SIGforum
P365X and Holosun 407

This topic can be found at:
https://sigforum.com/eve/forums/a/tpc/f/430601935/m/5560024915

February 07, 2026, 01:25 PM
Lightsped
P365X and Holosun 407
Bought a new P365X a few weeks ago. Love the gun. Also bought a Holosun 407k optic. When removing the optic slide plate, noticed the optic plate was really tight on the slide. Tighter than other optic plates.

Luckily had the correct tools. Got the plate off. Installed the 407k with the correct Holosun supplied screws. Fitment seemed nice and tight. But when firing the gun, the optic will become loose after the first shot or two. Did use blue Loctite.

Any ideas?
February 07, 2026, 05:40 PM
patw
The plates are pretty tight to say the least, mine was too.

My son has a 407k on his pistol and noticed it would come loose as well. I applied a little more blue loctite and screwed it down again. Gonna take it out this week to see if it holds.
February 09, 2026, 08:51 AM
Lightsped
Let me know how the 40k is holding up. Which screws did you guys use to mount it? The current 407k are coming with three different sets of screws.
February 09, 2026, 09:48 AM
oddball
My wife has the P365 Luxe and it just now sports a 507K GR X2 she bought last week. The plate came off fairly easy, the screws were tight, I pressed a soldering iron against to soften up the compound on the screws. The 507 fit perfectly, the screws needed were the M4 X 10 that came with it. The instructions stated to use 15lb of torque, which is a lot for the small screws. then I marked the positioning with a pencil. She has yet to shoot it, but we'll see if the 15lbs of torque did the trick.



"I’m not going to read Time Magazine, I’m not going to read Newsweek, I’m not going to read any of these magazines; I mean, because they have too much to lose by printing the truth"- Bob Dylan, 1965
February 09, 2026, 11:53 AM
Lightsped
Am interested to see how that works. When I attach the 407k to the P365, it feels nice and snug. But once two or three rounds have been fired, the sight is very loose as the screws start to back out.
February 09, 2026, 12:59 PM
Alyron
Oddball- i hope you were using inch/lbs not foot/lbs when torquing those screws.
February 09, 2026, 02:21 PM
oddball
^^^^^^^^^^

Yes, the tool used was a torque screwdriver that measure in/lbs. Did not use one of these Big Grin





"I’m not going to read Time Magazine, I’m not going to read Newsweek, I’m not going to read any of these magazines; I mean, because they have too much to lose by printing the truth"- Bob Dylan, 1965