Poor man's breech shims for D34 clones

[checkbit]

Hi folks. I just wanted to share what I've come up with for breech shims on my Umarex Surge. I found some Hillman nylon washers in .281 (ID) x .490 (OD) x .030 (thickness) at my local big box hardware store. The inner diameter and the thickness have to be modified to fit. After some careful sanding the shim drops right into the bottom of the breech seal bringing the o-ring up above the rim again. I hope this helps.

Happy Shooting!

[brapshwing]

Hey there Checkbit,  Question: Why did you not just swap out the breech seal on your surge?  The reason I ask it that I have a Surge as well and mine still shoot good groups, but the breech seal looks visually like it wouldn't hold air that well.  I was going to pull the breech seal and take it to the hardware store and find a replacement but I'm hesitant to, in the event I cant find a good replacement.  Don't want to wreck what I have since it works at this time.  But I'm anticipating it not working here at some point based on the look of it.

Also, did you turn the seal over and use the opposite side (Just in case it looked better than how it was installed from the factory)?

Troy

[checkbit]

Hi Troy - My breech seal was pressed flat by that silly safety hanger that sticks out of the breech. If you can find Danco #83 o-rings they are a perfect replacement. Still, even after that, the seal would settle below the lip of the seal housing within a week or two. That's when i decided to shim it. It sounds like you may be one of the lucky ones that may not need a shim. And yes, i have flipped the seal when it started to look worn. I love my surge and get great groups out of it. I hope this helps and happy shooting.

[longhunter]

A piece of waxed dental floss is also a good shim material.  That's what most of us use.

[brapshwing]

Thanks Brady, that was what i was after   5-16Idx1-2Odx3-32 Wall Thickness; #83  those are the dimensions for the o-ring that I didn't know.  I'm going to go pick up a few. I"ll probably do what Scott mentioned and put a poor mans spacer in there with the floss since that's what i have in the house..

I bought my Surge as a refurb from pyramid i think (or maybe AGD) but anyway, I got it because my buddy got one and the power seemed very impressive. it was only 69 bucks and free ship due to other purchases at the same time.  Anyway, turns out that they sent me a surge with a .22 barrel on it!  I was surprised to see it as well as confused, but mostly i was excited because it meant that i finally had a .22 cal gun in my safe.

SUffice it to say that umarex should have made the Surge with a .22 or .177 option. This thing shoots awesome.  Granted i cleaned the barrel and put a couple hundred pellets through it first.  But a couple weeks ago i shot a target the size of a HOSP at 32 yards.  I can get 4 out of 5 shots in a dime at 20 yards pretty consistently.  i have a 4x32 banner on it.  The breach seal replacement is to keep it that way..

[brapshwing]

I havent tried to source .22 umarex barrels that would be a swap for the Surge .177 but this magnum springer has the horse power to push a .22 pellet for sure.

[TooJung2Die]

If you can find Danco #83 o-rings they are a perfect replacement.

Don't know who gave me this info but it's valid for the Diana clones too.

Diana Breech Seals, Part #300312, are the same for Models 20, 24, 25, 26, 27, 28, 34, 35, 36, 38, 45, 240, and 350.

The seal is a Metric Buna O-Ring 8 x 2,5.

The equivalent North American spec O-Ring is 5/16" x 1/2" x 3/32".

The measurements match #109, (AS-568A-109), Parker O-Rings.

Commonly used in hydraulics, rarely used in plumbing.

Buna 90D O-ring

Note: the #109 O-Rings sold at TSC/Tractor Supply are an in-house part number and do not fit.

Most of the D34 clones will benefit from adding a breech seal shim. Soda can is a good shim material .004" thick.