New barrel for my Sten

Don't bother. The Sten already has better accuracy at decent range than a lot of AEG's. If it ain't broke...

Don't bother. The Sten already has better accuracy at decent range than a lot of AEG's. If it ain't broke...

Thanks but I'd still like to know !

The effect you are worried about won't happen with the sten ,you could go up to 450mm if you wanted without power loss.basically some of the cylinders that the piston live in have a port in the side part way down ,for shorter barrel guns this port allows air in and also allows the piston to accelerate without compression for a little way ,however it reduces the volume of air that the piston pushes up the barrel ,if the volume of air in the barrel is less than the cylinder the BB will stop being pushed before it leaves the barrel .the sten has no port in the cylinder so this effect does not happen.

Thanks Dadio! That somehow makes sense to me.
I wonder If there are people on this forum who tried putting a longer barrel in the Sten ?
If I could trouble you with one more question, some chap the other day told me that longer barrels dont neceseraly mean better accuracy as the longer the barrel the more chance the BB has to hit the walls and start to stutter. Is there truth in this? Considering the speed of the BB I thought this should only be a problem with the longest of barrels no?

You could start argument's on some forum's with that question the problem really is with tight bore barrels, some go down as low as 6.01mm but you need to clean the BB's and use only the best for that kind of barrel ,generally 6.03 to 6.04 is regarded as the best bore but some even recommend up to 6.08 stock TM bore as best ,length is an arguable point as well , the BB should float down the barrel cushioned on all sides by air escaping aground it ,once the BB is stable in the barrel then theoretically the barrels job is done and additional length is meaningless ,general rule of thumb 370 to 470 mm is all you ever really need ,my most accurate gun is my sterling and that's only about 300 mm barrel .

Must be a helluva sight to see you tromping around the field with a barrel of that length.
Thanks a lot Dadio, you've been a great help.

The reason why the sten is so accurate is the stability of the hop ,its very well fixed in place and suffer's no movement , on a lot of guns the hop is held to the gearbox by a spring and can move a bit backward and forward and usually a little wobble sideways as well ,any movement in the hop is magnified by the length of the barrel causing poor accuracy ,It's lazy engineering as it allows a lot of tolerance ,to build a fixed in position hop like the sten takes far more accuracy in manufacture.ha ha typo

But isn't the hop unit on the Sten also pushed against the gearbox with a spring? Or am I understanding you wrong? Or do they differ in versions.

That picture is not an Agm sten ,looks like a real one converted to airsoft .no there is no spring on the agm sten hop its just very well placed and supported.

On a related note: Has anyone else gotten a different brand of hop-up rubber in their Sten? My hop-up-chamber is so tight that everything else other than the stock rubber just peels of the barrel.

To get a new hop rubber on mine I simply had to use a lot of silicon oil, Teflon tape and patience.

Yup , keep the rubber dry on the barrel but lubed on the outside so it slides into the hop , if they are fitted dry its very difficult and can be very hard to remove at a later date ,if you have no silicone lube then washing up liquid is next best ,never use a mineral oil or wd40 as that will rot the hop rubber or tern it to jelly .the sten hop rubber is a normal type , nothing special about it .

Tried it now about 20 times. The rubber keeps rolling over the end of the barrel because the unit is so damn tight. There also seems to be a small ridge right on the inside, right after the C-clip's hole.

Its not a mad bull blue rubber is it ? They are thicker as they are designed for mad bull barrels that are not as large on outside diameter so the rubber is thicker .the other thing that helps is to gently twist as you push .I take it there's not a brass collar stuck in there , a lot of hop rubbers come with a brass collar that slips over the barrel and into the end of the hop behind the C clip to stabilize the barrel , if one of those has got in there somehow it would cause your problem.

No brass collar. Madbull barrel and madbull blue rubber. Would not fit