Improve the FAS 6004
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Re: Improve the FAS 6004
Bought a FAS 6004 used and it wasn't very powerful to begin with. Lots of torn holes. I noticed today my pellets weren't even penetrating the paper with cardboard backer. Chrono showed a bimodal distribution at 260 and 230 FPS. I went through most of the tips here and am now at 320 FPS with meisterkuglen pistol 7gms. I suspect the cylinder felt was getting dry and the oring showed blowby dirt. Shimmed the oring with some paper while I await the new mcmaster parts. Thanks for the tips. The pistol is delightful.
Re: Improve the FAS 6004
Replaced the paper shim with an aluminum and used the square edged McMaster beech seal and still getting 320 FPS. Apparently the 1 card stock shim was sealing now. A little silicone line on the stock o ring may have also helped. The square seal is a tiny bit small and tries to squirm out but hopefully it will bed down a bit a bit as the gun is stored closed.
Re: Improve the FAS 6004
I've had my FAS 6004 for about 8 months now and did all the mods some months ago and I'm pleased with the results. It shoots right at 335 fps. +or- 3 fps. which is very consistent imo. That is with RWS Hobbys 7gr. which it loves. It is as accurate as my FWB 65 in my hands. I'm a lefty and the factory grips with no mods fits my hand perfectly. I was not real happy with it when I first got it but after the mods and shooting it awhile it has really grown on me. I used the aluminum washer from Mcmaster Carr but used a nitrile o-ring in the breech insted of the square one from McM Carr. The square one wouldn't stay in place for me. I did have to recut the chamber slightly on my lathe as it was really bad as sent. I had trouble seating any pellets. Now the Hobbys fit snug but slip right in. Definitely bad machining on the chamber from the factory. The rest of the gun including the rest of the barrel (crown) were very nicely machined.
Re: Improve the FAS 6004
Hey guys, I just ordered the new Sig Sauer super target pellet pistol from Sig today. It's made for them from Chappada just like the 6004 with basically the same mechanicals but styled to resemble the Sig 210 with a walnut ambi grip and all steel construction. Specs seem about the same fore fps. at up to 400 fps. Looking forward to comparing the two side by side. Trigger and sights look to be the same. Will be interesting to see if theSig model has improved the issues of the 6004. I will do a report when I get it. See my write up in the lounge for details on the sale.
Re: Improve the FAS 6004
Received my Sig Precision Target pistol yesterday and I must say I'm pretty impressed so far. Quality seems pretty good, very similar to my Fas 6004. I fired about 50 RWS Hobbys out of it and It averaged in the low 350s fps.through my Caldwell cronograph. Low was 343 and high was 360fps. This was much better out of the box compared to MY FAS 6004 which shot around 300 fps. with the same pellets. After doing the mods. the 6004 is shooting an ave. around 340 fps.
Accuracy is about the same in my hands and pretty good for a practice pistol. I actually like the Sig's trigger better than the 6004s trigger out of the box feels pretty nice. Because I usually shoot two handed, I prefere the Sig grips and angle better. They fit my medium sized hands pretty well and since I'm a lefty work out well for me. The wood finnish is nice but I did notice the right grip is slightly smaller on it's outside dimensions. You can actually see more metal showing around the outside edges. The metal fit and finish overall is very nice on mine. The machining of the barrel and chamber is very nice and doesn't need further machining like my 6004 did. The crown is also very nicely done on mine.
Sights are similar to the 6004 but the rear notch seems narrower on the Sig which I'm not crazy about and I will open slightly (personal preference). Cocking effort to me is about the same on both guns. Anyways guys this is just a quick comparison and I'll post some side by side pics and target pics when I get time.
Accuracy is about the same in my hands and pretty good for a practice pistol. I actually like the Sig's trigger better than the 6004s trigger out of the box feels pretty nice. Because I usually shoot two handed, I prefere the Sig grips and angle better. They fit my medium sized hands pretty well and since I'm a lefty work out well for me. The wood finnish is nice but I did notice the right grip is slightly smaller on it's outside dimensions. You can actually see more metal showing around the outside edges. The metal fit and finish overall is very nice on mine. The machining of the barrel and chamber is very nice and doesn't need further machining like my 6004 did. The crown is also very nicely done on mine.
