On our Sig Sauer P365 comparison video, with the Surefire XSC and TLR-7 Sub, some YouTubers commented about possible rail damage from the P365. So we decided to run a 200-round test.
The issue, as reported by a few folks, is that the light can eject itself off the end of the pistol. Most pistols have a rail key, which is a slot in the rail that the light interfaces with. This slot provides positive light location, preventing the light from moving forward under recoil. The P365 does not have such a slot; it only has a proprietary rail that consists of a groove on either side of the pistol with defined ends at the front and rear. The TLR-7 Sub interfaces with this rail, using the front of the rail as the locating device. The aluminum rail mount of the Sub interfaces with the polymer of the Sig rail. And since the front of the P365 rail is a much smaller surface than would be provided by a sot, the Sub’s aluminum mount can eat away the front of the rail to the point where it can no longer retain the light on the pistol. This results in light ejection under fire.
We thought it would be interesting to see if this is a real issue. Using our P365 standard size pistol, the TLR-7 Sub, we attached the light using strong, but not overly aggressive pressure. We figure this is about the pressure that one would use when semi-permanently attaching that particular light to the pistol. We used the head of a Masterlock key to tighten the rail key, as it was easily available.
We took the pistol to the range with 200 rounds of PMC 115gr ammo. We checked the condition of rail at every 10 rounds downrange. I do not use the light aggressively as a “gas pedal” so any pressure on the rail was the result of the light moving around under its own inertia. At about the 50 round mark, I noticed some deformation on the right hand side of the rail, at the point closest to the muzzle. The light has obviously pushed itself forward on the rail, and was starting to push some of the P365’s polymer forward. Again, I did not check tightness of the screw or attempt to move the light back at any time.
I noticed a little similar deformation on the left side of the rail at the 100 round mark. It seemed less than the right side.
I continued shooting until the 200 rounds were spent. I did not see noticeable additional deformation, nor did the light come off. With the shot count goal reached, we then disassembled the light from the pistol. The light had not loosened or tightened; tension was the same as when I had put it on earlier. I could feel a bump at the muzzle end of the rail, where polymer had been pushed forward by the light’s mount. This bump was on both the right and left sides of the rail, but it hardly shows up in these pictures. I can feel it, but it’s hard to see.
Here are my takeaways from this experiment:
- I can see how its possible that users may experience the light eating away the rail and allowing the light to fall off.
- I suspect this can be minimized by secure tightening of the TLR-7 Sub on the rail, but given the deformation it is also possible that a high round count could end up with the same issue.
- I wouldn’t hesitate to train with the pistol and light to get 1000+ rounds through it. At least then I could be certain that the light would stand the test of time on the pistol. My personal guess is that the issue would not have gotten measurably worse in another 800 rounds.
- A properly mounted Sub is likely to stay where you need it during a self defense situation. If you train a lot with your Sig P365 with the Sub, simply check for damage at some regular intervals and take action if the light is coming dangerously close to coming off.
Does this issue concern me? Yes. Streamlight is a reputable manufacturer and I suspect there are ways to resolve this particular issue without a light redesign. Perhaps make a mount that interfaces with the full length of the P365 rail?
Would this issue prevent me from running the TLR-7 Sub for the P365 on the P365? No. I think mine would have been reliable for another 800 rounds.
Do you have experience running the Sub on your P365? If so, leave a comment below!
Really enjoyed reading the results and your thoughts.
In general do you recommend training with a light attached? I don’t own the P365 or a TRL-7 light, was just wondering….
We understand that many violent encounters happen in low light. We also believe in training with our carry setup so that we can be most familiar with what we are using most frequently. We are convinced that having a light attached to the pistol is better than not having a light, and as a result we carry with a light. And since we’re carrying a light, we train with it. When I train on my own, or in a class, I’ll be training with a light on my pistol. If training in low light, I’ll practice both my draw and my light activation. Hope that helps!
I was linked to this article by a comment on Reddit. My P65XL, equipped the TLR-7 Sub, experienced a total interface failure around 500-1000 rounds. I watched the light go flying off in the middle of a string of double taps and subsequent efforts to reattach it and tighten it down failed to work for more than a couple of rounds. Bummer
This does seem to be a real issue with the Sub on the Sig; hopefully you don’t think I’m discounting your experience. If you want to send me a picture of the “after” damage, I’m happy to include in the article above.