The Berger 25's that I shoot were made in the early to mid 90's, they are unreal accurate in the 17 Mach IV and the 17 Rem's that I had.
deflave, when you start shooting over 3800, IN SOME barrels, the copper can accumulate very fast(with in 15 rounds), and from then on, the accuracy can be fubar. I had an early Sako that would need de-coppering every 12 rounds. This was especially true on the load of 24g of 4320 which was going 4100 in my rifle.
When bullets keyhole, it is has always been my experience that there can only be a couple of things to cause this:
1. Twist rate too slow-does not apply to you on the 25's
2. Barrel copper'd up
3. Nick in the crown
4. Rare-oversize bore
5. Look at the leading edge of the case mouth on a loaded round. If you see copper on the edges that has been scraped off the bullet as it was being seated, you have found the culprit. Several fixes to this problem which may include annealing brass and/or purchasing a sizing die that uses a bushing. Be darn sure to put a heavy chamfer on the case mouth. Some people make the mistake of just barely de-burring the inside of the case mouth. This heavy chamfer acts as a bullet guide aiding the bullet as it starts to enter the case mouth. If the case mouth is too square, then the base of the bullet will be shaved off in spots, possibly causing the bullet to keyhole or worse.
Good luck!
Last edited by keith; 07/11/10.
