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Discussion Starter · #1 ·
I searched and I searched but I couldn't find any info on this....Bobo, I'm beggin' you to help bud....what size O ring and where to get?  I am referring to the rings that slide on the bottom of the magazine just above the Bersa or NAA finger extension.  On an LCP mag the right size may do a good job of hiding the gap when using a Bersa or NAA finger extension without interfering with functioning.  McMasters on the internet sells every size O ring known to man but I don't know what I need.  Thanks.
 

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O-ring?.....

I haven't used one like you mentioned but here is what I know about orings

I measured the magazine to be 0.44 X 1.07, that would give me a circumferance of 3.02".
this would be the circumferance of an oring with an inside diameter of 0.96"

an ANSI standard -000 series oring would be 0.070" thick.
the ID of 0.96 would fall between the -021 (0.93") and the -022 (0.99").  If the material is buna, the -021 should easily strech/

the -100 series oring would be 0.10" thick
the ID of 0.96 would fall between the -119 (0.93") and the -120 (0.99").

the -200 series would be 0.14" thick
....between -213 and -214

the -300 series would be 0.21" thick
....between -317 and -318

the -900 series would be 0.12" thick
....between -912 and -913
 

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This may or may not apply to LCP’s…

After installing Bersa extensions on P-3AT mags there is a space between the extension and the grip after the mag is inserted (the Kel-Tec standard mag bases don’t leave this space). The space does not cause any problems or malfunctions. To some the space looks a bit tacky. An o-ring around the mag tube fills in the space.

I can’t remember the exact size I used now, and mine have stretched a bit so measuring them probably wouldn’t help you.

What I did was take my unloaded gun with an unloaded mag into a local True Value hardware store (Lowes or Home Depot would be OK also). I went to the aisle where they have loose nuts and other fasteners in drawers. They also have drawers with o-rings. I found an o-ring that stretched fairly tightly around the mag tube, then inserted it in the gun to see if it was thick enough to fill the space but not interfere with insertion. Once I found the size that worked I bought one for each mag.

At the time when my gun was brand new and I was all excited about my new toy I thought it would be really neat, but now it’s not anything I really care about one way or the other. If I ever lost or broke one I probably wouldn’t bother replacing it.

I must say though, they will probably last forever. I've had mine for well over two years now and they are stretched a bit, but still work fine!

Bobo
 

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Discussion Starter · #4 ·
JFB said:
O-ring?.....

I haven't used one like you mentioned but here is what I know about orings

I measured the magazine to be 0.44 X 1.07, that would give me a circumferance of 3.02".
this would be the circumferance of an oring with an inside diameter of 0.96"

an ANSI standard -000 series oring would be 0.070" thick.
the ID of 0.96 would fall between the -021 (0.93") and the -022 (0.99").  If the material is buna, the -021 should easily strech/

the -100 series oring would be 0.10" thick
the ID of 0.96 would fall between the -119 (0.93") and the -120 (0.99").

the -200 series would be 0.14" thick
....between -213 and -214

the -300 series would be 0.21" thick
....between -317 and -318

the -900 series would be 0.12" thick
....between -912 and -913

Holy cow so which one do I get?

http://www.mcmaster.com/

Thanks JFB :)
 

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Discussion Starter · #5 ·
Bobo said:
This may or may not apply to LCP’s…

After installing Bersa extensions on P-3AT mags there is a space between the extension and the grip after the mag is inserted (the Kel-Tec standard mag bases don’t leave this space). The space does not cause any problems or malfunctions. To some the space looks a bit tacky. An o-ring around the mag tube fills in the space.

I can’t remember the exact size I used now, and mine have stretched a bit so measuring them probably wouldn’t help you.

What I did was take my unloaded gun with an unloaded mag into a local True Value hardware store (Lowes or Home Depot would be OK also). I went to the aisle where they have loose nuts and other fasteners in drawers. They also have drawers with o-rings. I found an o-ring that stretched fairly tightly around the mag tube, then inserted it in the gun to see if it was thick enough to fill the space but not interfere with insertion. Once I found the size that worked I bought one for each mag.

At the time when my gun was brand new and I was all excited about my new toy I thought it would be really neat, but now it’s not anything I really care about one way or the other. If I ever lost or broke one I probably wouldn’t bother replacing it.

I must say though, they will probably last forever. I've had mine for well over two years now and they are stretched a bit, but still work fine!

