RDS Went Flying

[Craig_AR]

Recently during a three day range class my new Holosun 508T departed the slide, hitting my cap as I was firing. We were out 500 rounds into the weekend when this occurred. I had co-witness tall iron sights, so I finished the drill before retrieving the sight.
Later inspection showed that the problem was not loose screws; the two screws had broken off at the slide. These were the loctite screws provided with the sight by Holosun. The gunsmith had attached the sight, torking the screws to about 11 instead of the Holosun-recommended 15, based on additional advice from more senior smiths and his own experience with Holosuns.

1. Anyone else have experience with this problem?
2. I am now a firm believer in having co-witness tall iron on every RDS gun.

 

[BCR#1]

I have an FN 509T w/a 508T and no problems with around 200 fired since mounting when new. I'll start checking for loosening of the sight after shooting a string from now on. Thanks for the heads up and hope the sight didn't get too dinged when it hit the ground.

Bill

 

[herrwalther]

Interesting. I have about as many rounds through my EDC mounted 507C. The main difference is I put my own Loctite on. I never have trusted that thin stuff they put on at the factory. I installed my own sight but don't remember the torque setting I used. Probably whatever I read in the manual.

 

[WestKentucky]

Did the bolts snap cleanly or did they leave a jagged edge, essentially asking DOD they shear off from being too hard or did they rip apart from being too soft? Seems a metallurgy issue, but I don’t know which direction it would be. Small parts are notoriously hard to accurately heat treat so they are batch treated in large lots so I’m wondering if they have an entire bad batch.

 

[Craig_AR]

Did the bolts snap cleanly or did they leave a jagged edge, essentially asking DOD they shear off from being too hard or did they rip apart from being too soft?

I only inspected the broken screws in the slide with my old-guy bifocals eyes and no magnification, so I cannot tell you. However, the smith who handled the repair said the screws showed deformation that may have been caused by over-torquing when installed. That might have been the source of the problem.

 

[Jim Watson]

What screw head? Small Torx flathead screws have a thin web between the socket and the bottom of the head, and are not hard to break.

 

[herrwalther]

What screw head? Small Torx flathead screws have a thin web between the socket and the bottom of the head, and are not hard to break.

I use a 507C which has very similar build to the 508T. This is what the provided screws look like. Next to a 0.7mm pen tip for size reference. I also noticed that Holosuns come with 4 sets of screws, so one breaking is not that big of an issue other than awareness of a problem.

 

[a2x4bbl]

Could we get a picture of everything?

 

[once0217]

I would almost bet, that to keep costs down, Holosun uses YFS fasteners which are known to be subpar.