Multi optic vs direct milled red dot optics

[GJM]

Some on PF have followed my DP Pro issues. Short summary is I broke eight DP Pro units between September 2017 and May 2018. They were all mounted on Glock 34 MOS (Gen 4 and 5) and Walther Q5 (multi optic capable) pistols. In late April and May, as I ran out of Walther and Glock multi optic pistols, I started shooting a pair of CZ Shadow 1 pistols with direct milled (by L&M) DP Pro optics. Neither broke, but I was pretty paranoid while shooting them, because of my prior experience.

Mid-May, I had a Cajun’ized P09 direct milled by Primary Machine for the DP Pro, followed a few weeks later by a second slide, identical to the first. To date, neither has broken. At a match in Missoula today, I was discussing optics with another CO shooter. His experience was interesting. He got 20,000 rounds out of a DP Pro direct milled on a G4 34. On his G5 MOS pistols, he has broken three DP Pro optics at right about 3,000 rounds each. Two had intermittent dots, and the third DP Pro broke off the mount and actually hit him in the forehead. Not loosened and came off, but actually broke the screws. What I find especially interesting about that third one, is the multi optic mounting system seems to support the optic not nearly as well as when an exact pocket is cut (and possibly better yet with studs milled in like the Primary Machine installation).

Pretty small data set, but my theory is in a tough environment like a slide mounted optic, the multi optic mounting systems are subjecting the optic to more stress, and contributing to earlier failures than with a direct milled installation.

[CleverNickname]

I broke an RMR and a DPP on a Unity Tactical ATOM G17 slide. I changed to a Suarez DPP-direct milled slide and I haven't had a problem yet.

[YVK]

I am several range sessions away from hitting a 3K mark for my DPP on a Unity Atomized G19x. Curious what will happen and wonder if I should get a hard hat.

[EVP]

I don’t run a optic but have kept updated and talk to many people that do because as soon as a reliable MRDS is available and gone through it’s teething issues, I will most likely go that route.

With that being said GJM your results mirror what seems to be the trend. Direct milled slide especially by ATEI and L&M seem to have the least problems then the MOS and core pistols.


I have been astonished with how many DP pros you have gone through. I know you have said you like it for gaming better then the RMRs but the issues you have gone through seem like a headache. Since you are competing with it I would only assume that the issues happen at the most inopportune times.


Really looking forward with hopes that the aimpoint delivers.

[Trukinjp13]

When I had atei do my slide up. They flat out said the pro mill is by far the best option. Even swaying me from having them universal mill it. I was blown away about the fitment of my rmr 2 on installation. It almost snapped in place. Like
Sight dovetails, I remember thinking even if the screws come loose this bitch is barely going to move.

Do y’all that have mos/core/etc loctite the plates to the slide and optic when you mount it? Or just loctite the threads.

Thank you once again for the knowledge you drop here.


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[einherjarvalk]

I've been shooting a MOS G19.4 and Type 1 RMR for about a year and a half now, with probably 2,000 rounds or so through it in that time. I had some teething issues with the initial install with the screws walking but adding more Loctite got it squared away. Unfortunately, it turned out that the RMR was defective (windage screw was walking) and when it came time to send it back to Trijicon for repair, I discovered I had too much Loctite on, and had to cut the screws out to actually get the optic off. Once it came back, I again had screw walking issues with light Loctiting after about 100 rounds, but added a tiny bit more torque got it back down and it hasn't moved in the 800 or so rounds since.

I honestly think a pro cut is better, but then you have the risk of never being able to swap your optic, so I'm willing to put up with the MOS system's shallow mount screws for the time being in case the ACRO turns out to be a game changer. I will note that I'm using the pre-Loctited factory Trijicon screws that come with the OEM sealing plate for handgun use, but was using Battleworx's screws previously and still use their mounting plate. Dunno if it makes any difference (probably not). Haven't had any dot flickering either, but I used a tiny bit of rubber band behind the side battery contact to "shim" it into staying in position as well.

[TAZ]

I’ve been running a 19.4 MOS with RMR1 fir a while now without any issues. I essentially bedded the mounting plate with blue loctite, then blue loctited and torqued the plate mounting screws per my machinist handbook recommended torque. The screws for the optic are blue loctited as well and torqued.

If the plates aren’t secure and can flex under loads generated during slide movement, I can see how that would transmit some stress to the optic. Either that or you have some movement of the optic assembly relative to the slide that causes added stress. I was quite surprised that none (AFAIK) of the mounting plate designs are dovetailed like the Atom. Would also like to see designs that use the Dueck RBU mounting system with a slip fit post rather than the simple screw. Anything that kills relative movement is a plus IMO.

[theJanitor]

On my 1911 with a RM06, and the required trijicon mounting plate, I also bedded the plate down with blue loctite first. On my Direct milled glock slide, I don't feel that worried, as the fit is really good. I've put paint witness marks on the mounting screws and the adjustment screws, as well.

We've seen a couple ATOM slides break mounting screws, and I believe it's because the screws are really short

[RevolverRob]

This is precisely what I noted in this thread: https://pistol-forum.com/showthread....-a-duty-pistol

Anecdotally, the situation appears that the multi-plate optics mounts are inferior to a specific mill application.

I believe the main reasons for this is:

That the plates are thin and held in place with screws. The simple reality is - that the thinner plate can flex, where the whole slide will not flex. It will flex and strain at the mounting points of the screws, resulting in stretching and movement around the mounting holes. Imagine, if you will, an additional sling-shot effect on the optic itself, that is both a forward and backwards movement, as well as side to side (and potentially torsional as the screws back out).

Additionally, you have a straight strength issue. Thinner plates held in place with screws are not made of the same hardened steel as the slide is. When you mill bosses directly into the slide, you're utilizing that high strength properly heat treated steel to hold your optic in place. And you're creating a pocket around the optic where it presses against that same hardened steel front and back, thus preventing it from working loose or have the same back and forth movement that a plate system could generate.

I bet if you put an acceleratometer or shock-watch type sticker on the optic of an MOS and a milled slide Glock and shot them side-by-side for the same number of rounds, you'll discover that the MOS mounted optic eventually (maybe not at first when everything is very tight) experiences a higher degree of force and acceleration on it.

[DMF13]

I know it's wishful thinking, but an industry standard for a slide mounted optic "footprint," would be ideal.