Sights are similar to the 6004 but the rear notch seems narrower on the Sig which I'm not crazy about and I will open slightly (personal preference). Cocking effort to me is about the same on both guns. Anyways guys this is just a quick comparison and I'll post some side by side pics and target pics when I get time.
Re: Improve the FAS 6004
Old post but time to report back in since modding a Chiappa SIG over lockdown...
Its not bad...From stock it returned 360 fps versus the 332 fps I got for my FAS when new (Finale Match)
Theres a minuscule improvement with R10 in accuracy above the Finale Match but velocity and breech entry shaved the R10.
Accuracy (stock) is is about the same for both guns.
I think the finish of the metal work slightly favours the SIG...it looked almost blued as i took it out the box. It maybe anodised...hard to tell. The FAS more of a matt black paint job...looks nice, very similar to the finish on a Webley Tempest. So could be a baked on paint job best guess.
The barrel finish of the SIG is better finished at the breech...Chiappa must have listened to the FAS groans, or gone with a better barrel maker...The seal also stands further proud for a better seal...hence the 30 fps difference in velocity.
Internal mechanics are almost identical, sharing a similar cylinder and transfer port/valve bulkhead and TP diameter.
For me however, the FAS is the better gun...Have i gone nuts?...Well its been said but not this time..
The opening lever on the FAS is an overlooked key for me. It snicks open with a fluid motion which better suits the position of the hand when going to cock the top strap.Nudging it with your thumb and drawing the top strap up is one clean movement.
It must have been designed with the target shooter in mind. It isnt bettered on any SSP no matter what anyone says...its a lovely action with no hand shift. Not so the SIG. the thumb needs to move back and up over the top of its release hammer, almost crossing hands. You have to use both side by side to appreciate it but if you have not used the FAS, the SIG hammer will not bother you.
The FAS sits lower...even with the Ambi grip...but obviously the 3 other grip options give it even more capacity.
The FAS trigger once set up has the edge and the sight base is longer and neater, being inlet flush with the action.
The problem with the FAS is its barrel. Its breech is not correctly finished and needs popping on a lathe to touch the inner recess or following the method on here...Its an easy job for an engineer but could be daunting for someone without hand skills.
It also wants a phosphor bronze brush shoving through to knock off a couple of high spot burrs inside ...You need to use a 10x glass to see them but they are present....Alternatively use the method on here, using wet and dry paper.
Next the breech seal of the FAS sits in a groove which is a shade too deep. It needs a backing washer or a twirl of floss to the rear of the O ring to lift it up to prevent gas loss and prevent lower edge of the barrel nicking the bulkhead face below the transfer port..Which can occur when this shallow seal beds in.The SIG groove is 0.3mm less shallow being just enough to not give rise to the same problem..
Once sorted the FAS velocity rises 30 fps and seals nicely without the metal of the barrel contacting the bulkhead face.
I use an O ring in place of the hard alloy barrel fixing washer ...it has a touch of give but keeps the barrel nudged up until the screws are tightened ...most throw out this alloy washer as in Stoffs post on here..but locking up the barrel can then be more of a guesstimate. With a prouder positioned seal, i still feel the positioning washer has its place!
Finally a piston pack of 0.3mm will give both guns a 30 fps shunt upto 400 fps territory if you want that.
In final conclusion, the SIG is almost like a MK2 version of the 6004, ironing out the little problems mentioned across this post but what it now needs is a Mk2 6004 because has the greater potential.
Its not bad...From stock it returned 360 fps versus the 332 fps I got for my FAS when new (Finale Match)
Theres a minuscule improvement with R10 in accuracy above the Finale Match but velocity and breech entry shaved the R10.
Accuracy (stock) is is about the same for both guns.
I think the finish of the metal work slightly favours the SIG...it looked almost blued as i took it out the box. It maybe anodised...hard to tell. The FAS more of a matt black paint job...looks nice, very similar to the finish on a Webley Tempest. So could be a baked on paint job best guess.
The barrel finish of the SIG is better finished at the breech...Chiappa must have listened to the FAS groans, or gone with a better barrel maker...The seal also stands further proud for a better seal...hence the 30 fps difference in velocity.
