available MOA

[shoots_5]

After getting to the 1000 yard mark with my 338 lapua I of course started thinking about shooting it to very extended ranges, and began to wonder if I had the necessary elevation adjustment available to shoot to the 1 mile mark. Turns out I'm darn close. I have a vortex viper 4-16 PST mounted to the 20 MOA rail. From my 100 yard zero with the 300AB I dialed up until I ran out of adjustment and found that I have 70.5MOA available. According to my ballistic program I'll need 73.3 to get to 1760 yards. So dialing 70 and holding a couple via the reticle I should be able to get there.... Now whether or not I can hit the broad side of a barn at that range is another matter, but it's kind of fun knowing the cartridge and optics are qualified!

I was actually a little bit surprised I had that much elevation adjustment available. The scope has 75MOA of total travel so I'm only wasting 4.5 MOA with the way it's set up! Anyway, had never checked how much actual adjustment range I had available before and to what theoretical range that equated to. Kind of interesting.

 

[DrMike]

That's pretty impressive stuff. I'm always intrigued by those who shoot long range. I don't do nearly enough. However, time and life intrude to conspire against doing that.

 

[shoots_5]

I've just recently started getting into the long range gig and I'm finding it to be about the worst addiction I've ever had! In fact, I haven't been able to get out and shoot for about 3 weeks now and it's killing me!

 

[DrMike]

I have no doubt it is a disease--one that is not easily cured save to surrender to its siren allure.

 

[usmc 89]

im not sure what the total moa of your reticle is below center but i would think its around 20 so if you dont have an ffp you can set your scope to half the calibration value there by doubling your moa and possibly hit the moon?

 

[BK]

Thanks for the report, Tim. I bought that same scope, and also a 20 MOA rail, for one of my 7WSMs, but need to get them mounted up. Too many projects, not enough time at home.

 

[shoots_5]

Usmc 89, good idea, but I'm worried about accuracy suffering in the transitional zone between our atmosphere and space.....maybe nosler can look into a bullet that will still stabilize through that for me. Also, I don't have space on my wall for a nice shoulder mount of the moon..... :wink:

And you are correct, it has a 20 MOA reticle. So, being a SFP scope, at 8x I would have 40 extra MOA of holdover giving me 110.5 MOA which puts the range out to 2170 yards.....but the bullet is subsonic by this point so who knows about accuracy. Predicted velocity at this range is 1003 fps, 670 ft-lbs, flight time 4.266 seconds.

 

[Desert Fox]

Wow! You've gotten 20 MOA for free. Beware though. Check and make sure that this was the case. On some scopes, the knob will continue to turn even though the erector already bottomed out. The only way to find out is to verify your come-up using a collimator.

 

[usmc 89]

Usmc 89, good idea, but I'm worried about accuracy suffering in the transitional zone between our atmosphere and space.....maybe nosler can look into a bullet that will still stabilize through that for me. Also, I don't have space on my wall for a nice shoulder mount of the moon..... :wink:

And you are correct, it has a 20 MOA reticle. So, being a SFP scope, at 8x I would have 40 extra MOA of holdover giving me 110.5 MOA which puts the range out to 2170 yards.....but the bullet is subsonic by this point so who knows about accuracy. Predicted velocity at this range is 1003 fps, 670 ft-lbs, flight time 4.266 seconds.

i think you would want to call berger on that one. and im not sure but i think your 300ab will go subsonic around 1700-1800??? curious now can you figure out where it hits the transonic stage and post it?

 

[IdahoCTD]

If you switch over to a SMK or Berger with higher BC's you'll have less drop and need less scope travel. It might be enough to keep the bullets above the speed of sound and flatten the trajectory enough to get you there with your set up.

 

[shoots_5]

Usmc, shooter shows it going subsonic at 1780 yards given my current environmental conditions and elevation. I think I need to find a place to go kill some rocks at around a mile or so, just for fun. Never have tried the bergers out of this rifle. Nobody local carries them in .338 that I've found and I hate paying shipping on heavy bullets. Someday I'm sure I'll try them. Running the ballistics on them certainly extends the range compared to the AccuBond.

