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View Full Version : What size riser, if any, for RDS?



dustyvarmint
08-22-2013, 11:30 AM
I'm a total AR NOOB so, pls take that into account :).

I have a flat top AR with BUIS only. My overall goal is to shoot as best I can with irons.

However, I'm taking a basic defensive rifle course in late October and the instructor highly recommends an RDS.

I have an RDS for another non-AR rifle, but how do I know what size, if any, riser I need for the AR?

thanks and happy shooting, dv

themonk
08-22-2013, 12:24 PM
Check out this video explaining CoWitness, both absolute and lower 1/3rd - http://youtu.be/ogX-cIx9hpk. Then decide which of those two option you would prefer and let us know what type of RDS do you have. From there we can point you in the right direction of what mount to get.

dustyvarmint
08-22-2013, 07:10 PM
Check out this video explaining CoWitness, both absolute and lower 1/3rd - http://youtu.be/ogX-cIx9hpk. Then decide which of those two option you would prefer and let us know what type of RDS do you have. From there we can point you in the right direction of what mount to get.

That is very helpful. I think I'd prefer an absolute CoWitness. I have a cheap UTG RDS (when considering the quality of this item, please keep in mind my goal is to use irons and I don't have much intent at this point to use an RDS for anything other than this class).

happy shooting, dv

LOKNLOD
08-22-2013, 07:41 PM
That is very helpful. I think I'd prefer an absolute CoWitness. I have a cheap UTG RDS (when considering the quality of this item, please keep in mind my goal is to use irons and I don't have much intent at this point to use an RDS for anything other than this class).

happy shooting, dv


If you truly intend to continue using irons only, I might suggest you stick with them for the class even if the instructor recommends otherwise. He'll understand if thats the case. The extra practice using irons will be beneficial; it doesn't make a lot of sense to put in tons of reps with something you have no intention of using outside the class.

That said, if you do use the red dot you might like it - the instructor likely recommends them for a reason other than they are easier to teach folks how to use.

DocGKR
08-23-2013, 01:53 AM
If you are going to only use irons, then use those in the class.

On the other hand, there is a reason why virtually every serious LE and mil user group of the AR15 FOW now uses red dots or other optics on their rifles...

Little Creek
08-23-2013, 07:11 AM
I have a Leupold Mark AR Mod 1 1.5-4 FireDot-G SPR mounted in a Leupolld 1 piece mount on my pet M4. It came with a MOE stock. I bought the 1/4" riser from Magpul and cut off the front portion of the riser so I could use the charging handle. This arrangement improved the check weld and works for me.

Failure2Stop
08-23-2013, 07:32 AM
Highly recommend lower 1/3 cowitness unless you are only going to be shooting the carbine at less than 50 yards.

Based off of that RDS, I would recommend sticking with irons until you has sufficient funds to get an Aimpoint Pro or H1, or one of the EoTech EXPS models.

Odin Bravo One
08-23-2013, 06:36 PM
If you want to shoot irons, shoot irons. If you want to use an RDS, then use an RDS. But either way you go, quality equipment is key.

If your intent is to shoot the carbine with iron sights, then you should train that way, and not let an instructor tell you otherwise. As an instructor/trainer, I absolutely recommend an RDS for most shooters. Part of my job is to make recommendations based on experience. But the other part is to increase your proficiency with your gun, the way you want to run it. If that is irons, so be it. If you want to run an RDS, I'm happy to assist there as well.

But I can't, in good conscience recommend, or advocate a low quality RDS simply because I know the advantage a RDS provides. It is only an advantage if it is reliable, and robust enough for the tasks it is being asked to perform. There is a very short list of RDS's that fit that description for a fighting rifle.

