Zeroing a 1903A3

Hello,
Lurker and first time poster. I found this thread,
https://www.milsurps.com/showthread.php?t=52813.
I was going to revive it but in the interest of playing nice with the powers that be , I didn't. The above post got close to what I was seeking but I still need some guidance.
My new to me '43 Remington 1903A3 came to me with a bubba'ed front sight. The short blade appeared to be from a non mil rifle. I did not fire it in that condition and have since had it changed out with an "A" blade.
Today's first firing of several different hand loads yielded some promising groups but they were all slightly right and low. The best 50 yd 5 shot group using 6 o'clock hold on a 8" bull was 5" low. Also slightly to the right but I can fix that later.
The rear sight was all the way down of course.
With this information could any one suggest how much I should shorten the "A" blade to give a 200 yd zero? (with a 6 o'clock hold on a 13"? black)


TIA,
Mike

After the sacrificial "A" blade is shortened, the plan is to get an appropriate blade.

shoot it at 100 yards first, then play with the sight..

I would also dare saying that you might want to shoot the first round at 25 or 50 meters. Just for the sake of it.
When I bring a new rifle to the range, if the sighting through the muzzle does not convince me, I go short. If the 25 are on paper and close enough to the bullseye that I can be safe shooting at 100, I go right away, without wasting further ammo, otherwise I first want to get there on the short distance. It goes pretty fast doing mistakes, and it pretty much also depends where you shoot and the rules applied there. It is not only a question of safety sometimes...
In any case, have fun!!!

"The rear sight was all the way down of course."

If you raise the rear sight, you will raise the point of impact at the target.

Since the 03A3 is new to you suggest you might check the following before starting to adjust the front sight height for elevation zeroing:
-Action screw tightness front & rear
-Barrel weight at the forend tip (should be pressure bedded; say 5-7lbs....if low or zero check bedding/stock)
-Boresight the rifle and check sight alignment

Also, since you didn't mention the specifics of the hand loaded ammunition you used for the testing note that the sights are calibrated for USGI '06 M2 Ball so try a similar load wrt bullet weight & velocity (150gr MV=2740fps) and see if there's a POI shift.

If you've gone through a similar set of checks (and even a stripped down inspection) & all seems ok with the bedding/action set up plus the ammo is ok then changing/adjusting the FS height shorter to raise the POI is the next step. IIRC there were 5 FS blade heights marked A-E for adjusting zero elevation.... E was the shortest......the actual heights are on the other post you noted. Or, you can calculate the required change to your A blade using the sight radius /range formula. Keep in mind that the lowest RS setting is 200 yds so with M2 ballistics the POI will be on the order of 2.7" high at 100yds & on POA 200yds. Since you're hand loading you've probably got this covered👍

The right windage error you noted should take a few left clicks on the RS windage knob to correct.... But suggest waiting to fine tune until after the FS blade is set.

Final thought, for the 6oc hold on the 13" black (POI 6.5" above POA) after setting up the elevation as noted above (POI=POA at 200yd target with RS on 200) simply set the RS slider to 300 yds. If you're shooting M2 ball ballistics it should get you pretty close to the 10 ring on the SR target.

Enjoy you're new 03A3.... Nice rifles!

gc1054,

Thank you for condensing many of the things I have read here and elsewhere into a much simpler format which outlines the route I have already trudged. While I do not and probably never will have ball ammo, my hand loads were developed with replication in mind. I believe I have come close enough. Earlier range time with my other '06's helped in this area.
I am currently traveling and haven't gotten back to working with the sights but perhaps later next month I can post my front sight changes.

Btw, the following link has helped, and as you have accurately noted, a 200 yd lowest RS setting is what I am chasing.

1903a3 accuracy and targeting test/specs/zero - CMP Forums

Thanks again.

Another benefit of setting up the sights as noted above is that they are quite useable over moderate ranges. I set my 03A3 up in a similar way and always use it in CMP games (200 yd....6oc hold with RS at 300) and occasionally in High Power matches over 200, 300, 600 yds with tweaked "M2-type" hand loads (run 155gr AMAX at 2750-2800...set the RS in a similar way at the different ranges) Things loosen up a bit group-wise at 600yds but some of that is me not seeing as well these days. And there's always some "hold adjustment" required. The fun benefit is that you can set up milk jugs at 300yds.....set the RS to 300 and shoot knowing you'll be close & with no need to think too much about..... "let's see... At 200 I'm 6" high on a SR target with 6oc hold....so at 300 POI is going to be....." Makes for more instinctive & fun shooting IMHO.

Have fun & a good shooting season.