Bad Varget?

[JDGray]

I ran a ladder test on some .308 loads, and was quite disappointed in the results. I'm looking for more velocity out of my 168SMKs for 600yrd target shooting, and my old load of 43gr varget used to give me a consistant 2640fps avg, but recently only chronoed at 2540fps. Its a different lot of powder, and realize it varys lot to lot, but now it takes 45.5grs to get the same 2640 out of my 20" barrel. The chrono is spot on as GMM ammo still clocks out at 2600 out of this rifle. To top it off, 45.5grs is a compressed load, as was 45.2, so getting 2700fps is out of the question. I'm still using Fed GMM brass, CCI200s, 2.800" oal. My ladder test looked more like a nice hunting bullet group(2.200"@ 335yrds) than a nice ladder test group. Powder charges went from 44gr up to 45.5gr in .3 increments, and the most disappointing part is the gun grouped very well at 44gr two years ago, and gave me 2720fps avg, and was not near a compressed load. The 45.5 load had no pressure signs, but don't dare add any more to it. It was suggested to me to try RE15, and now it looks like a great idea!

 

[Slamfire]

My ladder test looked more like a nice hunting bullet group(2.200"@ 335yrds) than a nice ladder test group.

That is a very tight group at that distance. You should cut and paste it on the wall and claim you do that all the time.

That is what I do.

Powder varies by lot. The stuff we get is blended to meet velocity and pressure curve requirements by weight. Accurate Arms told me industry standard was 10% differences per lots, claimed the kept theirs to 5%.

I don't know if I would call your lot of Varget bad, not with sub MOA groups at 300 yards, but you are certainly not getting the velocity you want.

There are lots of great 308 powders, let me suggest IMR 4895/H4895/AA2495powders so close in performance and size that you should just buy by price, and of course that staple IMR 4064. Shoots great, meters bad.

 

[JDGray]

The Varget is consistant with the same charge, but my spread across the 1.5gr range in my test, only varied 80fps on avg, so that explains the group I got. I'll load up some 155gr SMKs for some better velocities, but will try RE15 or IMR4895.

I'll post the pic here, as no one else appreciates them in my household

 

[snuffy]

The only thing I use a ladder for is to get up on my roof.

I question the reason you're attempting to shoot a .308 with a 20" barrel at 600 yards. Just seams like the wrong tool for long range.

I also question why you're so afraid of a compressed load. They are often the most consistent loads, they pose no danger. I don't know if your loads are approaching max, but don't stop because they're compressed.

 

[JDGray]

46gr is max, and I spose another .5gr wont fill the neck. I just don't like the fact that it takes 2.5gr more Varget then it used to, to get my 2640fps load back, let alone the 2700fps load that used to take 44gr to achieve. Aint enough room in the case anymore. Not trying to shoot 1000yrds, 600 is not to far for a 20" .308, come on snuffy I don't need more velocity than 2540, which used to be 2640 with 43gr Varget, just trying to get the 2700fps load back, that used to be very accurate and would help with bullet drop a bit.

 

[brickeyee]

I question the reason you're attempting to shoot a .308 with a 20" barrel at 600 yards. Just seams like the wrong tool for long range.

Unless you are forced to use such a short barrel, try a longer barrel or different powder.

 

[Walkalong]

Use a long drop tube and you can get more powder in the case.

I'm with snuffy on the ladder test.

 

[JDGray]

Some of you are kinda missing the point....
Not getting a new barrel, not needing to compress loads(not that its bad or scary to me), just wondering if Varget varies that much from lot to lot, that it takes 2.5gr more powder to get an established good load again? Another good load that shot great for me at 2700fps, looks out of reach now.

Maybe the first bottle of Varget was the issue, giving me great numbers, that I can not touch in the same gun now. My velocities are slightly lower than published with 24" barrels, as expected, but used to be kinda high for a 20" stick.

 

[Zak Smith]

I have never had that much variation in my .308 loads using varget. FWIW, I load over 46 grains with a 155 Scenar.

 

[1stmarine]

Varget is one of the most consistent powders there is even in extreme cold weather that is why it is a favorite for hunters among others.
Make sure you do not have other issues at play. one of the best way I find to keep the spreads consistent is to use a very light crimp that gives me consistent starting pressure and this way many times I get differences just in the single digits.

Accuracy load...
Elevation 560ft Temp. 70F. twist 1:10
168gr SMK + 44.5gr Varget + 2.800" COAL + 20" barrel ... 2615 FPS avg

20" is plenty for that range.
If you want more speed you need to go longer (barrel). I can pump it up to 45.8 but then accuracy suffers in my systems.

 

[gamestalker]

I personally prefer to load powders that spec. a compressed load. Velocity is more consistent, and it's easier to maintain consistent higher end working pressures. So I wouldn't worry about load data that takes you into compressed and especially if it is delivering such great accuracy.

 

[MtnCreek]

I've seen very little lot to lot differences in Varget. When I read your 600yd thread, I was very suprized w/ the velocities you were getting from your charge weight / barrel length. Have you changed crony's?

