Ballistics/Scope question.

[20thGix]

The coyote thread made me think about this. The ammo i use in my Marlin 30-30 will be 3.0" high @ 100yds. and -.2" @ 200yds. Currently i have it zeroed in @100yds. Now my question is should i be hitting 3.0" high @100yds and in theory "zero" @ 200yds. If that makes sense to anyone. I'm not gun expert so my terminology may not be correct but i tried not to refer to anything used in a Warren G song (e.g clip, gat).

[flounder]

I always zero at 100 but I know my drops and dial it or hold it for every range out past 1000 yards.

The key is to know your drops at different distances and either dial for the adjustment or hold for it. Holding generally requires a scope which is designed for it. I.e a mil-dot or another advanced ranging reticle.

[20thGix]

I wouldnt mind getting a scope with mil-dots but i also dont see myself taking a shot at anything past 200yds. I would probaly be pushing the limits of the rifle and round. Its not like im trying to head shot squirrels. Thats what the .22 mag is for. Thanks for the input.

[vf1000ride]

Setting your zero distance is personal preference. When I had my .25-06 and hunted back in PA, I had that rifle zero'd just short of 250 yards. That placed the bullet drop of any shot from 100-300 yards within a deers vital zone. +2@100, +.5@200, -4@300. Made the mental math much easier as once you were sure of your distance to target you only need to worry about windage.

For .30-30 it will have more drop than my example but the concept is the same. For hunting rifles I like to have my zero point be in the middle to long end of what I feel is my max distance shot. That allows you to hold a little low on close shots and a little high on the long shots, but you are splitting the difference and making any ranging errors to your target less of a concern. If you are looking to stay under 200 yards, a zero anywhere from 100-150 is not a bad choice. It puts your bullet a little high for the short shots and a little low at max distance.

[Beegreenstrings]

It is personal preference. Whatever you feel you can do and remember. The way you explained it sound like your rifle is zero'ed just shy of 200yds.

My M&P is zero'ed at 100. My 24" custom bull barrel is zero'ed at 150 and I use the mil-dots to compensate for anything closer or farther. when Nikon and Vortex brought the BDC scopes out they were nice. But They need to make one that is Self adjustable. Nikon's was based on a specific charge and a specific bullet out of a Encore. If you had anything other than this you were on your own figuring it out.

Vortex was based on the mildot but took away the other three sides of the parralex and same based on one specific cartridge and one rifle.

It is funny how far things have come... Especially in optics. My dad was in the US Army rangers back in the day. He was one of the top marksmen. He would tell me about these scopes they used. standard blue steel tubes. no focus nothing crazy just plain jane. Now he looks at what I have on my 223 and he is like, "can you hit the man on the moon with that thing"? It's funny!

Edited January 14, 2011 by Beegreenstrings

[r1crusher]

You could just find a scope with AO (Adjustable Objective). Set the AO for 100 yards, sight it in and be done with it. Now if the shot is 50 yards or 200 yards, just dial the AO to the appropriate distance and take your shot.

[flounder]

You could just find a scope with AO (Adjustable Objective). Set the AO for 100 yards, sight it in and be done with it. Now if the shot is 50 yards or 200 yards, just dial the AO to the appropriate distance and take your shot.

An adjustable objective has the yardage marks so that you have an easier starting point to focus the scope. It doesnt have anything to do with bullet placement on target.

You must be getting old.

[vf1000ride]

The only scope I know of that does anything like what R1 is talking about is the Burris Eliminator. http://www.burrisoptics.com/laserscope.html It uses a laser rangefinder to get distance and them computes your hold point from a set of programmable tables. Pretty trick setup, still afraid to ask the price of one.

[r1crusher]

An adjustable objective has the yardage marks so that you have an easier starting point to focus the scope. It doesnt have anything to do with bullet placement on target.

You must be getting old.

No, it doesn't but you won't find me messing with my windage and elevation knobs every other shot. 100 is always 100, 75 is always 75, and so on. The only 'dope' for you is the guy behind the scope.

The only scope I know of that does anything like what R1 is talking about is the Burris Eliminator. http://www.burrisoptics.com/laserscope.html It uses a laser rangefinder to get distance and them computes your hold point from a set of programmable tables. Pretty trick setup, still afraid to ask the price of one.

There are plenty of AO scopes out there, mine is a Bushnell. Just search a little more.

And if you need help: Midwayusa OA Scopes

[flounder]

The only 'dope' for you is the guy behind the scope.

True statement.

[vf1000ride]

The adjustable objective on a scope does not adjust bullet drop or the alignment of the crosshairs on your target. It compansates for parralax interally in the optics and allows the focal plane of the reticle to apear the same as the target. I have owned and shot several AO scoped rifles.

[r1crusher]

True, but I'm sure you understand the ability to properly focus your target accurately at long distances regardless of having a mill-dot or compensating for BD. If you can't see what you're shooting it doesn't make much difference.

