Using an RRA upper/ Lauer lower with Hahn block. Colt mags run fine. Promags wont function at all. The bolt seems to be pushing the round straight into the block. It is like the promag doesnt seat up high enough. I had 2 promags and 2 colt mags. A 20 rounder and 32 rounder.

Anyone else having problem with the promags?

Also anyone else change out the recoil spring? Seems to be a little slow. I can lock the bolt to the rear, hold the dust cover shut and then release the bolt. The bolt will stop when it hits the dust cover locking thingy. Make sense? Every other AR rifle I have will bolt will ride on into battery. Still make sense?

Shawn

Older stock promags suck and dont feed properly.  (I know from experience)

The newer manufactured ones allegedly function better, however I am unwilling to spend the funds on them to find out.

Quoted: Older stock promags suck and dont feed properly.  (I know from experience) The newer manufactured ones allegedly function better, however I am unwilling to spend the funds on them to find out.

I was under the impression that mine were the newer manufactured ones as well.

I fill the same way now. Even though they were priced right, I am not going to get into a hit and miss mag reliabilty problem.

I have the RRA mag block and it runs fine with the Promags and the RRA modified Uzi mag in a RRA 9mm upper.(Don't have any Colt mags).  The Promags, with this block, even hold the bolt open on the last shot.

What stock, spring, buffer combo are you running.  It does sound like your spring is weak if you are releasing the bolt from the FULL rear locked position and it will not open the dust cover.  If I set the bolt against a closed dust cover,  It will sometimes not open the cover until bumping the rifle (also a little lube will improve this if the rifle is pretty dry).

Check action spring for kinks and free length. Free length should be RIFLE: 11 3/4 Inches (29 85 cm) minimum to 13 1./2 inches (34 29 cm) maximum. CARBINE: 10 1/16 inches (25.56 cm) minimum to 11 1/4 inches (28.58 cm) max.

When looking at the Promags feed lips straight on, you'll notice the inner edge of the lips are square. Take out the follower and spring. Then, use an exacto knife and shave off the square edges. This will allow the rounds to ride a bit higher at the top of the mag and clear bottom edge of the feed ramp of the Hahn block. Garrison block required no such modification. Per Hahn tech, Hahn blocks are designed with Colt mags in mind and nothing else.

I bought 11 of the polymer Promags from Natchez for my Colt and they work just as good as the Colt magazines

If your bolt doesn't have enough "oomph" to get past a closed dust cover there is something very wrong.  Either your recoil spring is damaged or the bolt is binding on something.  My first guess would be the ejector, but you have to nail down the problem area.  Try removing the magwell block and see how the bolt moves.  That will tell you whether it's the recoil spring or not.  If that's not it, replace the magwell block, being very careful how it sits in the lower before you tighten things up.  A magwell block that is sitting too high will bind the bolt up.

After that, it's a matter of finding our exactly what's binding.

tag for promag fix.

Quoted: I have the RRA mag block and it runs fine with the Promags and the RRA modified Uzi mag in a RRA 9mm upper.(Don't have any Colt mags).  The Promags, with this block, even hold the bolt open on the last shot. What stock, spring, buffer combo are you running.  It does sound like your spring is weak if you are releasing the bolt from the FULL rear locked position and it will not open the dust cover.  If I set the bolt against a closed dust cover,  It will sometimes not open the cover until bumping the rifle (also a little lube will improve this if the rifle is pretty dry).

I am running using a Cav-Arms m4 stock. RRA 9mm buffer and the stock M4 spring.

I got the impression that the spring was too weak for this setup. Maybe a Wolf power recoil spring????

It has gotten a little bit better after running a couple hunderd rounds through it.  Still seems like it could use a better spring. Seems slow through the recoil cycle.

Check action spring for kinks and free length. Free length should be RIFLE: 11 3/4 Inches (29 85 cm) minimum to 13 1./2 inches (34 29 cm) maximum. CARBINE: 10 1/16 inches (25.56 cm) minimum to 11 1/4 inches (28.58 cm) max. When looking at the Promags feed lips straight on, you'll notice the inner edge of the lips are square. Take out the follower and spring. Then, use an exacto knife and shave off the square edges. This will allow the rounds to ride a bit higher at the top of the mag and clear bottom edge of the feed ramp of the Hahn block. Garrison block required no such modification. Per Hahn tech, Hahn blocks are designed with Colt mags in mind and nothing else.

