I’ve been trying to mount a Sig Romeo 5 red dot to a standard flat top AR-15 upper, and three times now the cross bolt has snapped into two pieces. I know what you’re thinking…I’m over torquing the bolt, however, I used a torque wrench set to 20 in-lbs for the first two bolts (per the instruction manual that came with the optic), and the the third time I dialed it back to about 16-18 in-lbs, and had the same result. After the first time it happened, Sig sent me a new base along with a replacement bolt and nut, which I swapped out before the third attempt, so I know it’s not an issue with the base. It doesn’t feel like I’m putting all that much torque on the bolt, certainly not enough for it to break like it is. I have mounted tons of optics like this with very similar cross bolts and never once had an issue. Any ideas?
What torque wrench are you using and is it reliable
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Wheeler Fat Wrench. It’s been reliable in the past, although I’m starting to wonder, and am not really sure how to check it.
Sounds like shitty hardware to me. Even if your torque driver started to magically use ft/lb (192-216 in-lb) that should still barely be over hand tight.
That wrench should be fine for this use. I think you are simply a victim of low quality threaded fasteners. There are a lot of them out there. I wouldn’t beat yourself up over this.
I’m sorry I don’t have any helpful suggestions other than to contact Sig again. I am sure you are not the only one having this problem.
Joe Mamma
I chalked the first one off as shitty bolt. But three? If there were that many you’d think others would be reporting problems. The guy i talked to at Sig swore I was over-torquing.
I bite the bullet and find cheap/used Aimpoint mounts for any Holosun or Romeo 5 that I have purchased. Usually an extra $30-40 each optic.
If Sig is sending replacements then no biggie. If not, PM me and I might be able to help with a mount.
I spoke to someone recently who had a similar situation. He was an experienced competition shooter mounting an optic from a well respected optic manufacturer. He was using a torque wrench too, and he kept breaking a particular screw. He would call the manufacturer each time to get a replacement.
He would call them, speak with someone different each time, and they would say they never had that problem before. But he knew that wasn’t true because he had called them before with the same problem. They claimed he had to be over-tightening it.
Eventually, he got a good part and everything has been fine.
If you look very carefully at the broken fastener, you can often see why it failed. If it’s not too much trouble and you are desperate, take a video of you installing the next one, and the torque wrench setting, etc. If it breaks, send the video to Sig.
Joe Mamma
Thank you. They are sending me another replacement screw and nut, if that one breaks I might take you up on that. I plan to only torque this one hand snug.