105 Scenars 1 moa higher

[6BR4U2]

Has anyone else had this happen....1 moa higher at 600 vs 107 moly smk's ....
same powder,gun,charge,barrel, ect.

I know flatlander has but they must have a way higher Bc than listed

 

[Asa_Yam]

Don't assume BC is significantly higher just because point of impact is higher. Other possibilities include:
- The Lapua load has a higher MV with the same powder charge due to deeper seating depth or longer bearing length;
- Barrel vibration patterns are different with the two bullets, resulting in bullets leaving the barrel at different points in the vibratory pattern. I've seen a similar pattern in Sierra vs Berger 155 grain .30 caliber projectiles. Both shoot to the same elevation, but the Bergers are consistently 3 MOA to the right of the Sierras at all distances.

On another board,or another thread on this board), there was a thread discussing two rifles that produced identical MVs, using the same ammunition components,same brand of components, not sure if component lots were identical). One rifle consistently shot 1/2 MOA lower than the other. The shooters swapped scopes, and repeated the test - and obtained identical results,i.e., no change from the previous test).

One means of resolving this question is to measure muzzle and target velocities, and/or time of flight for both projectiles. A two chronograph setup, an Oehler 43 Personal Ballistics Laboratory, or a Doppler radar are the tools necessary to conduct such a test.

 

[6BR4U2]

I don't know if 1 moa means "significantly higher" I just know what my targets at 600 this morning proved and it was 1 moa in elevation
my horizontal was ok .....

 

[Caduceus]

Has anyone else had this happen....1 moa higher at 600 vs 107 moly smk's ....
same powder,gun,charge,barrel, ect.

I know flatlander has but they must have a way higher Bc than listed

I've shot 105 Scenars and 107 MK's out of the same 6BR rifle and with identical powder charge weights, the Scenars leave the barrel approximately 40fps faster.

The same thing happens when I compare 139 Scenars with 142 MK's out of my 6.5/284.

The velocity difference is more than what you'd expect from a 2 and 3 grain difference in projectile weight. As Asa has said, bearing surface length and other factors probably lead to the Scenar's being a "faster" projectile.