First time reloading

[spark9701]

Hi,
I recently began reloading. I decided to reload 7.62x54r, and got the tools and components.
When I took them for a test in my mosin, I found the rounds were landing about 8 inches low from where I aimed at 50yrd.
The reload was done with
-once-fired S&B 185gr 7.62x54r case,
-Varget
-Sierra 125gr SPT .311 bullet
-CCI Large rifle #200
And I used Lee 3 set dies with expander/de-primer rod replaced for .311 cal.
I had 20 rounds reloaded, 10rd 53gr charge, 5rd 53.5gr, 5rd 54gr. All of them landed in the same area; around 8 inches low of my aim.

I haven't slugged the bore, thinking if off the shelf S&B rounds shoot ok, and from what I could research, they use .311.

Any guess to why its happening?
Could I get some suggestions for troubleshooting please?

Thanks

 

[mephisto002]

125grs is quite a light bullet for the 7.62x54R, the nominal bullet weight is 150grs.

Try 150grs bullets, and if they all group together, adjust your rear sight.

For some mysterious reasons (to me) lighter bullets hit lower.

Here is some reasoning from the internet:
Lighter bullets dont spend as much time in the barrel and don't have as much time to rise with the recoil. Assuming the lighter bullets are driven faster.

 

[cosmic]

125 gr is very light for that caliber. POI notwithstanding, how was the grouping? If it grouped OK, then you can accept that barrel harmonics and/or crown influence is at work.
Personally, I would chose another bullet in the 170 plus grain range. Hornady Interlock with flat bases would be a good place to start.

 

[Snider shooter]

Light bullets will shoot lower. If the group is acceptable just adjust your sites up. I use 205 grain lead bullets in my Mosins. To hit at 100 my sites are set for 200. One rifle has a taller front site and I set the rear at 400 to hit at 100. Heavier bullets usually do better in the Mosin.
Results your getting sound normal. Test it at farther distances to see how it shoots.

 

[spark9701]

125grs is quite a light bullet for the 7.62x54R, the nominal bullet weight is 150grs.

Try 150grs bullets, and if they all group together, adjust your rear sight.

For some mysterious reasons (to me) lighter bullets hit lower.

Here is some reasoning from the internet:
Lighter bullets dont spend as much time in the barrel and don't have as much time to rise with the recoil. Assuming the lighter bullets are driven faster.

Thanks, I will definitely pickup some heavier projectiles and try again.

 

[spark9701]

125 gr is very light for that caliber. POI notwithstanding, how was the grouping? If it grouped OK, then you can accept that barrel harmonics and/or crown influence is at work.
Personally, I would chose another bullet in the 170 plus grain range. Hornady Interlock with flat bases would be a good place to start.

The grouping was fine. Most were within 1-3 inches from each other. It was just hitting lower. I will definitely go get some heavier rounds. thanks!