Cross posted from the SDS Pistol forum. Is Dave Biggers manning the account?!?!?

Just picked a used (not much) Tisa Duty in .45, 5" barrel no rail. I won it on GB for $300. After shipping/tax/transfer I'm at about $380.
I wanted something cheap to leave at a weekend house that both fun to shoot and reliable for self defense. Fits the bill.

Strangely it came with a Taurus magazine. I have a stock of CMC Power Mags, so I brought it to test out today with both mags.

First mag of 8 rounds I used Federal Premium hollow points in the CMC Power mag. Ran fine until the last round. Round was chambered, but the slide hung up and did not push the round completely in. I'd say about 1/4" or so. I racked the slide and of course it locked back on the empty mag. Removed the round, reloaded it into mag, reinserted, non-issue. I initially attributed this to 1911's commonly being finicky with HP ammo.

Now I moved into 100 rounds of AE 180 gr FMJ. I alternated between the Power Mags and the Taurus mag that came with the gun. Almost every damn time I had the same issue with the last round. I even alternated rounds 4 here, 2 there.

Sometimes it would seat, but probably less than 10%. I should specify there NO issues from the 1st round in the mag to the 2nd to last round. It was always the last round in the magazine.

I ultimately found that if I removed the magazine, keeping the bullet partially chambered, and racked the slide a few times, I could eventually get it to go in.

I've seen reports that the feed ramps are not properly angled... But the round gets into the chamber, just hanging up somewhere some how.

My next thought was underpowered or worn out recoil spring. But if that was truly the issue it would have issues all the time (or at least more often then only the last round).

My Smith seems to think it may be relating to the magazine follower. I ordered a Wilson 46D as they are "the best" l, and we'll see if that corrects the issue.

Any other ideas? Anyone else experienced this?

Additional:
Sat down at the table with a box of FMJ and just kept han cycling 1 round at a time in the mag. Couldn't get the malfunction to happen.

So I controlled the slide and found that the round is hopping up before the casing gets underneath the extractor, which is preventing the slide from fully returning to battery.

So now I'm at either bad angle forcing the round up too soon, or maybe the magazine lips are too short and release the round too early.

Did you check your extractor?
Might be too tight, 1911s need the rim to slip under the extractor as it comes out of the magazine, rule used to be that dropping the slide on a round in the chamber can damage it.
Remove slide and slip a round under the extractor, it should hold under it's own weight and light shaking.

My Colt ANVIII fails to feed the last round all the time. It’s the mags. There’s a dimple on the follower that seems to catch the rim.

For me, it’s a range only toy, so I don’t care to invest in better mags. Try Wilson or CMC and I’ll bet your issues disappear.

I'm using CMC Power Mags and have a Wilson on the way.

Yes it sounds like a mag issue.  Try other mags shoot and repeat.  That should take care of it.  When I buy a new 1911 I clean and cycle it 200 times by hand with grease before I shoot it.   I have also polished the frame slightly on a couple of guns.   My RIA 1911 that I bought for $400.00 runs great never a malfunction and I used a few different mags in it.  Good luck

Sat down at the table with a box of FMJ and just kept han cycling 1 round at a time in the mag. Couldn't get the malfunction to happen.

So I controlled the slide and found that the round is hopping up before the casing gets underneath the extractor, which is preventing the slide from fully returning to battery.

So now I'm at either bad angle forcing the round up too soon, or maybe the magazine lips are too short and release the round too early.

Contact CS, if the problem isn't solved by the usual corrective action, it's time to get a RMA and see if we can repair it for you. Or hit up you local gunsmith.