.308 Starting load

[Rflshootr]

What about case capacity. I'm loading virgin Lapua brass and with 44 grains of Varget I'm getting a bit of crunch when I seat the bullet. Is that a concern and can I still go up to 45+ grains if I've got no pressure signs?

My Sierra program says 43.5 grains of Varget is max, in Federal brass with a Federal 210M primer, with their 168 HPBT. I'd back it down at least to 42.0 grains, and maybe more, for the first firing.
I wouldn't load the virgin brass with a max load. Wait until you have at least 1 firing on the brass, then work up in .5 grain increments.
Any time you change components, that can make everything different.

 

[leclairk]

My Sierra program says 43.5 grains of Varget is max, in Federal brass with a Federal 210M primer, with their 168 HPBT. I'd back it down at least to 42.0 grains, and maybe more, for the first firing.
I wouldn't load the virgin brass with a max load. Wait until you have at least 1 firing on the brass, then work up in .5 grain increments.
Any time you change components, that can make everything different.

Interesting that Hodgson website says 46gr is max for that bullet. I guess I will blow through the last 60 virgin cases before I really get down to load development.

 

[leclairk]

Also interesting that according to GRT I reach max pressure (approximately) on 168g Sierra TMK with 44g Varget and with a 168g Sierra HPBT at 46.2g. With my short barrel, TMK hits 2500fps and HPBT hits 2530fps. I'm shocked that the same weight bullet from the same manufacturer would differ that much in powder charge. Loading a TMK with 46.2g puts you at 72,000psi! Ouch. I'm newer to reloading and I would have guessed you could use approximately the same powder charge on an identical grain bullet.
Last question- what's the difference between SAAMI max and C.I.P max. GRT states max at 60,191 which is C.I.P. , SAAMI is 62,000. I like SAAMI much better!

 

[Rflshootr]

You have to take into account that every barrel is different.
Secondly, different lots of powder are different, different lots and brands of primers are different and the same goes with brass and bullets. There can be multiple 168 grain bullets, but the design can be slightly different. If the body length (bearing surface) is different, it can cause more or less friction and change the driving force which in turn changes pressure along with velocity. Sierra is usually conservative on their loads.....usually, but not in every case. All data has a starting load and a max load. There is a reason, and to be safe, you should stick to that. Bullet seating depth also has an effect on pressure because it changes the internal volume of the case. That is why they give you the tested O.A.L. Something as simple as that, can change internal pressure. Virgin brass has slightly less volume then does formed brass. It all matters. What you should be striving for is the best accuracy that you can achieve. Some barrels are more accurate at slower speeds, and some at higher speeds, but rarely do I find barrels that are at their most accurate point at max pressure. It would be nice if they were, but most aren't.
If you look at Sierra's and Nosler's data, you'll see that the accuracy loads with most powders, aren't the max loads, although some are. Your results may be different depending on components and seating depth, but that is why it is called "working a load up". You are just fooling yourself if you think making the highest velocity possible, with disregarding accuracy, is the best scenario. Most of the time, it is not. Having a short barrel is handy and maneuverable, but it comes at a cost, which is some velocity loss. Lighter bullets can help get you some more speed, and unless you are truly hunting/shooting at 500-600 yards or beyond, the heavier bullets will give you no gain over a lighter, faster bullet.
Now, here is some reading about pressure because I'm tired of typing.

Copper units of pressure - Wikipedia

en.wikipedia.org

CIP – The European Equivalent of SAAMI

I have no doubt that the majority of our readers know about SAAMI (Sporting Arms and Ammunition Manufacturers’ Institute), which sets the ammunition standards, cartridge and chamber drawings etc.These standards are guidelines for manufacturers, but many reloaders, builders, wildcatters and...

www.thefirearmblog.com

 

[Rflshootr]

Also interesting that according to GRT I reach max pressure (approximately) on 168g Sierra TMK with 44g Varget and with a 168g Sierra HPBT at 46.2g. With my short barrel, TMK hits 2500fps and HPBT hits 2530fps. I'm shocked that the same weight bullet from the same manufacturer would differ that much in powder charge. Loading a TMK with 46.2g puts you at 72,000psi! Ouch. I'm newer to reloading and I would have guessed you could use approximately the same powder charge on an identical grain bullet.
Last question- what's the difference between SAAMI max and C.I.P max. GRT states max at 60,191 which is C.I.P. , SAAMI is 62,000. I like SAAMI much better!

I would recommend, unless you are shooting very long distances, to switch over to a good 150 grain bullet and push it with IMR 3031 powder and a Winchester LR primer if you have some. I think you'll like the results of that combination. Since you use GRT, run the numbers with a 150-grain bullet and IMR 3031 and let me know if you like what you see.