Would anyone have any photos or schematics for a factory standard FAC version (.20) MFR showing both barrel and shroud details, or perhaps photos?
I recently purchased mine from an elderly gentleman who had to sell it as it was too heavy for him and his wife to use anymore. When it arrived I noticed it has a reasonably heavy metal shroud (1" diameter), which is completely open at the end, extending a couple of inches past the end of the barrel within.
I'm thinking I could fit a thin wall aluminium shroud, to reduce the weight, and also the length as well to make it flush with the end of the barrel.
Any drawings, schematics or photos would be greatly appreciated, to give me a heads up of how the shroud is mounted and what is inside.
There is a grub screw on the top of the shroud, at the very rear just in front of the block, which seems to thread down into a bush mounted on the barrel. I'm thinking that is likely how I'm going to get it started.
Regards,
Trooper
The end cap is missing, which probably doesn't help.
Not sure how Aussie law stands on shroud/silencing.
http://www.hurwitt.me.uk/airgun/Technical/mfr_silencer/silencing_the_theoben_mfr.htm
Usual method sub-12 is to make new supports and replace the steel with carbon tube.
28x25 ..1.5mm wall?
Quote from: Squinty on May 12, 2023, 09:36:00 AMThe end cap is missing, which probably doesn't help.
Not sure how Aussie law stands on shroud/silencing.
http://www.hurwitt.me.uk/airgun/Technical/mfr_silencer/silencing_the_theoben_mfr.htm
Usual method sub-12 is to make new supports and replace the steel with carbon tube.
28x25 ..1.5mm wall?
Thanks Squinty. No silencers are permitted in Oz, which is likely why the end cap is missing as I expect that all the internals were removed prior to the shipment heading off from UK in 2005. So I won't be going down that route, however I hadn't thought about the carbon fibre. Something that is light and will support the barrel is ideal, and I expect that the carbon fibre could be even better than aluminium.
I'll do some research on finding some suitable size carbon fibre. I'm thinking anything from around 3/4" to the standard 1" of the original metal shroud. Smaller than 1" will also provide more clearance for the bottle.
Quote from: Trooper on May 12, 2023, 10:00:11 AMQuote from: Squinty on May 12, 2023, 09:36:00 AMThe end cap is missing, which probably doesn't help.
Not sure how Aussie law stands on shroud/silencing.
http://www.hurwitt.me.uk/airgun/Technical/mfr_silencer/silencing_the_theoben_mfr.htm
Usual method sub-12 is to make new supports and replace the steel with carbon tube.
28x25 ..1.5mm wall?
Thanks Squinty. No silencers are permitted in Oz, which is likely why the end cap is missing as I expect that all the internals were removed prior to the shipment heading off from UK in 2005. So I won't be going down that route, however I hadn't thought about the carbon fibre. Something that is light and will support the barrel is ideal, and I expect that the carbon fibre could be even better than aluminium.
I'll do some research on finding some suitable size carbon fibre. I'm thinking anything from around 3/4" to the standard 1" of the original metal shroud. Smaller than 1" will also provide more clearance for the bottle.
you could go down to 5/8" i/d providing you have a way to hold the tube on.
Does it still have the 'skinny' barrel or perhaps the full 5/8"-15.85mm o/d?
I'm not sure what the barrel size is inside at this stage. That's one of the reasons I thought I'd ask about the schematic or photos, just to get a handle on where to start pulling it down, although I suspect that the exercise will start with that drub screw on the top of the shroud, at the rear.
Hope this helps sorry about the pic quality, I see squinty has already passed on the hurwitt link.
Skinny barrel is 12mm, but std 16mm to fit in the block.
The block end shroud support can be either tapered like this or straight side like yours on later models.
There is also a factory shroud extension 135mm just hollow space, but the bore hole does act like a baffle & they help,
problem is they're rare as rocking horse poo, I've just made a mod for mine, thread is 24mm x 1mm pitch.
If even the shroud falls foul of your gun law, you might be better off with a std 16mm barrel, as the open shroud can act like a megaphone down range.
Thanks Gents. Greatly appreciated.
Kind regards,
Trooper
So, I've removed that grub screw which does indeed secure the shroud and rear shroud bush onto the 15.66mm barrel. However the rear shroud bush is bonded to the barrel so I'm guessing that the way to remove the shroud is to actually remove the barrel from the block and then slide the entire shroud rearwards over the breach port and off.
