[taliv]

lapua claims max load for their 155g scenar in 308win is 44.9g which should produce a velocity in a 24" barrel of 2900 fps.

back in August, when it was 90*+ outside, at 44.84g I was getting 2776 fps average out of a 24" barrel. 125 fps is a pretty fair amount. it'll make a .9 mil difference at 1000 yrds.

I got busy and never got a chance to finish my load development.

now I'm ready to continue, but I'm sort of in a quandary. it's 30* outside, so it will be difficult to compare results. and I don't know how hard I want to push because I definitely don't want to create a load that will be dangerous come summer. at the same time, i'll feel a bit cheated stopping here.

[NCsmitty]

taliv, in August were you at your Max load using n540(I'm guessing that's the powder your talking about) or did you have room to wiggle? Now I hear that 500 series powders aren't as temp sensitive as the 100 series but I can't say that for fact.
Do you plan on shooting at the lower temps? If you use the known load @ 2776fps and try it now, it will give you an idea what to expect should you want continue development. You'll see if it drops FPS in the cold weather, and how much and give you a reference point. It's something to think about.

NCsmitty

[Jim Watson]

I have not worked much with Vihtavuori rifle powders but their pistol powders don't give the velocity claimed in their literature, sometimes not even close. You could search and post on the long range board
http://www.long-range.com/forums/index.php?showforum=62

I load .308 with Varget and got the 155 Scenar up to 2900 fps with 46 gr Varget, which is below the Hodgdon maximum of 47 gr (when shot with 155 Sierra.)

[taliv]

hey smitty, that's a good idea. No, I wasn't seeing pressure signs.
interesting info on the less temp sensitive for the double base powders.

i'm thinking about shooting in the precision marksmanship challenge in february in south alabama. dunno what the weather will be, but i suspect 30s to 40s.

Jim, that's interesting. very tempting. i just spent a wad on VV so i'm going to stick with it, but my normal HP/CMP loads use varget so i've usually got a keg of it on hand.

fyi, this is out of a gas gun, not a bolt gun

[Ol` Joe]

A lot of gas guns don`t like slower powders. I don`t knoiw exactly what you`re shooting but I`d try to keep powders in the 4064, 4895 burn range. VV-n550 is slower then the 4350 powders. You don`t want gas port pressures to be higher then the rifle was designed for.

[45ACPUSER]

You are comparing apples to oranges. You will get what your your bbl is capable of nothing more!
Not the answer you are looking for.
But, I will relate this.....as a bench mark I chrono'd some BHA 175gr Match 308 ammo out of my factory Rem 700VS 26in bbl. I had the gun rebarreled with a Mike Rock 5R bbl at 22inand the action trued up and pillar bedded. Now with the same box of BHA ammo I got the same velocity as the 26in factory bbl with only 22in.......barrel quality makes a whole lot of difference!