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Posted: 9/12/2010 5:30:57 PM EDT
I have my Stag (1/9 twist, 16" barrel) sighted in to hit dead center with at 100 yards with a 55gr PMC bullet.  I'm going to shoot a 64gr Winchester bullet out of it for the hunting season.  I know I have to go to the range and re-sight my gun in, but I just would like an idea of what kind of drop I should be expecting.  If I could get an estimate that would be greatly appreciated. Thanks
Link Posted: 9/12/2010 7:13:10 PM EDT
[#1]
You should not expect a drop, without knowing the actual velocity of both rnds out of your weapon it's impossible to guess. Even knowing the velocities it would still only be a guess. Slower bullets generally hit higher in relation to point of aim because they leave the barrel later in the recoil cycle than faster bullets.Time of flight  to target can not be easily judged by muzle velocity between two different weight bullets because the lighter bullets shed velocity quicker than heavier bullets of comparable shape. The best thing to do is actual feild testing of any loads your concered about. Second best would be software programs or manufacturer balisatic data. There are a few knowlegeable data heads around here that could get you pretty close. Considering barrel harmonics can shift impact left/right and up/down leaves actual zeroing everyones only option for best accuracy.
Link Posted: 9/13/2010 5:27:17 PM EDT
[#2]
i was shooting the other day and i started with 50 federal hp and finished with 64 federal tru and the poi was very close,, i would feel comfortable shooting coyotes or deer with these two bullets
Link Posted: 9/14/2010 6:20:46 AM EDT
[#3]
Quoted:
i was shooting the other day and i started with 50 federal hp and finished with 64 federal tru and the poi was very close,, i would feel comfortable shooting coyotes or deer with these two bullets


Cheers!! That was the response I was looking for.  I bought that 223 64gr Winchester Power-Point at $27 a box of twenty.  At that price I really don't want to waste a whole box sighting it in, rather two or three rounds intead.
Link Posted: 9/14/2010 9:41:02 AM EDT
[#4]
What range are you going to zero at? Most .223/5.56 rounds will actually require you to aim lower than intended point of impact to hit your target between 50-200 meters, depending on your zero.



50 meter zero should generally be "zeroed" at 200 meters.

Shorter than 50, aim higher (barrel is below sights).

Between 50 and 200, aim lower (sights and line of bore intersect at 50 yards and line from barrel continues upwards as does the bullet in flight).

At 200, gravity should pull the bullet back into line with the sights. Beyond 200 yards you aim high as gravity will pull the bullet below point of aim.



If you do 25 meter, replace 50 with 25 and replace 200 with 300. Same story, roughly.



Remember that this is just a "rule of thumb" and is not accurate for every single ammo type and bullet weight. But it should be close enough to keep you on target. Best way to learn it is to shoot it.
Link Posted: 9/14/2010 3:15:03 PM EDT
[#5]
I find with a 50Y zero

That M855 and 77smk are very close to the same POI



Tin can accuracy with M4 14.5 220y

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