Problem is the front of base piece still in the pistol is not radiused to allow the spring to slide over it.
Eventually the spring will bind against the sharp edge of the base piece, causing a malfunction.
Eventually may be a very long time though...
Would be interesting, take it to the range and see how long it works.
I would however advise against using for self-defense with this particular setup.
And in terms of press-checking, putting your hand that close to the muzzle can be a risky propositon.
Forward slide serrations allow one to grip the slide and pull back, without putting fingers near the muzzle. Anytime you have body parts forward of the muzzle, which a proper press check does... you open yourself up to being called "Lefty" or some such moniker.
I base the above comments, in regards to press-checks, on the training I have received as well as based on my experience at IDPA shoots, where a proper press check will get you DQed from the match. Based on those experiences I broke myself of the press check habit. YMMV.