Bobo
Thanks Bob.  The reason I asked is (and I think you might have sent me two a long time ago) is that the two O rings I have (wherever they came from) when used together do a good job of hiding the 1/8th inch gap between the bottom of the grip and the top of the mag on an LCP.  Not as much of an issue with the P3AT and a finger extension.  I'll take a ride tonight to Home Depot and see what they have.
 

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i can invision the following....

standing in the small parts isle, reaching into pocket, pull out the p3at.

dropping the mag, racking slide to verify chamber empty

and no one approaching to ask if they could help
;D ;D ;D ;D
 

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Discussion Starter · #8 ·
Well, I just came back from Home Depot and believe it or not I did get someone to help (in plumbing supplies) but I wish I could have pulled out my magazine and tested these little suckers out before I bought them.  I thought surely I had scored a homerun -  picked up a variety pack (different diameters) but they were all too thick and wouldn't allow the mag to go in or out smoothly  The O ring binded on the grip where it enters the rear of the mag well.  So what I need are thinner rings.  Back to the drawing board.  Be advised there is a bounty on thinner O rings.  And I am willing to orchestrate a trade - have lots of P3AT accessories. :)  I even have a brand  spankin' new 1st Gen P3AT grip - never used and a used 1st Gen slide with internals.  Details can be worked out.  Discuss amongst yourselves.
 

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I was thinking the building supply places had those pull out drawers with the orings in there by basic size.  thus you could sort by oring thichness with the -000 being the smallest.

I just called local autozone, but they do not have by basic size.

When I was measuring mag to get circumferance, I noticed my mag is tight agaisnt the hammer spring plug, then I rembered I have glued in a neoprine shim there to keep mag from rattling.

I can force in a 0.070" feeler guage there.  I also measure the depth from the outside of the grip to the magazine as 0.12".  

So the BS-021 should be a strech fit around, be a tight fit going between the hammer spring plug, BUT not proud with the grip.

Autozone mentioned they had the fractional discriptions so for a BS-021 the discription would be
CS 1/16 - ID 15/16 - OD 1 1/16
 

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Get yourself a o-ring kit of various sizes from  Northern Hydraulics, Buzzard Gulch Tools, or that Cummins outfit that travels with their tent tool sales.  I bought a couple of these kits when I operated my Heavy Diesel Repair shop (now retired)  Your local auto parts store (not the "zone" or that Irish place) should have these kits as well.  Good luck
 

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Discussion Starter · #11 ·
I have a big headache but I think I found what I need at McMasters-Carr (they have a million and one sizes of O rings in a variety of material).  Part is 1201T25.  It is t he same as the very thin O ring someone (?) from Ktog.org sent me a year or so back  -  2 on top of each other work nice.  Thanks.
 

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Part Number:  1201T25  $10.05 per Pack of 50

AS568A Dash Number - 014

Width  1/16"

Actual Width  .070"

[highlight]Inside Diameter  1/2"[/highlight] ?

Actual Inside Diameter  .489"

Outside Diameter  5/8"

Actual Outside Diameter  .629"

Material  Viton
 
Durometer  Shore A: 75

Color  Black

The -014 will sit on a dime and silver will be showing.  If that is the size you stretch to go around the magazine, I doubt if it was viton.  I'm not sure buna would stretch that much, but if it does, they will make the cross section very thin. (1/2 of free)

Now the -021 would just go around a quater and its thichness is the same as the quater's

http://www.mcmaster.com/ (page 3383)
021 15/16" x 1 1/16" 0.926" x 1.066" 100 9452K75 3.69
 

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A word of caution. Some people have had mags fall out during firing because they could not seat all the way due to excessive flashing around the floorplate which had to be trimmed. I don't know how much I would want to put down there that might even come close to not letting the mag seat properly? Since I don't use extensions I am not sure of the gap you guys are talking about but be careful not to have to "squish" it together or you could end up with mags falling out at an in-opportune time.

-Scott
 

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Discussion Starter · #17 ·
Nu_Agin_Shooter said:
JFB- You are indeed a number cruncher!
And a very helpful one. :)

I have found the diameter is less critical than the O ring wall thickness.  You want a wall thickness of less than 1/8th inch (the standard it seems).  The next size down is 1/16th (I haven't found anything in-between).  With the 1/16th in wall rings you may want to put two on. I found some at another hardware store this morning.
 
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