I don't believe Scripture supports your view 'that you can loose your salvation'... there's too many verse that says you can't and this one in particular seal the thinking on this, at least on my part:
1 John 2:19 (KJV)
[19] They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us.
If you are in fact God's you will remain God's... but if you are not then you will depart from those of God... seems pretty simple.
John here could simply be saying that 'they would no doubt have continued with us', to mean that they wouldn't have gone out. I don't see here that John is talking about salvation, he is talking about fellowship. But perhaps you are right.
2 Peter 2:20
For if, after they have escaped the defilements of the world through the knowledge of our Lord and Savior Jesus Christ, they are again entangled in them and overcome, the last state has become worse for them than the first.
Here it is very clear, the people were saved - they escaped the defilements of the world through the knowledge of our Lord and Saviour.
Then they lost their salvation - the are again entangled in them (the defilements of the world).
And further, their state becomes worse than if they had never been saved in the first place.
It seems to me this verse cannot be interpreted in anyway but people loosing their salvation.
Hebrews 6:4ff
For it is impossible, in the case of those who have once been enlightened, who have tasted the heavenly gift, and have shared in the Holy Spirit,
5and have tasted the goodness of the word of God and the powers of the age to come,
6and then have fallen away, to restore them again to repentance
Again very clear, undoubtedly speaking of people who were saved - been enlightened ... tasted the heavenly gift ... shared in the Holy Spirit ...
They loose their salvation - and they have fallen away
Again their state becomes worse than originally - it is impossible to restore them to repentance.
Again this verse seems impossible to interpret any other way than that these people lost their salvation
If 1 John 2:19 is the best you can come up with supporting your view, then it seems to me that your view has less biblical support than mine. Both versus I provides use significantly stronger language and provide a significantly more definite picture of believers who have fallen away, than your verse does, where it might suggest that believers will continue with us. Actually I must admit that there are a few verses in the Gospels where Jesus speaks of not loosing any of those that the father gave him, which seems to strongly support your view that believers can't loose their salvation. I'm not sure on some of those, I haven't really looked into them close enough, but I do think that Jesus might be talking about the disciples, rather than all of Christendom throughout the ages.