Thanks in advance...Gotta get me a chrono!!

.308
bullet 175gr BTHP Sierra Match King
powder 40.0 gn IMR 4064
Primer Winchester WLR
Brass Hornady
case length 2.015
COAL 2.80
barrel 20"

I'm showing 2371 fps in a 20". 45,900 psi, 96% fill and 96% burn.

I'm showing 44.2 grains of IMR 4064 as max at 62K psi and 2607 fps. The 44 grains will get you in the ball park. I use QL as a guide, and it's not always 100% on.

Thanks...Care to re run it with Vihta Vuori N550? Uses more powder. My lyman says 43.5-48.5 for the N550 and 48.5 is a compressed charge.It is also best powder for the job according to Lyman. Took me several months to get it. But I got it from a local and no hazmat

N550 is too slow for the 308, IMO.

48.5 is 2631 fps, 56,700 psi, 107% fill and 97% burn.

What is your favorite powder for this load??...long range!

.308 is pretty easy to load for powder wise.
Your original choice of IMR 4064 is a good one.
Varget is probably most chosen powder for the .308 if I had to guess.
But it's also first to get harder to find than a honest politician.
I think XBR 8208 or AR Comp along with Reloder 15 are really good performers too.
Would like to use some of the new IMR4166 when I find it

There's about 30 different powders that will work in a 308 with a 175. It depends on how aggressive you want to get with your powder. Take a look at this burn rate chart. Anything from about #82 to about #110 will work. Your Varget, R15 are really good, but can be hard to find. I personally have been trying the new powders that are coming out, like the Alliant Power Pro 2000 MR and now IMR 4166. I just got 4166 on hand, and hope to try it soon. I have been running 2000MR in my personal 308 ammo with a 175 Berger. The 2000MR will easily get 40-50 fps more than Varget with a 175 bullet in a 308. I am running a 175 Berger LR BT at 2842 fps (confirmed by chrono and with dope out to 1K yards). I have a 28" barrel, also to help with this high velocity. This load is very aggressive with this slower burning powder. If you went basic with your powder, anything in the 8208, 4895, TAC, 4064 will work. 4064 is a great powder, and I used it a lot for my 150's I hunted with years ago. You haven't said if this is for a bolt gun or gas gun. If it's a bolt gun, then any of these 30 powders will work well. If it's for a gas gun, I'd keep the to the faster burning powders, like 4895 and 8208. If you went with the new imr 4166, you could be some of the first to try it. It should be a really good one.

Burn rate chart:
http://www.hodgdon.com/PDF/Burn%20Rates%20-%202014-2015.pdf

I've long believed the most versatile rifle powder around is one of the 4895s. It'll work in just about anything, and beautifully in a few cartridges. I think .308 is one of them.

It is a gas gun. R25

Then I would go with the faster burning powders, like 4895, 8208, 4166, 4064.

Yup. Slow powders are liable to be rough on the action.

Anyone want to buy 2 pounds of N550? lol

Why on earth does Lyman list it as potential the most accurate load?

Maybe they tested in a bolt-action.

10/4

N550 is a double base powder, like R15 is. It's slower than R15, though. This data had to be in a bolt gun to get the 2750+ fps speeds. 48.5+ grains of powder in a 308 case is A LOT of powder! Definitely not a good choice for a gas gun.

A lot of powder => a lot of gas, definitely can be bad for a gas-operated gun. If you are configured to take advantage of slower burning powders (as in longer barrel, like 22- or 24-inch), then there are always adjustable gas blocks.

R25 20" I just listed it for sale in classifieds. Thanks Guys!

Lots of guys on the M14 forum are loading the following for their M1As and its rumored to be the same as FGMM and duplicates MK 318 LR

41.75gr of IMR 4064
175 Matchking
Fed 210M
LC or FC Gold Medal Brass

Its about the upper limit for a gas gun. The M1A guys will NOT use Varget, they say its too slow and breaks the gun (OP Rods bent and case rims ripped off). A long time favorite is 168 SMK and 39.5 +/- 0.2 gr IMR 3031 and CCI #34 in any military case.
YMMV.

Just bought an R25. I would be very interested in what your range results look like. I haven't fired mine yet but loaded a few rounds to try.