PDA

View Full Version : Muzzleloader Bullet Drop


Hawken1911
November 12, 2010, 07:36 PM
Hi Guys,

I have a new .50 caliber in-line muzzleloader. The 240gr. saboted bullets are supposed to have a velocity of 1700fps with (2) 50gr. pellets. Now, last weekend I zeroed it in at 25 yards because I have thick cover at my place and that's about the longest shot I'll have, BUT...I plan on shooting it out to 100 yards so I know what to expect. In the meantime, here's my question: How much bullet drop should I expect at 50, 75 and 100 yards? I don't even have a ballpark idea because I'm mostly a pistol person. If it's zeroed in at 25 yards, if I back up another 25 yards to 50 yards what will the difference on paper be, less than an inch, or an inch or more? If someone with a lot of muzzloading rifle experience can tell what might be typical, I'd really appreciate it.

Thanks,

Paul

Rifleman1776
November 12, 2010, 07:44 PM
This old time TRADITIONAL muzzle loader can't help with that sabot stuff. I suggest you contact the gun and/or sabot/propellant makers with your inquiry.

B.L.E.
November 12, 2010, 10:59 PM
Iron sights or a scope? Yes, it's important.

Since a scope is about 1.5 inches above the bore of the gun, the bullet may actually hit higher than zero at 50 yards if you sighted in at 25 yards.

zippy13
November 13, 2010, 01:05 AM
Doesn't the sabot mfg provide any info? As B.L.E. mentioned, you'll have to factor in your sight height above bore to their data.

Hawken1911
November 13, 2010, 07:43 AM
I have iron sights. I had no idea about a scope making a difference, but I can see how it would...I'll store that tidbit for future referrence.

I couldn't find any ballistics data from the powder or sabot manufacturer after a brief search. I thought I would because i know when I purchase rifle or shotgun ammo that info is often right on the box. Perhaps because with muzzleloading there are so many combinations of bullets/balls and powder/pellet types that it's not practical.

I was hoping someone with a lot of experience with inlines might be able to give me a ballpark idea or an educated guess based on my set up. Again, I will do some range testing when I can find time, but I don't know if it will be before the Monday rifle deer opener. I know I'm zeroed at 25 yards, so I was just hoping that if the concensus was that there wouldn't be much difference at 50 yards (say around an inch or less) then I would know that if a monster buck steps out a 'little' further than 25 that I could take it. If the bullet drop is significant then I will have to wait until I do personal testing before I would shoot at game past 25.

B.L.E.
November 13, 2010, 08:42 AM
I plugged 1700 fps into the JBM online ballistics calculator and assumed the same BC as a Hornady 240 grain .44mag bullet.

With iron sights .5 inches above the bore and zeroed at 25 yards.

0 yards -.5
25 yards 0
50 yards -0.3
75 yards -1.6
100 yards -4.0

With a scope 1.5 inches above the bore, also iron sights 1.5 inches above the bore like the sights on a AR-15.

0 yards -1.5
25 yards 0
50 yards +0.7
75 yards +0.4
100 yards -1.0

Remember that I assumed a BC for your bullet so these are ballpark figures. Even with the best ballistic computer program, garbage in = garbage out.

Here's the link to the online ballistic program I used.
http://www.jbmballistics.com/cgi-bin/jbmtraj_drift-5.1.cgi

Doc Hoy
November 13, 2010, 09:00 AM
Shot a .270 in Pennsylvania. He sighted for 25 yards and that put him dead on at 100. He accepted being high at 50 as a result of this technique. He hunted both in eastern and western PA and took a doe and a buck nearly every year.

If I remember correctly he shot a 150 grain speer at about 2800 fps.

I hope this is all correct. I am not a hunter nor a long arm shooter, but I worked with my uncle on some single shot loads for a pistol or two and for his Hawken.

I trusted everything he ever told me about rifles.

