Moderator Question

minktrapper

Can any of ye tell me what make this moderator is and what is the correct orientation of the baffles. Picture attached.

otmmyboy2

Can't tell what the make is, but from the construction I would hazard a guess it is a rimfire(.22 or .17) or airgun mod, and correct orientation of the baffles are cones pointing towards the bore of the firearm.

So final assembly should be:

Threaded cap for firearm muzzle -> spring(acting as a blast chamber essentially) -> baffles with the cone pointing towards the muzzle(like < based on the picture above).

This is obviously the way such mods are usually assembled(and I am not a gunsmith so should not be construed as an expert opinion), but given different manufacturers and specs and designs the only way to be absolutely sure it is assembled correctly is to check the manufacturer's specs.

There's the liability out of the way in case it does disintegrate 😉

minktrapper

How does it work? Is the spring there to push the baffles back to there original position after firing?

otmmyboy2

The spring works by both keeping the baffles in position and not moving around(either from movement or firing), and also providing tension against the endcap to keep the mod together and not constantly needing to be tightened, but also when the round initially goes off the blast from the muzzle will enter the area of the mod where the spring is and fill that area(the blast chamber) before progressing through the baffled part of the mod. The initial blast chamber basically makes the mod both quieter than entirely filling it with baffles, but also more robust because thin aluminium baffles being the first thing the muzzle blast hits would seriously shorten their lifespan and need to be replaced much sooner. A decently thick coiled spring is a much more effective absorber of that initial blast of pressure and heat.

At least, that is what the spring does in this design of mod.

garrettod

It's difficult to see from the photo, but is there a circular groove cut into it ?

If so, it may be an older Parker Hale.

minktrapper

Every baffle is a small chamber in its own right. The spring seems to push them all together therefore creating 6 smaller chambers for the projectile to pass through in quick succession. I must put it to the test over the next few days. Would it be too small for a .22WMR?

minktrapper

https://www.boards.ie/discussion/comment/121626658#Comment_121626658

No groove in it I'm afraid.

otmmyboy2

https://www.boards.ie/discussion/comment/121626659#Comment_121626659

Yup, each baffle creates a chamber for the gasses to expand into, but only the first, where the initial blast comes out of the barrel, is the blast chamber.

As far as too small, probably not, given the bullet diameters between 22lr and 22wmr are the same, but whether it can handle the increased pressure of a 22wmr vs a 22lr, possibly, but not for long. A lot of inexpensive rimfire mods will specifically warn against using magnum rimfire rounds due to the increased pressure which the mods are not designed to deal with.

There is only one way to find out for sure, but while it might work that is no guarantee it will continue to work, and not have the contents of the mod either deform internally and baffle strike(worst cast destroying the mod and potentially your threads on the barrel), or have sufficient overpressure to fire the internals of the mod out the front, as happened with my Atec Wave (manufacturing defect, probably).

minktrapper

Not too small as in bullet diameter but too small chambers. As in too much pressure being built up within the moderator.

otmmyboy2

I would say, based on the photo, yes, too small to safely contain the increased pressure compared to the 22lr.

otmmyboy2

If you do want to try it with a 22wmr then I would fire the firearm remotely(ie tied to something secure and pointing in a safe direction obviously), and after a single shot carefully inspecting the mod internals and the thread at the end of your firearm for any indications of problems/damage.

But I would honestly avoid trying it, not worth the potential for problems.

minktrapper

Definitely won't be trying it. No point in pushing the limits and potentially damaging hardware.

Grizzly 45

Looks like a "Chineseum" copy of a generic Air or .22 rifle can.

NO! Would deffo not be a good idea to try anything heavier cal than 22LR in this. Its volume is too small to contain anything bigger than a .22lr blast and the design of having the baffles close to the muzzle where there is the initial empty blast chamber in bigger cal designs would literally tear them apart or severely damage them after a few shots.

minktrapper

Think I bought it about 22 yrs ago.

civdef

A google image search comes up with this link with a very similar looking unit:

https://airgunforums.co.uk/threads/parker-hale-moderator.41963/

Parker Mods generally use stamped maxim type baffles rather than the cones in your picture though. Parker Hale used to be marked on the outside too.

minktrapper

Looks like it alright. Mine has an extra baffle though. And a shorter spring.

Would it actually make any difference which way the baffles were turned?

civdef

It does in theory as the cones are supposed to channel the expanding waves of gases, but I've never tried putting them backwards. It would probably be better than nothing anyway, though I doubt it would have the same effect?

There seems to be an awful lot of guesswork in designing baffles, apparently the expanding gases are very hard to model accurately even with decent (expensive) CFD packages.

I've messed around a good bit on 22lr with changing baffles / expansion chambers, clipping cones, K baffles, monocores etc - what surprised me was that a design that had a very simple monocore (but good volume) seems to outperform baffles that experts say should work better.

And then it's not even down to pure decibel reductions of sound pressure - the "tone" can make it sound quieter too.

minktrapper

The baffles are tight up against each other so do they open up when a bullet passes through them as the cones are facing the muzzle. Should the blast chamber be separated with a washer I wonder. Therefore creating two separate chambers (almost separate).

civdef

My gut feeling is it would work pretty well as-is, I presume the spring is holding things tightly enough that they arent rattling?

You might also notice the first shot sounds a bit louder than subsequent ones "first round pop". Large expansion chambers can do that - a bit of wd40 sprayed in on the spring might help a bit.