Sighting in with BM 25 Meter Target

[walsh]

[Mods...this is a double post. I accidentally put this question in "techniques"]

Using my BM carbine today I put the handle back on for a 200 yd shoot next week and checked the zero for the round I'm going to use. I don't think I'll have time to resize any brass and reload this week this week so I'm going to use a 55 grain PMC Bronze.

BM has a 25 meter target with grids and a big M in the middle that seems to say if I zero it on that target at 25 meters that I am good at 300 meters. "IF" that is right, with a 55 grain PMC round, do I need to adjust the front sight to be on target at 200 yds? I'll be shooting at 8"x13" steel plates.

If I do get a chance to reload about 125 rds I'll use 69gr Sierras in case it is windy and get out Friday to sight-in. So since whoever know the answer to this knows more about ballistics than I do, if a 69 grain is zeroed at 25 meters, is there a different adjustment for 200 yds than the 55 gr round?

Thanks in advance,

Walsh

P.S. FWIW, I had occular implants in Sept and have 20/15 in my LE but 20/30 in my RE and it's not stable yet to try to improve. Bifocals for handgun are going to be mandatory. I am working on upside-down bifocals from ESS for pistol shooting (LE dominant), but with my RE and the rifle, while the post is not clear, it's fascinating in that there is enough metal in the front sight to center that unfocused post such that my groupings at 25 meters when I was using my last handloads was quite good. I thought I wouldn't be able to shoot steel sights at all with a rifle until I worked something out with glasses. All eyes are different. Mine are 56 years old and YMMV

[Nuke8401]

Without knowing any specifics about your rifle, the ballistics of your loads; assuming your 69gr rounds is near max load you will only see about 1" difference at 200 yds compared to 55gr factory loads. This is the least of your worries; the 25 meter zero could easily have you off target by a foot or two at 300 meters given the multiplication of error from 25 to 300. What would I do if I didn't have access to a 100, 200, or 300 yards range? I would use the 25 meter target with the 55 gr bullets, if possible measure muzzle velocity and run a calc on handloads.com using 25 meters as the sight in distance, this will give you your holdovers (point of impact vs. point of aim) at any ranges you want 50, 100, 200, 300. Better yet, sight in at the maximum distance available to you and use that sight in distance and run the calc. The farther the distance the better.

Or you could just sight in at 25 meters, aim for the bottom 1/3 of the 8x13 plate and see what happens (with a true 300 meter zero you will be about 5-6” high at 200 yards).

As others have said and will say again, the only thing a 25 meter, 50 yard or other short distance zero is good for is getting you on paper (big paper) at distance 200/300 yards/meters.

You result WILL vary.

If I believed in luck I would wish you good luck, you’re going to need it!

David E.

[Jadeslade]

Skip the 69 grain. Use the 55gr PMC. Get your 25m zero around two inches below at 25m. Tighten it up at 100yd. Which should not take a whole lot. Then aim dead on at 200, then top of plate at 300. You really need a chrono and a program or a whole lot of time and ammo at known distance range. You may want to elevate one moa to be sure you are going to hit the 300yd plate. Stick with one bullet or you will doing support fire all day.

[whistlepig]

+1 on the above posts... The idea of "Battlefield Zero" has some merit for the zero to be useful over a wide range, but for the game I say that you want to have a more precise setup. You said a 200 yard match so Im guessing that 200 is the max and you will address targets in between as well. In that situation, I would run a 100 yard zero over the whole course, but thats just me. Whatever distance you decide on for zero, nothing will beat actually shooting that distance. Good luck.

[walsh]

Thanks for all the replies guys.

I can zero at the "zero range" at our club out to 75 yds. We have 3 bays just for that. I'm going to find the time to run out there and do that with calculations for changing to 200 yds, cut a large exploding target to 8"x13" to see through my spotting scope, and shoot at 200 yds Wed or Thursday. We are open until at least 7 PM so I might as well know it's not my zero. I know I'm not winning. There are at least 5 guys that will take-out 8 plates standing in 13 seconds or less with 8 or 9 rds. My right eye is the problem now, and ultimately perhaps a Bob Jones rear aperture, lense correction, sight piece might be better than shooting glasses. But if I'm sure I'm zeroed at a greater distance I won't need to start clicking and praying.

Thanks again.