trajectory question for .50

[ericrutters]

appoligies if im in the wrong category not sure where my ? fit im new to black powder and the guy i bought my flinter from told me he shot it with 80 grns of fff geox which is what i use as well will i shoot the same at 50 yrds using only 60grns or will i get some ball drop im shooting a .495 hornady prb this is to be a target load i still intend on using 80grns for hunting there is not much need to shoot more than about 75 yds in the thick undergrowth i hunt in most shots are 50 yds or less even with a modern rifle a 100yd shot is not a common thing in the woods of south central pa where i hunt lots of multi floral rose (briar bushes)

 

[Rifleman1776]

Best, really only, way to answer that for yourself is to do some shooting from the bench testing loads. At 50 yards the difference should be minimal but there will be a drop. It is only natural, less velocity, same projectile. It will drop.
BTW, many shooters, when dialing in a new gun will sight for a bit high at 50 yards to put on center at 100. Most of us, especially older guys, will do all sighting at 50 (shorter walk to target :redface: ), put on center there then hold over for 100 yards.

 

[Fred_Dwyer]

Agreed, you need to shoot it and see. I zeroed my rifle at 50 yards with 75 grains FFFg and tried 100 yards, it shot 4 inches high. That's OK with me, as long as I know. Each gun has its' own "quirks."

 

[Billnpatti]

There are many variables that will effect your trajectory. However, most of these are balanced out by your wibbles and wobbles if you are shooing offhand. Where these variables show up will be when shooting off sandbags on a bench. You will notice very little difference between 50 and 75 yards with either load once you have it zeroed for that load. At 75 yards, you will see a bit of drop but not enough to keep you from putting your shot into the "boiler room". If you are shooting your target loads at the range, be sure to re-set your sights for your hunting load before leaving the range. Fire a couple rounds to be sure that your sights are on and you will be good to go. 80 grains of ffG or even fffG is a common hunting load for prb in a .50.

 

[BrownBear]

I'm shooting 80 grains of 3f Goex from most of my 50's. I sight in at 75 yards because that suits my needs so well at other ranges. It puts the ball more or less right on at 25 even with reduced charges, about 1" high at 50, and around 3" low at 100. With that sight-in and reduced charges they starting lower at 50 and beyond, with 60 grains more or less right on at 50, almost 2 low at 75 and between 6 and 8 low at 100. With 30-35 grains they're still more or less on at 25 and around 1 low at 50. Haven't shot that load past 50.

Barrel length is a factor too, but you didn't mention that. Those #'s are for 32" and longer, but I don't see much difference with a 28" barrel. At 39" and 42" and 80 grains I gain a little at 100, but not enough to bother measuring. That would almost certainly be a little flatter past 100, but I haven't tried it. A 24" barrel and 80 grains needs to be shooting around 1" high at 25 and 2" high at 50 to be right on at 75. Dunno about 100 with that gun.

 

[longcruise]

A while back I played around with trajectories and sight in and came up with what I call the 3" rule. It goes like this The three inch rule

 

[ericrutters]

off to do some shooting today im going to start at 25yds with 50 grns and go from there ill post some pics later today i hope to get it dialed in to a 4" group at 50yds but time will tell

 

[ericrutters]

good info brownbear im shooting a 24" barrel with a 1:48 twist