7mm Velocity across different loads Tikka T3

[627PCFan]

I have 3 go to loads for my Tikka T3 7mm. All my loads are based on the most accurate in my gun after testing, not chrono data for velocity. What I did find out is that my velocities for all loads are over 200fps slower than manual data across 3 the bullets below. Shot velocity deviation across all three loads is less thant 50fps ave. I have heard in passing that Tikkas have "slower" barrels. Anyone else seeing something like this?

Load 1
140gn NBT, 64gn IMR-4831, CCI LM
3 string ave 2474 FPS
Calculated advertised veloctity 2988.125 FPS
Variance- 240 FPS

Load 2
168 Berger VLD, 68gn H-1000, CCI LM
3 shot string ave 2688 FPS
Calculated advertised veloctity 2918.7 FPS
Variance- 230.7 fps

Load 3
175 Hornady Spire Point, 64gn H-1000, CCI LM
3 shot string ave 2523 fps
Variance 151fps

 

[gamestalker]

I don't have any experience with the T3, but all other 7 mags I load for produce super tight groups at velocities much higher than what your seeing with those weight bullets. But I don't load 7 mag. with the powders your using either, which may have something to do with those low velocities, and the velocity spreads your getting too?

RL22 is what I've been using for 7mm RM for a very long time. I've tried others, but none have performed as well thus far.

GS

 

[ironworkerwill]

I've heard Tikkas shoot good, but not of slow barrels. Course, I don't own one either. I do find it odd.

I'd try some Mothers mag and aluminum polish on the bore. If it shoots good I would not fuss with it.

 

[bobnob]

I have a 270 Win that produces between 150 to 250 fps less than manual data when loaded to the same levels. I just load more powder or test with the next fastest powder.

I generally get about 2 to 3 grains over book max before I hit book max speeds, depending on the bullet used.

It is my theory that is has an ever so slightly larger bore than some others, particularly the barrels used when they developed the data.