55gr vs 75gr in a 1:7

[castle]

i recently had my 6920 out to the range. i normally shoot 55gr prvi m193 because i have alot of it on hand. i stopped by the local shop and the only thing they had heavier than 55gr was some 75gr match prvi bthp.

at the range the 75gr groups were double what the 55gr were at 50yds. i didn't shoot any 55gr at 100yds, but the 75gr opened up at 100yds which was expected.

any thoughts on this? i was expecting the 75gr to do much better, and be a bit better than the 55gr out of the 1:7.

what does your 6920 prefer in a factory loading. i'm pretty new to this rifle, so any help is appreciated.

[castle]

any help here?

[Mr.Goodtimes]

im not really sure but sometimes, accuracy wise, barrels can be a little picky with ammunition... try some different brands.... i have an eotech on my rifle and, at 100yds, coveres up the whole head on a silhouette so its had for me to really guage precise accuracy... at 100 yds i can shot about 2-3moa with either 55gr or 75gr.... i would try some different brands of ammo though, different weights and see what it likes.

[RogerinTPA]

i recently had my 6920 out to the range. i normally shoot 55gr prvi m193 because i have alot of it on hand. i stopped by the local shop and the only thing they had heavier than 55gr was some 75gr match prvi bthp.

at the range the 75gr groups were double what the 55gr were at 50yds. i didn't shoot any 55gr at 100yds, but the 75gr opened up at 100yds which was expected.

any thoughts on this? i was expecting the 75gr to do much better, and be a bit better than the 55gr out of the 1:7.

what does your 6920 prefer in a factory loading. i'm pretty new to this rifle, so any help is appreciated.

I have found that I have to fine tune my zero, depending on bullet weight, in order to gain the best accuracy. Going from 55gr to 62 gr at 100 yards, the difference will be hard see. 55 to 75gr will be noticeably different in zero, which you have discovered. It all depends on: Skill of shooter, accuracy of weapon, and type of ammo ( Match vs regular brass vs budget) being used. The 6920 is pretty accurate for me, depending on the ammo, if I take my time and do my part.

[castle]

i know every bbl is different and can have likes and dislikes contrary to a different bbl from the same mfr. i just figured with the 1:7 twist 75gr match would be better than 55gr ball from the same company.

i figured zero would change with the switch. i was expecting that the 75gr wouldn't shoot to POA, but would be a bit tighter overall. the 55gr at 50 yds with irons had most shots under 1.5", even during rapid fire. the 75gr was about 3.5" at 50yds with slow fire. this was from a bench with the forearm resting on a wool blanket.

i'll try and find some other 62 gr or 69gr stuff.

[Mr.Goodtimes]

somebody on here has a buddy or something whos 1/7 loves 45gr ammo... go figure? just buy some different brands and weights of ammo in small ammounts, take em to the range and see what she likes