20 or 40 MOA rail?

[Speedygoss]

Putting together a Sendero in .338 RUM for long distance shooting. This is my first extreme long range attempt. Id like to be zeroed at 200 yards. Looking at the night force rails they come in 20 and 40 MOA. Looking for pros and cons for both.

Thanks,
Speedy.

 

[orkan]

Speedy,

My recommendation would be for the 40MOA.

I don't shoot the ultra-mag, but I spend a great deal of time behind a 338LM. My primary load is a 285gr Hornady HPBT running at 2800fps. Given 50f, 28.00inHg conditions, and a 100yd zero... it takes 27.2 mils to get to 2000yds. 40MOA sloped base allows me to maintain a 100yd zero, and still take full advantage of the 338LM effective range.

At 27.2 mils (roughly 95 MOA), there is no way I could achieve that adjustment with a 20 MOA base, given my Premier 5-25 has a total internal adjustment capability of 29 mils. (roughly 100 MOA) I have 28 mils available in the turret, and as you can see, are very close to maxing it out on a 2000yd shot.

With a 20MOA slope, I would have to subtract 5.7 mils off the top of that number, giving me a maximum elevation adjustment of 22.3 mils. That would top me out at around 1800yds.

With this in mind, my recommendation for 40MOA is based on you having an optic with at least 100MOA/29Mils of total adjustment. If you don't, then you won't have a choice but to use 20MOA slope, and have reduced dial-able range.

Also, there is no reason not to run a 100yd zero with either of these setups.

 

[Speedygoss]

Speedy,

My recommendation would be for the 40MOA.

I don't shoot the ultra-mag, but I spend a great deal of time behind a 338LM. My primary load is a 285gr Hornady HPBT running at 2800fps. Given 50f, 28.00inHg conditions, and a 100yd zero... it takes 27.2 mils to get to 2000yds. 40MOA sloped base allows me to maintain a 100yd zero, and still take full advantage of the 338LM effective range.

At 27.2 mils (roughly 95 MOA), there is no way I could achieve that adjustment with a 20 MOA base, given my Premier 5-25 has a total internal adjustment capability of 29 mils. (roughly 100 MOA) I have 28 mils available in the turret, and as you can see, are very close to maxing it out on a 2000yd shot.

With a 20MOA slope, I would have to subtract 5.7 mils off the top of that number, giving me a maximum elevation adjustment of 22.3 mils. That would top me out at around 1800yds.

With this in mind, my recommendation for 40MOA is based on you having an optic with at least 100MOA/29Mils of total adjustment. If you don't, then you won't have a choice but to use 20MOA slope, and have reduced dial-able range.

Also, there is no reason not to run a 100yd zero with either of these setups.

Orkan,

This is exactly the info I was looking for. Thank you.
I will be running a Nikon Monarch 6-24x50 on it until a Nightforce is ordered. I will have to see what the MOA range is in this scope.

You guys on this forum are top notch.
Thanks again.

Speedy.

 

[bigngreen]

Orkan,

This is exactly the info I was looking for. Thank you.
I will be running a Nikon Monarch 6-24x50 on it until a Nightforce is ordered. I will have to see what the MOA range is in this scope.

You guys on this forum are top notch.
Thanks again.

Speedy.

The Nikon will not work well as it's only got 30 MOA of elevation, you can't put any cant into the rail, the Vortex PST would be a much better optic with 65 moa of elevation and close to the same price range, works well on a 20 MOA rail with the RUM then get a 40 MOA with the Nightforce.

 

[orkan]

Orkan,

This is exactly the info I was looking for. Thank you.

You are quite welcome sir.

If you haven't already ordered a nightforce, I would have you take a strong look at the Premier Tactical line of scopes. Their 5-25x56 is an amazing ELR optic.

Primal Rights • Primal Rights -- Premier Reticles - Tactical & Light Tactical

We have several 5-25's in stock, and it is my go-to precision rifle scope for long distances. For hunting rifles, the Light Tactical is a perfect fit.

Take a look. If you ever have any questions, or need some help, feel free to call.

 

[Speedygoss]

The Nikon will not work well as it's only got 30 MOA of elevation, you can't put any cant into the rail, the Vortex PST would be a much better optic with 65 moa of elevation and close to the same price range, works well on a 20 MOA rail with the RUM then get a 40 MOA with the Nightforce.

Bigngreen,

Funny you just posted this I just looked up the same info and came to the same conclusion. I then went straight to Vortex site and was comparing the PST FFP 6-24 and 4-16 for max elevation range. I already have the monarch collecting dust. That's the only reason I mentioned starting with that. Should work for load development.

