Subs through a Semi-Auto 22LR

[safetyfirst]

That's odd triffid, I had a 10/22 which had an almost permanent Parker hale on it and had thousands of trouble free rounds.

As they are blowback operated, would a suppressor not increase rearward pressure and bolt travel?

[ovenpaa]

Sounds about right, so do you keep shooting the dirty mod or use the clean one with different ammo?

I have tried two mods, the original one is so gummed up I suspect I would need a chisel to strip it and it cycles subs perfectly. The replacement is clean and easily stripped however it does not reliably cycle the same subsonic ammunition. Both cycle mini mags without issues.

[dromia]

If it isn't broke why fix/change it?

[Hunter87]

This won't work in my 15-22.

Mark

I hope that's not God damed halal

[ovenpaa]

If it isn't broke why fix/change it?

You are quite right and the original will be going back on for the next round of testing.

[Landy Dave]

I've had no particular problem putting sub-sonic ammo through various semi-autos - I think that normal 'target' ammo is sub-sonic to avoid stability issues around the sound barrier.

However I have had many problems using silencers on semi-auto's. There are two issues I think: firstly a reduced recoil impulse to operate the mechanism and secondly back-flushing of the exhaust gasses into the mechanism which builds up the crud very quickly. This is particularly noticeable on 10-22 magazines, which fail to operate very quickly if I'm using silencer.

Triffid

I get the same problem with my 10/22 with a SAK mod.

Which model do you use?

As per ammo my 10/22 has never been fussy, its just much more accurate with Eley ammo.

[Triffid]

I had no feeding problems with my 10-22 until I took it hunting. Admittedly I hadn't cleaned the rifle or magazine much before, but the first time I fitted it with a silencer (an old P-H), it didn't get through three magazines before they jammed up solid. Since then I've use it with a SAK silencer, with the same effect. The amount of cr@p that comes out of the mags when I clean them after using silencer is amazing, like half the Sahara in there. Perhaps it's just the cheap ammo I use ! Without a silencer there's no problems.

I think silencers work by slowing the gases down and letting them expand in a controlled manner (within the tube). Most recoil from a gun comes not from the bullet being accelerated down the barrel, but from the hot gases being released after the bullet has left the barrel, just like a rocket. So if the gases are slowed, there is less recoil to operate the blow-back mechanism.

Triffid

[safetyfirst]

I'm really confused about the differences between recoil operated, inertia operated and blowback operated actions here and I don't think I'm the only one, what's more I think two of them arête same thing.

Could someone with a beard and sandals step in and help us all out?

:)

[safetyfirst]

I'm really confused about the differences between recoil operated, inertia operated and blowback operated actions here and I don't think I'm the only one, what's more I think two of them arête same thing.

Could someone with a beard and sandals step in and help us all out?

:)

Nobody wants to correct anything here?

Amazing.

[Triffid]

I haven't got either a beard nor sandals, so I'm probably wrong, but:

There are two types of mechanisms that make semi-auto (and fully-auto) firearms operate, recoil and gas. In every case though, one of the most important things is to ensure that the bullet has left the barrel and therefore pressure in the barrel has dropped, BEFORE the bolt opens. Otherwise bad things happen to the person holding the gun.

For low-pressure rounds like .22LR, the weight of the bolt and it's spring pressure are enough to keep the bolt closed until the bullet has left the barrel. These are called blowback mechanisms.
For higher pressure round like 9mm /.45 etc, there must be some mechanism to lock the bolt and barrel together initially, until pressure in the barrel has dropped. These are commonly the swinging link in 1911-type pistols or Luger's toggle mechanism. Often I think these are called the recoil mechanisms and the firearms are recoil operated.
There are also those guns designed to be fired from an open bolt (eg Stirling & Sten guns). They operate by blowback, but the cartridge is fired before the bolt is fully home and the necessary delay given by the inertia of the bolt - this is advanced ignition.

Gas operation is more often used in rifle calibers - I guess because there needs to be even more control of when the bolt/barrel become unlocked. There is a gas-port drilled into the barrel part way up and high-pressure gasses are ducted off to operate on a piston, which unlocks and operates the bolt. eg AK47's, FN-FAL and M16's. Just like the pistol recoil mechanisms, there are variations on the design.

Triffid