BC for different style bullets at different weights?... anything would help. 
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Quoted:
Not to hijack this tread, but on the same subject, does any one know an effective way to obtain the BC for many standard bullets? I've emailed my current ammo's customer service in an attempt to obtain the BC so that I can work on some firing solutions, but with no response. Is there a chart that will give even an approximate BC for different style bullets at different weights?... anything would help. Go to the bullet manufacturer's website and look for the info,or check a reloading manual. Hornady's website, for instance, gives BC info for all its bullets. The BC for Hornady 75gr BTHP is listed as .395. Whatever BC is listed for their 55gr FMJ might not be exactly the same for M193, but it'll be pretty close. |
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Quoted: PRVI advertises a muzzle velocity of 2723 fps with that load - I assume out of a 20" barrel, and I assume you are also using a 20" barrel. PRVI does not advertise a BC for the bullet so I am assuming .395 - at the low end of 75 gr .223 bullets (but the difference will be pretty minimal anyway). Sight height is also important and I am again assuming you have a 2.5" sight height (distance from top of front post or center of reticle to the center of the bore - pretty common for an AR-15. With those assumptions in mind along with standard atmosphere, sea level elevation and a 100 yard zero you get: 25 yd = -1.4' 50 yd = -.6" 75 yd = -0.1 100 yd = 0.0 125 yd = -.02 150 yd = -.08 175 yd = -1.7 200 yd = -3.1 225 yd = -4.8 250 yd = -7.0 275 yd = -9.7 300 yd = -12.8 325 yd = -16.4 350 yd = -20.6 375 yd = -25.3 400 yd = -30.6 425 yd = -36.5 450 yd = -43.1 475 yd = -50.3 500 yd = -58.2 525 yd = -66.9 550 yd = -76.4 575 yd = -86.7 600 yd = -97.9 It's worth noting that with a 5" vital zone (+/- 5" from point of aim), the optimum point blank zero distance is 285 yards. If you do that it changes the trajectory substantially: 25 yd = -0.5' 50 yd = 1.3" 75 yd = 2.7" 100 yd = 3.8" 125 yd = 4.6" 150 yd = 4.9' 175 yd = 5.0" 200 yd = 4.6" 225 yd = 3.8" 250 yd = 2.5" 275 yd = 0.8" 285 yd = 0.0 300 yd = -1.4" 325 yd = -4.0" 333 yd = -4.9" 350 yd = -7.3" 375 yd = -11.0" 400 yd = -15.4" 425 yd = -20.3" 450 yd = -25.9" 475 yd = -32.2' 500 yd = -39.2 525 yd = -46.9 550 yd = -55.4 575 yd = -64.8 600 yd = -75.0 With a 100 yard zero you can basically hold dead on out to 150 yards and be very close to point of aim. However, beyond that you have some pretty significant hold over to contend with. If you zero for 285 yards, you just hold under the target 4" from 100-225 yards and not be more than 1' off POA. You can then hold basically dead on from 225-300 yards and not be more than about +/- 4' off POA. Or you can make it even simpler and just hold dead on out to 333 yards and never be more than +/- 5" off point of aim. Past 333 yards, you then also have less drop to correct for with the longer zero, so even with adjustable turrets on a scope you save some adjustment - about 3 MOA or 23" at 600 yards. Dakota, Where did you get this info? Do you have a calculator or program that does this for you? Thanks! |
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CheckMate07,
As you can see there are several ballistics programs out that can help with making charts of all sorts. These programs require some inputs. For example, are we using iron sights such as Service Rifle Competition rigs, or a scope ? You would then need velocity and unless you put faith in BC numbers you will need more trajectory points to curve fit or another distance velocity. I can give you the trajectory for PRVI 75 for my White Oak service rifle, but unless you are getting the same velocity as my 20" bbl, it will fall apart before you get very far. For example, at 2300 ft MSL and 72 degrees F these were the 1/4 MOA clicks for going from 200 to 600 with the most recent blue box PRVI 75. From my 200 yd zero, I needed 12 clicks up to get to 300. Notice this fits the old general rule of 3 MOA per hundred between 200 to 300. Maybe I should mention there is an old general rule pattern for Service Rifle loads which gets you on paper... I then needed 46 more clicks (11.5 MOA) to get to 600. Which again, is off by about 1/2 MOA but is nearly the same as the general rule. The old method general rule is reliable or it wouldn't have lasted this long. |
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