question on rifle sight-in

[Four Sixes]

Howdy,

Got a simple and some what strange question. I casted some bullets Using Dwight's Lee modified mold. Here are the result of my first group at 25 yd in calm wind condition. Bullet was loaded with 35gr FFg 777 with 0.03 wad. My first group using the 100yd rear sight were all low (~3 inches below the bulleye). Then I filped up the rear sight using the 200yd notch and fire it again. Here is the result. The first shot was way high at 12 O'clock (cold barrel), the 2nd shot was ~ 2inch high 12 O'clock, then my next 3 shots were right at bulleyes one next to each other.  I thought man, I can't get anything better than that. Then I moved the target to 50yds and tried it again. All my shots were like "shot-gun" effects, holes were everywhere except the bulleye where I was aiming.

My question is how could that be? I was bench rest using sand bags to rest the rifle on. Any suggestions how I could correct my problems?

Thanks.

4-sixes

[Harve Curry]

Go over all the basics. Bullet fit. Groove diameter, bullet diameter. Try different loads.
Are you resting the rifle the same way each time. I think just forward of the trigger gaurd is best, my opinion.
Check the crown. Check for lead fouling.

[Arizona Trooper]

Sounds like it's leading up. Shot good when clean and went to crap as it fouled. Try some leadex patches. If they come out black that's the problem. A leaded Spencer will overwhelm ledex patches, but it's a good test (guess how I know). Try Shooter's Choice Lead Remover. That stuff works great! If your barrel is new, or hasn't been shot in 100 years, it's probably a little rough and needs shooting in. Be patient.

[Appalachian Ed]

What lead alloy are you using? Have you slugged the bore to determine what to size your bullets to? How does the crown look?

[Four Sixes]

Thanks for all the suggestion.
I am using wheelweight to cast the bullet. The rifle is brand new from Armi-Sport and shot about ~300rds. The crown looks good and there is minimum of leading.
I did retry it with a different load (32.5 gr volume FFg 777 with .03 wad). At 50yds, the grouping is a bit better. The temp was 27C...I know I was nuts just can't wait to test the new load. Here are the results.

4-sixes