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Old July 5, 2012, 12:26 PM   #1
Pond, James Pond
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Another scope question. CF rifle scope choices.

I'm trying to gauge how good this deal is...

I am thinking of getting a centrefire rifle. More than likely in .308. I want to learn long range shooting. I will be fitting a scope.

I see no reason not to get the scope first if a good one turns up.
The shop I bought my rimfire Nikon and reloading gear from in the UK is advertising some Burris scopes as Clearance Stock.

They range from £400 to £450 and are the following:

BURRIS XTREME XTR 3-12X50 PLEX
BURRIS XTREME XTR 3-12X50 Illuminated Mildot (my preference)
Burris Signature 4-16x44
Burris Signature 6-24x44

These are in the UK and therefore in GBP.

I want to get a good deal.
I don't want to spend a lot unecessarily, but nor do I want to rush out and buy a scope unless the saving is particularly advantageous given that it may not see a rifle rail for some months!!

So, by comparison, here are some of the scope I could get for similar money, when converted into €.

For €450-545 I can get:
Delta Titanium 8x56
Delta Titanium 2.5-10x50
Delta Titanium 2.5-16x50
Delta Titanium 2.5-10x56
Meopta Artemis 7 x 50

The Burris XTR looks great, and I'm sure it is a great scope, but if the others listed are just as good, despite slightly different specs, I need not rush out and buy the Burris given that the others are at regular prices, not limited special offers...

If it is as good and is well priced, I'll take the plunge and get it... It'll just postpone my actual rifle purchase...

Thoughts? Opinions?
Thanks
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Old July 5, 2012, 05:18 PM   #2
tobnpr
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Get as much magnification as you can afford in a variable scope for long range.
Mirage may prevent you from utilizing all of it sometimes, but better to have it when you can use it. In any case, I wouldn't go less than 16X. Some will argue 10X is enough for 1000 yards. Not for me...

You need to define long-range...whatever it is to you.

You then need to determine what round you'll be shooting, and what the approximate bullet drop will be at that range.

Equip your rifle with a 20 MOA base. This will help in getting enough elevation adjustment from your scope. Verify that your scope WILL have enough elevation adjustment- even with a 20 MOA base- to compensate for your intended range.

Often, this requires a 30mm tube.

I got a great deal on a Weaver scope with 1/8 moa clicks- only to find out that it has a measly 30 MOA of elevation adjustment, and won't reach out much past 600 yards with a .308 match load- even WITH a 20 moa base.

Do your homework to make sure it will work at the maximum range you will be shooting.
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Old July 6, 2012, 01:44 AM   #3
Pond, James Pond
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Wow!

Superb post! Thank you!

OK, so I've done some initial reading and punched in some over the top numbers to allow for a margin of error on my part!!

Have a look at my understanding of what the specs mean and see if you agree....

I looked at one trajectory chart and it only went out to 500yds despite claiming to be for 1000 yds ().

Anyway, their data spoke of a 56" drop at 500 yds, so this means 56/5 (if 1MOA is 1" @ 100yds) giving 11.2 MOA at 500 yards.
Another link to this very forum talks about 369" of drop @1000yds based on a 300yd zero, so that would require 37 MOA.
The Burris XTR scope (although "only" up to 12x mag, has the best objective lens diameter) has a max adjustment of 90" @ 100 yards.

So, if I understand correctly that is 90 MOA of adjustment on tap.
Presumably this means 45" up and 45" down from centre.

It follows, therefore, that the Burris XTR, at 500yds is ample and doable at 1000. 1000 is a teeny-weeny bit ambitious but at least I know I'd the limiting factor and not my gear!!

Is this correct or have I missed something?
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Last edited by Pond, James Pond; July 6, 2012 at 02:19 AM.
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Old July 6, 2012, 08:06 AM   #4
tobnpr
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Bullet drop is not linear.

Depending on the muzzle velocity, and ballistic coefficient of the bullet, they will shed velocity- and drop- very differently.

High BC bullets will fly flatter for a greater distance because they shed their velocity slower.

Other rounds, like the popular 7.62 x 39, suddenly drop like a rock after a few hundred yards.

IOW, a bullet which has a flight time of 2.1 seconds, will drop far less than a bullet with a 3 second flight time...and because it will fly in a shallower "arc", will require less elevation adjustment above your zero.

You are correct about the 90 minute adjustment being 45 up/ 45 down.

A 20 MOA base will effectively increase the "ups" to 65 moa.

It's not total bullet drop that's calculated when adjusting elevation. Bullets fly in an arc, and it's calculated based on the minutes of angle above "your" zero distance, that the bullet must be in order to obtain the correct arc to intersect the target at the intended range.

As an example, one of my rifles requires 13 minutes of "up" elevation at 600 yards, with the rifle is zeroed at 200 yards. I've obviously eaten up some of the elevation adjustment for the 200 yard zero to begin with.

Make sense?

Last edited by tobnpr; July 6, 2012 at 08:16 AM.
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Old July 6, 2012, 11:46 AM   #5
Pond, James Pond
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A little blinded by science, this end!!

I can understand things much better seeing them in action, rather than looking at abstract numbers, but I found this chart for .308 (Table 1).

Taking the row showing a zero'ed scope at 100 yards, thus matching the data on the Burris scope page, the bullet drop at 1000yds is 421".

This means 42.1 MOA. According to what you've confirmed about the up/down adjustment being 45 MOA either way, I should have enough adjustment in the scope to make a 1000yds shot theoretically possible using that scope and a .308 round.... I think....

Am I on the right page here?
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