Secret to a good extreme spread with Varget?

[sam700]

As I posted in another thread, I'm currently trying to get a smaller extreme spread with varget in my .308. So far, with a 168 grain sierra match king, i've tried anywhere from 43.5 to 45.5 grains of varget and the best I could get is an ES of 40-50 fps. The load groups extremely well, but beyond 4-500 yards the large spread really causes my groups to string vertically.

Anyone have any tips for gettting my ES smaller? By the way, using a load of 49.5 grains of IMR 4350 gets me an ES of 10 FPS using the same primers, brass and bullets, but 4350 doesn't group as well up close as the varget does.

 

[jerkface11]

What primer are you using?

 

[918v]

Large ES is partly due to inconsistent bullet pull. Bullet pull is affected by neck tension and contaminants between the neck and the bullet- lube, carbon, dirt, etc. Try cleaning the inside of the necks to get rid of all the carbon and lube:

Thumbler's Tumbler + wet stainless media

or

Vinegar + bronze brush

or

Wet comet + nylon brush

or

Ultrasonic + vinegar (but US does not clean as well as mechanical means)

or

Use new brass

 

[ranger335v]

Do what BR shooters do, have seperate loads for short and long ranges.

 

[janobles14]

+1 on neck tensions and consistencies. i would recommend turning the necks after only neck sizing. i dont do much long range shooting anymore but it helped when i was reaching out there back in the day. varget is pretty consistent in my experience too. much less than other more temp sensitive powders.

 

[Offfhand]

Caution! Don't let your chronograph chase you down a blind alley. Look for other causes for your verticle stringing.

 

[GooseGestapo]

1. Sort your brass by weight. This alone can reduce the velocity variation. It may suprise you how much variation you can have within the same batch of brass.
2. Use one of the match or benchrest primers. You may have to try several different ones.
3. Ream the primer flash-holes and primer pockets.
4. Neck turn the brass, but only to take off the high-side to uniform them.

Also consider what "offhand" stated. You may have other issues going on with the vertical stringing. Considering the ranges you're shooting at, you may also need to "uniform" the meplats on your bullets. That's why the make and sell such a thing as a "meplat uniformer".

 

[W.E.G.]

Try IMR 4895.

 

[Ruger GP100 fan]

I've noticed variations in my Winchester necks and it concerns me that it more than likely is affecting accuracy. Should necks be turned with or without a seated bullet? Seems to me with would give better results.

 

[W.E.G.]

you may also need to "uniform" the meplats on your bullets.

To the extent that anybody really believes that "uniforming" the meplats of your bullets has any benefit, my understanding is that the advantage is uniformity of BALLISTIC COEFFICIENT,...

...not improved VELOCITY standard deviation over the chronograph.

See http://www.6mmbr.com/MCRMeplat.html

 

[Walkalong]

Correct. "Fixing" meplats will do nothing for ES. It is still in question if it does anything. The idea is it helps maintain consistency downrange

uniformity of BALLISTIC COEFFICIENT,.

resulting in more accuracy.


I can take bullets with the tips mangled and shoot them into one hole at 100 yards. That has been done by a number of people. The base is the single most important part of the bullet.

 

[Skip_a_roo]

Loading towards the top of the data has worked for me. I only use it in 223 though.

 

[Offfhand]

Post from above:

"1. Sort your brass by weight. This alone can reduce the velocity variation. It may suprise you how much variation you can have within the same batch of brass."

Intresting, like how much variation? Please explain why. Thanks

 

[Walkalong]

Different weight, different volume, different pressure, different velocity.

How much? Depends on many things.

 

[W.E.G.]

According to Quickload, a full 2.0 grains difference in H2O capacity makes this much difference with a 175-grain bullet pushed by 42.0 grains IMR 4895:

54.0 grains H2O capacity
2,560 FPS
51,530 PSI

56.0 grains H2O capacity
2,517 FPS
47,461 PSI

Most likely not going to get anywhere near that much variation in H2O capacity unless you are mixing military and commercial brass. I hear stories of military brass having "much less" H2O capacity than commercial brass. I compared Lake City 90 .223 brass with Remington commercial brass the other day. The H2O-capacity differences were miniscule. A whole 0.2 grains difference.

 

[ArchAngelCD]

From everything I've read about Varget and heavier bullets, you could use something better. Everyone I know just loves Varget in the .308 with 150gr bullets but that's it, not the 168gr bullets. If you like Varget but want better groups try IMR4064 which is a lot like Varget but plays well with heavier bullets.

 

[dodge]

I know with my 308 Varget works very well with 165 gr BTSP and 4064 not so well. I use 45.0 grs behind the Sierra 165 gr Gamekings. Shots at around 1" all day.

 

[kaferhaus]

match prep your GOOD brass.....

It ain't always about the powder and primer...

 

[Offfhand]

Post from above, responding to my earlier inquiry:

"Different weight, different volume, different pressure, different velocity."

Just for fun, calculate difference in volume of centerfire rifle cases varying by, say, 3 grains (assuming there actually is an identifiable volumetric difference). Then do the math on resulting pressure variation and announce your conclusion. Inquiring minds want to know.

 

[Hondo 60]

As stated above - consistency = Low ES.
Exact same powder charge.
Exact same case length
Exact same crimp.

If I were striving for a Low ES, I'd strongly look into an Ultrasonic case cleaner.
I've seen some brass that was run through those that looked brand new.

That would give you a consistent bullet pull when fired.

 

[kennedy]

my .308 likes H4895 best with 168 mk