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Sag · Member

I've got my AM77 and the cheap little 4x scope that came with it zero'd in pretty much perfectly at 7 yards... Getting the pellets to match was only a challenge of keeping my hand and trigger-break steady. (Okay, I'm just bragging a little there, I've never had a air gun that could do that before :P)

Anyway, is this a good zero range if I'm only looking to shoot up to 30 yards? I've been reading about pellet trajectory and the line-of-sight of the scope intersecting it twice during flight, and have noticed how it causes some shots to go high and some low, etc. and I think that I'll be able to compensate okay with hold-over ( though I haven't had a calm enough day to see, too much wind lately).

However, I'm still not sure if there would be any real advantage of zeroing in to 20 yards? From what I've read and seen from various trajectory software, my gun might have a much flatter trajectory over the range I want to cover if I zero in at 20 yards versus what I saw at a 7 yard zero, but I don't know exactly how much those figures pertain to my particular rifle in respect to velocity, height of the scope above the bore, and all the other variables plugged into such software.

Only real reason I prefer zero'ing to 7 right now is that I can do it in my garage which is preferable, so if it's "good enough" I don't know if I should keep it at 7 or if there's good reason to zero it to 20. I'll want to be able to hit on targets inside 1/2" anywhere within 30 yards, so I'm wondering if I'll be able to do that with the scope I ordered (9x w MilDot and adjustable objective) with the current zero figuring the hold-over, or if I'll still need to zero in to something that gives me a flatter trajectory through the line-of-sight.

Crosman140 · Senior Member

Someone who knows what they are talking about will be along soon.

With your current scope, I'd zero it at the distance you will be shooting at the most. If you mostly shoot 7 yards, zero at 7. If you shoot 20 yards, then 20.

Without mil dots, it will be difficult to adjust your point of impact. But with the new scope you are looking at, that will make this much easier.

I believe a lot of shooters zero at 20-25 yards and then adjust using mil dots and holdover for closer and further targets.

Currently, the two shooters I use the most are my Crosman G1, zeroed at 20 yards that I use for hunting, and my Crosman 1377 that is zeroed at about 10 yards for garage shooting. That way, I can grab the gun that is zeroed for the task and not have to make any major scope adjustments to go shooting.

Slavia · Moderator

Bozo · Veteran Member

Messing about with ballistics software is fun and will give you an idea of all the variables involved, but to get a concrete answer like you want you'll need a chronograph to go along with the software. Short of that, you'll have to do as Slavia said and get some targets, set them up every five yards and see what the pellets are actually doing.

My guess, without knowing the pellets you're shooting or the velocities involved, is that zeroed at 7 yards, you'll be shooting high at an intermediate range, say at 15-20 yards, and low at 30 yards, but that's just a WAG. Get a bunch of targets, measure off some ranges and do some shooting; then you'll know exactly what your gun/pellet/scope combo is doing whatever the range. Then write the results down on a 3x5 card and tape it to your stock for reference in the field. Once in the field, when you have a fairly good distance estimate to your target (or use a rangefinder so you *know* the range to the target) you can glance at the card and know exactly what your hold over/under needs to be. That card will still be handy when you get your mil-dot scope, but you may want to re-do it so it reads something like "27 yards=2nd dot down".

Remember that if you change scopes, use different pellets, or tune your rifle you'll need to do it over again.

Mark5043 · Silver Status Member

Hey Sag....Here's a link to Chairgun Pro.."It's free by the way".It's nice software to play around with,and has a fantastic set of tools. It will give you an idea of what's going on with your set up.However as Bozo said, You really need to get a chronograph to take full advantage of the program,if you want to be spot on in calculations.

http://www.hawkeoptics.com/us/chairgun/download.php

Sag · Member

domer_pyle · Senior Member

Chairgun is pretty realistic for what it is but if you want any type of accurate result you have to do the testing on the range. Chairgun is awesome for getting a ballpark idea or using it to see how zeroing at 25 yards compares to 45 yards and lots of other stuff. But you probably shouldn't rely solely on what it says

Sag · Member