Has anyone made a moderated shotgun?

[njc110381]

I've been looking at my moderated .410 recently and have been thinking that it really wouldn't be hard to make the parts and drill the barrels to make a 12g version? Has anyone done this? I can source a single barrel 20g or 12g easily enough and drilling it isn't going to be hard.

 

Anyone got any pictures of examples they've created?!

[chrispti]

I have not, but I know a man who did a 12g Benelli semi auto, and it works very well

 

Cant offer any more info Im afraid

[sitsinhedges]

AFAIK, you can make one only for yourself as it will be out of proof when drilled and unsaleable because of this. You need to be an RFD to do any such work for anyone else. The beauty is that you can tailor one to your own needs, maybe a slimmer tube or a more suitable donor gun etc.

 

It is my belief that 20gauge is the way to go and if you already have a modded .410 then you have some idea of the drilling req'd. A milling machine is best for accurate hole placement

 

Just make sure you consider the safety implications of what you are doing. A modded 20g is a marvellous tool

[njc110381]

I was thinking I could proof it myself after making it by firing the biggest cartridge the gun is chambered for whilst wedging it in a tyre and pulling on a string! As always with these things the risk falls on my shoulders but I do feel that as the custom makers simply drill holes in the barrel, me doing the same is not going to be any different structurally.

 

I have found a great 20g for under £100. That would do nicely. I will continue to check guntrader too though - buying one would be much easier!

[sitsinhedges]

I was thinking I could proof it myself after making it by firing the biggest cartridge the gun is chambered for whilst wedging it in a tyre and pulling on a string! As always with these things the risk falls on my shoulders but I do feel that as the custom makers simply drill holes in the barrel, me doing the same is not going to be any different structurally.

 

I have found a great 20g for under £100. That would do nicely. I will continue to check guntrader too though - buying one would be much easier!

 

Unless you have access to machine tools and the ability to use them it might not be cost effective to modify your own gun.

 

Interesting stuff on this site http://www.silencertalk.com/forum/viewforum.php?f=10&sid=f381428a1d2231d2927460553d2c199f

Edited December 26, 2010 by sitsinhedges

[Hornet 6]

I did it to a Greener GP years ago, started the drilling about 10 inches in front of the chamber, worked ok.

The front and rear collars were threaded in place, tightening the front one is what held the tube tight.

Never did get it proofed, but as I used a 'spare' barrel I just cut it up when I had no further use for it.

 

Neil.

[njc110381]

That was my thought. Pick up a cheap single barrel (preferably) 20 bore and have a go. If I **** it up I'll just chuck it in at the RFD and he can dispose of it.

[HDAV]

I was thinking I could proof it myself after making it by firing the biggest cartridge the gun is chambered for whilst wedging it in a tyre and pulling on a string! As always with these things the risk falls on my shoulders but I do feel that as the custom makers simply drill holes in the barrel, me doing the same is not going to be any different structurally.

You can do it to your own gun but if you ever wanted to sell it you would need to send it to a proof house for proof working on the basis of a cheap moderated gun once tried it you be for the scrapper anyway.its not so much making one, as making a queit one... how quiet does it need to be? a single 20b with subsonic shells is pretty quiet

[activeviii]

NJC... if you do find a 20 O/U hush then please do shout me as im after one still

 

or if you find a way of threading the ends of seamless pipe then get me one done as well for my 20g. i want to have a look at your 410 and take a drawing for my own use.

 

Phil.

[sitsinhedges]

You can do it to your own gun but if you ever wanted to sell it you would need to send it to a proof house for proof working on the basis of a cheap moderated gun once tried it you be for the scrapper anyway.its not so much making one, as making a queit one... how quiet does it need to be? a single 20b with subsonic shells is pretty quiet

 

I don't think you could send it to the proof house because if you went on to sell a gun that you had converted you would effectively be doing the work of an RFD without the relevant licence. Just accept it will be a scrapper when you've done with it, IMO.

 

FWIW, a fully modded 20g is very good if done well, far far better than a standard gun just using subsonic cartridges, but like reloading making one is not cost effective if your time is valuable but it is very interesting. You want a Pedretti type single as the platform so the tube will reach right back to the breech with the fore-end removed

[njc110381]

NJC... if you do find a 20 O/U hush then please do shout me as im after one still

 

or if you find a way of threading the ends of seamless pipe then get me one done as well for my 20g. i want to have a look at your 410 and take a drawing for my own use.

 

Phil.

 

I'm thinking you wouldn't have to thread it. What's wrong with O rings and self tapping screws?!

 

EDIT... And I know a really helpful fella with a lathe who could help make up the bushings!

Edited December 26, 2010 by njc110381

[sitsinhedges]

NJC... if you do find a 20 O/U hush then please do shout me as im after one still

 

or if you find a way of threading the ends of seamless pipe then get me one done as well for my 20g. i want to have a look at your 410 and take a drawing for my own use.

 

Phil.

 

You want standard 16gauge ally tube, nothing special. If it's good enough for shop bought Hushpowers its good enough for...

[njc110381]

Does anyone have a 12g hushpower they could measure for me? I need to know the pipe diameter. Thanks to anyone who can help.

[sitsinhedges]

Does anyone have a 12g hushpower they could measure for me? I need to know the pipe diameter. Thanks to anyone who can help.

 

A 12g Hushpower has a 50mm tube, you might just find that a 20g does nicely with a 38mm one just the same as your .410

[njc110381]

A 12g Hushpower has a 50mm tube, you might just find that a 20g does nicely with a 38mm one just the same as your .410

 

Cheers for that, much appreciated! I think there's a very good chance it will be 12g, simply because I've found one just down the road for £30. I have no idea of the choke or barrel length but something tells me it's not going to be 24" and full! I'll just cut it off and have no choke - I can't see as you need it for hide use anyway?