Internal mechanics are almost identical, sharing a similar cylinder and transfer port/valve bulkhead and TP diameter.
For me however, the FAS is the better gun...Have i gone nuts?...Well its been said but not this time..
The opening lever on the FAS is an overlooked key for me. It snicks open with a fluid motion which better suits the position of the hand when going to cock the top strap.Nudging it with your thumb and drawing the top strap up is one clean movement.
It must have been designed with the target shooter in mind. It isnt bettered on any SSP no matter what anyone says...its a lovely action with no hand shift. Not so the SIG. the thumb needs to move back and up over the top of its release hammer, almost crossing hands. You have to use both side by side to appreciate it but if you have not used the FAS, the SIG hammer will not bother you.
The FAS sits lower...even with the Ambi grip...but obviously the 3 other grip options give it even more capacity.
The FAS trigger once set up has the edge and the sight base is longer and neater, being inlet flush with the action.
The problem with the FAS is its barrel. Its breech is not correctly finished and needs popping on a lathe to touch the inner recess or following the method on here...Its an easy job for an engineer but could be daunting for someone without hand skills.
It also wants a phosphor bronze brush shoving through to knock off a couple of high spot burrs inside ...You need to use a 10x glass to see them but they are present....Alternatively use the method on here, using wet and dry paper.
Next the breech seal of the FAS sits in a groove which is a shade too deep. It needs a backing washer or a twirl of floss to the rear of the O ring to lift it up to prevent gas loss and prevent lower edge of the barrel nicking the bulkhead face below the transfer port..Which can occur when this shallow seal beds in.The SIG groove is 0.3mm less shallow being just enough to not give rise to the same problem..
Once sorted the FAS velocity rises 30 fps and seals nicely without the metal of the barrel contacting the bulkhead face.
I use an O ring in place of the hard alloy barrel fixing washer ...it has a touch of give but keeps the barrel nudged up until the screws are tightened ...most throw out this alloy washer as in Stoffs post on here..but locking up the barrel can then be more of a guesstimate. With a prouder positioned seal, i still feel the positioning washer has its place!
Finally a piston pack of 0.3mm will give both guns a 30 fps shunt upto 400 fps territory if you want that.
In final conclusion, the SIG is almost like a MK2 version of the 6004, ironing out the little problems mentioned across this post but what it now needs is a Mk2 6004 because has the greater potential.
Last edited by clarky on Wed Jun 10, 2020 5:30 am, edited 1 time in total.
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deadeyedick
- Posts: 1177
- Joined: Thu Jan 24, 2008 5:55 pm
- Location: Australia
Re: Improve the FAS 6004
IMPROVE the FAS 6004 ?
Sell it ! .....or better still don’t buy it in the first place!
Would such an unfinished condition be accepted by the military ?
Chiappa should market them as “partly assembled and fine tuning left to the purchaser”
Sell it ! .....or better still don’t buy it in the first place!
Would such an unfinished condition be accepted by the military ?
Chiappa should market them as “partly assembled and fine tuning left to the purchaser”
Re: Improve the FAS 6004
Its a fine gun aside from this issue of the breech seal and an easy fix if you follow the advice on here.
I think this design error occurred when they went from the Nylon seal of the 604 model being modernised to suit a std off the shelf O ring. A good idea but the recess in the barrel needed altering to allow for the correct depth. O rings seal perfectly and extremely cheap. You can buy a pack of 10 from RS for pennies but O rings must have the squeeze allowance to not go flush with the end of the barrel once under lock up pressure, unlike the nylon seal which do not have inherent compression.
The problem with Rejecting a FAS 6004 because of these little foibles (at this price point) is everything else is not good enough.
The 46M is a fair contender, if you do not mind operating an agricultural farming implement and only if you can find one.
The HW40/P17 variants not in the same class and a long way from being good enough for casual match use. Maybe casual plinking targets across the club 10 meter range but not competitive shooting. The 75 and Gamo Compact give a bit more but I have destroyed both with a well set up FAS. Trust me.
You could look for secondhand FAS 604 versions, or an Air Match but both are now very scarce and the Air Match highly unreliable but unlike the 6004 breech issue, it is mechanical malfunction issues with the 600.
