01 January 2014 ~ 14 Comments

ARP 055 – Optics, a Different Perspective Part 1

Marine-ar15-with-opticReed talks optics with fellow Marines

Welcome to Episode #055 of the AR15 Podcast.  I’m your host Reed Snyder and with us are several Marine guests. This is the podcast about your favorite black rifle!  This show is for you; whether you’re building your first AR or you’ve been building ARs for years. There is something we can all do to take our black rifle to the next level.

 

Otis Ripcord Giveaway

For times in the field when you just can’t reach your Otis cleaning system and need a quick and effective clean – reach for the Ripcord®. This convenient tool cleans from Breech-to-Muzzle® in one quick and easy pass. The molded rubberized core and Nomex® fibers together create a more effective way to trap and remove fouling.

Winner: Scott H

Reed and Tony,

I just wanted to thank you for the time and energy that you put into the AR15 podcast. I find it very informative and a helpful learning tool for the AR15 platform. I have pretty much been listening to your podcast and most all of the other podcast on the Firearm Radio Network for a year now. I have to say they are all entertaining and educational. I know it takes a lot of time and dedication to keep the network going and I for one, appreciate it!!!

Please enter me in the Otis Ripcord give-away.

Thanks, again

  • Brownells helps make this show possible.
  • They are there for you anytime you make a mistake, like when Jake shoots a spring across the room into his shag carpet.
  • Shop for AR-15 parts at Brownells.  Go to: ar15podcast.com/ar15parts

 

Tip of the Week:  Drinking Tips from Marines

  1. Franzia is not an acceptable beverage
  2. If you want to drink with a Marine,  learn to drink whiskey
  3. When at Fort Knox – Go to the Makers Mark Distillery
  4. Never get caught drinking in your squad bay

Main Topic

A USMC Look at Optics

 

 Listener Feedback

 War13usaf: Enjoyed your last episode very much and it hit home. I am an Air Traffic Controller as well with 11 years active duty, but am currently studying gunsmithing through Sonoran Desert Institute. I have been itching to trade career paths, but it might be too late for me as I\’m 29 and still have 2 years left on my contract. it was good to here a fellow controller and service member excel in another field. Any story can be inspiration to someone else!

Nathan:  You guys have a great podcast idea here.  Also, thank you for having a feedback email.  I enjoy most of your podcasts quite a bit, but would like to discuss some specific things about the AR Optics edition.  First, I think this is a very important subject which you guys knocked the ice off of, but now it is time to open the beer!  Maybe I can add some perspective here that is slightly different than the podcast showed.

 

First, my optics philosophy

Setting up your rifle’s optical system involves developing a specific purpose, clearly developing a spec for that purpose, evaluating every scope in the market that meets 90+% of the purpose(online and in hand if possible), set a general +/- $100 price range and dive into the optical decisions to get the market narrowed down to 1 choice.

The market seems to have 10 of everything, but there are really only a few scopes out there for any well defined purpose.  I will go through my AR optics choice made recently in the end.

Next, a little vocabulary which seemed to be a struggle on the podcast:

scope

Eyepiece – The part of the scope closest the shooter which holds the ocular lens and focus adjustment.

Ocular lens – The lens you look through.  This is where the image is focused on.

Eyebox or non-critical eye relief – This is the qualitative measure of how quickly and easily you can get your eye in position to view the target.  This is the key with AR optics.  AR’s are for war, hog hunting, coyote hunting, 3 gun, self defense, etc.  A scope/mount/setup which won’t present me an image immediately is meaningless.

Eye relief – Distance which the reticle gives you a full view of the reticle.

Eyepiece focus – The part of the scope which allows you to get the reticle focused on the ocular as you see it.  There are 2 types.  Locking focus most commonly used by Leupold.  Fast focus. . .used by most other brands.  Fast focus is fast and easy to setup, but can be moved accidentaly.  Leupold’s method is set it, lock it and forget it.  Since a rifle is for one person usually, I wish all were Leupold style.  Once locked, you KNOW it is good!

Zoom ring – Adjusts the magnification of a variable scope by turning this ring.  Some brands make a few models where the whole eye piece turns.  This is better with gloved hands. . .but is a pain with scope caps usually.  Whichever you choose, make sure this thing is going to turn easily and quickly when you need it to.

Magnification – This is the number of times smaller  or larger and object is or the number of times farther you see it at the same size.  I like 1x parallax free red dots for up close 0 – 50 yd work.  Actually out to 125 yds is not bad with a dot.  A 1-4x allows me to engage quickly from 10 foot to 200 yards pretty well.  I’ve shot deer at 250 yds with a 4x plex, so maybe I should say 250.  I find I need 6x to be moderately comfortable at 300 yards.  12x should get me to 1000 yards ok, but 25x would be ideal.  IMO, minimum magnification to distance is:

100 yds – 1x

200 yds – 4x

300 yds – 6x

500 yds – 8x

600 yds – 8x

800 yds – 10x

1000 yds – 12x

This is on a ~20″ or so target.  Varmints you might want to double the magnification and even triple it at 1000 yds.

Quick Tip #1 - MGM Switchview or similar. That might make an average scope faster.  Super fast! SpectorDR Throwlever $2600

Erector tube – The inner lens assembly that is moved by the turrets for zeroing the scope.  This part is critical for the shooter, because it determines the usable scope diameter or light pathway, what focal plane and the quality of turret adjustments.  Unfortunately, you have to have very good critical reading skills to determine anything about this part from scope maker’s information.

Objective – The part of the scope which holds the objective lens.  This lens and it’s quality are the main contributors to the scopes brightness.

ED, HD, etc – Usually refers to a higher grade of glass material.

