sighting in

[barber]

Using a 14 inch Contender  , 21/2x7  T/C scope, and 55 gr soft point Black Hills .223 ammo, how would I sight in at 50 yards, to be on at 200 yrds.  I can't get to a range yet, so this is just to get started.  Thanks

[Grumulkin]

To answer this question, one would need to know the muzzle velocity, the bullet's ballistic coefficient and then consult the long range ballistic tables in a reloading manual or online.

If you want to ballpark it, I'd try an inch high at 50 yards.

[Who Me?]

Here's a ballistic web site that I use:

http://www.eskimo.com/~jbm/ballistics/traj/traj.html

It's very easy to use and yields a lot of information.

[Graybeard]

Sorry but you WOULD NOT. It's a wild guess at best. If you want to be on at 200 yards you really MUST sight in at 200 yards. Fifty yards is just too close and aiming errors too great a percentage of group size to reliably sight in there and be on somewhere way out. If you can sight in at 100 yards you can at least get pretty close but 50 is just too close to do it.

If you know bullet BC and velocity you can ball park it but that's all.

[Aardvark]

Ballistics charts won't do you much good using a pistol length barrel..How are you going to compensate for all the lost energy in a short barrel?
Also you don't get as much spin from your rifling in a short barrel.
Trial and error seems to be the way to go.IMO.

If you intend to handload, you will want to find a good powder that will burn quickly enough in a short barrel...
I am going thru much the same thing with my 10" Contender .223.
I am using Unique powder and 55gr FMJBT bullets but have not yet calculated just the right amount of powder to use...It will take trial and error on my part to get it right and once I do I will repost my results..
Good luck with it.

[barber]

Thanks for the replies.  I didn't expect to be on at 200   by sighting in at 50 yards, I just wanted to be somewhere close for when I did get to a 200 yrd range.

[Graybeard]

If the goal is only to be "on paper" then sight in dead on to 1/2" high and you should be on paper but where? Beats the heck outta me.

[oneshotonekill]

Plugging some numbers for your set up into a ballistics program came back as approximately 1" high at 50 for a 200 zero.  I used an average BC for a 55sp and looked at MV's between 2600-2800 and the trajectory range at 50 for a 200 zero was 0.8-1.1" high.  So I would sight in close to 1" high at 50 then shoot it at 200.  I would think that should get you on paper at 200.

[Davemuzz]

Just curious,....but is your basement 50 yards long?

Dave

[Who Me?]

Ballistics charts won't do you much good using a pistol length barrel..How are you going to compensate for all the lost energy in a short barrel?
Also you don't get as much spin from your rifling in a short barrel.
Trial and error seems to be the way to go.IMO.

Wow! That's the most nonsense I've heard in one place in a long time.  The bullet doesn't care how long the barrel was that it just left.  All you need is the velocity of the bullet.  If you were to use a reloading manual or two instead of "trial and error", you would have the velocity. It might not be the exact velocity, but it would be close enough for this purpose.  With that information, and the BC of the bullet you are using, you could find the trajectory of your load and THAT will get you on the paper.

[KN]

Who Me is correct. Barrel length has nothing to do with it.

[Aardvark]

So WHO ME,  I guess you can answer this question...
Hypthetically, if a .308" diameter bullet with a BC 0f .450 Has a muzzle velocity of 2800fps in a 24" test barrel, What would the muzzle velocity be in a 14" barrel?

And really, do you honestly think I said in my post that a bullet really cares about what barrel it comes out of?
Or do you guess that bullets really don't care about anything at all,since they are inanimate objects.
Talk about nonsense..Sheesh.

[Davemuzz]

Ballistics charts won't do you much good using a pistol length barrel..How are you going to compensate for all the lost energy in a short barrel?
Also you don't get as much spin from your rifling in a short barrel.
Trial and error seems to be the way to go.IMO.

Wow! That's the most nonsense I've heard in one place in a long time.  The bullet doesn't care how long the barrel was that it just left.  All you need is the velocity of the bullet.  If you were to use a reloading manual or two instead of "trial and error", you would have the velocity. It might not be the exact velocity, but it would be close enough for this purpose.  With that information, and the BC of the bullet you are using, you could find the trajectory of your load and THAT will get you on the paper.

Whome's statement of using a Ballistic table to "get close" is a reasonable statement when you are shooting a bullet that you know the velocity of, or that you know what the velocity should be based upon the load data from the reloading book(s)...when the bullet is being shot from a closed breach gun such as the T\C or any bolt action rifle, regardless of barrel length.

However, if the bullet is being shot from a revolver, where the bullet has to "jump" from the chamber to the forcing cone, then Aardvark's statement of trial and error suddenly isn't all that "nonsensical".

Dave

[barber]

Now you guys really have me confused..........LOL

[Keith L]

Boys, lets keep this pleasant.  Nothing to be gained by name calling.  If it keeps up then I lock the thread and the discussion is over.

[Davemuzz]

Now you guys really have me confused..........LOL

All I am saying is if you look at any ballistic table, they will tell you that the numbers are derived at using "some type of barrel" (usually Lija). These ballistic numbers are all derived from closed breach barrels. If you take the same "load data" (ie: a 44 magnum, 357 magnum, 454 casull) and fire it from a revolver, you will get a different velocity (usually lower) than the load data has printed. Also, this velocity will vary between revolvers.

This is so because of the loss of power as the revolver has the gap between the cylinder and the forcing cone, which allows gas to escape and not push the bullet.... a closed breach barrel doesn't have this gap.

All revolvers are a bit different so the gap per-se, is a bit different. So, two identical revolvers will not shoot the same load at (necessarily) the same velocity.

Dave

[KN]

Every one here is right on some level or another. But if you are just guessing velocity to start with, with no printed data to start from, then you can not estimate 50yd, 100yd, or any other POI with any kind of accuracy. With out some kind of numbers to start with it's all SWAG.   

[Who Me?]

Okay, I had a bad day... sorry about that.  Let's start over.  Barber said he is using Black Hills .223 ammo w/55 grain soft points.  The Black Hills website lists that ammo at 3200 feet per second.  The website does not list the barrel length that was used to get this velocity.  For argument's sake, let's say they used a 24 inch barrel.  Now, when comparing my T/C Contender with a 14 inch barrel in .204 Ruger caliber with my Rem. 700 in .204 Ruger caliber, I lose about 200 feet per second in velocity with the 10 inch shorter barrel. Since the barrel Barber is using is 14 inches, we  can make an educated guess that the velocity out of his gun would be about 3,000 feet per second.  Using that velocity and the 55 gr bullets, the trajectory with the gun sighted in at 50 yards would be:

Range   Drop
(yds)   (in)
0   -1.5
50   0
100   0.4
150   -0.5
200   -2.8
250   -6.8

[barber]

Thank you, Who Me

[Who Me?]

Barber,
You are welcome.  I hope that cleared it up somewhat for you!   

[barber]

It sure did, Who Me,   Thanks again

[Aardvark]

Here is some numbers I came up with today at the range shooting thru my chrony.
Remington UMC 55grFMJ advertized MV--3240fps
My 10" Contender MV---2530fps
A loss of 710fps.
My handloads of 11gr Unique 55grFMJ-2350fps
My next load will be 11.5,12,12.5,and13gr Unique.Once I get to 2500fps, I will stop.
I am thinking that will be around 12gr.
Much less recoil and muzzle flash.