.22 silencer baffle hole....

[rhyslightnin]

What's a good usable size hole to put in a baffle washer for a silencer on a .22 air rifle? Now obviously it needs to be bigger than a .22 pellet (5.5mm) so I was thinking 6mm would do it but I've never made one before so I thought I'd ask
Thanks all
Rhys

[Rickenbacker]

I think like 7 or 8mm

[max headroom]

ask nige if he is still on here.

[madcarlos]

I think like 7 or 8mm

Sure mine was 7.6mm .

[Rich]

The effectiveness of the silencer depends in large part on the expansion ratio, the inside diameter divided by the hole diameter. Every millimetre you add to the hole size reduces that ratio quite considerably.

However the practical limit is set by how accurately and precisely you can make all the parts and get them centred and held such that they won't move in service, and how well the silencer is fitted to the barrel. You need the bore axis and the silencer axis to be precisely in line, and this brings in another issue insofar as barrels don't always have the bore precisely on centre, but the silencer position is usually fixed by the barrel OD.

I've tried making silencers with a very tight fit but in practice I've found 7mm to be as close as can be achieved and have no risk of clipping. If it's a silencer you can take apart easily and you don't mind having to make some more baffles to replace the bent ones, try smaller to begin with.

[rhyslightnin]

The effectiveness of the silencer depends in large part on the expansion ratio, the inside diameter divided by the hole diameter. Every millimetre you add to the hole size reduces that ratio quite considerably.

However the practical limit is set by how accurately and precisely you can make all the parts and get them centred and held such that they won't move in service, and how well the silencer is fitted to the barrel. You need the bore axis and the silencer axis to be precisely in line, and this brings in another issue insofar as barrels don't always have the bore precisely on centre, but the silencer position is usually fixed by the barrel OD.

I've tried making silencers with a very tight fit but in practice I've found 7mm to be as close as can be achieved and have no risk of clipping. If it's a silencer you can take apart easily and you don't mind having to make some more baffles to replace the bent ones, try smaller to begin with.

Thanks, good post!
I'm making a primary baffle/stripper for my new R10 so I can utilise the space in a new shorter lightweight carbon shroud I'm going to make. I want to do it with a female 1/2 unf screw thread on the barrel end and a male 1/2 unf on the other (so I can fit a stubby silencer) with the baffle as part of the machined piece. This I'm hoping to drill from the side between the baffle plate and the female 1/2 unf twice at 90° to each other so the air will vent backwards up the carbon shroud hopefully swallowing most of the initial blast, allowing the short silencer to catch the rest.
As it's only 1 baffle probably solid aluminium, I'm hoping it will help keep the rifle short as itl be maybe 10mm from the muzzle but be effective too. I should be able to make it quite tight then just ream it out if it's too close..
What do you think?

[u.k.neil]

I always made mine 6.5 mm mate.


Neil

[clunge]

The further from the muzzle, the more that engineering/fit imperfections are likely to show up. So if you are being ultra anal (who, me?), make 'em a bit tighter nearer the muzzle and have a slightly bigger hole at the far end cap.

I recently bought a Weirauch moderator from here and found that it was even quieter than the usual ones. Fortunately I had it on my .177, for when I had it apart, I found the holes were only 5.5mm.

Someone had improved it, so it makes a brilliant .177 specific mod.

Holes on my .25 mods are between 7.2mm and 8mm.

[angrybear]

I'd give it a min of 0.5mm clearance all round so 6.5mm in .22.

[rhyslightnin]

6.5mm it is.. now all I need to do is find a machinist & find out if my barrel is threaded or not....

[TORNADOS7]

Fairly sure the ports on Weihrauch silencers are 7mm...

[rhyslightnin]

Thanks all!!!

[bucketboy]

The further from the muzzle, the more that engineering/fit imperfections are likely to show up. So if you are being ultra anal (who, me?), make 'em a bit tighter nearer the muzzle and have a slightly bigger hole at the far end cap.

I recently bought a Weirauch moderator from here and found that it was even quieter than the usual ones. Fortunately I had it on my .177, for when I had it apart, I found the holes were only 5.5mm.

Someone had improved it, so it makes a brilliant .177 specific mod.

Holes on my .25 mods are between 7.2mm and 8mm.

I make my own mods, typically I make the first baffle bore only .25mm bigger than the pellet, getting bigger towards the endcap which will be about 1.0mm bigger.

With a full length shroud that is supported at both ends, tolerances in the baffle bore can be as little as .25mm all the way to the endcap.

The problem is that each mod/shroud has to be made to fit only one barrel and it very time consuming but if you have the time and skill it is worth the effort.

[rhyslightnin]

I make my own mods, typically I make the first baffle bore only .25mm bigger than the pellet, getting bigger towards the endcap which will be about 1.0mm bigger.

With a full length shroud that is supported at both ends, tolerances in the baffle bore can be as little as .25mm all the way to the endcap.

The problem is that each mod/shroud has to be made to fit only one barrel and it very time consuming but if you have the time and skill it is worth the effort.

I only want to make one baffle which will hopefully screw onto the threaded barrel and have a unf on the other end for my hugger belita. I'm thinking of buying a length of carbon tube which will fit over the existing shroud adapter at the breech end and will stretch over the barrel and the shoulder of the baffle leaving the unf thread on the end for a muzzle break or silencer. This will mean that the first section of air expansion will be the whole shroud, then the next a STD silencer, I'm hoping it'll just help keep the barrel short by using a stubby silencer but also quiter than just using a STD stubby silencer...
If I can get the bit made (femail unf to stripper & baffle to male unf) then it'll only cos approximately £25 on top of the silencer & the the bit...
I don't see it being problematic as it's going to be so close to the muzzle..

[averageplinker]

Fairly sure the ports on Weihrauch silencers are 7mm...

The exit hole is a 7mm hex fit so you can use a 7mm allen key to open her up to clean or tinker.