Grinding – The process of making the lens which is one of the main cost factors.  Generally speaking glass is ground for optics by a supplier.  These suppliers tend to supply most makers in their country.  <- This may be over generalized.  Generally speaking again, German, Leupold(US), Burris (US), Japanese, Philippines and then China is pretty much the order of quality, but there could be many exceptions..

Lens Coatings – These are put on the lenses of the scope to improve light transmission through the lens and minimize reflections inside and outside the scope.  Some also prevent fog or rain drops from building up.  The key is this can make a US Optics 24mm oj size be brighter than a Chinese 50mm obj.  Lens coating allow high end scopes and their users to “cheat” the exit pupil formula.

Exit Pupil – This is: EP = Obj diameter/magnification.  For example a Burris Fullfield E1 2-7 x 35.  On the high end, the EP is 5mm.  On the low end 17.5mm.  I find a scope with decent quality coatings and a 5mm exit pupil will see well at dusk and even past legal light.  At the low end 2 – 4x setting, this scope could be used in complete darkness with only a moonlit target.

Reticle: The place, usually a piece of glass where the crosshairs, ranging scale, mildots, etc are placed.  Generally speaking plex (+) is usually the cheapest and a Horus type ranging scale is the most expensive.  This is a key part in a scope’s performance and cost.  Choose wisely.

Illuminated Reticle – This is where the reticle is lit by a small light.  Sounds great. . .Super a night! <-NOT!  I have not used a US optics IR, but the ones I’ve used were bright enough that even in red they hurt my night vision and caused a haze in the optic.  Not awful, but hard to use in pitch black night.  In a CQB situation, this is likely great.  In a dawn/dusk, this would be OK with good to great optics.  Most of the time. . .Total waste of money!

Focal Plane

First Focal Plane – This is where the target and the reticle change in size at the same rate as you adjust the zoom.  The meaning is that a ranging or BDC reticle are always usable regardless of zoom adjustment.

Second Focal Plane – This is where the target changes in size relative to the reticle you adjust the zoom.  The meaning is that a ranging or BDC reticles are only usable at one zoom level, or you need a chart to determine the reticles measurements at other zoom levels.  Look at Nikon Spot On.  An FFP would not change with magnification.

Parallax – This is the situation where the target is not focused on the eyepiece at the exact same focal plane as the reticle.  Simply put, if your eye is in a different spot than it was when you zero’d the gun, you will have parallax error, unless you have dialed the side focus or objective focus to move the target to the reticle’s focal plane.  This has it’s greatest effect at close range(<50 yards) or far range(putting a little dot on a really little target) and high magnification(>15x).  With a 3-12 over 10 yards and under 600 yards, I say “total waste of money.)

Enough terms!

Quick Tip #2 – Objective caps used on the eye piece are often more secure and simpler in operation.(Butler Creek brand)

A Basic How-to of Using a Scope

First, a scope should be carried on it’s lowest power and objective(side) focus set at 150 yards, so targets which appear at point blank range can be engaged.  Second, when a target presents itself with time to adjust, the shooter should zoom to max power, adjust side/obj focus(fine tune by bobbing head while turning the side focus until the target does not move relative to reticle.), gather data(range/wind/target movement), calculate, adjust turrets/pick reticle aiming point, then fire at target.  Sometimes, the shooter needs to dial down from max power due to mirage or the need to see escape paths, etc.  <- That is where a high end FFP scope and/or a spotter really helps.  So, that is a very long process.  Targets which present themselves for shorter periods need shortcuts. . . .like that 25 yd whitetail buck who is moving when you see him.

Philosophies of Use

Point and Shoot – Shooting still or moving targets of ~15 – 20″ aim point at 0 – 250 yards are probably best shot with a point and shoot scope.  This can be a basic 4x plex reticle, red dot, basic 3-9 variable, or a higher end optic dialed in to simplified settings. I would guess 90% of all scopes are being used this way

Point and Shoot + Range – This to me is my favorite AR compromise.  This is a pretty good setup out to 400 – 500 yards in good conditions with practice.  It is typically a 1-4, 1.5-6, 2-7, 3-9, 2.5-10, etc with a smaller objective and a BDC reticle.  The best example is something like a Burris Fullfield E1.  These add a BDC to the point and shoot type or in the Burris case, a BDC with wind. . .This type of scope is typically shot from positions like prone and the target is typically ranged visually or with a rangefinder and shot by shooting to a different aiming point on the BDC.  Fast and accurate.  Frankly, I’m getting a switchview lever here and taking shots at max magnification.  I have no need for a FFR reticle here, but if you go to a 4.5-14, then maybe you should be looking FFP, in case 14x isn’t available to you.  I can’t say for sure, but in general SFP is fine.  Also, side focus. . .Since the ideal scope in this range ends at 12x or so, I see no need. . .just slows me down.  Of the 90% who are point and shoot types, maybe 10% of them shoot enough to be better served by this type.  IMO, this is likely 15% of the market at best.  15% include stealing 10% from the previous group.

Full Turret Type or Advanced Reticle Scope – This is usually too much scope for an AR. . .Who wants a 15 lb AR!  These start out with the fixed power Super Sniper and go through the US Optics stuff.  They often weigh 20 oz plus, can be used as a hammer, have glass from the best glass makers and  are best moved by truck!  That said, my go to bolt rifle has a 3-12 Burris XTR which I consider this type and am quite happy with.  Beware of fakes. . .There are many $20 – $600ish fakes in this market.  Frankly, this scope can’t be made for much under $600 and to really get what you want, think $3000 +.  In a word US Optics.  For fun, I configured my ideal scope. . .It was $3406. . .ouch!  Only in this style is a FFP reticle really valuable.