 

[BK]

Sounds like a roady to the desert is in order!

 

[shoots_5]

I'm headed to central Oregon over memorial day weekend....going to throw a couple of rifles in just in case but I'm guessing I'm not going to get a hall pass to go shoot. Maybe if I hand my wife some cash and tell her to go shopping I can manage to slip away for a few hours.....we'll see.

 

[usmc 89]

im not sure what twist your running on that probably a 1-10 a little faster twist would help extend your range a bit due to the extra stability through the transonic subsonic stage.

 

[shoots_5]

It's actually a 9 twist barrel, so that should help!

 

[JD338]

Man, you guys are killing me. Shooting 1 mile is awesome. That is pretty tough to do here in MI.but so is 1K!

shoots_5,
Funny that you did that because I did the same thing. My rifle has standard bases and a Mark 4 4.5-14x40mm scope and I can dial out to 1250 yds.
I don't know what a 20mm base would do but I think it might be similar to what you are getting.

Jeff,
that sounds like a pretty cool idea.

JD338

 

[aka Hunter]

I have a vortex viper 4-16 PST mounted to the 20 MOA rail. From my 100 yard zero with the 300AB I dialed up until I ran out of adjustment and found that I have 70.5MOA available. According to my ballistic program I'll need 73.3 to get to 1760 yards....

The scope has 75MOA of total travel so I'm only wasting 4.5 MOA with the way it's set up!

Can you help me understand something? I've always thought "total travel" available in a scope meant from bottom to top -- or half up and half down from center. If that's right, and a scope has 75 MOA of total travel it seems that it would have 37.5 of up-travel from center; with a 20 MOA base it seems that it would now have 57.5 MOA of up-travel from center.

If you're able to dial up 70.5 MOA, from where does the other 13 MOA come? Is it because the height of the scope above the bore forces you to dial down from center to get to a 100-yd zero?

-----------------

Edit -- I've rethought this and I now believe my statement about the 20MOA base increasing the available MOA from center is wrong. Rather than increasing up-travel from center, I believe the 20 MOA base simply eliminates the need for the first 20 MOA of scope adjustment; alternatively, it forces the scope adjustment into the down-adjustment range in order to zero at 100 yds.

Also, I believe my last question above is stupid. Actually, I believe the height of the scope above the bore forces you to use upward adjustment to zero your rifle (which is actually moving the reticle down); thus, that couldn't provide additional upward adjustment.

Basically, I don't understand how you could zero at 100 yds and be able to dial up 70.5 MOA on a 75 MOA-adjustment scope. Somehow, you must be near the end of your down-adjustment range at your 100 yd. zero in order to be able to go up 70.5 MOA. No offense intended, I just don't understand.

 

[shoots_5]

You are correct on your understanding of total travel. I would imagine its pretty rare that a scope is set to dead center in terms of available travel to be at your given zero yardage. Remember your zero is where the crosshairs meet the path of the bullet, it's not going to be parallel with the line of the bore. Gravity's a b$&/@!

On a side note....running the numbers using the Berger 250gr I can theoretically dial on my scope out to 1940 yards!

JD, sounds like you need to get a 20moa base and we can race to the mile mark!

 

[usmc 89]

You are correct on your understanding of total travel. I would imagine its pretty rare that a scope is set to dead center in terms of available travel to be at your given zero yardage. Remember your zero is where the crosshairs meet the path of the bullet, it's not going to be parallel with the line of the bore. Gravity's a b$&/@!

On a side note....running the numbers using the Berger 250gr I can theoretically dial on my scope out to 1940 yards!

JD, sounds like you need to get a 20moa base and we can race to the mile mark!

you have the constant taken care of for the most part that being gravity providing your hitting the altitude density on the nose in regards to your chart, now all you have to do is assess the deflection aspect and at that distance thats where the fun and the humblings establish a beachfront

 

[Ridge_Runner]

have you checked the scope for tracking accuracy, according to your figures, if you have 75 moa of travel, then you should have 37.5 moa of up, plus 20 for the base which brings the total to 57.5 moa of up, and most scopes tracking become less accurate the farther off center they are.
RR