The 22mag is a little harder on barels than most 22lr's but not as bad as your shots are hitting at 25 yards.
The crown is likely your first and best bet. (as stated above)
I have an old savage semi (50years or older), that likely had 10s if not 100s of thousands of rounds through it (at least 2500 from me in the past 2 years) and it still shoots 2MOA all day at 75yards with the right ammo off the bench.
Is it scoped? If so try open sights as advised above also. (It may be your scope or mounts)
Are you shooting off a bench rest? (careful aim and slow careful trigger pull is key)
Have you tried different ammo? (guns are like woman in bed, what works for one will not always work on another)
Is the wood touching the barrel and maybe pushing up against it? (this would normally set your shot off but likely in the same direction all the time. (not 4" at 25 yards though.)
Have you been drinking too much before shooting?
There's lots more but if your accuracy is that bad i bet you'll find your answer in one of those tips. (hopefully not the drinking one


)
Cheers.
Mike