B.L.E.
November 13, 2010, 09:58 AM
Shot a .270 in Pennsylvania. He sighted for 25 yards and that put him dead on at 100. He accepted being high at 50 as a result of this technique. He hunted both in eastern and western PA and took a doe and a buck nearly every year.


Iron sights? If so, the ballistics computer agrees. However, a 1.5 inch above the bore scope would have this bullet 2.7 inches high at 100 yards if sighted in for zero at 25 yards.

zippy13
November 13, 2010, 02:31 PM
Doesn't the sabot mfg provide any info?Perhaps because with muzzleloading there are so many combinations of bullets/balls and powder/pellet types that it's not practical.

Yes, it's not practical to provide specific flight data because of the many variables; but, they can give you the weight and ballistic coefficient of the bullet. If B.L.E. had that info, your chronographed velocity, and your height of sights, then he could have fed in into his ballistics calculator and given you some meaning full data and a chart of the sight line and bullet's path showing the points of intersection. Following the chart you'd know how hight, or low to hold at any range or the sight adjustments to make. Adding real time shooting environment data increases accuracy.

Then there's the pre computer old school method: If you have a Lyman Cast Bullet Handbook like mine, there's pages and pages of trajectory data for each of their cast bullets at 100fps increments. You select the bullet flight data appropriate to your load and plot the curve on graph paper. Then you draw a straight line of sight, based on the height of your sights and the range you set your sights to zero. Like the computer generated chart, you now know what adjustments to make at various ranges.

Those who've done this with any regularity have noticed that the higher the sights are above the bore, the greater the horizontal distance between the points where the sight line intersects the bullet's path. What this does is to artificially flatten your trajectory with respect to your sights. This means you have a better chance of keeping your hits within a kill zone without adjusting your sights or aim point.

When old school shooters went from iron to optical sights not only did they take sight alignment out of the equation, the extended point blank range (because of the higher sights) rewarded them with higher killing hit ratios. It's one of the reason modern battle rifles have optical sights or elevated open sights. Until you understand the relationship between sight line, path of bullet and zero range, you're shooting in the dark.

If all I've done is to add confusion to the darkness, may I suggest you download a ballistic program. Play around with the sight height and zero distance changes (using the same bullet) and observe what happens with the correction offsets -- you'll soon see the light. :)

Doc Hoy
November 13, 2010, 03:06 PM
It was iron sights. Neither my uncle nor my cousin owned a scope.

When I was a kid, I bought a 30-30 with a scope and when I showed it to my uncle he asked me if I was planning to go blind.

He shot bow and arrow as well and had four pairs of arrows split by a second arrow. I would not have believed it had I not seen it with my own eyes.

B.L.E.
November 13, 2010, 05:00 PM
To illustrate the effect of the bullet's ballistic coefficient, I plugged in the numbers using a 177 grain .495 diameter patched round ball, BC= .070 according to Lymann.

Iron sights .5 inch above the bore. 1700 fps muzzle velocity.

0 yards -.5
25 yards 0
50 yards -.5
75 yards -2.4
100 yards -6

Same bullet and sights but this time, zeroed at 75 yards instead of 25.

0 yards -.5
25 yards +.8
50 yards +1.1
75 yards 0
100 yards -2.7

Hawken1911
November 14, 2010, 11:23 AM
Thank you very much guys! I've learned a lot form this thread.

bighead46
November 14, 2010, 04:00 PM
IMHO I don't think there is a way to figure that out- only if someone else on the forum has a similar gun shooting a similar bullet. I'd guess that with open sights the sights and bore are closer together which may result in more bullet drop at 100 yards than would be the situation with a scope- where the line of sight is higher- meaning the angle between the sight's line and the bore is more- giving the bullet a higher trajectory, or angle, to be on target at 25 yards than would exist with iron sights- if that makes sense.

zippy13
November 14, 2010, 07:04 PM
Greetings bighead46 and welcome aboard.

Your observation is correct.
I suspect Hawken1911 wasn't factoring in the height of his sights above the bore when trying to forecast his bullet drop. He isn't the first to do so, and he won't be the last.

