Range Report .308 Safe Muzzle Velocity Questions

[Infidel45]

.308 AAC-SD, 20" Barrel w/2" Brake, .308 : Factory Barrel & Action/Bolt

Ok, was at range this morning re-zero'ing after swapping out scopes. After doing that at 100 yds, i then started moving out to 600 confirming Dope. Load was 118LR.

After shooting 2 mags of it, i switched to MK319 Mod 0: 130 gr OTM Barrier, 7.62 to see how it did in my 1/10 twist, 20" barrel seeing as it is designed for the 13" & 16" SCAR platform. I was pleasantly surprised at the accuracy and even more so at the trajectory. Here is my some range Dope from the session:

With 100 yard zero

118LR/175gr

380 yards: 2 mil holdover
440 yards: 2.7 mil holdover
600 yards: 4.5 mil holdover

MK319/130gr

380 yards: .5 mil holdover
440 yards: 1 mil holdover
600 yards: 2.3 mil holdover

Range only goes out to 600 or i would have tested it out further. I dont have a chrono but i did try to reverse engineer it through my Ballistic app on my iPad. The best i could get it to compare to my drop data showed MV around 3400fps, which i highly doubt is accurate. I know the ammo is spec'd for 2950 from a 16" barrel per Federal.

Now, i dont know what the actual MV is from my barrel, but i know just from my holdovers that this round is cooking. I do not see any signs of pressure issues in my throat or chamber and no extraction issues.

What is the max MV i should stay under with my factory action/barrel? Any problem with using this ammo regularly? It is pretty inexpensive and usually in stock online..and it shoots great, at least to 600 so far. So unless it will cause issues, i plan to keep using it.

Thanks

 

[Early Cuyler]

I just did the MV calibration in Shooter and got ~2640fps for the 118LR an ~4500fps for the 319 (using a Speer bullet as it was the only 130gr HP).

The 118LR sounds about right but the 319 is way high. My guess would be the holds were off? I doubt there is any way to get a 130gr bullet going out of a 20" 308win 4500fps without blowing it up...

 

[redbullitt]

I do not see why there would be any issues running that. i would first confirm zero with that fast load at 100 on paper, then take it out and see what the dope lines up as.

That velocity with the 130 grainer ought to be around 2900 or 3000 I would think.

lol I would like some 4500fps. I agree, something is going on there. Check that 100 and go from there!

 

[Infidel45]

I do not see why there would be any issues running that. i would first confirm zero with that fast load at 100 on paper, then take it out and see what the dope lines up as.

That velocity with the 130 grainer ought to be around 2900 or 3000 I would think.

lol I would like some 4500fps. I agree, something is going on there. Check that 100 and go from there!

Early--Holds are correct. I keep my log next to me and write down each hold after firing two rounds to confirm each.

Redbullitt-I agree with the ~3000FPS. From what I have been able to find online about this round (which isn't much) that is the velocity being mentioned from a 20" barrel.

I will check the 100 zero next time out. I was mainly just curious if there would be any issues (pressure or otherwise) using this round in my factory action'ed bolt gun.

Thanks guys..

 

[Hollywood 6mm]

2650 for the 118 sounds high. I have the same setup (AAC-SD) and M118LR was roughly 2550 out of my 20" tube.

As for the 319 data, I'd love to see what you got past 600 yards. Somehow I get the feeling it will start dropping quickly.

 

[Infidel45]

2650 for the 118 sounds high. I have the same setup (AAC-SD) and M118LR was roughly 2550 out of my 20" tube.

As for the 319 data, I'd love to see what you got past 600 yards. Somehow I get the feeling it will start dropping quickly.

Agreed-the Tech Data on the round that I read indicates the round has a "600 Yard Maximum Effective Range". But with only having to hold 2.3 Mils to hit a 600 yard target vs 4.5 mils with 118LR...it seems that the round still had some get up and go at 600 and had only dropped 50" or so at that point versus 97" with the 118LR.

I look forward to stretching it out also just for my own curiosity..