Guys,
I keep CORBON DPX ammo loaded for home defense in my P220.   If you're not familiar with it, it uses Barnes XPB bullets, which have wonderful terminal ballistics in tests.

Anyway, the nose of the bullets stick out just a little farther than regular 45 ACP.  I imagine this is because of the lighter density of the copper projectile.

Anyway, I have a new OEM magazine that has some lips stamped into the body of the magazine, apparently to keep the 2nd round from the top from edging forward as the top round is stripped from the magazine.

The problem is, I can't load the DPX rounds into this magazine, even with a HKS 451 magloader.  It seems the dimple won't allow the round to go far enough back into the magazine tube to allow the nose to pass by the front edge.

The rounds fit wonderfully into the old mags, and my ACT MAG, and they fed flawlessly too when I test fired two boxes of ammo for confidence.

Anyone else experience the problem?

Here's a pic.  The new mag on left, the old mag on right.  The new mag has a plastic follower, the old mag was upgraded with a steel follower from Brownells.  Also, old followers will not fit the new mag, cause they don't have a relief cut to pass by the dimple near the top.

I have found the new Sig mags to have tighter innear dimensions than the old Sig 7 rd mags, and the Act Mags.  I can fire the Remington 230 Golden Saber all day long with no problems in my Act or 7 rd mags. In my Sig mags, the bullet seats further forward, and will actually rub up against the Slide Catch Lever during cycling when it leaves the magazine and is chambered, occassionally locking the slide open with rounds still in the mag. If I chamber a round, and then eject it, I can see where the SCL rubs up against the bullet.

I have taken a file to my SCL, and removed a small amount to cure the problem, but it is disappointing that Sig didn't do a little more research when they came out with their new 8 Rd mags.

I noticed essentially the sam problem, but my issue is more particularly with the last round out of the clip.  I haven't yet shot the CorBon out of the gun.  I loaded a clip with the CorBon without problem.  Later, when I was manually unloading the rounds out of the clip, I didn't even realize that one round remained stuck in the clip.  I loaded up the other OEM SIG clip with the CorBon and exactly the same thing happened –– final round not wanting to come out of the clip.  Clearly the CorBon won't be my defensive round of choice in my P220.  Have you tried Hydra Shok?

I'm using DPX and it's really tight, but it seems to work fine.
The last round it very tight, but it seems to function fine.