O-ring for tailcap / body gap in Surefire 6P

[etc]

I have seen this many times and always wondered what size O-ring I need to fill that annoying space between tailcap and the body in Surefire 6P.

When de-holstering the lite, the bottom (sharp) part of the tailcap catches on the inside of the holster a bit, accelerating wear. The second issue is that dust and dirt collects in there.

Need a thick O-ring. I would think maybe even use 2 O-rings?

 

[BIGLOU]

Dont know size but you could get them here http://www.lighthound.com/O-Ring--SureFire-C-M-Tailcap_p_1359.html dont forget your CPF discount.

 

[ElectronGuru]

Dont know size but you could get them here

Thats for filling the O ring groove at the top of the threads (under the tailcap).
I believe the OP is asking for a ring to fill the gap between the tailcap and body.

 

[^Gurthang]

etc,

Look for a buna rubber or viton O-ring in a plumbing supply store. You'd probably want a 15-17 mm x 1.5 mm ~ 9/16 dia x 1/16 thick. You can use silicone but most of the silicone rings I've encounted are not the durable.

 

[fivemega]

I have seen this many times and always wondered what size O-ring I need to fill that annoying space between tailcap and the body in Surefire 6P.

The space doesn't bother me other than when de-holstering the lite, the bottom (sharp) part of the tailcap catches on the inside of the holster a bit, accelerating wear. Plus dust and dirt collects in there.

Need a thick O-ring. I would think maybe even use 2 O-rings?

Dont know size but you could get them here http://www.lighthound.com/O-Ring--SureFire-C-M-Tailcap_p_1359.html dont forget your CPF discount.

As long as metal ring is removed, tail groove o'ring will work. It will be little stretched and partially fill up the gap.
Pair of 18mmx1.5mm will fill up the gap width but not depth.
Pentacap will completly fill up the gap and that's why can not be used with metal ring.

 

[etc]

Pentacap will completly fill up the gap and that's why can not be used with metal ring.

What is Pentacap and where do I get that beast?

 

[Kestrel]

What is Pentacap and where do I get that beast?

Sounds like something from FiveMega maybe? :ironic:

 

[fivemega]

What is Pentacap and where do I get that beast?

Sounds like something from FiveMega maybe? :ironic:

Extra length of Pentacap will fill up the gap while round one has same length of original $urefire.

 

[BIGLOU]

Maybe this could also help. This is the O-ring that comes with the Novatac New Style Clip. Noticed it is also like a little combat ring.

 

[Howecollc]

After lots of playing around, I finally settled on using two Buna-N o-rings which were 5/8" ID x 3/4" OD x 1/16" (.070" actual) cross section. Stretching the 5/8" o-ring over the 7/8" body reduces the cross section down to .056" (just a hair under the .0625" depth of the gap). The difference isn't visible. The tailcap contacts the o-rings one quarter of a turn shy of being fully tightened, and the extra resistance for that last quarter turn does make one-handed twisty action a little difficult. As I've never found one-handed operation very doable anyway, I use a Z59 clickie, which makes the extra friction a moot point, as would using a McClicky in a Z41. I got the same "o-ring contact at 1/4 turn shy of fully tightened" using both my Z41 and Z59 so I'm going to assume that all Surefire tailcap tolerances are close.

For those wanting smooth, no-contact action all the way until fully tightened for their twisty Z41 you can use a 9/16" ID x 11/16" OD x 1/16" (.070 actual) cross section o-ring. Its cross section is reduced to .051" when stretched over the body. The tailcap almost touches the o-rings when fully tightened, but the o-rings looked a little shallow sitting in the .0625" deep gap, more so even than Fivemega's suggestion of two 18mm x 1.5mm o-rings would.

The absolute perfect size is going to be a 19.5mm ID x 1.5mm cross section metric o-ring. Stretched cross section will be .055" which will be just enough difference to let the tailcap fully seat easily while still filling the depth of the gap adequately. Metric o-rings are very hard to find locally in anything other than a box of 100 at an MRO supply warehouse, and even then, finding anything over 14mm isn't likely. But for the man who doesn't care to drop $10 to $15 shipped at McMaster Carr online, they are indeed available. I also noticed a few o-ring sellers online that offer single piece quantities and $5 shipping, so you could get 2 o-rings for around $6 from them. Since you're already dealing with shipping minimums, I'd also advise spending the extra money to get Viton o-rings, which aren't going to have any ozone cracking issues in the future.

Glad to now be able to move on from this; that gap has been bothering me since Xmas.

9P with 5/8" ID x 3/4" OD x 1/16" Buna-N o-rings

 

[HotWire]

Nicely done. I'm off to the hardware store! Yay!