Range Report Effective range 168gr sierra

[kentactic]

i searched and didnt get any straight answers.

ive shot the 168gr FGMM out to 800 yards with good results. id shoot further but havent had the time to drive out to the desert. but anyways i keep reading that 850 is pushing it because its "flirting" with subsonic speeds. yet according to the ballistic calculator it dosent go subsonic until beyond 1000 yards going 2550 at the muzzle, Elevation 1555ft. i used .447 as the BC

so is JBM screwed up or whats going on here?

and for the purpose of this discussion lets define effective as holding 1 MOA under ideal conditions.

-Kenny

 

[Lowlight]

Re: Effective range 168gr sierra

Don't know what ballistic calculator you are using at that speed with a 168gr going 2550fps you are at 1116fps at 844 yards, which is below supersonic.

You didn't specify temperature but let's bump it up to 90 degrees and you get 1115fps at 950 yards... still not supersonic nor 1000 yards.

The calculator actually marks transonic at 910 yards at this temperature.

168s under normal circumstances have no business being shot past 800 yards.

 

[kentactic]

Re: Effective range 168gr sierra

weird... im using JBM... wonder what im missing...let me add that im only getting 12.1 mills of UP @ 1000 yards and the card that has shown to be dead nutts for me is at 12.9 mills of adjustment @ 1000 yards.. i have no clue what info i used to create that card but maybe that ones using the same info your using.

any ideas what data im missing?

i input as follows on JBM:

caliber .308
BC .447 G1
bullet weight 168gr
Muzzle velocity 2550fps
temp. 90
sight height 1.75in
elevation 1555ft

with all that the velocity @ 1000 yards is 1177 drop 12.1 mills

 

[Lowlight]

Re: Effective range 168gr sierra

At 1000 yards with a dope of 12.5 mils you have a MV of 1083fps...

There is not "dead nuts" at that point, especially if you make it 12.9 mils.

 

[kentactic]

Re: Effective range 168gr sierra

out to 800 yards my data has shown the correct UP adjustment with 12.9 being the 1000 yard adjustment. all im saying.

so now my question has shifted to what the hell is wrong with me/my calulator? we seem to be putting in similar info yet with two very different answers.

 

[jbmillard]

Re: Effective range 168gr sierra

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kentactic</div><div class="ubbcode-body">weird... im using JBM... wonder what im missing...let me add that im only getting 12.1 mills of UP @ 1000 yards and the card that has shown to be dead nutts for me is at 12.9 mills of adjustment @ 1000 yards.. i have no clue what info i used to create that card but maybe that ones using the same info your using.

any ideas what data im missing?

i input as follows on JBM:

caliber .308
BC .447 G1
bullet weight 168gr
Muzzle velocity 2550fps
temp. 90
sight height 1.75in
elevation 1555ft

with all that the velocity @ 1000 yards is 1177 drop 12.1 mills
</div></div>

It's your BC value. .447 is only good above 2100 f/s. You're not above that for most of the trajectory. Using Litz' measured G7 BC, it goes subsonic at about 900 yards. As to drop, I can't answer that because I don't know what your zero range is (I didn't see it -- did I miss it?).

Brad

 

[kentactic]

Re: Effective range 168gr sierra

oh yep sorry zero range is 100 yards.

ok i used .220 as my G7 BC and it came up with 13.1 mils of drop and goes sub sonic just before 900 yards. sounds right according to what everyones saying.

not quite recreating the card i have but thats ok.

 

[notquiteright]

Re: Effective range 168gr sierra

Ken-
I get around 2750fps out of my 168 round. 2500 seems awfully slow.

My elevation for the local ranges, ahhh those within 100 miles of me, is 1200'.

I can drive the 168amax out to 1000 yards. Maynot be the best round for out past 800 but with a bit of training it can be done. patience and a good spotter are worth big bonus points.

Good Luck

 

[FLIGHT762]

Re: Effective range 168gr sierra

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JBM</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kentactic</div><div class="ubbcode-body">weird... im using JBM... wonder what im missing...let me add that im only getting 12.1 mills of UP @ 1000 yards and the card that has shown to be dead nutts for me is at 12.9 mills of adjustment @ 1000 yards.. i have no clue what info i used to create that card but maybe that ones using the same info your using.

any ideas what data im missing?

i input as follows on JBM:

caliber .308
BC .447 G1
bullet weight 168gr
Muzzle velocity 2550fps
temp. 90
sight height 1.75in
elevation 1555ft

with all that the velocity @ 1000 yards is 1177 drop 12.1 mills
</div></div>

It's your BC value. .447 is only good above 2100 f/s. You're not above that for most of the trajectory. Using Litz' measured G7 BC, it goes subsonic at about 900 yards. As to drop, I can't answer that because I don't know what your zero range is (I didn't see it -- did I miss it?).

Brad </div></div>

Brad, Thank you for that. I've been using the JBM calculator for some time, I didn't know about using the G7 BC with the bullets in the " Litz" catagory. Making more sense now!

 

[arborpro]

Re: Effective range 168gr sierra

Near 800 yrds sounds about right with Federal GM velocity's. I think that bullet was initially designed to shoot 300 meter UIT matches.
LEOs started shooting them for there tactical marksmen round(and still do). some time after that the legendary stories heard around the range was these rounds could take you out to a 1000. which I'm sure they will do. hell when i was a kid .22 long rifle ammo had printing on the box that said they where dangerous up to 1 or 3 miles. don't think they met accurate to that range though.

 

[kentactic]

Re: Effective range 168gr sierra

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: notquiteright</div><div class="ubbcode-body">Ken-
I get around 2750fps out of my 168 round. 2500 seems awfully slow.

My elevation for the local ranges, ahhh those within 100 miles of me, is 1200'.

I can drive the 168amax out to 1000 yards. Maynot be the best round for out past 800 but with a bit of training it can be done. patience and a good spotter are worth big bonus points.

Good Luck </div></div>

yeah im not reloading. im shooting the federal gold medal match with the 168gr sierra matchking bullet. it chrono'd at around 2550 average out of my 20'' barrel. id imgine with another 200fps 1000 yards is a little more plausable.

 

[kentactic]

Re: Effective range 168gr sierra

ok guys im thinking about trying the 155 scenars.

im going to give southwest ammunition a try.

im guessing around 2750fps out of my 20'' barrel so im looking at

9.8 mils drop @ 1000 yards @ 1265 ft/s... i used .236 as my G7 BC, does that sound about right?

all other info is the same as above.

 

[Niles Coyote]

Re: Effective range 168gr sierra

Sounds about right. I am usually right near 10mil in my 20" tactical which is running at ~2750

 

[kentactic]

Re: Effective range 168gr sierra

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Niles Coyote</div><div class="ubbcode-body">Sounds about right. I am usually right near 10mil in my 20" tactical which is running at ~2750 </div></div>


cool thanks for the response. ill give it a whirl. are you also using the 155 scenars from southwest ammo?

 

[kentactic]

Re: Effective range 168gr sierra

well i shot out to 887 yards with the 168 sierras today.. it performed great at that range... wind was blowing... i was holding up to 3.5 mills on the reticle and i was getting hit after hit on 12'' steel 10.1 mills was the elevation adjustment. no complaints from me.. just thought id give my little update...