What screws for Holosun EPS on S&W Shield Plus Carry Comp & what IWB holster light?

[TacticalSpeed]

What screws for Holosun EPS on S&W Shield Plus Carry Comp & what IWB holster light?

I looked through plenty of threads online and plenty of people having the same problem as me, but I did not see where anyone was actually purchasing the correct length screws. Obviously, the screws provided with the EPS are too long.

What screws are folks purchasing from the aftermarket that will actually work to direct mount this thing, but not be too long?


Also, does anyone make a IWB holster similar in style & function to the Stealth Gear Ventcore? I'm running that now, but they do not accommodate the TLR-7 or TLR-1 HL lights

 

[dajogejr]

6-32 is the thread.. just need to figure out how long you need them.
I honesty have a bin full…you tell me how long you need…I’ll send them to you for postage.

 

[TacticalSpeed]

6-32 is the thread.. just need to figure out how long you need them.
I honesty have a bin full…you tell me how long you need…I’ll send them to you for postage.

Posted because I don't know how long

 

[dajogejr]

Posted because I don't know how long

Heard.. don’t currently have an EPS so I can’t help.
But…you could use the tooth pick method as a very, very crude starting point.
Bottom out a tooth pick and mark it where it is flush with the optic, that way you’ll have a rough idea of the total depth…and can back off from there.

You need at least 2 threads to secure an optic, obviously, more is better here.

 

[dajogejr]

Not sure if you were able to figure it out, but my advice is get a pair of 6-32 in 3/8 and a pair in 1/2.
More is always better, if the 1/2” bottom out, go back to the 3/8.
I have 4 6-32 x 10.8mm screws in a bag from Vortex that are made for S&W 2.0.
I’m gonna guess they’ll work if you haven’t found something already.

 

[MikeNV]

"You need at least 2 threads to secure an optic, obviously, more is better here."

With all due respect, two threads is way too little thread engagement. The general rule of thumb for steel is 1.0 to 1.5 times the screw diameter. M&P optic threads are SAE 6-32, with a diameter of 0.138. Doing the math 1.0 to 1.5 x .138 = .138 to .207; 32 threads/in = .03125/thread; .138 / .03125 = 4.416 threads (round up to 5); .207 / .03125 = 6.624 (round up to 7). So, in my opinion minimum 6-32 thread engagement should be 5 to 7 threads.

As a rule of thumb, I like to use a minimum of 3/16 of screw length (6 threads) for thread engagement.

To the OP, I don’t own a Holosun, but I understand they provide custom SAE 6-32 screws with a metric standard 90-degree countersink angle with their optics. Standard SAE screws have an 82-degree countersink angle which won’t match your optic. I would recommend contacting Holosun and attempting to get the length you need with the correct metric countersink and 6-32 thread. It would be hard to believe they don’t have a custom screw to mount one of their optics to a M&P.

As you might be able to tell, I believe in matching countersink screw angles with the optic countersink angle when so designed. I realize some optics are designed without a countersink (flat) and some for shouldered screws.

The link below shows graphically how mismatched countersink angles affect surface area contact. I know many will say they have used mismatched countersink screws without incident, but it’s just another fact to complicate your life when choosing optics and screws.

Good luck!

https://www.forwardcontrolsdesign.com/rmr-sight-to-plate-screws-vs-holosun-screws.html

 

[dajogejr]

Mike, while I tend to agree with you.
However…I remember a video or post from someone trusted in the industry, stating two threads..
Yes, I’d like and prefer more too.
I thought it was Dave Dawson, but the only one I can find is him saying use Red Loctite for sight screws…which everyone says not to do, but he does a great job of saying how, how much, etc., which I don’t know if people follow. I thought the two thread was in that video, it’s not.

 

[MikeNV]

dajogejr - No idea how the person you mention came up with 2 threads? I believe the 1.0 to 1.5 x diameter rule of thumb for steel is an accepted general starting point for minimum thread penetration in the design and engineering world. Two threads would be on the order of .45 x diameter.

 

[dajogejr]

dajogejr - No idea how the person you mention came up with 2 threads? I believe the 1.0 to 1.5 x diameter rule of thumb for steel is an accepted general starting point for minimum thread penetration in the design and engineering world. Two threads would be on the order of .45 x diameter.

I’ll do some digging…. And again, I want more as well…