[walther_gsp]

True, but I'm sure you understand the ability to properly focus your target accurately at long distances regardless of having a mill-dot or compensating for BD. If you can't see what you're shooting it doesn't make much difference.

True, but the OP is also talking about a 30/30 here. For his purposes, the parallax issues from 100-200 really aren't going to matter and he's not likely to need magnification for those ranges.

I would just zero at 100,confirm your drop at 200 , and call it a day. Holdover will be fine for most stuff with a 30/30. Optiona'lly, you could get a red dot with a 2 Moa dot. Zero it so that your POA/POI is the TOP of the dot (use it as a front sight post/six o'clock hold) at 100. At 200 yards, 2 moa is roughly 4 inches. So with your 3.2" drop, you could use the dot with a 12 o'clock hold (bottom of the dot) and be pretty darn close to POA/POI. For shots in between, center the dot and you should be fairly close.

[20thGix]

It is personal preference. Whatever you feel you can do and remember. The way you explained it sound like your rifle is zero'ed just shy of 200yds.

I have it zero'ed @100. I just need to get out somewhere and shoot past 100yds. Here's another question for you guys.

If the mid-range trajectory is 3"@110yds and max point blank range is 232yds but @200yds im only -.2" does that mean the round drops 2.8" in 32yds? The site im gettin my info from say the round will rise 3 and drop 3 from line of sight in 232yds. Seems like a long drop in such a short distance past 200. Per the site im getting my info from.

Edited August 15, 2011 by Casper
fixed quote

[walther_gsp]

It is personal preference. Whatever you feel you can do and remember. The way you explained it sound like your rifle is zero'ed just shy of 200yds.

I have it zero'ed @100. I just need to get out somewhere and shoot past 100yds. Here's another question for you guys.

If the mid-range trajectory is 3"@110yds and max point blank range is 232yds but @200yds im only -.2" does that mean the round drops 2.8" in 32yds? The site im gettin my info from say the round will rise 3 and drop 3 from line of sight in 232yds. Seems like a long drop in such a short distance past 200. Per the site im getting my info from.

If you want to see what the bullet is doing, put the data for the round in a ballistic calculator. It'll give you a better idea of what it is doing vs the rise/drop thing you are looking at. Basic physics says its going to travel in an arc, but what you want to concentrate on is what is does after your zero which will most likely be drop.

Edited August 15, 2011 by Casper
fixed quote

[vf1000ride]

I have it zero'ed @100. I just need to get out somewhere and shoot past 100yds. Here's another question for you guys.

If the mid-range trajectory is 3"@110yds and max point blank range is 232yds but @200yds im only -.2" does that mean the round drops 2.8" in 32yds? The site im gettin my info from say the round will rise 3 and drop 3 from line of sight in 232yds. Seems like a long drop in such a short distance past 200. Per the site im getting my info from.

It will depend on the bullet used to some degree but those numbers don't seem to far off. Most charts I have seen for the .30-30 give poor performance numbers past 200 yards. The round nose bullet design while very deadly close up is not ideal for longer shots. Between 200-300 yards most tables show the 150gr .30-30 round losing roughly 4 inches every 25 yards, so even worst than the numbers you have found and that will get even more extreme as the distance increases. You have to remember the arc the bullet takes in flight is not a nice rounded shape. It tapers off very rapidly as distance increases.

Take for example (much larger distance used to help prove the point) the .30-06 ammo I use in my match rifle. It's a 168gr round at 2750fps. For 1000 yard competitions I would need to zero my rifle at 600 yards. That puts the flight of the bullet at (remember, all in inches) +34@300, 0@600, -33@700, -240@1000. Between 300-600 yards it loses 34in but from 600-700 it will lose 33 more, and yes, that is 240 inches of drop between 600 and 1000 yards. My initial point of aim to take a 1000 yard shot is 20 feet higher than the target and that is with the gun already zero'd for 600 yards.

[vf1000ride]

To R1crusher, sorry man you got me totally confused with what your trying to come across with as info on these AO scopes. Your first post you make it sound like that by adjusting the AO focus ring you are adjusting the scopes point of aim.

Your second post you blatantly say that you don't adjust the elevation for each shot, you just set the elevation adjustment at 100 yards and then for the distance you want to shoot at just change the AO setting to hit what you want. (and yes I know who Midway is and how to google thanks)

Your third post you almost admit you know the AO feature is only for focus. Seeing your target still isn't going to help if you don't understand he theory of how your equipment works.

If you are using your AO adjustment and believe this makes a change to the point of impact or somehow corrects bullet drop for distance please let me know what scope you own as I will sell the Bushnell Sportview 3-9X32mm with AO I currently have on my Ruger 10/22 and buy the model you have.

[20thGix]

Thanks for everyone's input.