Range Report How can I tell FGMM 168gr from 175gr???

[ruth]

Guys,

I just received some FGMM 168gr and 175 gr 308 ammo. The problem is that the ammo is all mixed together. Is there a way to physically ID and distinguish FGMM 168gr ammo from 175gr ammo? The stamping on the brass just say "WIN 308 FC"

 

[MontanaMarine]

Re: How can I tell FGMM 168gr from 175gr???

I'd start weighing them, and look for a trend of about 7 grains difference.

 

[EMorr]

Re: How can I tell FGMM 168gr from 175gr???

Given inconsistencies in brass weight from cartridge to cartridge and lot to lot in the federal brass and assuming the 175 grain rounds use a slightly lighter powder charge. I would say you do what MontanaMarine suggested but it probably won’t be as simple as separating the light rounds from the heavy ones, there will likely be some middle ground that can’t be so easily determined but it should work for the majority of them.

If you have an OAL gauge that measures from the ogive you could check and see if they come in at different lengths and use that as a way to separate the rounds. The last option I can think of is if you reload you can pull the bullets weigh them and then reassemble the rounds one at a time.

 

[tomthebaker]

Re: How can I tell FGMM 168gr from 175gr???

When I load them in my (Magpul) magazines, the 175 gr. just barely fit, and the 168 gr. fit easily, so I believe there is an OAL difference.

 

[quickdraw17]

Re: How can I tell FGMM 168gr from 175gr???

I also think there is a OAL difference. I seem to remember a couple of years back I measured a few and the 175's were 2.800 and the 168's were 2.775 (or something like that).

 

[5R Milspec]

Re: How can I tell FGMM 168gr from 175gr???

I could be wrong but I think I read some where that one or the other had crimped primers.for me I cannot say I have been reloading for about 18 years now.so buying ammo hasn't been in the pic for me some time now.

 

[jpspeeddemon]

Re: How can I tell FGMM 168gr from 175gr???

i measured both a few months ago, both are loaded to 2.800 OAL with +/-0.003 standard deviation.

I also measured length from bottom of case to ogive using a hornady 30 cal comparator as follows:
168s averaged 3.230" +/-0.003
175s avg 3.217" +/-0.003

go figure, thought the 175s would seat a little longer

 

[DirtyRod]

Re: How can I tell FGMM 168gr from 175gr???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 5R milspec</div><div class="ubbcode-body">I could be wrong but I think I read some where that one or the other had crimped primers.for me I cannot say I have been reloading for about 18 years now.so buying ammo hasn't been in the pic for me some time now. </div></div>

Based on the 3k fired cases I have, 168s come both crimped and uncrimped.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Noodles</div><div class="ubbcode-body">I also think there is a OAL difference. I seem to remember a couple of years back I measured a few and the 175's were 2.800 and the 168's were 2.775 (or something like that). </div></div>

Some of the older red box 168s were loaded shorter. As Jpspeeddemon noted, all the new stuff seems to be ~ 2.800.

 

[jbell]

Re: How can I tell FGMM 168gr from 175gr???

Shoot them and look for a POI shift and then you will know

. Sorry, just kidding. I would call Federal and ask them if there is a way to tell.

 

[Force_Multiplier]

Re: How can I tell FGMM 168gr from 175gr???

weigh em

 

[Luke]

Re: How can I tell FGMM 168gr from 175gr???

Shoot them at the 1000 yard line. The 168's will probably group bigger than the 175's