Will measure the spring tomorrow. Will also take your advice on the promags. Thats the trick though. Getting the follower to compensate for the mags setting low.

I bought 11 of the polymer Promags from Natchez for my Colt and they work just as good as the Colt magazines

Rub it in.

If your bolt doesn't have enough "oomph" to get past a closed dust cover there is something very wrong. Either your recoil spring is damaged or the bolt is binding on something. My first guess would be the ejector, but you have to nail down the problem area. Try removing the magwell block and see how the bolt moves. That will tell you whether it's the recoil spring or not. If that's not it, replace the magwell block, being very careful how it sits in the lower before you tighten things up. A magwell block that is sitting too high will bind the bolt up. After that, it's a matter of finding our exactly what's binding.

Thanks for the info. I looked it over really good yesterday. I thought to it might have something binding up. But everything seems to move without binding up when I am running it with ammo or not trying to hold the dust cover shut. It seems like the recoil spring just doesnt have the "oomph" to get the forward momentom going fast enough. It is noticable when firing also. Seems really slow on the recoil cycle. Much slower than say my M4. I am going to keep playing with it untill it works itself out or I find the problem.


Thanks,
Shawn

When looking at the Promags feed lips straight on, you'll notice the inner edge of the lips are square. Take out the follower and spring. Then, use an exacto knife and shave off the square edges. This will allow the rounds to ride a bit higher at the top of the mag and clear bottom edge of the feed ramp of the Hahn block.

Quoted: Will also take your advice on the promags. Thats the trick though. Getting the follower to compensate for the mags setting low.

No, I meant shave off the square inner edges of the feed lips not the follower. See the original tip with photo by Tomster HERE.

Quoted: When looking at the Promags feed lips straight on, you'll notice the inner edge of the lips are square. Take out the follower and spring. Then, use an exacto knife and shave off the square edges. This will allow the rounds to ride a bit higher at the top of the mag and clear bottom edge of the feed ramp of the Hahn block. Quoted: Will also take your advice on the promags. Thats the trick though. Getting the follower to compensate for the mags setting low. No, I meant shave off the square inner edges of the feed lips not the follower. See the original tip with photo by Tomster HERE.

Ok I see now. I will go with what -Tomster- did this coming week. Hopefully I can report back some good news by tuesday or so.

Thanks Orange_Neck

Let me toss a tid-bit out there for somebody with Promag and spare $5,  wonder about using the "LAGE" stainless steel feed lip repair kit designed for the zytel M11 mags... try to provide longer lip life, and smoother feed from mag -

I have the same setup as you.  RRA upper, Lauer lower,  Hahn dedicated mag block.  

Colt feed fine with everything, Promags did fine with all ball type ammo except the aluminum cased blazer.  Bolt hold open with both of them.

You may have gotten an older promag, check natchez they have the newer ones and are dirt cheap.

Quoted: I have the same setup as you.  RRA upper, Lauer lower,  Hahn dedicated mag block.   Colt feed fine with everything, Promags did fine with all ball type ammo except the aluminum cased blazer.  Bolt hold open with both of them. You may have gotten an older promag, check natchez they have the newer ones and are dirt cheap.

I thoght when I bought them they were the newer ones. Oh well. I checked out Natchez. They are out of stock right now. Will get a newer one to try out once they get some more in.
Gonna try what -Tomster- did today and see if i can correct the ones I have.

Shawn

Quoted: Also anyone else change out the recoil spring? Seems to be a little slow. I can lock the bolt to the rear, hold the dust cover shut and then release the bolt. The bolt will stop when it hits the dust cover locking thingy. Make sense? Every other AR rifle I have will bolt will ride on into battery. Still make sense? Shawn

I think he is holding the dust cover shut, unless he meant something else.

Quoted: Quoted: Also anyone else change out the recoil spring? Seems to be a little slow. I can lock the bolt to the rear, hold the dust cover shut and then release the bolt. The bolt will stop when it hits the dust cover locking thingy. Make sense? Every other AR rifle I have will bolt will ride on into battery. Still make sense? Shawn I think he is holding the dust cover shut, unless he meant something else.

Nope. I was/am holding the duct cover shut. Seems to be getting better though.

On a positive note. The -Tomster-'s fix for the pro mags worked on the first one so far. Hand cycled a full mag with out a hickup. Will live fire Thursday and report back.