I posted this elsewhere tonight, but I figure I had better post it here at this thread as well. I hope the info is helpful.
I finally just got my package of CE2 R4 cartomizers from Vapor Junction. Nicely packaged for what it is worth, but for the life of me I don't understand why so many of our suppliers use such over-sized boxes for such small shipments. Oh well, whatever, the shipping method works. I was eager to start using these things right away, and am using my first one right now. I've had little experience when it comes to using cartomizers before, so keep that in mind when you read the rest of this post.
Filling the thing using the standard method wasn't all that hard, but it does help to have read dozens of posts on the subject here at ECF before attempting to do so (including this thread right here). Luckily I had a small syringe for the job I got for free months ago from an Intellicig e-liquid order. I'm not sure using one of my other larger syringes would have worked at all with the one little flexible tip you get with your cartomizer order from Vapor Junction. After using the vaporizer for a short period of time I tried topping the device off and reassembling the device per Adik Ted's recommendation. I used a small paperclip with one end slightly bent and curved by a small pair of pliers. Turned out to be not that difficult to get the 3rd (innermost) ring out. It is semi-clear, and fairly flexible, but it is in the tube pretty tight. Care has to be taken so as not to damage the ceramic cup assembly, so I used only a very small but sharp curve on the end of the paperclip to achieve the task. Momentarily I was worried, but it ended up popping out without too much trouble. You just have to be carefully at what angle you are leveraging the paperclip. (You will have to leverage it using the cartomizer tube outer wall.) I used a vinyl coated paperclip, which I then cut the vinyl coating off of at just the very tip where I then bent it to use as a hook. Having the vinyl coated portion of the paperclip intact where it made contact against the cartomizer's outer wall probably helped keep the paperclip from sliding around and doing unwanted damage. The hook in the paperclip only has to be a very few millimeters in length to be effective.
Now that I've topped off and have reassembled the cartomizer, using only the reversed 3rd inner ring and the white end plug piece (with the 2nd inner ring completely removed from the assembly), I am now trying to figure out if I like these things or not. Right now it is hard to say. The vapor volume production and flavor delivery don't seem much different from a standard atomizer/cartridge arrangement. My one much older m402 battery isn't really performing as well as it used to, so I switched to my slightly newer battery (still waiting on a new battery set delivery from LiteCigUSA). It is still hard to say if either one is any better than the other as far as basic performance goes. I fully expect the cartomizer to keep going a lot longer without having to be switched out or refilled, and that is the biggest overall difference so far.
Flavor taste seems a bit different, though I can't put my finger on the exact difference. I think the cartomizer delivers more throat hit, but I can only distinctively feel the difference in my nose, not my throat so much. Leakage has not been a problem at all so far, in either the 2 or 3 ring configuration. I will probably get more out of these cartomizers when I get my m402 batteries that don't have the automatic cutoff feature many people find annoying.
A fully assembled m402 with the cartomizer attached is only about 1mm longer than a standard cartridge/atomizer setup on an m402, maybe even less. The stainless steel finish on the cartomizer very nearly matches the one on the stainless steel battery I currently have, which makes for a very non-analog cigarette looking package. The look of using the stainless steel finished cartomizer on my black m402 battery actually looks alright. I kind of even like it. Oh well, too late to order black batteries instead of stainless steel right now. I'll have to try these cartomizers out for much longer than the last hour or two I've been using one if I'm going to be giving an honest opinion on them. The big thing will probably be how much vaping I get out of one before it has to be refilled. This one I'm using now I filled with liquid all the way up to the top of the inner ceramic cup that holds the atomizer coil. I still needed a fairly small syringe head to do that, but I didn't need the tiny flexible one that came with my cartomizer 5-pack. I could've probably dripped too, but with the cartomizer at an angle. I don't think I would have not gotten quite as much e-liquid in that way, but I may just need practice.
As a side note, I also got my 12mg Halo Torque56 today, but have not tried it with the new cartomizers yet. Instead, I'm using it with a 3-piece m601 I don't use much these days, mainly because it is a ridiculously oversensitive automatic. It does produce good vapor though, just not particularly incredible taste. I like the Halo Torque56. Previously I had tried a small 18mg sample size of it many months ago. At the time I thought it was overpowering, but that it had potential. I have always wanted to try it in a lower nicotine level. Apparently the lower nicotine level helps. Unlike Halo's Freedom e-juice, which is perhaps more sweet by comparison, the Torque56 is a bit more nutty in flavor, and also more tobacco-like overall. It is still a bit sweet, as a tobacco flavor probably should be, but the nuances are different. It also has more woody flavor components, and I think it is maybe a bit less chemical-like in flavor than the Freedom e-juice, even without steeping.
Anyway, that's more than enough for now. I'll get back to you folks later.