Difference in load data between sources...

[precision_shooter]

Latest Hornady book shows max charge of Varget with 155 grain bullets is 44.9gr. Hodgdon website lists 47.0grs. max. Which set of data do you go with, The powder mfg or a long time cartridge mfg?

I shot some test loads, 5 of each, at 42, 43, and 44 grains of powder and they all shot 3-5 inches lower than cheap factory ammo.

Should I trust the Hodgdon data and start my next batch near max from the hornady book and go up?

 

[Lost Sheep]

Take a look at the firearm from which the testing was done. Also, the primer used. Each ballistics lab doing their own testing will come up with different data from which to publish their manuals. So, even though each lab is trying to publish data that conforms to SAAMI standards, such variables as exact chamber dimensions, hardness of the gilding metal, amount of freebore, and temperature on the day of testing will make differences.

Many loaders stay between the averages of all the books they have on hand until they have enough experience with their particular firearm to tell if there is odd behavior from their loads. A chronograph is helpful as well as careful examination of the fired brass. For example, if you are getting case-head separation (even though your dies are properly adjusted), enlarged primer pockets or other signs like shorter case life than "normal". These help identify if your mini-ballistics-lab is producing higher than SAAMI pressures.

Good luck.

Lost Sheep

 

[precision_shooter]

Ah, didnt realize their data was that subjective. I examined every fired case as they were extracted from the rifle. I didnt notice any flattened primers, enlarged primer pockets or have any case head seperation. The rounds did feel a little light on recoil compared to the factory rounds. Guess I need to invest in a chronograph as my next reloading tool. For now, my next loads I will start around 44.5 grains, work up in .2 grain increments and examine the fired cases for any signs of over pressure.

Any other suggestions on things to look for or things to try?

 

[Jim243]

Hard to tell without knowing the caliber of bullet you are shooting.

But guessing it is 30-06 or a 270 I would say it is your powder that is at fault. Varget is a good powder for lighter weight bullets, at 155 grains I would be looking for H-4895 or IMR 4350 as the powder of choice.

The difference in load data might be due to the OAL's used by each of the sources. Generally I go by the bullet MFG load data first then if I need to adjust by the powder MFG.

Just my thoughts.
Jim

 

[precision_shooter]

Oops! Yeah it might be helpful to know about the caliber and rifle.
im loading for .308. Rifle is a Savage 10 with 18" barrel and 1:10 twist. Bullets are 150gr SST, 155gr Berger VLD, and 155gr Amax.
I was told, maybe incorrectly, that I should stick with 150gr + bullet weights with varget and 1:10 twist.

 

[steve4102]

Lyman 48 says, 47gr -48gr

Nosler says, 48.5gr

Speer #13 says 47gr

You be the judge on who's data you should go with. What does Berger say?

 

[Bart B.]

Precision Shooter, 150's through 168's shoot most accurate from .308 cases through 1:12 twist barrels from 22 to 26 inches long. 1:10 twist barrels are great for 200-gr. bullets in .308 cases and 1:11 is perfect for 190's and 180's.

Why a factory would put a 1:10 twist in a .308 Win. barrel is beyond my reasoning unless they want all bullets up to 220-grains to shoot reasonably accurate. Just watch out for occasional poor accuracy with 150's; they're spun too fast from 1:10 twists and the unbalance of the bad ones will cause them to shoot poorly due to the centrifugal forces as the exit the muzzle.

But most folks think a 1:10 twist is perfect for all 30 caliber barrels 'cause the .30-03 and .30-06 started out that way. They look confused when told Palma rifles with 30 inch barrels shoot those bullets most accurate from 1:13 or even 1:14 twist barrels. They're aghast learning the .30 BR cases shooting 110 to 135-gr. bullets winning benchrest matches do so with 1:17 and 1:18 twist 30 caliber barrels.

 

[SSA]

Every bullet I've tried (all 150 to 180 gr) in my 1:10 Remington has worked well.
46 gr Varget is likely to work for you.

 

[precision_shooter]

Thanks for all the info!
I don't have the Berger reloading manual and they don't offer any info online, have to purchase their manual...

I'll work up some loads in varying powder charges from 45gr-47.5gr and see how she shoots.

All of the rifles I've had/still have in .308 have 1:10 twist rate barrels with the exception of my Tikka T3 which has 1:11. My last Savage 10 had 24" 1:10 twist and shot 150's into .3" 5-shot groups at 100yds.

 

[schmellba99]

Why a factory would put a 1:10 twist in a .308 Win. barrel is beyond my reasoning unless they want all bullets up to 220-grains to shoot reasonably accurate.

This is your answer as to why they put a faster twist.

 

[Bart B.]

When three dozen folks take three dozen different rifle barrels, 3 dozen different lots of primers, cases and powder to develop a "load" for a given cartridge, there will be three dozen different charge weights presented. If one or more of them also list peak pressures they got, each pressure number will be different, too.

I'd start with about 6 to 7 percent below the average of all max charge weights presented.

 

[precision_shooter]

I dropped down about 5%, starting at 45.5 and loaded up in .3 grain increments with max charge of 46.7 grains

5 of each of the below charge weights with 155gr Berger VLD and 5 with 155gr Amax at .020" off the lands.
45.5gr
45.8gr
46.1gr
46.4gr
46.7gr

Any more than 46.7 and I think I will be crushing the powder considerably. Lets hope one of these shines above the rest.