Went to the range today and took 150 rounds with me to help "break in" my 4566TSW that already had 200 rounds through it. I had 50 rounds of reloads with the 185 gr Sierra JHP with 9.5 gr of AA#5 and 50 rounds of Speer's old 200 gr Flying Ashtray at 9 gr of AA#5. These 100 rounds fired flawlessly with no FTF, FTE-nothing. There was no problem in any way.

I had another box of 50 of Ranger T 230gr P+ that did likewise up until the last magazine when I got one FTF on the last couple of rounds left in the mag. It had jammed up into the first part of the chamber-nose up. What a bummer after such a good day.

Ideas or speculations to this mishap would be appreciated as all seemed well until the last part.

Was the gun new when you purchased it, or new to you? If it was a used gun, it might need new springs. Either weak magazine springs or a weak recoil spring could have caused that failure to feed.

On the other hand, if the gun is brand new, it might need additional break in or just have been a fluke. The 45xx series of pistols are very reliable, but any gun can have a problem. It might not like that ammunition. It could be any number of things. If it was brand new, keep shooting it and see how it does. If it was used, perhaps replace some springs.

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Hello Cleveland, Rock and Roll

I bought it NIB about two months ago and it came with three mags. I had recently ordered several recoil springs for the 4506 and decided to get a few for the 4566TSW while I was at it along with five mag springs.

I looked at the recoil spring that was in it when I got it and compared to the ones from S&W and they were the same length as were the magazine springs.

It now has about 350-400 rounds though it so, I'd say it's broke in by now. I may have to go back to standard 230 gr Ranger T's instead of the P+ rounds or perchance it may need a slightly stiffer spring for the +P loads. The 4506 didn't matter what you shot in it and it had the standard spring. I shot LSWC's to CorBon 200 gr +P ammo and it's never failed in the 20 years I've owned it.