Range Report Cor-Bon 190gr SMK vs. Federal GMM 175

D

Downrange308

Private
Minuteman
Apr 28, 2009
4
0
61
AL, USA
www.sam.usace.army.mil
#1
Greetings, All. I've had this buzzing around in my head for the past couple of days... Any of you have an opinion regarding the Cor-Bon .308 190gr. SMK ammo, especially versus a benchmark 175SMK like Federal or Black Hills? Does the better BC of the 190 offset its greater weight at longer distances?
Cor-Bon .308/190SMK 2600fps/2853 ft-lbs. BC= .525
Blk Hls .308/175SMK 2600fps/2627 ft-lbs. BC= .496

I'd be interested to hear experiences/recommendations. Thanks !!
 
#2
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

I'm not a ballistics guy so don't know how to put it technically, but the BC has weight figured into it...or it is part of the equation....or something.

High BC always wins, no matter the weight of the bullets.

100 grain bullet at 3000 fps with a BC of .35 will always drop more than a 300 grain bullet with a BC of .50 at the same speed.

Now watch....kombayotch or Bryan will chime in and prove me to be a moron....which I've never argued.
 
#3
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

Jason is right, all things being equal, the bullet with the higher BC will drop less and drift less in the wind when launched at the same velocity. Just plug the numbers into JBM and you'll see.

I shoot both of those bullets at nearly those same velocities. Both produce excellent groups, but the 190 has a slight advantage in terms of ballistics. The difference isn't great, so I'd suggest you try both loads and choose the one that shoots best in your rifle.
 
#4
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

The 175 is a great bullet. If you are a number cruncher or OCD (sometimes I get like that), the 190 or 208 will provide the least wind drift at distance (800+). If you compare the numbers for shorter range, the 155's have the least drift (600 or less). So, IMO, if you were looking for a bullet to fill a specific task, (like F T/R at 800, 900, 1K), I'd look at the 190 or 208. If it were for match shooting where most of your shots were inside 800 yards, then I'd look at the 155's. The 175 fits in between these bullets. The heavy bullets require more elevation, but it's as simple as turning the turret more. I'd rather have less wind drift and dial more elevation, than have less elevation and need to hold further for more wind. My $.02.
But, pick a bullet that will shoot the best in your rifle, and shoot the heck out of it. Once you learn the ballistics of the round, you hopefully will learn how to hold for wind.

Oh yeah- Welcome to the Hide!!
 
#5
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

I shoot 190 VLDs in my .308, I've found that they buck the wind a lot better than the 175's in my rig. They do move a little slower, but I subscribe to the same nonsense Chad does...
grin.gif
 
#6
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Meat_308</div><div class="ubbcode-body">Cor-Bon .308/<span style="font-weight: bold">190SMK 2600fps</span>/2853 ft-lbs. BC= .525
Blk Hls .308/<span style="font-weight: bold">175SMK 2600fps</span>/2627 ft-lbs. BC= .496
</div></div>

<span style="font-weight: bold">If</span> both loads have the same Muzzle Velocity, then the one with the higher BC will retain velocity better and shoot flatter with less wind drift.

Haven't tried the Cor-bon myself, so I can't confirm the actual velocity.
 
#8
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BOLTRIPPER</div><div class="ubbcode-body">whatever the wind compensation is for the 175.....the 190 is about half </div></div>

sure you are not comparing to .300WM?

Cause 190gr SMK vs 175gr SMK is no where close to half the wind value of a 175 in .308W
 
#9
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

launch them both at 3000fps for argument sake and at 1000yds:

175 = 8 MOA drift with 10mph wind
190 = 7.3 MOA drify with 10mph wind
 
#10
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Captain Kick-Ass</div><div class="ubbcode-body">launch them both at 3000fps for argument sake and at 1000yds:

175 = 8 MOA drift with 10mph wind
190 = 7.3 MOA drify with 10mph wind </div></div>

Not half, but thats still the difference between an 7/8 ring hit vs an X
 
#11
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Smokin</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Captain Kick-Ass</div><div class="ubbcode-body">launch them both at 3000fps for argument sake and at 1000yds:

175 = 8 MOA drift with 10mph wind
190 = 7.3 MOA drify with 10mph wind </div></div>

Not half, but thats still the difference between an 7/8 ring hit vs an X </div></div>

assuming a .308 could launch a 190 as fast as it could a 175
 
#12
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

Not trying to change this thread. But until you can shoot both bullets in your gun there is no way to know what is better. But as a side note if you have a 175 SMK and a 190 at the same speed the 190 will perform better. But the big question is whitch one your gun likes best
 
#13
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

Well, I wanna add something. It does have better wind "bucking" capabilities but the BC is what your after. Try to launch it as fast as you can.

I was running 190 SMK @ 2615 and could go up to 2660 ish but the numbers became inconsistancy the further I went up after 2615 fps.

They pack more punch too. Last year I had to reweld all three of my steel targets two extra times because they were hitting harter then the 175 SMK.

Oh, scrach what I said, your running factory. I would go with the Black Hills Ammo 175 due to the cost over proformance. However, anything Corbon is the shit, I live 10 miles from the factory, I can smell them being made.
 
#14
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

I have heard of 190smk's being pushed just shy of 3k fps, but did not hear any range report for results. has anyone else handloded something similar?

I was also wondering about hornandys a-max 208g load data if anyone has it. I know this is a 300wm bullet, But someone has had to tinker with it.

I am wondering in a 308 case how fast it could be pushed, and would it be even feasible.
 
#15
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

I've seen 190's come out of a 308 doing 2700 ish and 208's come out at 2650 ish both with outstanding accuracy. There is merit to driving big heavy boolets with the correct powder. If your desired effect is terminal effect then heavier is obviously better. Wind can be compensated for but if you miss your guess the effect on the heavies will be less which is a good thing.

Reloader-17 is the heat for running 190 and up in a 308 but it is a much denser powder so you haveto get your head past the 45.0gr of powder max in the case. There is not much data on it but the testing I and some friends have done is impressive.

To quote someones sig line "Play with it, carefully"

Cheers,

Doc
 
#16
Re: Cor-Bon 190gr SMK vs. Federal GMM 175

I get 2695fps with my load for a 190SMK in a 26" bbl. Recoil is not an issue in a 22lb rifle, but George was right: the 190's still suck in .308. I can't seem to find a good velocity/COAL combo to get them to perform as well as do my 175 VLD's beyond 500 meters.
 
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