If you wish to move on twice the price...or more, you might find second hand PCP models, but there is a learning curve with power curves and the support kit.
Ultimately, I was only giving a comparison review. It is up to the individual to choose.
I think this design error occurred when they went from the Nylon seal of the 604 model being modernised to suit a std off the shelf O ring. A good idea but the recess in the barrel needed altering to allow for the correct depth. O rings seal perfectly and extremely cheap. You can buy a pack of 10 from RS for pennies but O rings must have the squeeze allowance to not go flush with the end of the barrel once under lock up pressure, unlike the nylon seal which do not have inherent compression.
The problem with Rejecting a FAS 6004 because of these little foibles (at this price point) is everything else is not good enough.
The 46M is a fair contender, if you do not mind operating an agricultural farming implement and only if you can find one.
The HW40/P17 variants not in the same class and a long way from being good enough for casual match use. Maybe casual plinking targets across the club 10 meter range but not competitive shooting. The 75 and Gamo Compact give a bit more but I have destroyed both with a well set up FAS. Trust me.
You could look for secondhand FAS 604 versions, or an Air Match but both are now very scarce and the Air Match highly unreliable but unlike the 6004 breech issue, it is mechanical malfunction issues with the 600.
If you wish to move on twice the price...or more, you might find second hand PCP models, but there is a learning curve with power curves and the support kit.
Ultimately, I was only giving a comparison review. It is up to the individual to choose.
Last edited by clarky on Wed Jun 10, 2020 5:10 am, edited 1 time in total.
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huckleberg
- Posts: 43
- Joined: Tue Jun 09, 2020 11:59 am
Re: Improve the FAS 6004
Just got a brand new one a few weeks ago, after only ~600 of the RWS 7gr pellets mine is right royally ditched out and in need of this repair.
Does anyone have a few extra of the McMaster parts mentioned? I will happily compensate. Otherwise I will order some and have plenty to offer others here (they are sold in multipacks only).
Does anyone have a few extra of the McMaster parts mentioned? I will happily compensate. Otherwise I will order some and have plenty to offer others here (they are sold in multipacks only).
Re: Improve the FAS 6004
Sadly no spares buddy but if do order ill buy some off you...im constantly being asked to perform said mods on them ..
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huckleberg
- Posts: 43
- Joined: Tue Jun 09, 2020 11:59 am
Re: Improve the FAS 6004
I ordered some should arrive soon.
Re: Improve the FAS 6004
I have taken some measurements for people having this problem with their 6004.
To prevent the breech face ditching into the transfer port bulkhead, you require to have 0.2mm to 0.3mm clearance to be safe.
You have to allow for that little bit of bedding in that comes with all guns from new but because the 6004 seal is so on the edge of things, i recommend this 0.2mm minimum clearance. Locking the barrel up with some feelers or the folded paper method shown on here will set this gap, then locking your barrel in place.
Once you have done this, only then would i start thinking about the seal.
Whichever seal you then use, be it an O ring, Nylon original from the 604, or rubber washer, It must sit proud beyond the breech face by 0.5mm. This is to take up the safety gap we have set up, plus 0.1 mm of squeeze to seal and perhaps 0.1mm for any error build up.
Floss is quite useful if you cannot make a backing washer. It is delicate but none compressive, meaning it will not alter under load.
So...Set barrel to 0.2mm gap to Bulkhead block...O ring to be 0.4 to 0.5mm proud of breech face.
Since doing this to club members guns, no one has had blow by and 100 percent reliability shooting at 370 fps with Finale or R10
The 30 to 35 fps from piston packing is more tricky and not recommended for the un-skilled.
To prevent the breech face ditching into the transfer port bulkhead, you require to have 0.2mm to 0.3mm clearance to be safe.
You have to allow for that little bit of bedding in that comes with all guns from new but because the 6004 seal is so on the edge of things, i recommend this 0.2mm minimum clearance. Locking the barrel up with some feelers or the folded paper method shown on here will set this gap, then locking your barrel in place.
Once you have done this, only then would i start thinking about the seal.
Whichever seal you then use, be it an O ring, Nylon original from the 604, or rubber washer, It must sit proud beyond the breech face by 0.5mm. This is to take up the safety gap we have set up, plus 0.1 mm of squeeze to seal and perhaps 0.1mm for any error build up.
