I'm planning a pistol build on a 5.56-sized receiver that will, hopefully, later be SBR'd.  I'll shoot mostly 9mm out of it, but I'm pretty sure I'll eventually buy a 5.56 upper as well.

If I'm not mistaken, the three best aftermarket magwell conversion blocks are the Hahn (three options to choose from), RRA, and Spike's, in no particular order.

I believe Hahn is the best known, and seems to sell for between $175-$200.  The other two look very similar, but sell for less money; starting around $125, IIRC.

I don't want to spend more than I have to, but I want a reliable product, that isn't going to give me headaches.  With that said, I do understand that some fine tuning may be needed to get the going in the beginning.

All else equal (price, durability, etc.), I prefer to load the block from the top of the receiver, without tools.  I'll be using some converted Uzi mags that I've had since I owned a Norinco, and later IMI Uzi B.

For those who've been there and done that, which Mag Block do you recommend?

Thanks in advance

Happy Hahn conversion owner here. Top lock model.

On the second go around I purchased a Black Creek Precision dedicated 9mm lower for $125. Thinking the dedicated lower is the better mouse trap and more cost effective to boot.

Still have a PSA mag block I picked up on one of their sales. Rumor is Rudy can do magic and make these run flawlessly.

My .02 is either buy a dedicated receiver or call Rudy

I got one of Rudy's(Mad-Machinist) blocks in my sbr. It locks up very well and no rattle. Just out of CS i'll be doing business with him from now, He bent over backwards to get me the right setup for my rail and suppressor.

I have two top insert Hahns. They run flawlessly. Tools NOT required unless you want a LRBHO (not needed or even a good idea anyway). Buy once, cry once...Hahn FTW.

Talk to the Mad-Machinist (Rudy aka Macon Armory) about fixing you up with what you need for your 9mm build.  My first 9mm build consisted of his parts and everything ran 99% flawless with one minor hiccup that I quickly too care of myself.  He's very good with customer service and will reply to your emails, even on weekends!  Good luck with your build!  Cheers

I went with Hahn top loader, back when I built my 9mm Hahn & Metalform had the hands down best reps for reliability. And isn't Hahn the only one with feed ramps?

Hahn toploader does NOT require any tools with the standard 5.56 bolt catch. Pops right out with the mag release button and clears the bolt catch. I started with just a 9mm upper and used my first 5.56 lower, I'd swap on the range all the time, and the Hahn block swaps faster than upper do.

Now if you want LRHO then you need a long finger bolt catch, which does NOT clear the Hahn top loader. So after installing the Hahn block you replace your std. catch with the long finger catch and you now have LRHO and you're block is 'dedicated'.

Bottom loaders don't have this issue but because they have some up-down play you have to get them mounted just right. I prefer the 'plug n play' of the top loader.

RRA & Spike's make fine blocks, but IMHO Hahn is the best.

Standard top load hahn - easy in/out with 5.56 bolt catch (no LRBHO) or semi-dedicated if used with 9mm long finger bolt catch (as pictured)


Dedicated top load - has bolt hold open actuator and uses 5.56 bolt catch - botl catch must be removed for install/removal of block


There's no beating the quality of the hahn blocks.

The best deal right now is probably the KAK block for $100 - it's a dedicated top load that seems to work just about as well as the hahn, but it does not have the same level of quality and attention to detail as the hahn blocks.

I started out with a bottom loading hahn block (bc I heard they were the best) and had several feeding issues. I replaced it with another bottom loading hahn block, but still had the same feeding issues. Along with replacing everything twice over, finally I replaced the bottom loading block with the hahn dedicated block (with the LRBHO) and my gun has run like a champ since.

Go with a top loading block.

This is what I'm using and no problems or complaints. It recently survived a kaboom that totally blew up in the upper. As far as removal goes it takes about 5 minutes.

RRA never had a problem

I think as long as you go with any of the good ones (Hahn, RRA, Spikes, Mad Machinists) you will be able to get it to run flawlessly

Just go with one of those that is in stock for the best price from a reputable source

I definitely want a top loader.  I think the above is what I need.  I don't want to have to remove the 5.56 bolt catch every time I change calibers, and believe if that's done enough times, you probably run the risk is widening the channel for the roll pin.

I understand the cry once thing, but do the Hahns ever go on sale?

Thanks again!

I had a RRA block and the first outing I had some issues. Put it in another lower and it worked fine. I think the first outing was as much my fault for not knowing how to adjust the block properly and the interactions of the parts I was using. Later I put the RRA block in an old Cav Arms Poly lower and that thing ran like a finely crafted, well oiled Swiss watch.

Nothing at all wrong with the RRA block based on my own experience. OH, and it does have built in feed ramps.

Very sorry to hear about your troubles with the Hahn bottom loading bloc, especially if I led you down that path.  Mine works perfectly in Colt rifles, I haven't tried it any others.

I have a Spike's Tactical 9mm mag block but I'd like to add a Hahn for comparison.

Any pointers to an in-stock Hahn top loading mag block? Everywhere I've looked appears to be out of stock.

Price?

Brownells has the dedicated Hahn block in Stock right now.

Thanks. I'll give that one a try as an alternate option. I don't think I'll be swapping back and forth between calibres for this lower anyway.