How many mils is enough? Vortex Viper

[iflywhirlybirds]

I just picked up a Vortex Viper PST 6-24x50 FFP and I noticed it has a lot less hash marks then my SWFA 3-15x42. In fact it has a total travel of 19 mils, while the SWFA has a total of 36 mils. I'm gonna take a wild stab and say the magnification differences are what cause the shortcomings as they are both 30mm tubes. I had planned on putting this on my 300WM for shots out to 1500m. It has a 20 moa bases which makes around 5.75 mils more of the 19 useful. My question is, how many mils are enough? I have heard nothing but good things about this scope so I was kind of shocked by the difference.

Thanks in advance.

[bsumoba]

a general rule of thumb is that about 1/2 of your total elevation adjustment will be usable. Add the 20MOA cant scope and that adds about 5.6 mils.

So you have 19 mil of total travel. Divide that by 2 and you have 9.5 mils. Add 5.6 mils for the cant from the 20MOA scope rail and you have roughly 15.1 mils of "UP" travel"

Now, plug your ballistics into JBM. I assumed a 200gr berger hybrid bullet and 2850 fps and based on this, you can get to 1450 yards more or less before you run out of elevation.

That being said, the best way to determine how much actual elevation you have is to get a zero at 100 yards for example, set the scope zero, then simply turn the knobs UP and count how many mil you have until it stops. Its also a good tracking test to do this, then go back to zero and shoot and see if your point of impact changes

So you asked how much is needed...its purely up to you, but you need 26.7 mils to get to 1800 yards assuming the ballistics I mentioned above.

You can get creative.......

You can get a 200 yard zero, then calculate your ballistics. Assuming the above load, you need 23.3 mils to get to 1800 yards. I would then use the reticle and use the 9 mil hash mark as my new center hold off point and that gives me 9 mils. So, subtract 9 mils from 23.3 mils and I get 14.3 mils. I would then dial 14.3 mils on the scope (which I can do with this scope), and now I can get to 1,800 yards

[boomer135]

I have the Viper PST MOA. With a 30MOA rail I have 60MOA of usable elevation (about 18Mil). To the crosshair that should get me to 1655 yards.

With viewable reticle holdover at max power I can max out @ 1900 yards.

These are my numbers at my velocities, but should get you in the right direction.

If I were to stick around this area I would have dropped the cash on the HD Gen 2. But when I move back east my local range only goes to 1k so It will work for my application.

The PST is a good scope but not having a true zero stop pisses me off. I hate when my turrets slip and I don't want them to.

[JMP]

The Vortex PST is a good all around tactical scope for a short action. It's no good for the ranges you describe, and that is largely a result of the limited elevation range. The Vortex Razor is what you want in the Vortex line for longer shooting.

You really can't have too much elevation adjustment in your scope, but you end up having limitations due to size and expense.

[iflywhirlybirds]

Thank you all! I guess this means this bad boy is going on the Ruger Precision in 308, Ill keep the SWFA on the 300WM

[JMP]

Yep, the PST is perfect for a 308. The SWFAs have a lot of elevation for their scopes' general geometry. I wouldn't vouch for the tracking at the extrema, but the 5-20 has 36 mil of clicks up. It was recently brought up in a different thread.

[diver160651]

How many mils is enough? Vortex Viper

Thank you all! I guess this means this bad boy is going on the Ruger Precision in 308, Ill keep the SWFA on the 300WM

Cooking with gas! Good choice..

Most newbies to ELR, even old season salts from other disciplines, think high magnification is the end all and almost alway choose it over the proper travel. When not shooting peak to peak and laying near the ground in the heat, it defeats most high magnification anyway, the ability to dial and keep your systems full functionality is a wise choice...


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