Beeman .22 cal O-Ring help

[ThomasT]

Hello everyone,

I need help with trying to find the correct O-Ring size to fit inside the Breech End of the Barrel. I purchased this Pistol ( Beeman 2028 ) over a month ago and it was missing the O-Ring that fits inside the Breech end of the Barrel. I contacted Beeman and spoke with Peter Hernandez and he told me that he would send me the correct replacement but I have not received it.

So what I am trying to do is figure out if any Beeman rifle in .22 caliber uses the same O-Ring. All I need is the “ID” and the “CS” ( cross section ) ( see the 2nd photo ) dimension and I can order some.

I made this drawing showing how my barrel is made, ( 1st photo ). If anybody has a .22 caliber Beeman rifle that uses the same configuration and can give me the dimensions of your O-Ring, I would appreciate it.

Just inside the Bore on the Breech end of the Barrel there is a machined offset groove that the O-Ring fit in.

Thank you,
ThomasT

[WobblyHand]

Don't know the exact answer, but maybe this might help.  You know the caliber.  So the ID needs to be smaller than that in order for the oring to seal.  I'd look up standard metric o-rings around that size and see what's available.  Maybe you can find something close.  A place like Captain O-rings will have loads of choices.  You can get an estimate of CS by fitting some material into the slot.

Now, it could be a custom size - that happens.  But maybe you will get lucky just by the steps above.

[Robert 5mm]

I know Barra 1100 barrel is a direct swap for the 2027 barrel.

I would guess the .22 is also - so I think the bolt is also - and it has the o-ring

https://barraairguns.com/products/1100z-22-bolt-conversion

[ThomasT]

I know Barra 1100 barrel is a direct swap for the 2027 barrel.

I would guess the .22 is also - so I think the bolt is also - and it has the o-ring

https://barraairguns.com/products/1100z-22-bolt-conversion

Hello Robert,

Thank you but from the drawing that you sent, it appears that Barra use two different "rings" at the breech opening. My Beeman 2028 use just one.

Thanks again,
ThomasT

[ThomasT]

Don't know the exact answer, but maybe this might help.  You know the caliber.  So the ID needs to be smaller than that in order for the oring to seal.  I'd look up standard metric o-rings around that size and see what's available.  Maybe you can find something close.  A place like Captain O-rings will have loads of choices.  You can get an estimate of CS by fitting some material into the slot.

Now, it could be a custom size - that happens.  But maybe you will get lucky just by the steps above.

Hello WobblyHand,

Yep I already looked at a Metric O-Ring chart and just too many to choose from.

Thank you,
ThomasT

[WobblyHand]

Have any idea how wide the groove is?  Can you carve a pop-sickle stick, or plastic or something like that to fit it in the groove, or a piece of copper wire you bent in an el?  I'd bet it is about 1.5 or 2mm CS, and maybe 4.5 or 5mm ID, since you say it is a 22 which is 5.5mm bore.  That could narrow down your choices...  You know it isn't 3mm, that would be way too thick, and it's probably not 1mm, because the o-ring would probably fall out.  If you send me a self addressed stamped envelope I could send you a few 1.5 (CS) x 5 (ID) o-rings to try, if you are willing to try. 

[ThomasT]

Have any idea how wide the groove is?  Can you carve a pop-sickle stick, or plastic or something like that to fit it in the groove, or a piece of copper wire you bent in an el?  I'd bet it is about 1.5 or 2mm CS, and maybe 4.5 or 5mm ID, since you say it is a 22 which is 5.5mm bore.  That could narrow down your choices...  You know it isn't 3mm, that would be way too thick, and it's probably not 1mm, because the o-ring would probably fall out.  If you send me a self addressed stamped envelope I could send you a few 1.5 (CS) x 5 (ID) o-rings to try, if you are willing to try.

Hello again @WobblyHand,

To hard for me to explain but bending wires / full scale drawings in my AutoCAD / digital measuring , this is as close as I can guess:

ID = 4.5mm
CS = 1.5mm
OD = 7.5mm

I am fairly comfortable that the groove is between 7.33mm and 7.5mm, so the closest that I can get is what I am showing above. I pushed a pellet down the barrel and measured the skirt at 5.5mm.

Do you have any O-Rings that size? If so I will be glad to pay you for a couple to test.

Thomas Travis

[Robert 5mm]

Thomas

If O.D. = 7.5 and CS = 1.25 then I.D = 5

I.D. = OD - 2xCS or 7.5 - 2.5=5

And sorry, I do not have any

[ThomasT]

Thomas

If O.D. = 7.5 and CS = 1.25 then I.D = 5

I.D. = OD - 2xCS or 7.5 - 2.5=5

And sorry, I do not have any

Hello again Bruce,

Yep I just sent you a PM and stated that my math is incorrect, so I change it.

