FAS 6004

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brink

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Jul 17, 2018
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Missouri, United States
I bought one a while back and have been shooting JSB Match Light Weight 7.72 grain pellets in it and it shoots well. But I'm about to run out of them and tried the JSB Match Light Weight 7.33 pellets and several RWS pellets and a few light weight domed pellets and they will not shoot out of the barrel they just stay in the chamber area and have to be pushed out from the muzzle. Are these guns that picky on pellets? Does anyone here shoot one of these guns and which pellet do you use?

RB
 
One of the things about .177 pellets, is the diameter. As you've seen, it's not so much the weight as it is, the diameter.

You need to buy the smaller diameter pellets for this gun. I "think" that it's Pyramyd has the diameters listed in the description. One of the shops notes the diameters.

I've shot the RWS, Meisterkugeln, they work great, one of the H&N's work well, I've forgotten which one. AND...like you, I had one brand (don't recall!) not make it down the barrel.

And yes, while accurate, they are an under or low powered gun. It may help to keep the barrel clean.

Mike 

Heads up - I tried these earlier this afternoon. DO NOT try the RWS R 10 Match pellets..! Need you ask why ?
 
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Thanks guys, for the replies. Yep, it is low powered I didn't realize just how much until I started shooting it. Barely punches holes in paper and not very clean holes at that. But it does shoot nice and holds very well. RWS Meisterkugeln was one of the pellets that stuck. The tin of the JSB Match 7.72 that shoots is marked 4.5 and I have a note written on the tin 4.48, maybe I measured these. I don't remember as it's been too long ago, but I will do some checking and clean the barrel and see what happens.
 
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We use JSB lights, and RWS Basic’s in our FAS 6004.

A pellet that we know does not work in the FAS 6004 is RWS Hobby, do not waste your time with that one.

The FAS 6004 is a fun pistol to shoot! With a little work you can bring it up to 400fps to 450fps, allowing other ammo choices. Look at this thread, from Target Talk-

https://www.targettalk.org/viewtopic.php?f=4&t=53523&hilit=Fas+6004

 
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That there is some good information Deacon_Blues, thank's a lot!

Update, I cleaned the barrel and it was not dirty as expected and was looking things over noticing how the barrel and port face come together I started not seating the pellets as deep as I had been. My normal procedure was to seat the pellets with my fingers and then force them a little deeper with finger pressure thinking to get a consistent seating depth. I think that was letting too much air blow by, so now I'm just seating them barely into the chamber maybe even leaving them out just a bit and let the barrel and port face finish seating them and it's working! It shot all the JSB's Match 7,0 gr, 7.33 gr, and the 7.72 gr, pellets. Still doesn't like the RWS Meisterkugeln but that's OK, it might take some work like Deacon_Jones posted to improve function.
 
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Just as a note, a typical pellet's skirt is significantly larger in diameter than its head. Playing with different head sizes is not a solution for this sort of issue.

I've found JSB's to work well in lower-powered guns as the skirts are both on the smaller side, and made of thin soft lead, so they start down the bore with minimal persuasion. RWS's traditional designs (Meisters, Hobbys, Superdomes, etc.) are the very opposite - big skirts that are stoutly made.

You might also benefit from a pellet sizer - which again, works on the skirt and not the head. Seating pellets past the beveled breech leade, as you noted, pretty much accomplishes the same thing in a pneumatic (but causes other problems in a springer).
 
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brink -

Open the barrel/slide, just a little, do not cock.

Put a "little" silicone grease, or Vaseline if you don't have silicone, in the breach o-ring. Now close the barrel into full lock.

Now open the gun, and look at the breach block where the air comes from, and look for the witness mark that the greasy o-ring left. There should be a full, round mark on the breach block.

If there is, that fitup is good, the o-ring is good. If the mark is not a full circle, you'll need to do a little work filing-sanding the breach block to make the fit parallel to the barrel. THEN, you'll need to refit the barrel to give it the correct sealing pressure, fit the breach block.

Somewhere (use the search function) in this site is full information on how to perform the above steps. It's not difficult, just time consuming to do it correctly.

Mike
 
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I got out my 6004 and fired a few R10 pellets into my homemade target. They shoot just fine. I figured since they worked in my pistol they might work in yours as well. Evidently that is not necessarily the case. Thanks to MikeW for pointing that out.
Click to expand...

Interesting.

My R 10 pellet did not move ! As I do with all of my single fire guns, I push the pellet into the breach, then put my thumbnail over the pellet and push, to verify that the back of the pellet is at least...in plain with the back of the barrel, and not sticking out to interfere with the breach block when closing the gun.

I know that the seal of the barrel o-ring to the breach block is tight, as I did some work right after buying the gun and seeing that there was an difference in the angle of the two parts. I then moved the barrel back to make sure that there was / is enough pressure to put some squeeze into the o-ring to seal the gun.

