GAP Zero versus Weight of Bullet Question

TattooBlade

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I posted this in ballistics too, but I know more folks are in this area and I'm looking for info...

I shoot a GAP 308 with a Bartlein with 5R rifling. Both 168 and 175 grain SMKBTHP hit at the exact same spot at 100 when zeroing. I picked up a box of 150 grain and I'm curious if you think they will also hit the same spot at 100. I will get to the range to confirm at some point, but I'm sure someone here shoots multiple grains and can tell me.

Where will I see the most gain or loss with a lighter round?

Thanks!
 

762frmafr

Gunny Sergeant
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Re: GAP Zero versus Weight of Bullet Question

It may shoot to the same POI at 100 yards, but honestly what difference does that make unless you will only be shooting at 100 yards. Every one of those loadings will have different DOPE. Now if they all have the same zero, well then you don';t have to re-zero when switching ammo, but you will have to know your DOPE at certain yardages. Which in this game is more important thatn POI at 100 yards.
 

Megahoser

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Re: GAP Zero versus Weight of Bullet Question

Depends on the load...with enough tinkering you could make all three have identical POI at 100yds. 168s should be slightly higher at 100yds and 150s should be higher still. But like I said, it depends on the load.

Why do you care?
 

Brutas

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Re: GAP Zero versus Weight of Bullet Question

Federal says 51.6 inches vs 52.0 inches of trajectory at 500 yards with a 200 yard zero.
 

JSTARSZ

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  • Feb 6, 2008
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    Re: GAP Zero versus Weight of Bullet Question

    I will bet not. Recently I was shooting a GAP M40A3 and was shooting 168 SMK's and decided to go to the Nosler 175 and I was surprised that it was 1 MOA different at a 100 yards. So extrapolate that out to 500 and I bet it would be way off.
     

    TattooBlade

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    Re: GAP Zero versus Weight of Bullet Question

    Yeah I shot both 168 and 175 from 100 they were exactly the same. I even shot mixed bunches and they all went to the same hole. I agree about knowing the dope for downrange. All I'm really concerned with for now is hunting out to about 100 since that's the max distance where I'll be. I was curious about trying different rounds for deer or hogs.
     

    hamstur

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    Re: Zero versus Weight of Bullet Question

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TattooBlade</div><div class="ubbcode-body">31 viewers were sleeping....

    Come on folks, share with my your knowledge... </div></div>

    I think more people opened this because of the word 'GAP' but your question is really vague & 100 yards is a really short distance to assess ballistics.

    For my rifles using the same load recipe, even 168AMAX and 168BTHP do not have the same POI at 100.
     

    TattooBlade

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    Re: Zero versus Weight of Bullet Question

    What it boils down to is that I might be going on an unexpected hog trip where 100 yards is max. I picked up some 150 Barnes TTSX that I'd like to try but not sure if I'll get to the range prior. My 168 and 175 hit exactly the same at 100 yards. Without a range trip, do you think the 150 will hit the same out to 100 or close enough for hunting. For competing I use the 168s or 175s and have all their dope figured out.
     

    hamstur

    Smelly
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    Re: Zero versus Weight of Bullet Question

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TattooBlade</div><div class="ubbcode-body">What it boils down to is that I might be going on an unexpected hog trip where 100 yards is max. I picked up some 150 Barnes TTSX that I'd like to try but not sure if I'll get to the range prior. My 168 and 175 hit exactly the same at 100 yards. Without a range trip, do you think the 150 will hit the same out to 100 or close enough for hunting. For competing I use the 168s or 175s and have all their dope figured out. </div></div>

    If that's the case, you'll be fine. POI on all my 150-180 always fall within 2-3 inches of each other at 100 yards while load testing.