gamestalker
member
Well, weeks later, lots of tuning, load development, trips back and forth to the gun smith, and so on.
Last trip to the range. last week end, it finally started shooting sub moa, but some what sporadically, some good tight groups, then one odd flier. But as time has gone on the groups just kept getting better, and better, which lead me to believe that we were getting it tuned better and better. Well, today while cleaning it up for the next trip to the range this coming weekend, I noticed something about the muzzle brake, the cleaning patch was catching on it. Upon closer inspection I saw where the bullets were grazing the brake. In fact, and I assume, early on they were actually make more than just grazing contact, and had actually put a pretty good groove where they were hitting it. By appearance and after taking some measurements, it looks like about .001" + of contact with the bullet. The metal was piled up and some copper jacket was deposited in the groove as well, obvious it was being contacted. So apparently the last 150 or so rounds have cleared a path for the bullets to get by with only light grazing, thus the slow improvement in groups over time.
So rather than take it back for the third time to this well esteemed gun smith, over 40 yrs. of positive experiences. I just went ahead and cleaned up the bad spot in the brake with some compound, and suitable fitting tools to maintain a true round exit hole. I ended up increasing it by .005" just to make sure we will not have any further contact with the bullets.
BTW, does anyone know what an acceptable clearance should be for a brake? This is a 300 Win, mag, so obviously .308" is the projectile size, the exit hole ID was originally .328" allowing .010" clearance, is that enough? I would imagine so, if the brake is aligned square that is, which it obviously isn't. I increased the ID by .005" just to make sure we don't encounter any more impacts.
GS
Last trip to the range. last week end, it finally started shooting sub moa, but some what sporadically, some good tight groups, then one odd flier. But as time has gone on the groups just kept getting better, and better, which lead me to believe that we were getting it tuned better and better. Well, today while cleaning it up for the next trip to the range this coming weekend, I noticed something about the muzzle brake, the cleaning patch was catching on it. Upon closer inspection I saw where the bullets were grazing the brake. In fact, and I assume, early on they were actually make more than just grazing contact, and had actually put a pretty good groove where they were hitting it. By appearance and after taking some measurements, it looks like about .001" + of contact with the bullet. The metal was piled up and some copper jacket was deposited in the groove as well, obvious it was being contacted. So apparently the last 150 or so rounds have cleared a path for the bullets to get by with only light grazing, thus the slow improvement in groups over time.
So rather than take it back for the third time to this well esteemed gun smith, over 40 yrs. of positive experiences. I just went ahead and cleaned up the bad spot in the brake with some compound, and suitable fitting tools to maintain a true round exit hole. I ended up increasing it by .005" just to make sure we will not have any further contact with the bullets.
BTW, does anyone know what an acceptable clearance should be for a brake? This is a 300 Win, mag, so obviously .308" is the projectile size, the exit hole ID was originally .328" allowing .010" clearance, is that enough? I would imagine so, if the brake is aligned square that is, which it obviously isn't. I increased the ID by .005" just to make sure we don't encounter any more impacts.
GS