Suvorov
08-23-2013, 06:59 PM
I think you will find that using your low cost RDS will most likely serve as a detractor in your training as you will be fighting with it and it may very well go down at some point in the course. If you lack the funds to go with a good quality optical sight ($400 will get you an entry level aim point or eotech with mount), then just take the course using irons. You will learn the same fundamentals and skills regardless of sights used. Just make sure you have quality irons as well.

themonk
08-25-2013, 08:18 AM
UTG makes a couple of RDS so you'll have to look at this and determine if its right - http://www.amazon.com/UTG-Medium-Profile-Riser-Mount/dp/B003TX2BD4/ref=pd_bxgy_sg_text_y this is the medum riser for absoluter cowitnness, if you want lower third you would go with the high riser.

I do think having a red dot is a game changer, that being said I think training is more important. Take the dot you have, learn how they work and make sure you bring the tools with you to the class to remove it if it goes down.

dustyvarmint
08-25-2013, 07:19 PM
Well, the majority certainly convinced me that if I'm going to use the rifle for any serious purpose that a quality RDS is pretty much the way to go. At this point the class is a recreational shooting opportunity (I think Gun Nuts Caleb may have coined that in one of his blog posts) that will teach me how to use my AR more proficiently.

I particularly liked that while the majority think an RDS is necessary, no one was rude or aggressive about it. Appreciate that.

Due to Uncle Sam's DoD furlough a $400 Aimpoint PRO is not in the budget, but that is the exact model the instructor recommended. I'm more convinced, now, than before, to use the UTG and see what the RDS thing is all about. Being a total flat top I can rip the irons off and put them back on if I choose as well as do the same with the RDS. Zero remains within 6 inches at 100 yards when removing and reattaching the irons.

My big quandry, sparked by Failure2Stop, is whether I go Absolute or 1/3. I'll have to watch the video a couple more times.

I measured the UTG RDS to center and the irons to center; the RDS is approximately 7/16" lower to center than the irons so for absolute I think I have to go with the UTG 15mm QD riser.

Thanks for everyone's input.

happy shooting

Chuck Whitlock
08-25-2013, 09:30 PM
Being a total flat top I can rip the irons off and put them back on if I choose as well as do the same with the RDS. Zero remains within 6 inches at 100 yards when removing and reattaching the irons.

happy shooting

The whole point to co-witnessing is that you don't remove the iron sights, so that they are available as back ups if your RDS fails.

6 inches is a significant zero shift.

hossb7
08-29-2013, 11:45 AM
If you only have access to a UTG dot, i would skip it alltogether and use irons only.

They're a pretty cheaply made red dot, and if you use it at a training class and it fails then your hard earned time and money will be compromised because you'll be spending the class fighting your optic rather than learning.

As others said, use irons for the class but long term i would strongly suggest saving for an Aimpoint PRO (or similar) to replace the UTG dot.

Rich
09-04-2013, 02:37 PM
I find center cowitt works best For Me !

I use 14.5 carbines with Fmarked FSB

Never ever did the FSB get in the way of shooting when using center cowitt mount . Aimpoint or Eotech

Even using a 1-4x scope the FSB isn't a problem.

I find when using a lower window cowitt or a larue mount that it will spoil the excellent cheek weld ! SOPMOD LMT Defender 2000 with Larue mount and ML2 aimpoint
Other than that the larue mount kick ass.

I do like Aimpoint over Eotech I own both.

My 2001 Aimpoint ML2 hasn't let me down. And have never found it with a dead battery.

My 2005 Eotech 551F has had some problems with battery drain. But she has been doing well using Duracell only! But still hard to trust 100%
Other users have had problems as well . so be warned.

BWT
09-09-2013, 04:00 PM
I have a astigmatism, Red Dots bloom for me (regardless of quality). I wanted to evaluate if I could ever shoot a RDS well.

I bought this,

http://www.amazon.com/gp/aw/d/B00200E0HM/ref=mp_s_a_1_1?qid=1378760155&sr=8-1&pi=AC_SX110_SY165

For the price it's worked great and been reliable for north of 1,500 rounds. I'm going to buy a PRO one day, but it was good enough for what I needed.

I'd recommend that and a mount. It's reliable enough to evaluate a RDS, but not so expensive it'll scare you off.

I hope this helps.