FX want consistent shot strings from your Fx impact m4

[Deleted member 58109]

i think i finally found a real good replacement o ring for that 2.84 x2.62 that drags on the valve rod.
after taking the gun apart and completely cleaning every bit of factory grease out of it.
i was inspecting the plenum tube i noticed that it didn't have the small white o ring like i see people replacing, it was black.
and dragged across the rod bogus.
then i thought of Polyether Urethane did some math and came up with these.
1/8 id x5/16 od x 3.32cs Duro 90.
long story short got some swapped it out best thing since sliced bread.
shot strings from sitting don't matter here is 2 shot strings from today after the gun sitting 24 hrs.
its tuned for 32g aea slugs rolled the wheel from 11 to 5 no other adjustments and shot jts 29,34g semi domes.
reg is set 128-130

 

[Vetmx]

I believe your miracle oring is the one that all our sticky M3’s came with. If you read the slow first shot topic from a while back, we refer to it as the PUR oring. The issue is where your oring rests in the plenum, it’s shaped like a cone. Like a drill made the hole. We made discs and cut the same angle as the base of that hole is on one side. Then left the other side perfectly flat so the oring rests on it and won’t extrude. Your issue will return when your magic oring starts to limber up and extrudes into that beveled plenum beak.

 

[Deleted member 58109]

I believe your miracle oring is the one that all our sticky M3’s came with. If you read the slow first shot topic from a while back, we refer to it as the PUR oring. The issue is where your oring rests in the plenum, it’s shaped like a cone. Like a drill made the hole. We made discs and cut the same angle as the base of that hole is on one side. Then left the other side perfectly flat so the oring rests on it and won’t extrude. Your issue will return when your magic oring starts to limber up and extrudes into that beveled plenum beak.

wrong answer! no impact comes with this o ring that i can confirm 100%
and like i said if you read what i wrote you would acknowledge there is no slow shots.
its obvious you did not correct the problem with whatever you did but me being a rookie and you having no idea of my background
makes you ignorant.
i fixed my gun and the shot counts speak for themselves let me know when you gun can shoots as good.
and no my problem won't return like yours did its obvious you didn't address the problem or do enough homework.
this isn't my first merry go round i had a life before this,,
NEXT!

 

[Vetmx]

wrong answer! no impact comes with this o ring that i can confirm 100%
and like i said if you read what i wrote you would acknowledge there is no slow shots.
its obvious you did not correct the problem with whatever you did but me being a rookie and you having no idea of my background
makes you ignorant.
i fixed my gun and the shot counts speak for themselves let me know when you gun can shoots as good.
and no my problem won't return like yours did its obvious you didn't address the problem or do enough homework.
this isn't my first merry go round i had a life before this,,
NEXT!

Easy bud. Take a few breaths. My Impacts are fine.

 

[Deleted member 58109]

Easy bud. Take a few breaths. My Impacts are fine.

mine is too now.

 

[Vetmx]

A 2.84x2.62 is a standard 104 oring. Just the metric measurement of the 104. Poly urethane is what FX puts in our guns. PUR? Get it? How you got a black oring mystifies me. Here’s what the FX warehouse, when there was one sends. The second pic is the standard measurement oring in Viton that we use with a peek disc. Not trying to have a pecker measuring contest, just wondering why your gun came with what appears to be a buna oring.

 

[Deleted member 58109]

A 2.84x2.62 is a standard 104 oring. Just the metric measurement of the 104. Poly urethane is what FX puts in our guns. PUR? Get it? How you got a black oring mystifies me. Here’s what the FX warehouse, when there was one sends. The second pic is the standard measurement oring in Viton that we use with a peek disc. Not trying to have a pecker measuring contest, just wondering why your gun came with what appears to be a buna oring.

View attachment 519541

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why it came stock with a black o ring beats me , maybe whoever built it just threw what they had in it not sure.
my cousin owns a rubber plant probably makes 70% for most car truck farm etc.
it's his lab that tested the o ring that came out of my gun and its a buno70, really,,, it was him that came up with a compound for the o rings
these are not just urethane the ones that fx supplies are with a silicone base and that's why their white o rings drag as well.
he is making another compound that is more durable and slicker than these as i told him i will try them but I'm not touching it unless it acts up.
he is the rubber chemical genius..
so, i know no fx guns come with this particular o ring so far, I've put 1200 rounds through this since
it has not acted up once the previous o ring would have after 200 shots as it did.

 

[Trucker3573]

Easy bud. Take a few breaths. My Impacts are fine.

lol no doubt DAMN

 

[greenbeans]

According to schematics the M4 does no longer come with PUR90 but “FPM90”, which seems to be Euro Talk fork FKM. My M4 had a PUR anyway, I guess FX is throwing in whatever they want… NBR is a new one though…

 

[addison]

 

[Jay308]

According to schematics the M4 does no longer come with PUR90 but “FPM90”, which seems to be Euro Talk fork FKM. My M4 had a PUR anyway, I guess FX is throwing in whatever they want… NBR is a new one though…

Thats what I don’t understand about FX, they will install whatever is on the bench. At the price point, it’s kinda ridiculous.

