Vihtavuori N555 in 6.5x47 Lapua - now with ladder test

[Gil P.]

Heres some data for any of you who are thinking of trying Vv N555 in 6.5x47:

Rem 700, 26" Rock Creek Barrel 5R, 139gr Lapua Scenar bullets, CCI 450 primers. Cases FL resized w/ .288 bushing, all trimmed to uniform length. No neck turning or annealing, cases are on 4th firing.

I tested velocities on two separate days

8/15/21 first shot is slow due to clean barrel
103 degrees, 27.60 inHg 22% humidity, DA 5717
38.5gr (clean barrel) 2566fps, 39.0gr 267fps, 39.3gr 2688fps, 39.6gr 2703fps, 39.9gr 2712 fps, 40.1gr 2730fps, 40.4gr 2754 fps.
No pressure signs.

8/21/21 first shot is slow due to clean barrel, I was testing for the upper limit of pressure this time
93 degrees, 27.58 inHg, 31.8% humidity, DA 5260

39.6gr (clean barrel) 2646fps, 39.9gr 2714fps, 40.2gr 2740fps, 40.5gr 2778fps, 40.8gr 2787fps, 41.1gr 2819fps

41.1gr showed a little cratering on primer. I wouldnt load any higher than that.

You need a drop tube and decent technique when charging powder, just like RL16.

 

[Mulligan]

@bbarber25

 

[Gil P.]

It looks like I have 2 nodes. One at 39.9 - 40.2, the other at 39.8 - 41.1. What do you all think?

Target shot at 548 yards.

4mph to 15 mph wind blowing from left to right, about 90 degrees F outside.

 

[tvaught]

@Gil P.

Can you list the muzzle velocities for each shot in this ladder, or are they the mvs you listed above? How many rounds on the barrel?

 

[Gil P.]

@Gil P.

Can you list the muzzle velocities for each shot in this ladder, or are they the mvs you listed above? How many rounds on the barrel?

I've only got a Magnetospeed chrono, so I do not have velocity data for the ladder test.

The velocities listed above were recorded before the ladder.

Barrel has about 500 rounds on it.

 

[Gil P.]

I fired some of the ammo I loaded in August of 2021 that is noted in my previous posts.

6.5x47 Lapua, 139gr Scenar, CCI 450 mil primer, 40.1gr Vv N555

Jan 8,2023 velocity 55.5 degrees

2737 fps, 2735 fps

Aug 15, 2021 velocity (same load) 101 degrees

2730 fps

Conclusion: Vv N555 is not temp sensitive in this chambering with these components.

I only fired three shots because my ear pro wasn't cutting it and I dont want to lose more of my hearing.

Anyway, not counting the first shot; I pulled the bullet on it to check for charge weight and lost a few kernels, it was also the first shot on a cold and clean barrel. I shot it just to warm the barrel, and I didn't resize the neck before putting the bullet back into the case.

Shots two and three measured 2737 fps and 2735 fps. Then I had to leave because my ear kept ringing.