Optimus and phantom breech seals



Author Topic: Optimus and phantom breech seals  (Read 1169 times)

Offline 1216bandit

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Optimus and phantom breech seals
« on: December 05, 2012, 07:22:08 PM »
Are there rubber o rings  that can used instead of the hard nylon type for breech seals?  The optimus is .177 and the phantom is .22. 
Thanx...Dan
« Last Edit: December 05, 2012, 07:24:44 PM by 1216bandit »
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Offline LAalex

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Re: Optimus and phantom breech seals
« Reply #1 on: December 05, 2012, 07:45:38 PM »
  I would think that there's an O-ring that would fit, but I can't say.  I've never measured the size of it.  If I remember tomorrow I'll put the calipers on mine and get a measurement.  I know that there is a plumbing O-ring that works for the Dianas, not sure if it's the same size. 

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Offline 1216bandit

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Re: Optimus and phantom breech seals
« Reply #2 on: December 05, 2012, 08:13:37 PM »
No reason to go through the trouble Scotty, you may end up damaging your seal.  I can take a measurement also, and I am sure my seal is bad so no big deal if it gets buggered up.  I just thought someone may be using a rubber o ring and know what size fits best.
RWS 34 .22 ARH kit
RWS 34 Panther .177 with Vortek PG2
xs-25 from MIke
xs-12 from Mike
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Offline john

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Re: Optimus and phantom breech seals
« Reply #3 on: December 08, 2012, 12:53:38 AM »
how do you know your seal is bad...?...just curious. I removed one of two shims I had under a breech seal the other day and the velocity dropped 100fps so I put it back pronto.
« Last Edit: December 08, 2012, 12:55:21 AM by john »
Benj Trail NP .22 HW, modified shroud, semi-floated Summit stock, home-tuned including deburing, honing, new Crosman piston seal, JM piston buttons, muzzle crowned, trigger group shimmed/debured, padded cocking lever, w/ CP3-9x40AO (3500CPHPs, 500CPUMs, 175CP pointed hunting, 4000RWS superdomes, 250 JSBExpress, 1000 JSBExacts, 250 H&N FTTs, for a total of almost 9K shots so far)
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Offline 1216bandit

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Re: Optimus and phantom breech seals
« Reply #4 on: December 08, 2012, 04:47:37 PM »
Groups started to open up and when I looked at the seal it was pretty much just flush with the breech surface and was really low at the top.  With the amount of use this gun gets it sure cant hurt! 
« Last Edit: December 08, 2012, 04:52:13 PM by 1216bandit »
RWS 34 .22 ARH kit
RWS 34 Panther .177 with Vortek PG2
xs-25 from MIke
xs-12 from Mike
.22 Marauder
.177 Marauder Milo74 reg with goodies from Scott

Offline john

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Benj Trail NP .22 HW, modified shroud, semi-floated Summit stock, home-tuned including deburing, honing, new Crosman piston seal, JM piston buttons, muzzle crowned, trigger group shimmed/debured, padded cocking lever, w/ CP3-9x40AO (3500CPHPs, 500CPUMs, 175CP pointed hunting, 4000RWS superdomes, 250 JSBExpress, 1000 JSBExacts, 250 H&N FTTs, for a total of almost 9K shots so far)
Falcon Prairie Sporter Carbine .22 Bull Barrel Multi Shot

Offline 1216bandit

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Re: Optimus and phantom breech seals
« Reply #6 on: December 08, 2012, 05:23:36 PM »
Interesting read...thanx!
RWS 34 .22 ARH kit
RWS 34 Panther .177 with Vortek PG2
xs-25 from MIke
xs-12 from Mike
.22 Marauder
.177 Marauder Milo74 reg with goodies from Scott

Offline john

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Re: Optimus and phantom breech seals
« Reply #7 on: December 09, 2012, 02:08:04 AM »
What I wrote was about my Trail NP but I'm guessing it's the same for your guns. The first time I ordered a spare breech seal from Crosman, the seal they sent was same diameter but disappointingly short. ??? I thought they has made a mistake and ordered the taller version. Later on, I ordered a spare Trail barrel/breech and was surprised that the spare had a shallower circular channel, obviously designed to take the shorter version of the seal, but it does require two of the metal shims (also from Crosman). So life with Crosman is like that "box of chocolates." You never know what you're going to get. Not complaining...at least parts are available. For a long time I could not figure out how they machined a sloped channel...but now i realize they simply channel first and face off the breech second. Duh! ::)

When I eventually decided to replace that original taller seal (by then dark yellow with use), it was brittle, unlike the soft white new one...oh, maybe my velocity spread would narrow with a new one...?...wrong, no noticeable improvement of any kind...so the old brittle one was still doing its job. Actually not sure how the seal does its job. I assume the air blast expands the seal radially outward against the outer wall of the channel and ovals it so that it spreads out against the bottom of its channel and the against the face of the compression tube.

Oh, and the channel edges of the new barrel/breech face...very sharp, so sharp that the fresh seal got shaved when pressed in, so i ended up sanding those edges. Always learning with these guns.

Also if not sure you're going to like a new seal or o-ring, thread a short length of dental tape (its wider than floss) thru the seal before seating...leave it long enough to grab...the gun doesn't even know it's there while shooting...you can pull that seal out easily anytime.
« Last Edit: December 09, 2012, 02:50:18 AM by john »
Benj Trail NP .22 HW, modified shroud, semi-floated Summit stock, home-tuned including deburing, honing, new Crosman piston seal, JM piston buttons, muzzle crowned, trigger group shimmed/debured, padded cocking lever, w/ CP3-9x40AO (3500CPHPs, 500CPUMs, 175CP pointed hunting, 4000RWS superdomes, 250 JSBExpress, 1000 JSBExacts, 250 H&N FTTs, for a total of almost 9K shots so far)
Falcon Prairie Sporter Carbine .22 Bull Barrel Multi Shot

Offline 1216bandit

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Re: Optimus and phantom breech seals
« Reply #8 on: December 09, 2012, 09:06:21 PM »
Thanx again John for the tips, will be careful of the sharp breech edges!  All I can say for sure is what was once a very accurate rifle is not quite as accurate.  All the screws are good and tight and barrel pivot washers are brass so no play in that area.  The piston seal was changed when I installed the e3650 spring which was not that long ago, so I really hope the breech seal brings back the accuracy!
RWS 34 .22 ARH kit
RWS 34 Panther .177 with Vortek PG2
xs-25 from MIke
xs-12 from Mike
.22 Marauder
.177 Marauder Milo74 reg with goodies from Scott

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