I had my BA 4.5" barrel sent to Macon Armory and he reprofiled it real nice. Previously, I had problems with the round jamming, nose up, with hollow points (Gold Dot 147gr G2). It happened occasionally, but if I tried a single round in a magazine, trying to feed it BHO or manually it ftf over half the time. The more rounds in the magazine, the less chance of ftf, it seemed, so I wondered if it was magazine related. I sent the barrel to Rudy anyway at Macon and I tried several times to replicate the same malfunction by single rounds in a magazine and it didnt jam the 5-10ish times I tried. Used magpul and KCI glock magazines, and the success rate significantly increased. Magpul magazines would jam nose up, surprisingly 1 out of 2 kci mags would jam with the nose stuck at the bottom of the feed cone instead of upwards (the more classic HP hiccup). Looking at the truncated feed cone Rudy did I'm 100% sure it isn't the barrel at this point. I've narrowed it down to these possibilities:

1. The magazine spring needs extra power. 33rnd and the 15rnd springs seem easy to find, but I have a Magpul Pmag 21 rnder that I have no idea if an extra power spring is available for it. Anyone know?

2. The follower is causing my malfunction. Do I need to sand it down somehow? I did interestingly have an issue with the bolt staying locked open with 1 round left in the magazine. It could be the lower's fault. I had the bolt locked open, inserted a magazine with 1 round, and the follower hit my bho just good enough to keep it locked open. I then put in a 2nd round in the magazine, chambered a round, and ejected the round. It didn't stay locked open (which is good!). Wondering if I need to file my BHO mechanism or the follower itself to prevent it from possibly locking open when I have 1 round left.

3.The bolt somehow picks up the rounds wrong occasionally. I've read people have ftf problems but switch bolts and the problems go away.

4. Possibly my magwell. I noticed when any magazine is empty, it slides in my magwell butter smooth. When they are loaded, I guess it swells the magazine by a few thousands of an inch and it's a bitch to get my mags seated, even with bolt held open. I have to insert, and slam the floorplate with my palm. Sometimes more than once if it's a 33rnd on a closed bolt because of how tight the fit it. Could the magwell be like...squeezing my magazine when it's trying to expand out a bit which causes some more friction on the follower/casings, causing slower feeding...something like that?

Specs:

Davidson Defense Billet Upper no FA
BA 4.5" Modern 9mm Barrel 1/2 x 28
FM Products BCG (13.85oz)
FM Products 9mm lower with BHO
Some chinese handguard because I had to cut it down to like 3.5" to fit the short barrel
PSA LPK with SBA3 Brace (using RightToBear reduced power spring, 9mm buffer ~ 6.7oz, 1 quarter)

I have used 2 magpul mags (15 and 21 rnd) and 2 KCI 33rd magazines. 115gr round noses feed 100% before I had the barrel reprofiled. Maybe this gun just hates these specific Gold dots. The damn elastomer tip things get shredded off inside my KCI magazines and I get deposits inside my gun in general. I honestly don't know why the rounds are nosing upwards and getting stuck. When I slowly feed the rounds in they all hit the bottom and ride up into the chamber. The only time I can get the rounds to shoot upwards is when you slowly push the round out of the magazine, and towards the end the follower pushes the nose with enough force while the rim is barely being held by the feed lips.

Any thoughts? Bummed out because I had a PSA AR9 before this that didn't jam, but it had a different diet of 124 gr HST, 135gr Critical Duty, and 147gr Hi-Shoks. It did strip it's gas key though...hence I like the FM BCG since it's a 1 piece design.

https://imgur.com/AliBGst

The reason I reload long and use only very pointy RN bullets(Berry 147 jrn). Round blunt noise bullets would jamb once in a while.