[sitsinhedges]

Cheers for that, much appreciated! I think there's a very good chance it will be 12g, simply because I've found one just down the road for £30. I have no idea of the choke or barrel length but something tells me it's not going to be 24" and full! I'll just cut it off and have no choke - I can't see as you need it for hide use anyway?

 

 

The choke also helps the shot get thru the baffles without destroying them. There is a guide on the silencer forum IIRC, that uses a 3" tube and nothing forwards of the muzzle, just a ported barrel which is quite simple to build. There is a chap on the silencer forum called JacksonBrown who should be able to forward details.

[njc110381]

I wondered if it could be an option to put quite a lot of ports in the barrel at the end and keep it at 30"? I'm thinking 2" tube would be a good place to start and I could drill holes in the barrel one by one until I reach a noise level that's acceptable?! I really don't know but for under £50 I'll just hack it about until it either works or falls to bits.

Edited December 26, 2010 by njc110381

[Hornet 6]

I started with 10 cross holes, but ended up with 14 so 28 in total (1" centres), started with 2 inch tube, but also tried 1 1/2 and 3 inch, ended up with 1 1/2"

If I was doing it again I would use 2 inch but off set downwards so the sight line is as low as possible, I would probably use carbon tube as well.

 

Neil.

[sitsinhedges]

I started with 10 cross holes, but ended up with 14 so 28 in total (1" centres), started with 2 inch tube, but also tried 1 1/2 and 3 inch, ended up with 1 1/2"

If I was doing it again I would use 2 inch but off set downwards so the sight line is as low as possible, I would probably use carbon tube as well.

 

Neil.

 

 

I considered both of those options but the things that deterred me were the alignment of the close fitting baffles, centre of a circle is easy, and the fact that you cant thread carbon fibre, you have to bond stuff to it instead AFAIK.

[njc110381]

That's a good point about the alignment of the baffles. I too was thinking about offsetting the bushings to hold the mod lower on the gun. I think I'll start off like that as I will only need a front and rear bushing if the porting idea works, but if I have to cut it shorter and go with baffles too maybe going for a central hole may be better. The bushings are the easy bit so if I have to make them twice it's not the end of the world.

 

I've got a gun sussed and some 2" tube. All I have to figure out now is what to make the bushings with and perhaps some baffles. I'm thinking some sort of hard plastic for the bushings, not sure about the baffles yet but something hard seems sensible in case they get hit by pellets!

[Hornet 6]

I considered both of those options but the things that deterred me were the alignment of the close fitting baffles, centre of a circle is easy, and the fact that you cant thread carbon fibre, you have to bond stuff to it instead AFAIK.

 

The alignment is easy, two discs with shoulders to suit the tube, and bored to fit the barrel, the rear one being made to lock on the taper of the barrel.

No thread needed on the tube, just a nut on the front to hold the front disc in place which compresses the tube.

Not sure what baffles you mean, mine was modelled on an original hushpower which is just a barrel length tube, empty of any baffles.

My home made off set one actually had a layer of glass matt packing, the stuff you buy to re wrap the exhaust baffles on 2 stroke engines.

 

Neil.

[njc110381]

Ah, mine's different to that then. On mine it has a rear threaded bush and a front bush on the barrel, but the tube is 7" longer than the length of barrel after the rear bush. Inside that extra 7" there are very basic baffles. From what I can make of it (they're fixed in so I shoved something up it to feel about a bit) they seem to be concave on both faces to make up little round chambers for the gas to swirl around in.

 

To hear that yours doesn't have this is very interesting as that would have been the hardest part to build. It also would have meant that I would either have to chop the barrel and lose the choke or have a modded length of 37"!

[HDAV]

Have a look at how they do the porting of trap gun barrels, I don't know slot about this sort of thing but if the outer tube almost rested on to top of the original barrel and you potted the sides and bottom of the barrel you could maintain the sight plain of the original rib. Using plas wad carts should prevent shot escaping into the baffles as would using holes smaller than shot sizes used, no6?

[sitsinhedges]

Have a look at how they do the porting of trap gun barrels, I don't know slot about this sort of thing but if the outer tube almost rested on to top of the original barrel and you potted the sides and bottom of the barrel you could maintain the sight plain of the original rib. Using plas wad carts should prevent shot escaping into the baffles as would using holes smaller than shot sizes used, no6?

 

 

Shot doesn't escape into the porting, the only real effect if you use plastic wads or a plastic obturator is that the pressure pushing forwards forces the back cup of the wad hard gainst the barrel walls and has the same effect as a cheese grater when it passes the ports. You get tiny slithers of plastic inside the gas tube. No problem you just empty it now and again. Obviously wads with petals are to be avoided going thru the baffles forward of the barrel in case they stick and cause an obstruction to the next shot.

[stubby]

Ah, mine's different to that then. On mine it has a rear threaded bush and a front bush on the barrel, but the tube is 7" longer than the length of barrel after the rear bush. Inside that extra 7" there are very basic baffles. From what I can make of it (they're fixed in so I shoved something up it to feel about a bit) they seem to be concave on both faces to make up little round chambers for the gas to swirl around in.

 

To hear that yours doesn't have this is very interesting as that would have been the hardest part to build. It also would have meant that I would either have to chop the barrel and lose the choke or have a modded length of 37"!

 

my 410 hushpower, has the internal plates too, but the one that holds the barrel in line with the centre holes came adrift, and when looking down the barrel from the front, you could see the barrel was offset, meaning you was always off when trying to shoot, I simply took the washer that had come adrift, and use the smallest jubilee clip I could find, pushed the baffle onto the end of barrel, then jubilee clip, holds everything in place and straight, sorted