Lee Factory Crimp Die to improve concentricity

I'm loading cast .38 Special 148g dewc and .45 ACP 200g swc's, both from tumble lube molds. I'm aiming towards increased concentricity and see that offered with, for example, the Redding Competition seating die. I'll probably go that route at some point in the future. I'd like to try the LFCrimp die expecting the sizing ring to iron out any bulges caused by the bullet not being seated with perfect concentricity within the case. 
Is that a realistic expectation or does the sizing correction only flatten that bit of bulging bullet with the rest remaining askew?

One precaution that people voice when asked about the Lee FCD is that it might size the bullet down - more a problem with lead - and this might be detrimental to accuracy.  I don't know if that has been thoroughly tested. Other experienced shooters here might have good information on the subject.  I don't. 

Getting the bullet straight and square in the case might be important for extreme precision. I don't know if that has been thoroughly tested in a bullseye gun. But, it does not appear to be all that important for a typical handgun at a typical handgun distance of 25 yards, according to this article which tested that hypothesis:

https://americanhandgunner.com/gear/crooked-seated-bullets-and-accuracy/

If you have tipped or off center SWC in your 45, Photo escape makes a die that pushed the bullet in by the shoulder.  Fixes that problem.

David

IMHO, the secret concentric rounds is allowing the case to move and center itself in the die.  If you have a bit of play in your shell holder, that's good.  If your dies can move slightly, that's good too.  That way, the case has room to shift slightly and center itself into the die. If you look at a Forster Co-ax press for example; the die can move back and forth, and the universal shell holder can allow the case to move left and right, resulting in perfect concentricity.   

That being said, a good seating plug in your die will help even more, like the Photoescape one mentioned.  Just make sure the case mouth has enough flare to allow the bullet to enter properly.  I believe in the Lee FCD, as crimping should be done as a separate step.  But as far swaging your bullets into concentricity, all your really doing is deforming your bullets - not good.  Refining your technique will get you good results.  Reloading is as much of an art as it is science.

Great input, thanks! The article in American Handgunner from the above link is very interesting with, to me, a surprising conclusion. Photo essay's seating die soundsgood. The Lee factory crimp die is inexpensive and seating a crookedly placed bullet and then examining after pulling it would answer some questions.

For 38 Spl wadcutters a friend turned the seating die stem on a lathe for me so it could fit in the case when seating a bullet. That way the case doesn't crumple if you have a slightly long case and all the bullets seat at the same depth. I can used mix brass (headstamp or case length) and then sort for automatics and revolvers. For 45 a seating stem that contacts the SWC shoulder is used.

I like the Lyman M profile for expanders, and use an NOE expander for 45 and a custom Dillon powder drop for 38. Both make pretty ammo with no bulges.

Came across of this tread for the first time, and want to make clarification.  I make PTUs, - powder transfer unit as I call them, that are similar in concept to Lyman M die.  Concentrical bullet seating was the objective I pursued in my designs.  With my PTUs bullets can be easily inserted to certain depth in the case assuring seating coaxial with case' vertical axial.

You can access my website by clicking on the at most left logo in the forum's banner.

AP