175 SMK @ 2752 FPS too hot?

[JNel]

Fellow Hiders,

Is anyone pushing the 175 SMK @ 2750 or faster?

Details;
I have been working up a load for my .308 to ween myself off FGMM 175's. I did my OCW test and found 2 nodes from my rifle at 43.2 grains and 45.0 grains with Varget/175 SMK's/FC brass. I then loaded up 4 different lengths @ 45 grains to be test fired to determine my seating depth. 2.82" produced excellent results out of my 700 PSS. There are no pressure signs (i.e flatend primers, ejector marks, heavy bolt). Here is 5 shots at 100 yards.

Chrono results
2752 Average
16.29 Extreme spread
6.0 Standard deviation
Density Altitude was 4647 ft (50 deg, 25.7 Baro)

This is over the max charge according to Sierra, but Hodgdon has it as their max load. On the Hodgdon site some of the other powers are producing higher pressures at lower velocities with the 175.

This load is shooting great, but I'm wondering if I changed altitude, what change in pressure would be expected? I don't want to be shooting somewhere else and see pressure signs. Do you think 2752 fps is too fast for the 308, and I should develop the lower node or stick with this?

Your opinions are appreciated.

Thanks, Jack

 

[LRS_Ranger]

Re: 175 SMK @ 2752 FPS too hot?

That's my 175SMK load.. 45gr Varget, Federal match brass, and BR2's. I expect that I am getting similar velocity to you, though I don't think I've ever ran that load through the chrono. I haven't had any issues with it thus far...

 

[esromvre]

Re: 175 SMK @ 2752 FPS too hot?

no pressure signs no problem i run mine at 2750.

 

[SScott]

Re: 175 SMK @ 2752 FPS too hot?

My Magic 175 SMK load is:
45 gr Varget
RP brass
Tula primer
FL sized
Seated 2.810
2715fps at 1,000 above sea level, in a 26" barrel.
No pressure signs but borderline, I did see signs when I was in the 2750fps range.
SScott

 

[NRAShooter]

Re: 175 SMK @ 2752 FPS too hot?

As long as you are not blowing primers, imprinting the extractor on the case head or having to hammer the bolt open, it should be okay. Your brass may wear out sooner as the FC brass tends to be on the soft side. Pay attention to your primer pockets as they'll be the first to go. Flattened, cratered, leaking or falling out primers are generally a sign of too hot.

If you want to technically evaluate your load try running a load density profile on your recipe. That should give you the theorectical psi and load desnsity factor of your reload.

If you do, let us know what it shows!

Good luck.

 

[vman]

Re: 175 SMK @ 2752 FPS too hot?

Should be ok.

 

[Shooter21]

Re: 175 SMK @ 2752 FPS too hot?

I'm running 208 AMAX at 2725, so you should be fine

 

[GUNNER10]

Re: 175 SMK @ 2752 FPS too hot?

im running about 2750-2800 with 42 grains of IMR 4895 out of a 26 inch barrel. thats with a 178 amax out of LC brass

my buddy that owned the gun befor me was able to get 2900 out of winchester 768 i belive but am not sure of the load. when i run out of IMR i may change, but considering i have had great success with 4895 in my AR10, it may not even be worth it to change, its nice to run 1 powder for 308.

if i need to go long thats what the 300 and 338 are for

 

[MinorDamage]

Re: 175 SMK @ 2752 FPS too hot?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: drunkhumpinmonkey</div><div class="ubbcode-body">I'm running 208 AMAX at 2725, so you should be fine </div></div>

Are you using RL-17 or the new 2000mr?

Josh

 

[XTR]

Re: 175 SMK @ 2752 FPS too hot?

<span style="font-style: italic">edited post, I was posting from memory and someone pointed out to me that I was wrong. Take a look at the JMB calcs and figure out what you need to get out to 1000 yds and stay above mach 1 taking into acct you lowest velocity. The first accuracy node above that point is where you want to be, you don't need to push it. Look at the ballistics numbers and see what it really gets you other than shorter brass life and wear and tear on the rifle.</span>

 

[JasonB]

Re: 175 SMK @ 2752 FPS too hot?

24in Barrel

2775fps

45g Varget
BR2 Primers
Lapua Brass

2.2200 length to the Ogive

Shoots tight no pressure signs

 

[SavageStag]

Re: 175 SMK @ 2752 FPS too hot?

Wow, I was getting ejector marks at 44.5 grains varget.

2.226 at Ogive
Lapua brass
Fed 210GM

 

[mattj]

Re: 175 SMK @ 2752 FPS too hot?

I got almost exactly 2750 out of 44.5g Varget in Lapua brass, BR2 primer, from a 26" (1:10) factory Savage barrel.

The pressure was fine, but I ended up going away from that load because it was so compressed that I had trouble getting the bullets seated deep enough to not get jammed in the lands (which became a problem when I tried to eject a live round).

 

[JNel]

Re: 175 SMK @ 2752 FPS too hot?

Thanks for the input guys.

I think I'll load up some more and check them at 300.

 

[clmayfield]

Re: 175 SMK @ 2752 FPS too hot?

I get 2735 fps out of my 175gr FGMM, so I don't think it is too hot, but it really is going to depend on a bunch of factors. Speed is an indicator of pressure, but it is not the only one. If you are not getting any other pressure signs and you are at 2750, you are probably fine.

 

[Supersubes]

Re: 175 SMK @ 2752 FPS too hot?

Altitude/pressure changes aren't going to affect chamber pressures, but temperature will.

None of the.308's i have ever worked with would go that fast without pressure. Just my experience.

 

[9sigman45]

Re: 175 SMK @ 2752 FPS too hot?

My F-tr match load is:
175gr SMK
44.9gr Varget
Laupa brass
CCI BR2
loaded long ;>)
2,805fps
29" Bartlien on a single shot Templar by GAP
with NO pressure signs at all