Floss is quite useful if you cannot make a backing washer. It is delicate but none compressive, meaning it will not alter under load.
So...Set barrel to 0.2mm gap to Bulkhead block...O ring to be 0.4 to 0.5mm proud of breech face.
Since doing this to club members guns, no one has had blow by and 100 percent reliability shooting at 370 fps with Finale or R10
The 30 to 35 fps from piston packing is more tricky and not recommended for the un-skilled.
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huckleberg
- Posts: 43
- Joined: Tue Jun 09, 2020 11:59 am
Re: Improve the FAS 6004
I received the McMaster stuff in less than 24 hours. I did a basic version of the repair instructions, but the McMaster parts are notably smaller than the inlet on the barrel. I ended up cutting the shim with a razor blade to fit it in, and reusing the normal O-ring. That seems to have the desired effect for the most part. Will try again tonight to redo the repair based on the most recent post above.
OH, and I found some weird silicone grease lying around that I used on the breach face, seemed to help things. It's some weird thick milky-clear grease that I believe is designed for use on food-grade equipment, meaning there are no petroleum solvents in it. It think it came with one of our cooking appliances in the past.
OH, and I found some weird silicone grease lying around that I used on the breach face, seemed to help things. It's some weird thick milky-clear grease that I believe is designed for use on food-grade equipment, meaning there are no petroleum solvents in it. It think it came with one of our cooking appliances in the past.
Re: Improve the FAS 6004
The main thing is the shim so you should seal now. I also used the stock O ring but machined up a shim washer out of some alloy which looks very similar to the McMasters washer.
I would just put a smear of pellgun oil on the O ring to help lube it as it will not block the transfer port.
Good luck setting it up.
I would just put a smear of pellgun oil on the O ring to help lube it as it will not block the transfer port.
Good luck setting it up.
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huckleberg
- Posts: 43
- Joined: Tue Jun 09, 2020 11:59 am
Re: Improve the FAS 6004
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huckleberg
- Posts: 43
- Joined: Tue Jun 09, 2020 11:59 am
Re: Improve the FAS 6004
how's about something like this ... https://www.grainger.com/product/SUR-R- ... ing-55AA83
Re: Improve the FAS 6004
Yeah both useful ...the green worth a try.
Im working out of one of those selection boxes from Radio Spares (RS) ..its got the lot in it incl. main piston seal.
There is 20 of everything in the kit. Allows me to do club shooters Gamo Compacts and 75s etc..
Im working out of one of those selection boxes from Radio Spares (RS) ..its got the lot in it incl. main piston seal.
There is 20 of everything in the kit. Allows me to do club shooters Gamo Compacts and 75s etc..
Re: Improve the FAS 6004
Things have evolved a little and i now believe I have a final solution to these problems when taken together with Slofs breech refinishing and gap setting ( I do not want to steal any credit for that part)
Since my last post, I since ordered a set of Quad rings from RS..
These are square section O rings which seal all the way across the face...
Turned out to be much better than a regular O ring when sealing the FAS breech....all sorted. 100 % air tight gasket.
.....Further...I have also experimented by replacing the piston seal O ring with one of the Quad seals.
It allows the none skilled to add compression without machine work. The Quad seal sealing right on the front face, rather than 1mm back on the top dead centre of the O ring...Instant compression increase with no mechanical modifying required.
The quad seals recess also acts as a little lube trap...
I will feed back after a months testing of their durability before I jump up and down too much.
Since my last post, I since ordered a set of Quad rings from RS..
These are square section O rings which seal all the way across the face...
Turned out to be much better than a regular O ring when sealing the FAS breech....all sorted. 100 % air tight gasket.
.....Further...I have also experimented by replacing the piston seal O ring with one of the Quad seals.
It allows the none skilled to add compression without machine work. The Quad seal sealing right on the front face, rather than 1mm back on the top dead centre of the O ring...Instant compression increase with no mechanical modifying required.
The quad seals recess also acts as a little lube trap...
I will feed back after a months testing of their durability before I jump up and down too much.
Last edited by clarky on Wed Jun 24, 2020 9:54 am, edited 1 time in total.