I just bought a ciener 22 conversion for my m16 and was wondering what the shortest barrel lenght I can use?  By "shortest," I mean how short can I get it without running into reliablity problems.  I'd like to cut it down to 3-4 inches - possible?

Thanks in advance

PBR

No reliability problems at all. You can dead nuts certain count on the ATF locking you up for a nice long vacation if you cut the barrel to that length.

If it's a registered receiver, sear or lightning link than you can go as short as you want. Shouldn't be any reliability issues since its blowback design.

Again, I'm going to use it on a RR M16 (the transferable kind) and thanks for the replys.

PBR

I am running one with a 6" Shilen barrel with a suppressor screwed on the end. the darn thing is quite accurate. seems to shoot best federal gold match ammo. it seems that .22 ammo with heavy lube (like most euro made ammo) does not funtion well. this ammo is also subsonic in this setup.

I run a 4" barrel with a can.I use CCI blazer ammo and it stays subsonic.It will also run with out the can.SJR556.

I also have a 4" bbl, and it'll run with subsonics and no can, but that took some tweaking to achieve.  I always recommend a lite lower spring set, as it absorbs less energy from the round to actuate.  This in turn allows the installation of a stiffer Lakeside bolt recoil spring, making round stripping and chambering MUCH more positive.

Consider three stages of mods...

Stage 1)  LIGHT polishing and burr/edge removal of bolt + rail.  DON'T polish down to shiny metal. leave some park which will retain lube.  Try 400 or 600 wet/dry paper for this task.

Stage 2) Replace hammer and disconnector spring in the lower with a Lakeside light spring set; add a Lakeside stiffer recoil spring.  You can cut the recoil spring down as necessary so the gun will actuate.  With a shortie bbl and subsonics, there wasn't enough ooomph with mine to overcome a full length of the Lakeside recoil spring, so I ended up cutting two loops at a time until the gun ran with SS ammo.  At that point, anything more potent will also run the gun.  A can improves the functioning, so do this can-off.

Stage 3) For frequent FA bolt bounce, I had to install a ball and spring detent anti-bounce mechanism.  The ball + the standard weight cured  BB forever, but this is a machining mod and not something that can be easily done well with hand tools.

Good luck.  .22LR is by far my favorite round for FA, and I dream about my soon-to-be-delivered LM7!!

Thanks for the great info guys.  I'm pretty sure I'll go with the 4" barrel and "tune" as needed (thanks for the detailed info Gorilla).  BTW, I'm waiting for an LM7 also - it looks like it shouldn't be too much longer judging from Eric's posts on the lakside forum.  That thing is gonna be awesome!

Thanks again,
PBR