Took the Ruger lightweight cmdr to the range today.  First few mags ran fine, then the trouble started.
It had been cleaned the night before. Mag used was a chip mccormic.  First batch of ammo was 185 gr HP reloads, then switched to Federal HST.
Still had the same issue with the HST on the last round.
Maybe set that mag aside and try some others?  I have 6 or so Chip McCormic mags so maybe one has a weak spring?

So wierd.

What position was it in when it ftf'd?

Definitely try some other mags.  Even the CMC mags can have an issue.

I just went three months trying to work reliability problems out of my CMD.
Two main problems I found was the Extractor was crap and the hammer strut was cheap stamped sheet metal.

That is nearly always mag related.  You have six mags.  Mark them All and note the trouble maker next time

Yea with it being every time on the last round i would certainly be testing some other mags.

NIB Colt defender same issue.

Ran fine during slow fire.

Did mag dump as fast as I could get front sight.  Zero issue FMJ.

Changed to HP (230 GDHP) and doing the same thing as OP.  Last round looks like it tipped up toward the sky and didn't make the move into chamber...

Slow fire with HP no issue - 100% function.

I'm thinking weak spring also....only brought one mag with me so plan to re-try with the other 4 mags to make sure.

Update for those who might be interested.

Brought in the extra OEM Colt 7 rd mag and a very old USGI 7 rd 1911 mag from my fathers 1918 production 1911.  Doubt the mag is that old but that's where the mag came from.  Shooting on PD indoor range.  Warm and dry and no one to bother me.

Ran about 150 rounds of mixed 230 gr GoldDot and 230 gr Black Talon - old stuff from when I carried G21 on the road around year 2000.

All shots were rapid fire - as fast as I could get front sight.

Thus far 230 gr FMJ functioned 100 % in both OEM Colt 7 rd mags so the issue is the shape of the HP IMO.  That in conjunction with maybe spring tension in magazine, feed lip length and follower design - more on that below.

Observations -

The USGI mag follower has the dimple I've read about that allegedly was put there to help solve this very issue - "inertia jump" of the last round trying to go into chamber before the slide comes forward - causing that "nose-up jam" against the upper lip of chamber.


USGI mag also had longer fee lips.  I've read where that is an issue also that is addressed by Tripp magazines.  Maybe others too but those are the ones I am leaning towards buying...check their site for pics of the different feed lip lengths.

GoldDot and Black Talon in Colt OEM SS 7 rd mags do the nose up jam almost every magazine.  And when it happens it is the last round in the magazine = lowest amount of spring tension.

GoldDot & Black Talon in USGI 7 rd magazine 100% function.  Combination of feed lip design, mag spring tension (although this is a very old magazine...would think its worn..?) and that dimple on the follower.

MY conclusion -

Magazine is the culprit.  Combination of feed lip length and shape, follower design (dimple vs no dimple) and HP profile bullet.

MY solution thus far -

Ordered three Tripp mags today.

In case anyone is interested I will post results when I get them.

Good news is this gun is very accurate...so there's that...

*EDIT*

Duh! Did some interweb searching and found a ton of info on this exact issue.   Appears I'm reinventing the wheel.

From a dozen articles I've skimmed mags are #1 issue then extractor and then recoil spring and then feed ramp angle... Stay tuned

I agree with the others — Classic weak spring malfunction.  I will always suggest trying a Wilson 47D magazine to fix magazine issues.  I have used and abused Wilson 8/10 rd magazines since ‘98 — They always work.

I have Tripp-Cobra rebuild kits in my Colt 7 rd magazines, excellent springs and followers.  They load smooth and easy, they administratively unload very reliably

If I was you, I would've tried 1 Tripp before ordering 3.  CMC's have worked for me in the 1911's I've owned.   Point being, try first.  There was a time when the Wilson's were the Gold standard though and people had a tenancy to start there.  At least that's how I kind of understood it.

I personally never had mag issues in the 2 1911's I owned though.  Mec Gar, Wilson or CMC's.

Checkmates with hybrid feed lips:
https://www.checkmatemagazines.com/index.php?option=com_hikashop&ctrl=product&task=show&cid=26&name=cm45-7-b-h-magazines&Itemid=298

Years ago I made and purchased feed lip anvils.

I was getting tired of paying to have mags modified to shoot SWC for Bullseye competition.

Eventually they get dropped and the lips deformed.

Feeding starts having problems.

Find a good one and compare.

It only takes a few blows with the anvils and a 16 oz dead blow hammer to fix them.

It works well for adjusting release points for large HP bullets (like the Speer 'flying ash tray') or SWC.

Get the lips right and the extractor will have grabbed the base before the lips have released it completely.

Check your extractor tension.  My guess is too much tension. After dropping a Nowlin extractor into my SA, I had a FTF on the last round in the mag every time.  After properly tensioning the extractor, the issue went away.

While waiting on the mags bought and installed Wilson "tactical" thumb safety.  A little filing/fitting and she works good.

Lead to me learning more than I ever knew about the break down and reassemble of a 1911.

Mags in.

200-ish rounds of GoldDot 230 and no issues.  100% function.

Mag lips (Tripp brand 7R-45-WO) are much closer together than the OEM Colt mags.  Also during loading you can feel the tighter (more powerful) mag spring.

So here's hoping it continues to be good to go.

Gonna hit the range again Thurs with another 200 rds of GD and 100 rds of BlackTalon for final testing before I'll carry her.

EDIT
Final report from me anyway....100% function with HP and Tripp mags.

Cheers!
Attached File

Went to the range today with another 1911 of mine but same mags as last time.  I forgot to mark the mag last time out, however, same issue this time with one of the mags.  
All the others ran fine except this one.  FTF on 2nd to last round.  Put some tape on it and set aside.  Going to replace the spring and try this one again.