Range Report FGMM 168gr Ballistics

SLO

Sergeant
Full Member
Minuteman
Jun 13, 2012
186
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Portland, OR
When an ammo manufacturer posts muzzle velocity, is there a way to tell what barrel length is used? For example, FGMM 168gr says that muzzle velocity is 2650. Is that an accurate number to use for my 24" 5R barrel?
 
Re: FGMM 168gr Ballistics

Test barrel is often 24", but that's not necessarily written in stone. I have a couple rifles with 5R barrels and I seem to be getting a little better than the box values. Using the box MV value MAY get you in the ballpark, but you really have to determine MV with your rifle and specific ammo to know for sure.
 
Re: FGMM 168gr Ballistics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gstaylorg</div><div class="ubbcode-body">Test barrel is often 24", but that's not necessarily written in stone. I have a couple rifles with 5R barrels and I seem to be getting a little better than the box values. Using the box MV value MAY get you in the ballpark, but you really have to determine MV with your rifle and specific ammo to know for sure. </div></div>

Thanks! Is there a way to calculate based on ballistics rather than use a chrono?
 
Re: FGMM 168gr Ballistics

Of course, you can make estimates based on drop at known distances. You simply record your drops (scope elevation change to zero at each distance is one method) at various known distances (the more the better). Then you adjust your MV in a ballistic calculator such as JBM until the predicted drops match your actual drops as closely as possible with all the pertinent atmospheric and load data entered. Again, this can give a pretty good estimate, but I would generally much prefer to do it the other way around. Specifically, using an average MV from at least 10-shots or 2x10-shot strings, use the ballistic calculator to predict the drop at specified distances for the determined MV. Then see how well the predicted drops match the actual, as opposed to the other way around.
 
Re: FGMM 168gr Ballistics

D.O.P.E. the only way I have found to get dialed in. Like in the above posts using the manufacturers velocity gets you in the ballpark, once your spot on after dialing it in closer record the data. Once you've compiled your drop and different ranges you can make a drop chart specific to that load and weapon.
 
Re: FGMM 168gr Ballistics

I use shooting solution for android, its given me a pretty accurate drop chart so far gets me within inches of my target. The NSSF has some great videos up on YouTube if you haven't already checked them out.
 
Re: FGMM 168gr Ballistics

I use Ballistic on my iPhone. When I plug in the chronographed velocity as measured from my 24" 700P (2660 fps) the resulting table is dead on at most any distance I care to look at. The few readings that deviate from my actual dope are within a quarter MOA.

HRF
 
Re: FGMM 168gr Ballistics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hrfunk</div><div class="ubbcode-body">I use Ballistic on my iPhone. When I plug in the chronographed velocity as measured from my 24" 700P (2660 fps) the resulting table is dead on at most any distance I care to look at. The few readings that deviate from my actual dope are within a quarter MOA.

HRF </div></div>

Is that for 168 gr?