 

[Deleted member 58109]

in any case I'm trying these new o rings and so far, it's been really good.
these were not bought from o rings plus or the o ring store as they don't have any with the same compounds. they were made
the newer ones he is making are grey and those he said will be better, but he is 2 weeks out before those are made.
this was for the non-know it all rookie air gun enthusiast's that may be interested.

this is a new hobby for me and kills time until the race season is here cant wait to smell burning rubber and nitro again.

 

[greenbeans]

in any case I'm trying these new o rings and so far, it's been really good.
these were not bought from o rings plus or the o ring store as they don't have any with the same compounds. they were made
the newer ones he is making are grey and those he said will be better, but he is 2 weeks out before those are made.
this was for the non-know it all rookie air gun enthusiast's that may be interested.

this is a new hobby for me and kills time until the race season is here cant wait to smell burning rubber and nitro again.

Seems to be working, you’ll have plenty of customers on classifieds if your strings stay as epic as they are right now for a couple of months without swapping the oring.

 

[jfgdds]

A 2.84x2.62 is a standard 104 oring. Just the metric measurement of the 104. Poly urethane is what FX puts in our guns. PUR? Get it? How you got a black oring mystifies me. Here’s what the FX warehouse, when there was one sends. The second pic is the standard measurement oring in Viton that we use with a peek disc. Not trying to have a pecker measuring contest, just wondering why your gun came with what appears to be a buna oring.

View attachment 519541

View attachment 519542

Why did you choose a durometer of 75 vs 90? That's what appears on the print on the back side of the bag on the left. The new M4 is using a FKM (viton) oring in dura 90. Also, it is possible the viton comes in black. Im interested in the peek upgrade as well. I have a lathe so i will be making the part myself. Also, I spoke with tech support at oring store and he seems to lean heavily towards polyurithane as the material of choice in this application. My own research shows that viton is superior to distortion in the form of compression set though. Polyurithane may be better in the area of mechanical wear but a shorter shelf life. I want the best oring for the job. Thanks

 

[jfgdds]

A 2.84x2.62 is a standard 104 oring. Just the metric measurement of the 104. Poly urethane is what FX puts in our guns. PUR? Get it? How you got a black oring mystifies me. Here’s what the FX warehouse, when there was one sends. The second pic is the standard measurement oring in Viton that we use with a peek disc. Not trying to have a pecker measuring contest, just wondering why your gun came with what appears to be a buna oring.

View attachment 519541

View attachment 519542

Just checked a site. Viton dura 90 orings are available in black so the oring in question could be a viton as that's what the new M4 is supposably coming with.

 

[rc4fun]

These are a custom size and some kind of poly. I think this is the same guy that was selling them here? Post #12
https://www.ebay.com/itm/2671220679...o=s7zvH6DUSn6&sssrc=4429486&ssuid=wynGtrltQi6

 

[bigHUN]

I can recall talking to my local (Canadian) FX dealer somewhere back around 2022, and he recommended me to replace this oring to NBR90 (metric of course). In meantime I had a Plenum upgrade and repeated the process again.
I also polished the portion of a Valve Rod where this oring contacts the steel.
In meantime I had a Plenum kit upgrade and repeated the process again.
We had a lot of discussion here @ AGN about these back in that time.
I never had any issue ever since with my MK2, and probably well over 15K shots that oring still in the Plenum.
I have a bag of spares if ever need any surgery on the Plenum again.

 

[jfgdds]

I can recall talking to my local (Canadian) FX dealer somewhere back around 2022, and he recommended me to replace this oring to NBR90 (metric of course). In meantime I had a Plenum upgrade and repeated the process again.
I also polished the portion of a Valve Rod where this oring contacts the steel.
In meantime I had a Plenum kit upgrade and repeated the process again.
We had a lot of discussion here @ AGN about these back in that time.
I never had any issue ever since with my MK2, and probably well over 15K shots that oring still in the Plenum.
I have a bag of spares if ever need any surgery on the Plenum again.

Ok. NBR is just the standard buna oring used throughout the impact, in a dura 70 hardness of course. Glad it worked well.

 

[jfgdds]

in any case I'm trying these new o rings and so far, it's been really good.
these were not bought from o rings plus or the o ring store as they don't have any with the same compounds. they were made
the newer ones he is making are grey and those he said will be better, but he is 2 weeks out before those are made.
this was for the non-know it all rookie air gun enthusiast's that may be interested.

this is a new hobby for me and kills time until the race season is here cant wait to smell burning rubber and nitro again.

If you look carefully the back of the bag says the oring store and the oring is part number U90104. Their white polyurithane oring may be superior to the white polyurithane oring fx uses.

 

[Vetmx]

If you look carefully the back of the bag says the oring store and the oring is part number U90104. Their white polyurithane oring may be superior to the white polyurithane oring fx uses.

That’s why I’m done with this topic.