5.5 inch Model 41 barrel

I bought a S&W 41 5.5 inch barrel from Midway. I just got back from the range where I tried the barrel and had some FTF issues. Out of approximately 400 rounds fired I had about 8 FTF. It doesn't seem to be a lot but with my 7 inch barrel I had none. The failures come with the initial round mostly, but sometimes during the course of fire. I am using CCISV ammo. I am wondering if it is a recoil spring problem since the barrel seems to be heavier, a need to polish the ramp, or a barrel break in time. If the ramp needs to be polished what is a good method to use?
Thanks in advance for your suggestions.

Mark some ammo so that you can tell if the top leading edge of the chamber is shaving lead from the bullets, or bottom leading edge. Most likely it's the top. That will tell you where to do some minor polishing.

failure to feed or failure to fire?

It is a failure to feed and the top of the lead is damaged.

Sounds like you need to adjust your mags as a start

The front lips often need to drag a little on the cartridge.  Squeeze them in to do so.  I think it was Larry Carter said that about 208 mags.  41 and 208 mags are very similar.  And I do that as a rule on CT HS mags.

I polished the ramp, cleaned the chamber and, what I think was the issue, I replaced the recoil spring with a Wolff 7 pound. The 41 feeds and fires flawlessly now.
Thanks for all the suggestions.

Glad you got it running, since it worked well with the 7 inch barrel I figured it was the new barrel.  Hope it shoots well too.