EXPS3-4 with the Grendel

[cory]

I've been thinking about using the Eotech HHS I as the optic for my current build that's slated to get a 16" Lilja barrel.

I like the Eotech M4 reticule with the 300m, 400m, 500m, and 600m dots as it takes out some of the guess work, unfortunately it's designed for the M855 at 2680fps MV. I emailed Eotech technical support with some questions, so I could translate the dots to the Grendel's flight path of the projectiles I use.

I've been emailing back in forth with Michael at Eotech who was incredibly helpful. I was going to use bullet drop for comparison and he was quick to correct me on that and then sent me this reticule model.
Eotech EXPS3-4 M-4 reticle MOA outline.jpg

I've assumed I'd get approximately 2400fps with a 16" barrel and a 200 yard zero for the top dot. Then I used that model to determine the range of the other 3 dots utilizing Shooters App. My results are below in the jpeg.
EXPS3-4.jpg

Can someone using another ballistics program confirm my results please.

Side Note if anyone has used the EXPS3-4 with Grendel, I'd love to get your opinion on it and any field data you have.

[VASCAR2]

YOUR ROUND 123 GR. 0.51 B.C.
Range Muzzle 100 200 300 400 500 600 700 800
Trajectory -2.5 2.2 0 -10.3 -29.9 -60.5 -103.8 -162 -237.8
Come UP in MOA 0 -2.1 0 3.3 7.1 11.5 16.5 22.1 28.4
Come UP in Mils 0 -0.6 0 1 2.1 3.4 4.8 6.4 8.3

I used the Hornady Ballistic program and I think your close enough for government work. You'll be hard pressed to see most targets beyond 300 yards without magnification. My 16" 6.5 Grendel produces 2645 average FPS with factory 123 grain AMAX. My 20" 6.5 G produces about 2445 with 31.0 grains CFE CCI 450 primers with 123 grain Nosler CC. I figure out of my 16" my reload will be under 2400 FPS. Until you chronograph your load or shoot at distance you won't know for sure.

[Tedward]

I've been thinking about using the Eotech HHS I as the optic for my current build that's slated to get a 16" Lilja barrel.

I like the Eotech M4 reticule with the 300m, 400m, 500m, and 600m dots as it takes out some of the guess work, unfortunately it's designed for the M855 at 2680fps MV. I emailed Eotech technical support with some questions, so I could translate the dots to the Grendel's flight path of the projectiles I use.

I've been emailing back in forth with Michael at Eotech who was incredibly helpful. I was going to use bullet drop for comparison and he was quick to correct me on that and then sent me this reticule model.
[ATTACH=CONFIG]4060[/ATTACH]

I've assumed I'd get approximately 2400fps with a 16" barrel and a 200 yard zero for the top dot. Then I used that model to determine the range of the other 3 dots utilizing Shooters App. My results are below in the jpeg.
[ATTACH=CONFIG]4061[/ATTACH]

Can someone using another ballistics program confirm my results please.

Side Note if anyone has used the EXPS3-4 with Grendel, I'd love to get your opinion on it and any field data you have.

What kind of magnification for those distances? Isn't the Eotch just a red dot? Seems like that would be for 200 yards max. I have one on my Beowulf but not over 100 yards for anything accurate.

[VASCAR2]

This is pretty good reference for using the E O a Tech.

http://bullpupforum.com/index.php?action=dlattach;topic=4484.0;attach=6374

[Tedward]

This is pretty good reference for using the E O a Tech.

http://bullpupforum.com/index.php?ac....0;attach=6374

That's what I see when I look thru mine. Not much good but for an elephant at 300 to 400 yards, or the side of the barn...

[VASCAR2]

Yes, I think the ranging dots on the E O Tech just clutter a very good product. The Red dots are really at their best for close range snap shooting. If your going to stretch the range and use the ranging dots your probably going to need one of the rear magnifiers. Most of the magnifiers I've seen are 3 or 4 power and had a quick disconnect mount or a flip mount, to move the magnifier out of the way. I think this is the reason your seeing a lot of 1-4 or 1-6 scopes on the market 1 power for close snap shooting and 4-6 power for those 200 - 600 yard shots.

I have several 3-9 scopes on 3 power they are still pretty quick with a wide field of view. You also see 3 gun shooters with a red dot on a 45 degree mount then a scope for distance shooting.

[LRRPF52]

What kind of magnification for those distances? Isn't the Eotch just a red dot? Seems like that would be for 200 yards max. I have one on my Beowulf but not over 100 yards for anything accurate.

You can shoot accurately with them because the dot is so small, much smaller than an Aimpoint RDS. If you can see it and compensate with it for trajectory and wind, you can hit it. Not ideal past 400yds, but in good lighting and with good eyesight, it's capable of making hits on silhouettes out pretty far.

I have been able to group 1 MOA at 300m with the Eotech from an 11.5" AR15 5.56 NATO carbine using 55gr FMJ. The impacts were very loud as well on the AR500 steel target.

On the Army Qualification range, I always hit the 300m target using the Aimpoint with 4 MOA dot.

[kamrr4437]

If you want all out accuracy i would go with a scope. If your looking for quick aquisition of the target getting on it quick and killing the hell out of it an Eotech just cant be beat really. I dont have one on my Grendel but i have them on some of my 5.56s. I can shoot consistently out at 300 yards and hit a silhouette everytime on our assault deck at our club range. I can hit the 400 yard silhouette as well but not consistently. Its real small lol. But i know the guns well enough to know where to hold. I have a hard time hitting the one we have at 450 yards ive done it but i wouldnt want to bet on it lol. With the Grendel and my Viper scope though i can do one shot and per and kill them all. Upsets the hell out of some of the guys on the range lol. The Eotech is a really nice sight. I even have an Aimpoint PRO on one and its nice as well but i really like the 1 moa dot on the Eotech. In my opinion its the finest of the red dots. But if you want to split some hairs get you a good scope. I would go with a FFP as well. One more thing i would like to add about the Eotech i like the model that has the double A batteries ive had one of my Eotechs since 09 and i have only changed batteries 4 times and i use it alot. That particular gun goes to the range with me everytime. The reason i like it is because you can find double A batteries anywhere even a convenience store. For the other kind of battery your going to have to go to an electronics store or Best buy or Walmart something like that. But this is just my experiences with the Eotech. My wife also likes this sight as well. But since she has shot the Grendel of mine with a scope has changed her preference for what she wants on the build im doing for hers. Good luck with your decision after all thats the fun of it you get to make it the way you want it!

Keith

[VASCAR2]

I always keep lithium batteries in my E O Tech 512, Lithium do very well in cold weather and have a long shelf life. I always had extra AA batteries in my police car but I never needed them. I normally changed the Lithiums about once a year and moved the old batteries into a mini mag to finish out their life. I don't think a lithium can leak acid like an alkaline battery.

[cory]

Thanks for all the input!

I think I'm going to put the HHS I (EXPS3-4 w/magnifier) on my current build that's slated to get a 16" Lilja barrel.

However, I've got a 20" barrel too and I'll likely but a relatively lower power scope on that one.

[LRRPF52]

My understanding was that cory would be using his 16" Grendel as a brush-busting hunting gun in the thick of the Alabama woods, hence the Eotech. Shouldnt have to worry too much about trajectory with that set-up, but still nice to know information.



If you use a 200yd zero (recommended), 123gr SST/AMAX, 2450fps here's where the dots fall:

5.6 MOA dot will be between 368 yds at 47 F temp, 49 % humidity, sea level

10.5 MOA dot will be 485 yds

16.6 MOA dot will be 604 yds

To simplify, you could call them 370, 500, and 600yd dots.