So when reassembling, is there anything 'tricky' to know about setting the barrel in position, or is it simply a matter of reinserting the barrel as far back as it will go and tighten. I did note what I believe to be a barrel locating grub screw under the front scope ring.
I also assume that this screw, with the arrow, is the actual barrel clamp.
Is there anything else I should know before getting into it?
barrel removal
https://rapidforum.co.uk/forum/index.php?topic=161.0
bolt/probe adjustment
set the barrel flush with the block and adjust the probe
https://rapidforum.co.uk/forum/index.php?topic=151.0
Thanks Mate. The more I see of this MFR, the more I like it.
If not already done so, the shroud should unscrew from the bush, it can however take both hands, full 10 white knuckles to move it :o
If you can remove it you'll be able to see what set up you have for shroud support at the muzzle, because the bush will not pass the std support.
Quote from: angrybear on May 13, 2023, 11:16:21 AMIf not already done so, the shroud should unscrew from the bush, it can however take both hands, full 10 white knuckles to move it :o
If you can remove it you'll be able to see what set up you have for shroud support at the muzzle, because the bush will not pass the std support.
Thanks Mate, I noted that the shroud, with the attached bush, wouldn't pass over the muzzle support, which is why I was thinking I'd have to remove the barrel first and then slide the shroud and attached bush/mount rearwards over the breach port end. I wasn't sure if the rear shroud bush/mount was threaded or soldered etc.
You should end up with something similar to this, bush, muzzle support, end cap & tube which is threaded both ends.
Hey guys some really and i mean really nice photo`s being uploaded lately in really good detail.
Very impressing guys, loving it. Just click on the thumbnail and its in very great detail.
;)
Quote from: angrybear on May 13, 2023, 03:26:17 PMYou should end up with something similar to this, bush, muzzle support, end cap & tube which is threaded both ends.
Thanks Mate, greatly appreciated. That does make it clearer as 'a picture says a thousand words'.
Would any of you learned Gurus on here know what the male thread is that screws into the rifle, out of the the standard 280cc bottle on the MFR? I don't seem to be able to include the photo.
It measures up as 13.15mm O/D with verniers but seems to have a pitch of 19TPI.
I'm thinking the 55 degree, 1/4" BSPF.
The valve seems to be crooked in the bottle. Because of that, when screwing the bottle in, the flat base (nearest the muzzle) wobbles all over the place like a drunken goat, and when it locks up, fully screwed in, the bottle presses against the barrel shroud.
So one solution I'm thinking of, and I'm definitely not that keen on it, is to to turn up a female bush out of normal bright, then while still mounted in the chuck, screw the bottle valve into it. Then with the lathe on 30-40 RPM it should confirm if it is in fact crooked. I could then put paper masking tape around the flat base of the bottle, then using the tail stock, gently slide a lead pencil towards the bottle until a mark appears on the paper tape, which will the direction of error.
Now here's the part where one would have to hold their breath and cross all fingers and toes.........when 'gently' nudging the bottle over with the hand until at least until it enough of the error has been removed that the bottle no longer touches the shroud when screwed fully in. But of course I'd then be concerned about damage to the valve or bottle itself. But on the reverse side of that coin, it can't be left to press against the shroud either.
it's 1/4" BSP, in downloads is thread size list.
TBH I'd think it more likely the shroud is out of line, a straight edge along the top of the block should pick that up,
but if you just roll the bottle on a flat surface your eye will spot if the valve is out of true.
Quote from: angrybear on May 21, 2023, 10:42:53 AMit's 1/4" BSP, in downloads is thread size list.
TBH I'd think it more likely the shroud is out of line, a straight edge along the top of the block should pick that up,
but if you just roll the bottle on a flat surface your eye will spot if the valve is out of true.
Thanks Mate. I actually did do both of those checks before posting and it is definitely the valve in the bottle. The shroud alignment on the barrel is perfect, and so is the barrel. I placed a 600mm Stabila level along the top of the block to confirm that with verniers.
I have two bottles and the second one doesn't wobble around when screwing in, and when it is fully screwed in, it doesn't touch the shroud at all.
Being a newbie, I am still trying to find my way around this forum and haven't stumbled across the download section until now. That's pure GOLD! Sincerely, THANK-YOU to everyone who has contributed to that resource.