As far as loading Varget hot, it performs best for me when it's pushed toward max or a little less.

IMHO, don't give your barrel length a second thought; 20" .308 is plenty at 600yds.

Fine shooting either way.

 

[JDGray]

My chrono I think is fine, it still clocks Factory GMM ammo at 2600fps avg, every time. My rifle shot that ammo very well, and I didn't push it to much harder with 43gr Varget at 2640, for my close up target load. At the time of load development a few years ago, 44gr Varget clocked at 2700fps, and shot great too(But now shoots at 2583 Avg). I ordered a set of scale weight checks, but that still doesn't explain needing to compress loads all of a sudden to get 2600fps again, as the old powder only needed 43gr to do it leaving plenty of room in the case. It has to be the powder, or more like the older Varget was more powerfull. I used to buy it by the 1# bottle, but now I'm working on a 8# keg.

As to barrel lenght, yeah, there are people shooting 16" AR-10s farther than that....And my VXIII 8.5-25x50 LR, has plenty of elevation adjustment, heck 600yrds is only 1 turn of my turret, got 2 more to go!!

 

[918v]

If your new lot of powder is slower than your old lot of powder, rework the load. I'm sure you can get to 2600 FPS safely.

 

[mstreddy]

JDGRray,

As some have mentioned there is some variance from lot to lot -- If we are looking at one lot giving you 2700 and another 2583, then the difference is only 117fps from one lot to the other -- that is only about 4.5% difference either way you slice it. 117/2583=0.0452; 117/2700=0.0433 -- So well within a range of 5% for variance from lot to lot.
That is some mighty fine shooting though!

Take care,
EM

 

[JDGray]

Thanks
Yeah I guess 5% is not bad if you look at in that light

 

[Zak Smith]

5% is the wrong light to look at it in. 5% of MV is enough to cause a miss at 1000 yards, easily, and 5% of charge is enough to take a safe load and blow primers.

 

[45ACPUSER]

That is way too much Varget for Fed Brass. Not if you are using Lapua or Win. But, you should recheck you data source for the components used.
Change primer to BR2 or 210M.

 

[JDGray]

5% is the wrong light to look at it in. 5% of MV is enough to cause a miss at 1000 yards, easily, and 5% of charge is enough to take a safe load and blow primers.

And this is why I'm trying to get to the bottom of it, and it causes misses at 600yrds too....

 

[JDGray]

That is way too much Varget for Fed Brass. Not if you are using Lapua or Win. But, you should recheck you data source for the components used.
Change primer to BR2 or 210M.

You may be on to something here, as Sierra data shows 43.5gr max using Fed brass....Genaric Lee data shows 46gr for 168gr pills. I see no pressure signs at 45.5 where I stopped testing, and that had me up to 2651fps Avg, 45.2 had the best ES at 6fps and 2617avg and was the first sign of compressed loads.

 

[trapper500]

I agree with snuffy one needs a longer barrel for that long a distance not putting down your gun in any way .I like at least a 24" or longer barrel.The Standard length for the .308 is 22"

 

[coloradokevin]

IMHO, don't give your barrel length a second thought; 20" .308 is plenty at 600yds.

^^ No kidding! I don't know what the others are talking about, since I routinely shoot my 20" barreled .308 to those distances. The .308 isn't an ultramag, and you don't need a long barrel to get reasonable-for-caliber velocities. In fact, the 20" is becoming a very popular barrel length in the .308!

As for the velocity variations, your grouping at 335 yards looks great. Chronographs have been a thorn in my side for a while, and I somewhat wonder if that could be the culprit. Also, is everything else the same? Same brass? Same sizing technique (FL or neck)? Same primers?

 

[Ridgerunner665]

I've shot a good many Varget loads from a couple of 20" 308's (Model 7 SS and an SPS Tactical)...and 2,540 fps with 43 grains is just what it should be with 168 SMK's (or most other bullets in that weight class). In either of those rifles, it takes 45-46 grains of Varget to reach 2,600 fps with 168 grain bullets (I shoot mostly Nosler Ballistic Tips and Custom Competition...the latter being quite similar to the 168 SMK)

I suspect your previous data....or your chrono.

Reloder 15 won't be a lot different...I found it slightly more accurate, and got slightly more velocity.

 

[JDGray]

Thanks guys!
I suspect the older Varget as the issue, giving me better velocities. As I have stated, Fed GMM ammo has always shot at 2600(2 yrs ago, and last week), so I believe my chrono to be accurate. I have used the same Fed brass, CCI 200s, 168SMKs, trim when it gets over 2.010", same FL dies, no crimp, same 2.800" oal as always. I'll just see how accurate the 2600 load is now, as it used to give me .500" groups at 100yrds, but the test I did still looks good for a group at 335, and with varied charges.

 

[Zak Smith]

You didn't change primers did you?

In my 7mm RM, switching from a 215M to a BR2 is equivalent to 1.5 grains of RL25