The E-3650 is indeed a good spring and a pretty good fit and drop-in if machining a fitted guide and tophat is not an option. It's also far superior to the Crosman spring in quality, composition and fit. Same with the seal. The Chinese replacement seal composition is the same and is no where near the quality of a good aftermarket seal such as the Apex or others. I would never replace Chinese parts in a gun with more Chinese parts unless there were no other option available including replacement seals and springs. And when it comes to those guns, I just don't tune them because I know that I'll not provide the customer with the results that I would expect. I've never understood why one or possibly two people continually suggest or even present it as an option other than perhaps cost but in my opinion, but that's not a good reason if it's worth the difference in improvement to the individual.
The Chinese seals that are used are a very inferior seal and not the least bit forgiving. As a parachute designed seal they are almost useless because of the material composition and because they are so hard, do not allow for even expansion. Because they are so hard, even under the high pressure they are subjected to, they still do not seal anywhere near as efficiently as a seal made of better materials. Also, they do not lube and provide equal distribution as a good seal does and are quite often the cause of excessive dieseling and/or detonation, are usually the cause of wide velocity deviation and inaccuracy and when that happens, hot spots are created on the seal making the seal even harder in those area thus perpetuating the problem even more. This is even more of a problem if the incorrect lubes are used.
Of course there is no comparison to my TurboTune and that’s not to be suggested but I have used some of the E-3650's for those that didn't want or could not forego the additional expense of the TurboTune. And the difference in the wire diameter and extra coil will have no impact in not being able to cock as long as the tophat height has not been increased. Gene and I did a number of side by side springs and guides fit checks and with all thing considered, it is a good alternative for those that home tune their gun. As a drop in, it doesn't resolve or make the gun perfect but sure is an improvement over the Crosman or Chinese parts hand down.
If you want to follow another’s suggestions and consider using what I would call inferior parts for tuning a gun rather than just "replacing a broken part", that's fine. But if you are going through the labors and "expense" of tuning your gun for improvement for accuracy, consistency, a better shooting cycle and planning on keeping it for awhile then to me it sure makes sense to at least put quality parts in it so that you can attain your expected results given your capabilities and access to tools. And it costs very little more to do it right. Just don’t let someone mislead you into using parts that will not accomplish for you what you expect. You may see some improvement but it’s not going to be what it’s capable of. If you want to simply replace a broken Chinese spring with another Chinese spring….fine… but if you are tuning your gun, give it some additional thought and make it really worth the effort.
