308 Win, Varget, Nosler 175CC

[Markk9]

This weekend I did an OCW test with Varget, Nosler 175CC's, new Hornady brass, and CCI LR200 primers, at 100 yards. Started at 43.2 and worked up in .3 grain steps to 46.0. Found 2 nodes, first at 43.5, right at .768 MOA, second at 46.0, .801 MOA.

The 46.0 load I have the chrono data for, 5 shots, AVG 2694, SD 4.76, MIN 2687, MAX 2699 SPRD 12. The more I think about this load, the more I think the 46.0 is to much. I'm thinking, of load up 25 more of the 43.5 load and take them out to 200 yards and get some chrono data.

Rifle is an Armalite AR-10 with a 20" barrel.

 

[Phil McGrath]

This weekend I did an OCW test with Varget, Nosler 175CC's, new Hornady brass, and CCI LR200 primers, at 100 yards. Started at 43.2 and worked up in .3 grain steps to 46.0. Found 2 nodes, first at 43.5, right at .768 MOA, second at 46.0, .801 MOA.

The 46.0 load I have the chrono data for, 5 shots, AVG 2694, SD 4.76, MIN 2687, MAX 2699 SPRD 12. The more I think about this load, the more I think the 46.0 is to much. I'm thinking, of load up 25 more of the 43.5 load and take them out to 200 yards and get some chrono data.

Rifle is an Armalite AR-10 with a 20" barrel.

You got that much Varget in a .308 case? In my M1A I load mil-spec cases with 175's and 41.5 fills them up too the shoulder. Something isn't right, 46grs has too be overflowing the neck... I suggest if your burning that much powder you take a look at IMR-4320.

 

[Markk9]

I check the powder charge when working up loads on a beam scale and electronic scale. The powder only came to the base of the neck.

 

[BW64]

I'm at 44.0 of Varget with the 175CC & getting 2770 fps but my barrel is 26". Lyman book says 45.2c is max. Hogdgon says 45.0c is max!! That's a lot over max!!!!! Are you getting any signs of pressure??

BW

 

[Markk9]

Here is a photo of the 5 cases from the 46.0 load.

 

[nastynatesfish]

If those were new cases is say you over pressure a bit. Just due to the ejection swipes on them. Not normally good to run a gas gun as hard as a bolt. You beat it up pretty bad. I'd try some h4895 or arcomp

 

[X-Caveman]

I'm in the "46.0 is too hot" camp - especially for a gas gun. Be careful.

 

[mic2377]

I would say it is too hot. I shoot a 308 AR regularly and would not keep using a load like that.

Even if the pressure looks OK from a primer standpoint, the brass will end up being destroyed in short order. I was experimenting with some 155 SMK's and H4895 (in the 44+ gr range), and stopped after a few cases looked like that. Somehow a TAA (once-fired mil) case snuck into the bunch instead of the Hornady brass I was using, and it popped its primer. It was a wake up that the pressure really was high and more than the ejector swipes that are not infrequent in semi-auto 308's.

I think with typical powders and projectiles ~2600 fps is about as fast as 175's can be pushed out of a 20" semi-auto 308. I would honestly be pretty happy 2600 fps. If you really want to crank out speed, give some 2000-MR a shot. It has not delivered the most consistent accuracy for me in semi auto's though.

I do know that if you load reasonably, you can get good case life from a semi-auto. I have able to get >8 firings from WCC/LC brass in my 308 AR.

 

[jlow]

I would also agree that 46 grain is too hot. FWIW, I’ve just been working on a load for my 18” AR-10 using 175 gr SMK, Lapua brass, Varget, and Tula primers. I am already getting ejector marks at 44.3 gr with MV around 2580 fps. The case difference will affect this data a bit but if you look at Hodgdon’s data, the max load for this setup is more like 45 grs, and those are some preety strong ejector swips, so…

 

[swadiver]

Try H4895. 42 to 42.4 gns works very well for me with 2775 fps out of a 26", 1 in 10 twist Criterion barrel. easily .3's", 5 shots @ 100yds

 

[mao0720]

46 gr of varget is nearing the upper end for 155gr bullets and Lapua brass in a bolt gun! I've got to be honest I'm not sure how you haven't broken bolt lugs or completely blown out primers yet. Back off to 41gr and work back up, you'll probably find something good around 43gr.

 

[chapstix97]

43grn Varget Lapua brass 2725 fps out of my 25 inch barrel. Magneto speed.

 

[NC308]

I shot 46.5 varget with 155 lapua's and it was a max load in my 700. And a max load with the 175's was 45gr in my 700. And these where all with the bullets loaded longgggg compared to sammi spec.

 

[M14AMU]

You've been lucky....so far! The next shot......maybe not!!