RIStrutStopper

Okay... I'm using 90 grains of 777 and was hittingright onat 50 yards. Without changing anything, went out to 100 and noticed about an 8 inch drop. I'm using 240 grain T/C cheap shot (gun seemed to group good with them at short distances...) Is this typical? Should I be using more powder to decrease the drop at higher yardages? Had to quit playin yesterday because it was so humid and foggy that my powder was clogging in the flask and I could barely see my target out at 100...

cayugad

That seems like an unusual large drop for the projectile. Normally if you sight in 2" high at 50 yards it should put you in or very close to the bulls-eye at 100 yards. For instance, I sight in at a 3" bull at 50 yards, wanting my group at the very top of the bull. At 100 yards normally the group will hit in the bottom 3rd of the bull. This way I know I am on at all distances...

I would try the same thing on a day when the humidity was not so bad and see what the results are. Also I have one rifle that shoots the 240 grain Cheap Shots and XTP's real well out to 75 yards. After that for some unknown reason the group breaks up real bad and accuracy is not in correlation to the earlier grouping. I switched projectiles to a 375 grain Buffalo Bullet SSB and then the group held fine out to 100 yards and better. It just must have been something the rifle did not like about the bullet.

Good luck with your rifle.

bigcountry

Wow, even with open sights 4" would have been the max. The higher you mount a scope, the less drop at 100 you would get. 1.5" is the norm for me for scope height. 2" drop at 100 is typical

RIStrutStopper

Yeah, something must have been out of whack yesterday. I need to get back to the range on a less humid and less windy day and try this again. that was a huge drop.

jcchartboy

Bigcountry,

Just so I understand this....The height of your scope mounts effects the trajectory of a bullet between 50 and 100yds?Or is that not what you meant to imply?

bigcountry

Yes. For his case, to have same POI at 50 and 100, he would have to be 3" over center of bore to center of scope which I guess is possible if you have high see thru's. Thats considering 1800fps launch .18BC. Same as with a slug gun.

with standard 1.5" scope height, you would have to be-1.5" low at muzzle, 1" high at 50, 1" high at 75, and dead on at 100.

With see thrus, -3" low at muzzle, dead on at 50, 0.3" at 75, and dead on at 100.

jcchartboy

I understand you now...you were discusing line of site. I mistakenly thought you were discusing actual trajectory.

(-8" will always be -8",. Unless of course you are looking at the trajectory in a straight line through a portion of its arc.)

Mark whiz

I use the higher see-thru sights on my Knight and with all my loads, I tend to see that the gun will hit dead center on the bull at 25yds and then starts rising from there. Usually I will be about 1.5" high of the bull at 100yds with the exact same load - depending on the coefficient of the bullet used.

eldeguello

No, the actual trajectory of the bullet in relation to the center of the bore of the rifle is unaffected, BUT the apparent trajectory in relation to the line of sight changes depending upon the height of the scope above the center of the bore. Thebullet has to rise more to cross a higher line of sight for the first time, than it does to cross a lower one the first time (ascending). Since the ANGLEbetween the line of thebore and the line of sight is greater, the bullet will rise to a higher "maximum ordinate" enroute to the spot where it crosses the line of sight the second (descending) time. Therefore, the spot where it crosses the second time is further downrange than it would be for ascope mountedlower, giving the effect of a flatter trajectory. The actual path of the bullet from muzzle to the earth is the same either way. What has changed is the angle between the center of the bore and the earth -the bore is pointing higher if the scope is mounted higher!