No problem, thank you for all the help anyway.

ThomasT

[WobblyHand]

Have any idea how wide the groove is?  Can you carve a pop-sickle stick, or plastic or something like that to fit it in the groove, or a piece of copper wire you bent in an el?  I'd bet it is about 1.5 or 2mm CS, and maybe 4.5 or 5mm ID, since you say it is a 22 which is 5.5mm bore.  That could narrow down your choices...  You know it isn't 3mm, that would be way too thick, and it's probably not 1mm, because the o-ring would probably fall out.  If you send me a self addressed stamped envelope I could send you a few 1.5 (CS) x 5 (ID) o-rings to try, if you are willing to try.

Hello again @WobblyHand,

To hard for me to explain but bending wires / full scale drawings in my AutoCAD / digital measuring , this is as close as I can guess:

ID = 5mm
CS = 1.5mm
OD = 7.5mm

I am fairly comfortable that the groove is between 7.33mm and 7.5mm, so the closest that I can get is what I am showing above. I pushed a pellet down the barrel and measured the skirt at 5.5mm.

Do you have any O-Rings that size? If so I will be glad to pay you for a couple to test.

Thomas Travis

I'd go back and edit your post, and remove your address, if I was you.

I have a bag of 1.5 CS x 5mm ID o-rings if it will help.  That comes out to 1.5mm CS x 8mm OD, which is very close to your measurements.  This means the o-ring may slightly protrude more in the bore, and give a better seal.  Unfortunately, I don't have 1.5 x 7.5 OD, but do have 1.5 x 7 OD.  The 1.5x7 will be too small. 

So if you want a few 1.5x8 just send me a SASE to the address I PM'd you.  The o-rings would be gratis.  Just helping out.  If they are the wrong size, at least you will learn that.

[ThomasT]

Have any idea how wide the groove is?  Can you carve a pop-sickle stick, or plastic or something like that to fit it in the groove, or a piece of copper wire you bent in an el?  I'd bet it is about 1.5 or 2mm CS, and maybe 4.5 or 5mm ID, since you say it is a 22 which is 5.5mm bore.  That could narrow down your choices...  You know it isn't 3mm, that would be way too thick, and it's probably not 1mm, because the o-ring would probably fall out.  If you send me a self addressed stamped envelope I could send you a few 1.5 (CS) x 5 (ID) o-rings to try, if you are willing to try.

Hello again Bruce,

Thanks for the "heads up" and did remove.

I have one more trick that I am going to try if the liquid rubber is still good. I will explain if it works 

ThomasT


Hello again @WobblyHand,

To hard for me to explain but bending wires / full scale drawings in my AutoCAD / digital measuring , this is as close as I can guess:

ID = 5mm
CS = 1.5mm
OD = 7.5mm

I am fairly comfortable that the groove is between 7.33mm and 7.5mm, so the closest that I can get is what I am showing above. I pushed a pellet down the barrel and measured the skirt at 5.5mm.

Do you have any O-Rings that size? If so I will be glad to pay you for a couple to test.

Thomas Travis

I'd go back and edit your post, and remove your address, if I was you.

I have a bag of 1.5 CS x 5mm ID o-rings if it will help.  That comes out to 1.5mm CS x 8mm OD, which is very close to your measurements.  This means the o-ring may slightly protrude more in the bore, and give a better seal.  Unfortunately, I don't have 1.5 x 7.5 OD, but do have 1.5 x 7 OD.  The 1.5x7 will be too small. 

So if you want a few 1.5x8 just send me a SASE to the address I PM'd you.  The o-rings would be gratis.  Just helping out.  If they are the wrong size, at least you will learn that.

[Moke]

I bought a box of SAE and Metric O-Rings at Ace Hardware (separate boxes based on standards).  Incredibly handy boxes of rings.
For my Beeman Chief, I love Tractor Supply. They have O-Rings packaged in 5-packs (6 packs?). And, they order via computer, based on the sales. So, the shelf is automatically restocked without having to worry about someone not doing an adequate job on reordering based on what they see for shelf stock.

[ThomasT]

I bought a box of SAE and Metric O-Rings at Ace Hardware (separate boxes based on standards).  Incredibly handy boxes of rings.
For my Beeman Chief, I love Tractor Supply. They have O-Rings packaged in 5-packs (6 packs?). And, they order via computer, based on the sales. So, the shelf is automatically restocked without having to worry about someone not doing an adequate job on reordering based on what they see for shelf stock.

Hello @Moke

Good to know, thank you.

ThomasT