https://www.youtube.com/watch?v=6Awhu027mLs

Got this for free from a redditor that said he was having issues with it but I thought I'd try to fix it.

As far as I can see the mag block is as far up as it can go without blocking the bolt and the magazine is extremely solid when inserted.

It doesn't jam every time but about half, more often on the last round. I also notice that if I try to let the bolt forward slowly it pops the round off the magazine but doesn't hold onto it, it just ends up loose in the ejection port. Not sure if that is normal or not.

Buffer is spaced so that it bottoms out about 3/16" away from the bolt release with quarters and I'm using an extra strength 308/pistol cartridge spring.

Magazines are 10 round ASC, I have 3 and it does this with all of them, after lubing the followers as well.

Watched the video looks like the same jam I was having with the ASC magazines last round always jammed and empty magazine hold open did not work. Fixed it by modifying the ASC plastic followers. Ended up sanding quite a bit of the right side of the follower that held the bullet at too high of a upward angle. Filed the left side of the follower just a bit to have the bolt hold open work by giving more lift to the follower.

Picture unmodified follower on left modified on the right, black marker is where I filed some plastic away to operate the bolt hold open, red marker where quite a bit of ramp was sanded away mostly toward the front to prevent the jams. Modified 5 of the ASC magazines and they all work perfect now no jams and empty magazine hold open works.

Thank you, this is useful. I wonder if you also opened the mag lips too? I posted in Calguns and they seemed to think that a normal strength spring might help, and if that didn't then the mag lips could be opened up to allow the rounds to seat higher/at a better angle. I wonder if your mod also addresses the same issue in a different way? Either way, I'll try the spring first, and then either your mod or opening the lips.

I'd like to get it working with what I have even if it takes a bit of effort, $40 for Metalform mags is steep and these seem to be good quality, just a bit out of spec for what my gun wants.

Never touched the feed lips or springs on the magazines just modified the ASC plastic follower, shot the 9mm carbine at the range today no failures of any kind using 20 and 32 ASC magazines, shot pretty darn well at 100 yards with Bushnell AR 223 3-9 power scope. There was three different sized gongs at 100 and hit them every time off the bench. Fun gun think it will be used a lot, 223 lower with KAK bottom install adapter, KAK 8 oz buffer carbine 223 buffer spring, JSE 9mm stainless barrel 16 inch upper

Just an FYI - metalform mags are regularly $20 and somewhat frequently on sale for $13 from psa.

Very interesting. I'll definitely try the followers first then. I wonder if the lip gap is different as well though, do you have a top view?

Sadly I live in CA so I can only get 10 round ones, PSA never has those and I've only been able to find them for $40ish so far, haven't checked much though since I thought ASC was good to go.

Sorry about the multi posts but I just found ProMag 10 rounders: http://gunmagwarehouse.com/media/catalog/product/cache/1/image/700x700/9df78eab33525d08d6e5fb8d27136e95/C/O/COL23.jpg

They look like they have a similar follower angle to the Metalform ones. Are they any good?

http://gunmagwarehouse.com/media/catalog/product/cache/1/image/700x700/9df78eab33525d08d6e5fb8d27136e95/C/O/COL23.jpg

Have anyone outside enemy lines that can cut them down to 10 rounders for you?

I clicked this thread because I have a PSA mag block and I've seen very little talk about them good or bad.

Mine works fine. I got it when they were marked down to $29.99!!! (Wish I had gotten a dozen)
They seemed to stop selling them right after I got mine. I suspect they wanted to push their own PSA 9mm lowers instead of offering a "competing" product.

Anyway, I also wonder if it's the mag that's the problem.

I was told that ASC are hit or miss and that I may need to file the follower to get it to work.
Instead of dicking around, I just bought PSA Metalform mags. The gun ran fine right from the start. (built from ground up)

Unfortunately no, and it's probably not cost effective anyhow. I ordered a single metalform 10 rounder for now from Greg Cote, I'll try that first.

http://i.imgur.com/gjGnX7P.jpg

Not sure if that much of a gap is normal.

I did your mod, it solved it more or less. I noticed that sometimes the magazine allowed the rounds to angle too high up, your mod keeps them flat. After I did a couple mags I took it to the range, had two misfeeds in about 130 rounds. Bolt held open about half the time, I guess I need to remove more material. I'm sure I can get it more reliable by more sanding, polishing, etc. As I said earlier I also have a Metalform in the mail, was curious enough to see how well they work out of the box.

Anyways thanks Ronbo1, you got it.

Hahncholo,

Glad your seeing improvement by modifying the followers of the ASC magazines. Had a couple followers that did need some more sanding to get them 100% reliable, after doing 5 magazines was ready to be done was a pile of plastic dust below the little gun vise. Did communicate by e-mail with the designer Barry at ASC about the high angle of the follower on the magazine and sent the same picture posted here of the modification to the follower.

Maybe a change will be made to the followers at ASC. The reason went with the ASC to begin with was the 20 round magazine length as the 32 round don't work off a bench unless the rifle is up in the stratosphere. The PSA at $12.99 are a great deal but only in 32 round

I hope you find a simple fix to the feeding problems you have with changing the magazine follower's profile.  I did the same and it helped but the fix for mine was to buy a Hahn block.

I have 2 Colt mag 9mm's, a Spikes block and Palmetto dedicated lower. I like them both, and also like the ASC 20 round magazines, but with the mag, I have come to accept that 10 minutes of mods to each mag are part of the package to make them work.

My routine is:

-Relieve part of the plastic mag follower where it contacts the mag lip, so the last round is presented higher.
-Relieve any part of the mag feed lips that are contacted by the bolt carrier as it moves forward into battery
-Smooth the transition at the depressions inside the mag body

The last item recently came up with my latest batch of Tula steel case ammo. The 3 mags previously had maybe 200 to 300 tops on each one with no issues after taking the first two steps. Now I need a third step. The mags have two vertical indents on each side that guide the cartridge as it is lifted. I noticed that this batch of ammo can not get past the initial hump. I can literally drop out the last 3 or 4 rounds, and the rest of the mag will stay loaded, with the cartridges stuck at this transition. I have not gotten to fix this yet on mine yet, but when the same thing happened to a buddy, we wrapped some fine sandpaper on a paint stirrer, and reached inside the mag body to smooth this area out, and eliminate the hang up. We took off just a tiny bit to ease the transition, a minute or two of targeted sanding. I'm pretty surprised to see an issue like this, but it happened to me twice today with 2 of my mags, so they need the sandpaper treatment.

I could hold the mags with the cartridges jammed at the transition, empty space where 4 or 5 cartridges should be against the feed lips, and bang the mag against my hand and the rounds would not budge.

I considered that perhaps my new case of ammo has a different coating contributing to the hangup, or that I should clean out my mags. I also thought that possibly the follower was getting hung up on the catch for the mag release, but that was not the case. On my friends mag, sanding the transition corrected this, I'll do mine soon.

I think this is a lot of work to do, but no one else has 20 round mags for that price, so I'm doing what I need to. I just got some metalform 32's in. I'll try them next.