B.L.E.
November 14, 2010, 09:19 PM
IMHO I don't think there is a way to figure that out- only if someone else on the forum has a similar gun shooting a similar bullet. I'd guess that with open sights the sights and bore are closer together which may result in more bullet drop at 100 yards than would be the situation with a scope- where the line of sight is higher- meaning the angle between the sight's line and the bore is more- giving the bullet a higher trajectory, or angle, to be on target at 25 yards than would exist with iron sights- if that makes sense.

Welcome to the forum.

The actual bullet drop is exactly the same but with a sighting plane high above the bore, the two points where the bullet's arc shaped path intersects the sight line are farther apart, effectively giving the gun a longer "point blank" range.
I'm using the artillary definition of point blank, that being the target is close enough to not have to consider bullet drop when aiming.

More than one person has destroyed their chronographs by forgetting that the barrel is about 1.5 inches below the scope.

The height of the scope above the bore is the main reason I am not a fan of scopes on .22LR rifles. You are trying to make a head shot on a squirrel up in a tree and you forget the barrel is 1.5 inches below the scope and you shoot under the target every time.

grafik0117
December 16, 2010, 02:36 PM
I found a chart describing bullet drop between 100 and 200 yards compiled by Toby Bridges. He took nearly 600 shots with 20 different bullets using 100 grains of 777 FFFg. Here is the link:
www.hpmuzzleloading.com/Technical.html


In summary, he ranks them by drop as follows:

5.25" - 195-gr. PR .357 Dead Center

6.90" - 260-gr. PR .400 Dead Center

7.30" - 240-gr. PR .400 Dead Center

7.40" - 260-gr. PR .400 Extreme Elite HP

7.50" - 300-gr. PR .430 Dead Center

7.90" - 240-gr. PR .400 Extreme Elite HP

8.85" - 340-gr. PR .451 Dead Center

9.70" - 250-gr. Parker .451 Ballistic Extreme

9.90" - 250-gr. Barnes .451 TMZ

10.8" - 250-gr. Hornady .452 SST

11.2" - 275-gr. Parker .451 Ballistic Extreme

11.5" - 290-gr. Barnes .451 TMZ

11.8" - 245-gr. Barnes .451 Spit-Fire

12.3" - 300-gr. Hornady .452 SST

12.9" - 285-gr. Barnes .451 Spit-Fire

13.8" - 295-gr. Power Belt .499

14.9" - 223-gr. Power Belt .499

15.9" - 260-gr. Harvester Muzzleloading .451 Scorpion Hollow Point

18.7" - 250-gr. Hornady .452 XTP Hollow Point

21.2" - 300-gr. Hornady .452 XTP Hollow Point


I found the PR Dead Center and Extreme Elite HP bullets here:
http://www.muzzleloadingbullets.com/

bighead46
December 16, 2010, 04:14 PM
Hawken 1911: what kind of accuracy are you getting on those 240 grain bullets? Some of the shockwaves and their clones are really acccurate- I was getting 1 1/2" groups at 100 yards without even tweaking the loads very much. My black powder groups were better on the range that day than most of the guys shooting modern arms. There are also the powerbelts. I didn't like the powerbelts to start but I was using too much powder. Depending on what you plan to hunt there may be bettter bullets although I know some guys really like the 240 on thin skinned stuff like deer. Personally I found the 240 in a sabot really tough to load- I was using a mallet and absolutely had to swab between shots.

cvbrewer
December 19, 2010, 01:21 PM
http://www.powerbeltbullets.com/powerbeltbullets/copper-series-bullets.html/

This site has info about ballistics for different bullets, charges, and barrel lengths. I think they are using an "average" height of sights above bore.

zippy13
December 19, 2010, 02:40 PM
I think they are using an "average" height of sights above bore. I beg to differ, I checked out several of their tables and they specifically use a 1.5-inch height of sights. You may have missed the negative 1.5 at the muzzle -- the bullet is 1.5 below the line of sight.