YHM EOTECH riser - AR15.COM

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Posted: 12/13/2005 2:33:15 PM EDT

I'm new to the forums, so forgive me if I'm beating a dead horse, but I haven't seen any discussion about YHM's EOTECH riser (part #Y-220). First of all, I have seen the Larue mounts, but I'm CHEAP, and I won't spend the money because I don't want the throw-lever mount. I have a DPMS A2 fixed rear sight (non-carry handle type) on an A3 upper and I want to co-witness without having the front sight tower blocking my view. YHM advertises that it raises the EOTECH 1/4 inch.

Question 1: Does anyone know if the YHM EOTECH mount leaves enough space on an A3 upper to mount the DPMS sight behind the mount?

Question 2: Does a 1/4" lift still give a decent sight picture to co-witness?

Question 3: I also noticed that they have 1/2" picatinny risers. Would this elevate the EOTECH too high to co-witness the iron sights?

Both products are listed on this page: http://www.yankeehillmachine.com/store/rails.html

Posted: 12/13/2005 4:19:56 PM EDT

[#1]

Quoted:
I'm new to the forums, so forgive me if I'm beating a dead horse, but I haven't seen any discussion about YHM's EOTECH riser (part #Y-220). First of all, I have seen the Larue mounts, but I'm CHEAP, and I won't spend the money because I don't want the throw-lever mount. I have a DPMS A2 fixed rear sight (non-carry handle type) on an A3 upper and I want to co-witness without having the front sight tower blocking my view. YHM advertises that it raises the EOTECH 1/4 inch.

Question 1: Does anyone know if the YHM EOTECH mount leaves enough space on an A3 upper to mount the DPMS sight behind the mount? I have an ARMS 40 BUIS behind my YHM EOTech riser w/ no problems.

Question 2: Does a 1/4" lift still give a decent sight picture to co-witness? Yes.

Question 3: I also noticed that they have 1/2" picatinny risers. Would this elevate the EOTECH too high to co-witness the iron sights? 1/4 inch works well for me. I think that 1/2 inch will be too high.
Both products are listed on this page: http://www.yankeehillmachine.com/store/rails.html

Posted: 12/13/2005 4:41:32 PM EDT

[#2]

I have the YHM EO Tech riser on my work rifle. I have been very happy with it. Gives a good lower 1/3 cowitness, and plenty of room for my BUIS. It hasn't moved once I figured it out (at first I didn't realise you had to tighten the front two screws, and was pissed when it moved all over the place). For the money, you can't beat it - even though it isn't QR like the Larue, nor does it give you as many mounting options.

Good luck.

Posted: 12/13/2005 4:43:37 PM EDT

[#3]

I had a YHM EOtech mount on my CMT flat top upper with EOtech 551 mounted on it. After zeroing the iron sights and optic, I noticed the mount would not stay secure. The two set screws that hold the front of the mount (toward the FSB) to the flat top rail would not secure the mount. I noticed the mount was tilting upward. I could push down on the optic and the mount would reseat itself. I removed the optic, removed the mount and reinstalled it, really torquing down the screws. Before I could get to the range, I noticed the mount was again tilting upward from normal handeling of the rifle. I have since removed it, and I am living with the center of the field of view cowitness...........I really liked the bottom 1/3 cowitness the mount provided

Posted: 12/13/2005 4:50:44 PM EDT

[#4]

Thanks for the replies. I think I'll chance it and get the YHM riser and see how it works. Has anyone had the same problem as CQB27 withthe front screws and if so, has anyone found a fix for it? I'll be mounting it to a M1S upper.

Posted: 12/13/2005 8:50:26 PM EDT

[#5]

I have the YHM riser and at first I noticed the front screws didn't lock the mount down. You have to really tighten the crap out of them as the screws just spread the split blocks aparts and wedge them between the rails. Atr first i was scared I might strip the screws but they are fine. I added a little purple loctite to make sure the screws wouldn't back off.
I could see that is the space between the rail blocks were out of spec then you might not get the front screws to tighten down correctly.

Posted: 12/21/2005 3:51:21 PM EDT

[#6]

Any updates on the riser? Im also thinking about getting one.

Posted: 12/21/2005 5:54:09 PM EDT

[#7]

Using an LMT BIS...

Can that YHM be mounted with the Eothinie and still have full easy access to buttons? (i.e. can it be mounted far enough forward to clear the sight and still have all feet on the flat-top?)

ETA: Pics please.

Posted: 12/22/2005 10:29:59 PM EDT

[#8]

Here are some quick pics of my eotech mounted. I have no problems reaching the buttons.

