I recently loaded some Hornady 150 gr. bullets in front of 57 gr. VVN 160 for my Howa .30-06 and some of these in front of 50 gr. VVN 140. Although N 160 is regarded too slow for light bullets in .30-06, the groups I get with this powder are considerably tighter( 0,4-0,7 MOA) than with N140 (1+ MOA) which is regarded a more suitable powder for this application.
Can anyone explain this?

Load density.

I find VVN-140 & 150 too fast for the majority of regular hunting bullet weights in the .30/06 Sprg. although the VV data & manuals state otherwise.

I use VVN-160 for almost all of my .30/06 Sprg. applications and found his powder affords excellent accuracy and velocity with 150 thru 180 grain bullets.

57.0 grs. of VVN-160 is a pretty mild load for a 150 gr. bullet in .30/06 Sprg.; but if it shoots accurately, why not?.

Gerry,

Thanks for your reply. Load density could well be the reason.

60.5 gr. of 30-06 is listed as max load for 150 gr. bullets in .30-06 If you think 57 g. is pretty mild, what would your suggestion be for a "normal" load?

R-Deer,

Extrapolating loading data outside of controlled conditions is pretty un-scientific to say the least but WTF.

Each rifle and chamber is a law unto itself.

I'm using 60.0-61.0 grs. of VVN-160 (depends on the batch) with either 165 gr. Nosler Partitions or Sierra HPBT's without any undue pressure signs and my chronograph appears to bear out that there's not anything untowards happening, either. My VV manual shows 61.7 grs. of VVN-160 as max with a 167 gr. Scenar bullet.

I will admit with new, unfired R-P nickel plated brass cases I may have to settle the powder in the cases using the vibrating tumbler to avoid a compressed load but after the initial firing the powder settles nicely right around the junction of the case neck/shoulder area. I'm firing these in a Blaser R93 and I've got the bullets backed off the lands far enough to provide good accuracy & functional reliability without infringing on case volume too much.

Yes, the 167 gr. Scenar is the intial load where VV's data starts using VVN-160 in the .30/06 Sprg.; all load data for bullets lighter than this use VV's 130, 140 & 150 series powders.

I'll second Gerry. My Sauer 202 shoots .5 MOA (5 shots) with N 160 / 60.5 + 165 Sierra GK and N 160 / 56.5 behind a 180 bullet.

Andre, I can't read what you wrote on these targets, but from the groups I guess the 1st and 4th are 180 gr
and 2nd and 3rd 165 gr?

The reason I ask is because I get identical results with mij Howa, 150 gr: tight groups with slight horizontal stringing and more open groups with 180 gr. Nosler partition!

R-Deer,

As ususal I appreciate André's confirmation of what I consider a solid bullet/powder/cartridge match. It's not the speediest .30/06 Sprg. loading; with my cheap-o Chrony Beta I get right around 2700-2725 fps from this combination in my Blaser R93 w/22.6" Attaché tube but it is extremely accurate and deadly on game. What more do I require?.

I don't have any target photos but my results appear pretty similar to André's target #3 on any given day; sighted @ 2" high at 100 meters which makes for @ dead-on at 200 meters.

As an aside, when groups are routinely & consistanly shooting into mini-clusters that size out of a hunting rifle I personally don't get too upset at what you are referring to as "vertical stringing"....especially at my age. Those 4 targets depict excellent grouping and reflect a great deal of attention to detail in loading, good equipemnt, properly assembled, sighted-in & solid bench technique. A huge confidence builder for me when in the field.

Have Fun with your Hornady 150 gr. RN's.

Indeed rifles and powders don't read the load books. My own 30-06 showed appalling accuracy with 150gr and standard offerings such as H4350. When I moved to VVN150 I got real accuracy at the max of 54gr. The rifle is safe at 55gr having a throat a mile long and seating very long.

Reindeer,
Like Gerry (again ), I don't think the slight stringing of the groups to be of any meaning. These groups were shot with a hunting rifle topped off with a 6x scope. As long as all 5 holes cut each other at 100m, I'm happy. OTOH, I have a .222 target and two .308 Win sniper/target rifles mounted with 20 - 24 x scopes and with these I feel uneasy at the mere thought of stringing groups.