I have an ae mk2 with a nightforce nxs 5.5-22 zero stop. Currently my stick is zeroed to 168 grain fgmm. However I am thinking about moving past 600 yards to the 1000 yards range, and I hear for that purpose the 175 grain smks are much more stable. If my plan was to switch between the 168 and the 175 grain bullets are the zeroes much different at 100 yards? Or should I just switch to the 175 sell my fgmm, rezero, and call it a day? Anyone out there shoot two different grain bullets using the same zero?
- Thread starter swangz
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Re: 308 168 grain bthp vs 175 grain smk
I saw with my own eyes 168s lose their vapor trail at ~800 yards while I could make/call consistent hits at 1000 with the 175smk.
Ballistic coefficient in action.
I saw with my own eyes 168s lose their vapor trail at ~800 yards while I could make/call consistent hits at 1000 with the 175smk.
Ballistic coefficient in action.
Re: 308 168 grain bthp vs 175 grain smk
rezero at 100 with the 175. Find your velocity and call it a day.
rezero at 100 with the 175. Find your velocity and call it a day.
Re: 308 168 grain bthp vs 175 grain smk
A 100 yd zero will be almost identical between 168s and 175s. Around 300 yds is where the dope really starts to change. But to get to 1000, 175s are where it's at. 68s become unpredictable past 700 for me at least.
A 100 yd zero will be almost identical between 168s and 175s. Around 300 yds is where the dope really starts to change. But to get to 1000, 175s are where it's at. 68s become unpredictable past 700 for me at least.
Re: 308 168 grain bthp vs 175 grain smk
I just switched to the Lapua 170 lock base for the very reasons noted above. Better BC,(.525 for the Lapua vs .505 for the Sierra 175) and a little more weight. My guess is that between the extra weight of the Sierra and the slightly higher BC of the Lapua, the two bullets will carry pretty well to 1000 yards.
I just ran a comparison of the two bullets through my EXBAL program.
170 Lapua W/ BC of .525 starting @ 2675 FPS will be 1006 fps @ 1500 yards
175 Sierra Match W/ BC of .505 starting @ 2660 FPS will be 1003 @ 1500 yards
That is awfully close...3 feet per second is probably closer than the ES/SD of Federal GMM ammo
I just switched to the Lapua 170 lock base for the very reasons noted above. Better BC,(.525 for the Lapua vs .505 for the Sierra 175) and a little more weight. My guess is that between the extra weight of the Sierra and the slightly higher BC of the Lapua, the two bullets will carry pretty well to 1000 yards.
I just ran a comparison of the two bullets through my EXBAL program.
170 Lapua W/ BC of .525 starting @ 2675 FPS will be 1006 fps @ 1500 yards
175 Sierra Match W/ BC of .505 starting @ 2660 FPS will be 1003 @ 1500 yards
That is awfully close...3 feet per second is probably closer than the ES/SD of Federal GMM ammo
Re: 308 168 grain bthp vs 175 grain smk
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">A 100 yd zero will be almost identical between 168s and 175s</div></div>
So if that is the case then I should be able to just switch the ammo from 168 to 175, leave my current zero, and just use a ballistic calc from there to see if I can hit paper?
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">A 100 yd zero will be almost identical between 168s and 175s</div></div>
So if that is the case then I should be able to just switch the ammo from 168 to 175, leave my current zero, and just use a ballistic calc from there to see if I can hit paper?
Re: 308 168 grain bthp vs 175 grain smk
FGMM comes in the 175's too.
FGMM comes in the 175's too.
Re: 308 168 grain bthp vs 175 grain smk
yeah just wondering if i need to change my 100 yard zero or not when i move from 168 to 175 in the FGMM. Maybe the only way to find out is if i just buy a box and try it...just wondering if any one else has tried it.
yeah just wondering if i need to change my 100 yard zero or not when i move from 168 to 175 in the FGMM. Maybe the only way to find out is if i just buy a box and try it...just wondering if any one else has tried it.
Re: 308 168 grain bthp vs 175 grain smk
What's the big deal? Just take the 175's out to 100 and re-zero. And consider reloading - chances are the factory stuff isn't tuned to your rifle and is not loaded as hot as it could be...
What's the big deal? Just take the 175's out to 100 and re-zero. And consider reloading - chances are the factory stuff isn't tuned to your rifle and is not loaded as hot as it could be...
Re: 308 168 grain bthp vs 175 grain smk
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: zaku65</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">A 100 yd zero will be almost identical between 168s and 175s</div></div>
So if that is the case then I should be able to just switch the ammo from 168 to 175, leave my current zero, and just use a ballistic calc from there to see if I can hit paper?</div></div>
That's what I do. 155s, 168s and 175s all hit the same spot at 100 for the most part. If I ever had to change the zero, it was such a tiny amount, and probably due to climate or powder charge.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: zaku65</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">A 100 yd zero will be almost identical between 168s and 175s</div></div>
So if that is the case then I should be able to just switch the ammo from 168 to 175, leave my current zero, and just use a ballistic calc from there to see if I can hit paper?</div></div>
That's what I do. 155s, 168s and 175s all hit the same spot at 100 for the most part. If I ever had to change the zero, it was such a tiny amount, and probably due to climate or powder charge.