I just double checked it. There's a nice even witness mark on the breach block of the full o-ring, all 360° of it.

Yet, as Deacan noted, his gun will not shoot the Meister..., and mine will !?

Deacon - If there is "currently" a full squeezed witness mark on the breach block from the o-ring...making tighter will NOT change anything! A good seal is a good seal. Give the toilet paper test a try. If the breach is leaking, it will move the paper when shot. I'll go verify mine now./

Mike

Toilet paper verification - no movement.
 
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Interesting find.

I just put an RWS R 10 Match into my Sig Sauer ASP, which has the same power plant as the 6004 FAS, the ASP shoots the R 10 fine !

So, I tried my 6004 again with the R 10 pellet, it shot fine !!? Maybe an over sized pellet diameter on the first try ?

Back when I got my ASP, the barrel o-ring was nicked (gun bought new). I put an "X" ring in the barrel, been great, no leakage. I'll put one in my 6004 FAS tomorrow, see if the mark on the breach block changes.



Mike
 
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Its an intermittent fault with the breech seal of the FAS which was cured for the SIG…It causes blow by on tighter fitting pellets…

See my posts on Target Talk to get the issue corrected and improve M.V…with any pellet…Try H&N match ..

For lubrication go with Pellgun Oil or Silicone Oil or light Hydraulic oil, but avoid any grease as it will eventually get forced into the valve. You want a light oil which when fed into the valve via air pressure, simply flows through and not clogging up within to restrict flow….


 
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I put 8 or 10 more R 10's through my 6004 today without a hitch. I also put 5 or 6 of the Meisterkugeln's through it too, no problem again.

I have no idea why the lack of shooting the R 10, other than maybe...it had been a while since the last time that I shot it !? It needed to wake up from its deep sleep !



Mike

P.s. - Steve - I have some H&N Match "Green" that I'll try.
 
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Yes try those …i have not tried them. 

The issue with the 6004 is a microscopic glitch. When in 604 guise, it used a quad ring seal of Nylon which was more proud in the groove.

In moving from cottage industry to full blown production techniques for the 6004 they switched to off the shelf O ring….understandable and a cheap easy spare…..but…..

O rings require carefully designed grooves, giving an ideal squeeze, but they just used the existing groove….

In an ever attempt to get the gun to seal with the O ring seal, you just end up forcing the lower edge of the barrel to score into the TP block…or not sealing at its base.. Once raised with a backing shim, or using a Quad seal, the barrel will be plenty clear enough to not score but seal hermetically….and power will be 30 fps higher and consistent..
 
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I enjoy shooting the FAS!

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I have had my 6004 for about 2 years and did all the mods including the chamber and putting a spacer behind the breech o-ring. With the RWS Hobbys I get just under 400fps. and very accurately. I also had to re-crown it as the machining on the barrel was sub-par for a gun at the price point I feel. Mine may be the exception but it loves the Hobbys. I also have the Sig Sauer brother to it and the the over all quality is better on the Sig even though they both come from the same company.
 
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Steveoo said:
Its an intermittent fault with the breech seal of the FAS which was cured for the SIG…It causes blow by on tighter fitting pellets…

See my posts on Target Talk to get the issue corrected and improve M.V…with any pellet…Try H&N match ..

For lubrication go with Pellgun Oil or Silicone Oil or light Hydraulic oil, but avoid any grease as it will eventually get forced into the valve. You want a light oil which when fed into the valve via air pressure, simply flows through and not clogging up within to restrict flow….
Click to expand...
Digging up your old stuff again...

I am trying to get a decent fps from my Sig ASP, it started quite low, not even 300fps; by polishing the breech face, tidying up the breech, re-positioning the barrel and adding 0.4mm to the front of the piston, I have got it up to the mid 340's - nowhere near the 400 fps I would like.
It has got a new O-ring breech seal, but would like to fit an X-ring; the thing is that I can't find one that has 1.78mm cross section and 7mm ID. The nearest is either 6.07mm or 7.65mm, I can't find one on the RS website, (and don't need a bag of 50!) where else can I look that will ship small quantities?
Alternatively, would the 6.07mm stretch over the 7mm central part of the breech, or would the 7.65mm squeeze in and not try to pop out?

I have found a suitable X-ring for the piston that has 2.62mm cross section and 17.12mm ID, the same seller also has the 1.78mm cross section, but only has stock of the 6.07mm seals. Would these be okay, or should I wait for the 7.65mm to be in stock? Or are neither of them suitable?
 
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Always go for the smaller size, stretching over the barrel. as opposed to squeezing inside a smaller O/D.
It means it might end up being a little shy of the O/D but it does not matter, but will probably grow out to fit in time.
Squeezing in will just cause distortion.
O rings often fit with a slight stretch inherent in a given design
 
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