Originally Posted by Faina338
What wuold be your choise?? Faina
I'm a little surprised that you're only getting 2600 fps from the 6.5x55 with a 139 Scenar. I'd expect closer to 2800 fps at safe pressures. You didn't say what action (age, model, and manufacturer) your rifle has. What weight and barrel length are each rifle? Does the 338 Lapua have a brake? Will it be allowed in the competition?
You didn't say what the matches consist of. Number of shots in a match? Shot offhand, prone, or bench? Offhand and prone more test the shooter's aim, hold, and trigger release. Bench shooting more tests the rifle ad the shooters ability to dope wind.
My choice would be to shoot some matches with each rifle. Obviously the 6.5x55 will be a lot gentler and cheaper to shoot. It should be easier for learning to shoot well at long range. The 338 Lapua should be more accurate on windy days when wind deflection uncertainty is dominant. Shooting it will certainly help you learn to shoot that rifle well. If you just stay home on windy days you'll won't learn to shoot in wind.
Why are you attending the matches at all? You should consider that before you start.
I attend matches (and practice by myself -
first to learn to be a better shooter.
second to learn the characteristics of various firearms.
third to improve the loads and ammo for each firearm.
and a distant fourth to try to shoot more accurately than others at the match.
The latter can drive you insane or broke buying equipment which may be useless for anything other than winning that kind of match. For some people though that's the only objective.
Shooting in a controlled environment with scores is a better indicator of progress than just shooting by ones self. It's hard to judge how much of your group size is from tricky winds and how much is just poor marksmanship. Shooting against a group of people at the same time will help sort that out. On the other hand fixed distance fixed target competition teaches nothing about range estimation, wind estimation (not just correction from the last shot) and how to lead moving targets at varying distance, angles, and speeds.