BigChongus 765 Posted July 2, 2012 Report Share Posted July 2, 2012 Posting this so that hopefully no one makes the same mistake I did. When you finally get the old brake off and press the new one on, index the FSB by shooting the gun it first, before you drill it out for the pins. When I initially installed the brake, I indexed it by making the ears on the FSB level with the rear sight leaf (which is a common way of doing it, apparently). As it turns out, the left ear on mine is*slightly* higher than the right, so when I used that as a guide, the FSB slightly canted to the left. It wasn't noticeable to look at it, but when sighted in, the sight post had to be pushed way to the right to compensate. I ended up re-drilling the holes out to 1/8" and re-indexing it. However, this time I centered the front post with digital calipers (was about 5.01mm between the post and each ear), and adjusted the block itself to center the shots before re-drilling the holes. As it ends up, the FSB is now perfectly straight, and the rifle is shooting dead-on with the sight post perfectly cented. I also checked by slightly tightening my front sight tool on the FSB, and then laying a level across the tool, which further affirmed that the block was now straight. Just trying to save someone the same headache I had. 3 Quote Link to post Share on other sites
evlblkwpnz 3,418 Posted July 3, 2012 Report Share Posted July 3, 2012 You would be surprised at how many people overlook this concept and end up scratching their head wondering where it went wrong. Things would be pretty boring if we stopped learning how to improve our techniques and I am sure that this bit of info will do someone some good. Very good contribution. I work my way from the back of the weapon to the front. RSB is adjusted to the trunnion perfectly, then the FSB is adjusted to the RSB and bore. Front sight is then centered. I usually need very little adjustment, if any. Quote Link to post Share on other sites
thebuns1 4,323 Posted July 3, 2012 Report Share Posted July 3, 2012 pics make everything better! but seriously, thanks for sharing the tip and glad you got it squared away. Quote Link to post Share on other sites
jamesavery22 54 Posted July 6, 2012 Report Share Posted July 6, 2012 laser bore sight. No need to fire the rifle before you shoot. You'll always have some level of drum adjustment after everything is put together. Even those cheap laser bore sights that go in the chamber will do. Center the drum in the FSB by eyeballing it. Before pressing the FSB all the way on line up the front and rear sights so they are on the same point of aim as where the laser hits. Aim at something 25ish yards away. Press all the way on. Verify front and rear sights still aim at where the laser hits. Drill, ream, pin. Then shoot and adjust drum as necessary. Quote Link to post Share on other sites
BigChongus 765 Posted July 8, 2012 Author Report Share Posted July 8, 2012 (edited) No need to fire the rifle before you shoot. You'll always have some level of drum adjustment after everything is put together. Not necessarily the case. The point of doing it the way I mentioned makes sure the the shots are centered with the sight post being centered. It eliminates the need to move the drum. Edited July 8, 2012 by W8lifter Quote Link to post Share on other sites
jamesavery22 54 Posted July 9, 2012 Report Share Posted July 9, 2012 No need to fire the rifle before you shoot. You'll always have some level of drum adjustment after everything is put together. Not necessarily the case. The point of doing it the way I mentioned makes sure the the shots are centered with the sight post being centered. It eliminates the need to move the drum. Your method is a great guide. It won't get the rifle zero'ed. It has the potential to get you very close. Even then some adjustments will still be needed. Lining up the front post to the rear sight in relation to the barrel assumes the bore is concentric to the OD of the barrel. Which is rarely the case. Throw in little things like imperfect crowns and muzzle attachments. While they usually very minorly affect trajectories they still will. It's a great first step. You have to keep walking afterward Too many stars have to be aligned for everything to land up perfectly. Always shoot after the build is final and always assume you'll have to make at least minor adjustments to obtain a acceptable zero with irons. Quote Link to post Share on other sites
BigChongus 765 Posted July 20, 2012 Author Report Share Posted July 20, 2012 (edited) Well, this is where it got me. I'll take it! 25yds, resting on the mag. Edited July 20, 2012 by W8lifter 1 Quote Link to post Share on other sites
Red Star 38 Posted July 20, 2012 Report Share Posted July 20, 2012 looks like you're a little to the left.... I'm just giving you a hard time mate thats a fine group you got there... VERY fine indeed. 1 Quote Link to post Share on other sites
thebuns1 4,323 Posted July 21, 2012 Report Share Posted July 21, 2012 def. good shooting, and shows the potential of this caliber. Quote Link to post Share on other sites
jamesavery22 54 Posted July 23, 2012 Report Share Posted July 23, 2012 Definitely good shooting. That's cool you can get the irons that close with your proceedure. Still have to say to the masses that you should always expect some adjustments after everything is built. Most folks building these rifles will not have the same "no adjustments needed" experience. Quote Link to post Share on other sites
finishman2000 2 Posted July 25, 2012 Report Share Posted July 25, 2012 laser bore sight. No need to fire the rifle before you shoot. You'll always have some level of drum adjustment after everything is put together. Even those cheap laser bore sights that go in the chamber will do. Center the drum in the FSB by eyeballing it. Before pressing the FSB all the way on line up the front and rear sights so they are on the same point of aim as where the laser hits. Aim at something 25ish yards away. Press all the way on. Verify front and rear sights still aim at where the laser hits. Drill, ream, pin. Then shoot and adjust drum as necessary. yup this is the way to go. Quote Link to post Share on other sites
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