Re: 308 168 grain bthp vs 175 grain smk
Switch to FGMM 175gr and don't look back.
If you keep both, things get overly complicated.
I have found that 168gr do group tighter at 100 - 200 yards though.
YMMV
Switch to FGMM 175gr and don't look back.
If you keep both, things get overly complicated.
I have found that 168gr do group tighter at 100 - 200 yards though.
YMMV
Re: 308 168 grain bthp vs 175 grain smk
175 FGGM shoot very well for me. They're the same price as the 168's. Why pay the same for more limited range?
175 FGGM shoot very well for me. They're the same price as the 168's. Why pay the same for more limited range?
Re: 308 168 grain bthp vs 175 grain smk
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: zaku65</div><div class="ubbcode-body">yeah just wondering if i need to change my 100 yard zero or not when i move from 168 to 175 in the FGMM. Maybe the only way to find out is if i just buy a box and try it...just wondering if any one else has tried it. </div></div>
I would. My remmy 5r shoots 175's a bit high and to te left. Not too much, but @ extended range it would be a lot. But saying that, I agree with everyone else. Shoot up all of your 168's and start shooting the 175's
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: zaku65</div><div class="ubbcode-body">yeah just wondering if i need to change my 100 yard zero or not when i move from 168 to 175 in the FGMM. Maybe the only way to find out is if i just buy a box and try it...just wondering if any one else has tried it. </div></div>
I would. My remmy 5r shoots 175's a bit high and to te left. Not too much, but @ extended range it would be a lot. But saying that, I agree with everyone else. Shoot up all of your 168's and start shooting the 175's
Re: 308 168 grain bthp vs 175 grain smk
I use 168´s only because I have a stock pile but when they are gone I will only shoot 175´s outta my 5R oh and I am definitely going to try those 170 lapua´s thats a damn good bc .525 @ 2675 fps
I use 168´s only because I have a stock pile but when they are gone I will only shoot 175´s outta my 5R oh and I am definitely going to try those 170 lapua´s thats a damn good bc .525 @ 2675 fps
Re: 308 168 grain bthp vs 175 grain smk
http://www.lapua.com/en/products/reloading
According to lapua G1 .498. I shoot Berger 175gr BT LRs G1 .515 one of the higher 175s i've seen. Though the hybrid 168 has a G1 of .519.
http://www.lapua.com/en/products/reloading
According to lapua G1 .498. I shoot Berger 175gr BT LRs G1 .515 one of the higher 175s i've seen. Though the hybrid 168 has a G1 of .519.
Re: 308 168 grain bthp vs 175 grain smk
Just stick with 168s... so that leaves more 175s for me. I started with 175s and have never even shot 168s but once. 175s do everything a 168 will do but not vice versa. 175s buck wind better.
Just stick with 168s... so that leaves more 175s for me. I started with 175s and have never even shot 168s but once. 175s do everything a 168 will do but not vice versa. 175s buck wind better.
Re: 308 168 grain bthp vs 175 grain smk
Haven't gone to 1k yet but 175smk's group better past 300yds for me. FGMM are good for how cheap they are. Tried out this brand called Buffalo Bore a little bit ago, they group pretty nice. I see Black Hills and Southwest Ammunition get mentioned in here quite a bit. Hornady has some 178gr superformance that seem loaded kinda hot. Could give those a try.
Haven't gone to 1k yet but 175smk's group better past 300yds for me. FGMM are good for how cheap they are. Tried out this brand called Buffalo Bore a little bit ago, they group pretty nice. I see Black Hills and Southwest Ammunition get mentioned in here quite a bit. Hornady has some 178gr superformance that seem loaded kinda hot. Could give those a try.
Re: 308 168 grain bthp vs 175 grain smk
Where I am, close to sea-level, my buddy decided to shoot a match with 168s. They perform VERY well in his rifle at 100 and out to 650 where we practice.
However, once he got to stages beyond 700, his groups were barely on paper and there was some key-holing.
I can't fathom why anybody would buy 168s if they intend on shooting beyond 700 yards.
To the OP: If you have 168s, keep them, shoot them up. Use them for positional practice at short and medium range. From now on, only buy 175s.
Where I am, close to sea-level, my buddy decided to shoot a match with 168s. They perform VERY well in his rifle at 100 and out to 650 where we practice.
However, once he got to stages beyond 700, his groups were barely on paper and there was some key-holing.
I can't fathom why anybody would buy 168s if they intend on shooting beyond 700 yards.
To the OP: If you have 168s, keep them, shoot them up. Use them for positional practice at short and medium range. From now on, only buy 175s.
