I have an Outback II I was wondering if the IOU upgrade from Gemtech was worth it or if there was some other upgrade that might better.

Have done it twice and would again. Audibly not better to the ear but, for cleaning it was for me. Especially if you silicone treat your mono core.

Absolutely, I love mine.

I have the Gm-22 along with several of the top rimfire cans out there right now. I ordered the Gm-22 for specialty use on several ultra-light rimfire rifles I own. The 2.5oz weight is nuts and 5" length is great when you need a can that you forget is even attached at times weight wise.

On a rifle the Gm-22 is awesome,as quiet as any other top end can I have and the tone is very nice with gemtechs monocore design. I honestly really, really like the tone/sound of the GM-22 on a rifle and to my surprise I use it much more than I though I would having several other great cans. It's became a favorite of mine with my PWS Summit/10/22's/AR-22 using the Tac-sol SB-X lite-weight barrel setups. The Gm-22 performance on my rifles made me order a Mist integral also.

 Pistol wise like most folks with Internet and YouTube I knew the Gm-22 had FRP on pistols so really hadn't planned to use it on my pistols. I already had a great performing pistol can in the Element II also short and 4oz lite weight very nice match on handguns. Soon after getting the GM-22 I figured out a dash of white lithium grease or few drops gun oil in the Gm-22 holly cow it sound great wiping out most all the FRP. I now kind of perfer it on my pistols with the element II because they are both lite-weight, short at 5" and 1" diameter.

I have also found the Gm-22 pretty easy to clean and very easy to shoot "wet" because it lighting unscrews fast to add grease/water/oil to the stack. In fact I shoot it wet 90% of the time out hunting so it's crazy quiet on my hunting rifles. I normally have no issues getting follow up shots at game whe shooting the Gm-22 on a locked breech rifle. The quiet,low tone of first shot going off seems to confuse any other game close by long enough for me to reload and get a second or third shot off.

Yesterday morning I was a couple minutes from starting a 14 hour shift so didn't get to really elaborate on just how worth it I thought the upgrade was.  I had an original sealed Outback 2 purchased in late 2006 (took possession January 2007) as my first silencer.  I loved that thing with thousands and thousands of rounds.  I didn't really keep track exactly how much went through it but it was, conservatively, north of 6,000 rounds (~80% rifle).  It was never cleaned using any sort of soak.  Around 2010 it became sufficiently loud that I stopped using it entirely so it sat in a box in my safe.  My AAC Prodigy effectively became my only rimfire can for several years.  I missed out on the original upgrade program they offered where you could pick your own baffle material, glad I did as this latest upgrade turned out better IMHO.  As soon as the IOU program was offered I jumped on board because of all the new capabilities it conferred, most importantly the ability to service it by the owner.  The IOU upgrade also permitted me to use it on my then go-to rifle, a ruger 77/22 mag, and my M11/9 SMG w/ Lage 22 kit.  


Gemtech was nice enough to take this picture for me by request.  Several of those original K baffles are almost solid lead/carbon!!


My IOU upgraded Outback 2 sounds great on everything I've used it on so far, Ruger 10/22, Walther P22, and various rimfire ARs including a belt-fed Razorback.  I can hardly describe how much fun it is to shoot steel plates at 200 yd with a suppressed belt-fed 22 and iron sights  I may be less sensitive to FRP than others, but when shooting my IOU OB2 against my brother's Spectre 2 on P22s back to back, I could not tell much difference.  Neither could my brother or the third party observer listening from 10 yd away w/o knowledge of which was being fired when.  Of my hosts so far, the 22 mag bolt gun is probably the most impressive to me.  Out in the open, the combination is silly quiet compared to what I am used to the 22 mag sounding like.  Again, it sounds excellent on everything I've tried and is just stupid lightweight.  Taking it apart is super easy, but I always loosen and re-tighten the core after shooting due to experience with my AAC Prodigy.  Also, once you clue in to the fact that servicing the core doesn't mean it needs to be spotless, cleaning is easy too.  I pull out the core, knock it a few times on the work bench, brush out the bigger crap, brush out the tube, add a dab of grease to the internal threads, and reassemble.  Also, I would like to buy a beer for whoever it was at Gemtech that decided to integrate the 1/4" drive feature into the IOU/GM22 core.  For me, the $249 allowed me to transform what had become a government regulated paperweight back into a star performing multi-role user-serviceable silencer.  I have had zero problems with the core loosening from the tube which I read another user had experienced.  I have absolutely no complaints about this upgrade, if I had 10 more OB2s I would have upgraded them all and not batted an eye after seeing how effective it was.

ETA:  I believe someone from Gemtech also mentioned that, at that time (late 2014/ early 2015) the IOU core going into the upgrades was slightly quieter than the GM22.  I may have to look for that post but I am 95% certain.  That is also great

I had Gemtech do the IOU update on my old sealed AAC Pilot.  I was in the same boat as the poster above.  Old sealed can with thousands of rounds through it.  It was starting to get loud and I'm sure it had gained some weight.

What I got back from Gemtech exceeded my expectations.  The new core looked awesome and they did an excellent job of getting the "guts" out of my old tube.  Dr. Dater informed me that with my particular can I would have a little more FRP than usual as the Pilot is longer, hence a larger entry chamber.  As others have said on a rifle the FRP will S non-existent.  Pistol does have some pop.  For me, the upgrade was a no-brainer.  I was able to turn basically a worthless stamp into a brand new serviceable can with excellent performance.  I did have some issues with the core coming loose, but a little teflon tape on the core threads seems to have fixed that.  I've got five other 22 muzzle cans and three integrals so it does not get much range time now.  For about six months though it and an AAC Prodigy II were it and it went to the range every week or so.

Cleaning is a breeze, and no you don't have to get them spotless.  Haven't tried the lithium grease or gun oil trick but I will....

And thanks much Gemtech for making this upgrade available!

I sent my OBII in for the upgrade as well.  I like that I can clean the suppressor.  I felt like the money spent was worth it long term.

I also like that my OBII is now rated for 22 mag.  It appears that the OBII is full auto rated?

I would like to add that I started to silicone pre treat all of my cans especially my Gemtechs with a monocore. It cuts cleaning time down a substantial amount and I am able to clean the hard to reach angles with a boresnake. I buy silicone by the gallon on Amazon and worth every penny.
Here is the article Silicone






Just wipes down after range time

This reaffirms my current tap-on-the-bench cleaning method for mine.  My favorite thing about this can though, is you don't even notice the weight on whatever host you are using.

Had my outback redone within the last year.  I'm very happy with it, glad I finally sent it in for the upgrade.

Does anyone know what the current turn around time is on the upgrade?

I waited a while for the rush to die down.  I think mine was around 4 to 5 weeks.

absolutely love mine! :)