Posted: 12/28/2005 10:05:12 PM EDT

[#9]

I had the same problem initially with the YHM riser. After tightening the front set screws though, it has been fine. No loosening and no loctite needed to keep it there. I really like YHm stuff. The prices are good and quality is right up there IMHO.

Posted: 12/29/2005 8:14:54 AM EDT

[#10]

I have one, and I like it. Its secure, and provides a nice Co witness. I just did some training with the rifle, and it stayed tight after about 500 rounds in a couple hours.

Posted: 12/29/2005 11:57:16 AM EDT

[#11]

Any problems with this mount and canting the Eomabob?

Posted: 1/6/2006 8:04:48 PM EDT

[#12]

Also, how rock solid is this mount from drops and such? Will the sight be yanked off easily?

Posted: 1/6/2006 8:12:38 PM EDT

[#13]

I bought one but took it right off before even doing any final tightning. I want my eotech higher but I dont like that the mount is not quick detach. It also is limiting in the mounting positions it allows.

Posted: 1/9/2006 1:05:06 PM EDT

[#14]

The YHM 220 won't fit with the DPMS A2 buis because the DPMS doesn't allow enough room for the 220 mount.

Yes, the 1/4" rise will give you an excellent co-witness, a 1/2" rise is just too much for most.

No, there shouldn't be any cant with the riser mount if you install it correctly.

It's a rock solid mount but do use a drop of loctite (222 or 242) on the cross bolt. DO NOT use loctite on the set screws for the expansion lug.

Posted: 1/9/2006 2:01:29 PM EDT

[#15]

Quoted:
The YHM 220 won't fit with the DPMS A2 buis because the DPMS doesn't allow enough room for the 220 mount.

Yes, the 1/4" rise will give you an excellent co-witness, a 1/2" rise is just too much for most.

No, there shouldn't be any cant with the riser mount if you install it correctly.

It's a rock solid mount but do use a drop of loctite (222 or 242) on the cross bolt. DO NOT use loctite on the set screws for the expansion lug.

What about the LMT fixed BUIS?

Posted: 1/9/2006 7:19:01 PM EDT

[#16]

Have you considered a RRA Dominator mount? Has a built in BUIS and allows lower third co-witness. Also seems as though it might be a little more sturdy than the YHM. On the other hand, $40.00 isn't too much to gamble on trying the YHM...... I've been looking for something to raise my EOthingie too.... Maybe I'll try it.

Posted: 1/9/2006 7:23:40 PM EDT

[#17]

Forgot to ask. Does the front part of the YHM EO mount bitch up the finish on your rifles at all? Don't get me wrong, I don't mind the dings that come with use, but I try not to put anything on my rifle that will unnecessarily mar it. It is usuall a sign of something that isn't made or designed well.

Posted: 1/9/2006 7:53:47 PM EDT

[#18]

Another question, will is allow the battery compartment of the EOTech sit over M4 handguards?

Posted: 1/9/2006 8:12:19 PM EDT

[#19]

Quoted:
Another question, will is allow the battery compartment of the EOTech sit over M4 handguards?

Way more so than just the flat-top did on my Bushmaster actually. The hand guard gets in the way, but the riser took care of that issue.

Posted: 1/10/2006 8:27:36 AM EDT

[#20]

Quoted:
Have you considered a RRA Dominator mount? Has a built in BUIS and allows lower third co-witness. Also seems as though it might be a little more sturdy than the YHM. On the other hand, $40.00 isn't too much to gamble on trying the YHM...... I've been looking for something to raise my EOthingie too.... Maybe I'll try it.

You don't have to pay $40... check here

Forgot to ask. Does the front part of the YHM EO mount bitch up the finish on your rifles at all? Don't get me wrong, I don't mind the dings that come with use, but I try not to put anything on my rifle that will unnecessarily mar it. It is usuall a sign of something that isn't made or designed well.

No, it won't mar up your rifle, it does clamp at the rear so there's a risk of it scratching your receiver finish but it shouldn't.

Posted: 1/10/2006 8:32:37 AM EDT

[#21]

Quoted:
Quoted:
The YHM 220 won't fit with the DPMS A2 buis because the DPMS doesn't allow enough room for the 220 mount.

Yes, the 1/4" rise will give you an excellent co-witness, a 1/2" rise is just too much for most.

No, there shouldn't be any cant with the riser mount if you install it correctly.

It's a rock solid mount but do use a drop of loctite (222 or 242) on the cross bolt. DO NOT use loctite on the set screws for the expansion lug.

What about the LMT fixed BUIS?

Yes, it should fit with the LMT sight.