Apart from the nib, what differences are there between the M200 and the M400 to justify the price difference?

If I replaced the nib with an M400 one, would I get an M400?

It is right the main difference between a m200 and m400 is the nib. 14k duocolor against a steel monocolor nib.
Besides that, the 200 has 1 gold ring at the piston knob. The m400 has 2. At the bottom of the cap the m200 has one gold ring saying "pelikan germany" in a simple engraving. The m400 has 2 rings with a more fat engraving saying " pelikan souverain germany".
And the last thing I can find comparing both pens is, above the clip, on top of the cap. The m200 have a black knob with the pelikan logo on it. With the m400 the top is still the same (black) but the ring under it is goldcolored.

Robert has pointed out the main differences, if you add an M400 nib to an M200, you actually get an M250 (I often swith 2 spare 14ct nibs between my M200s, one is currently sitting in a Red demo, the other in a Black O/S M200).

Andy

I think it worth noting that the 400s are typically "celluloid acetate" while the 200s are some other kind of less expensive plastic.

How do you know this?

Well, I don't know the price difference twixt the two - it may be minimal. I just have been told by numerous Pelikan collectors, repair folks, sellers, etc. that those stripes are celluloid. Not "true celluloid" (on modern pens) but "celluloid acetate" which I know little about in terms of chemical composition. I guess I'd say it's "common knowledge" among Pelikan "experts."

Is there a difference in the piston mechanisms between the M200 and M400?

Scott

It's also worth noting that modern M4xx's have a silly trim ring near the nib, whereas the M2xx series do not. This matters to some. Best,
David

Almost . The M250 has a plain 14k nib, whereas the M400 has a part rhodium "bi-colour" nib. Functionally they are the same, however.

One of my favourite Pelikan "combinations" is an old-style domed cap brown (tortoiseshell) striped M200 with an 18k pre-'97 M600 nib.

HTH,

Martin

I suppose a couple of my 200s may have been 250s to start with as the nibs are plain gold and were on two old style M200s I picked up very cheaply, I must admit I assumed they came from a similar vintage 400.

The Tortoise M200 must be quite rare, I didn't realise they existed until you mentioned a while back that you had one and I also saw them mentioned on a website.

Andy