For an extreme long range rifle do people tend to choose a 24x over a 16x max?

 

[Speedygoss]

You are quite welcome sir.

If you haven't already ordered a nightforce, I would have you take a strong look at the Premier Tactical line of scopes. Their 5-25x56 is an amazing ELR optic.

Primal Rights • Primal Rights -- Premier Reticles - Tactical & Light Tactical

We have several 5-25's in stock, and it is my go-to precision rifle scope for long distances. For hunting rifles, the Light Tactical is a perfect fit.

Take a look. If you ever have any questions, or need some help, feel free to call.

Greg,
I am looking into these now.
Thank you.

Speedy.

 

[orkan]

For an extreme long range rifle do people tend to choose a 24x over a 16x max?

Absolutely. Magnification is your friend when you are trying to reach out there to a mile and beyond.

 

[bigngreen]

The 24x would be nicer but I shoot the heck out of a 4-16 HS LR at ranges well beyond a mile and the only thing I fight is the stupid thick reticle. The 6-24 PST is still on the light end for MOA but you can get a rail that will get you real close to the bottom and make a mile+ with a 338 RUM, the FFP model has a ridiculous thick reticle through, unless you feel you need it I would go SFP for the much finer reticle!!!

 

[orkan]

unless you feel you need it I would go SFP for the much finer reticle!!!

There are a great many scopes with fine FFP reticles. I think it is a huge mistake to handicap yourself with SFP for the sake of getting a fine reticle.

It's very important when shooting distance to be able to dial back the magnification in order to overcome mirage. With a SFP reticle, your wind holds are lost when you come off max magnification. There are also situations when hunting where it's not desirable to be on max magnification.

I'd stick with FFP for sure. Just choose a different model if the reticle is too think for liking on a vortex. The Premier 3-15 Light Tactical with GenIIXR reticle is a very good choice if you are looking for mid magnification and a fine reticle.

Still though, I would heavily recommend the 5-25 if you are planning to get something done at a mile.

 

[Speedygoss]

I have learned so much from these posts. Thank all of you for taking the time to explain your expeiance on this subject. I would have never thought about reticle thickness prior to getting behind an already purchased optic at long distance. It only makes sence to stick with a FFP reticle for doping the wind.

Thanks again guys.
Speedy.

 

[bigngreen]

There are a great many scopes with fine FFP reticles. I think it is a huge mistake to handicap yourself with SFP for the sake of getting a fine reticle.

It's very important when shooting distance to be able to dial back the magnification in order to overcome mirage. With a SFP reticle, your wind holds are lost when you come off max magnification. There are also situations when hunting where it's not desirable to be on max magnification.

I'd stick with FFP for sure. Just choose a different model if the reticle is too think for liking on a vortex. The Premier 3-15 Light Tactical with GenIIXR reticle is a very good choice if you are looking for mid magnification and a fine reticle.

Still though, I would heavily recommend the 5-25 if you are planning to get something done at a mile.

I've never felt more handicapped shooting than with a FFP optic, and I found them just un usable for to much of my hunting. I do like the Premier 5-25 with the gen 2 XR, it's about the only fine reticle FFP I've seen and I'd actually love to own that optic but you gotta be honest, if guys are talking Vortex money even bringing up the Premier is a little out of place. The light tactical would be difficult to use with 40 moa and a reticle that is twice as thick as the 5-25 it's a moderate range optic on it's best day IMO.
I don't really have any personal like or dislike, I just look at an optic as a tool and for my hunting and shooting SFP is much more useful and workable right now, if my shooting changes then maybe the FFP will be the best tool.

 

[orkan]

The GenIIXR in the Premier light tactical is nice and thin, just like in the 5-25.

Have you ever looked through one?

In any event, I quite commonly come across people advocating SFP for the very reasons you state. They all have one thing in common:

They all need more exposure to FFP reticles in order to learn just what they are missing. In just about every case, they have only looked through a handful of FFP optics, and then form a summary judgement. Oddly enough, in most other area's of their life they require a higher sample size in order to make any claim.

In any situation of shooting you would encounter, I can show you a FFP optic that will not only get the job done, but excel at it.

 

[tom m.]

I have used a gen 2 xr, ffp in a 5-25 s&b... it was fine enough for elr work at 25x. However, it was not thick enough for any distance at lower power. Never seen mirage bad enough to dial down lower than 25x so I would recommend a sfp. Moa or mil is personal preference, but do yourself a favor, pick turrets/reticle that match. This way when you run her out of up, you can start bracketing without doing math. I prefer moa only because it's a finer adjustment, unless they're making .05mil clicks.

Tom