If I want to permanently pin it into the lower.

I bought a genuine Colt block and had it sort of permanently installed (held in place by Loc Tited screw through the front of the mag well) and with Colt mags, it runs like a top. I've got around 2000 rounds through the rifle and the only glitch I've ever had was on the very first round (FTF). It's run perfectly otherwise. Colt blocks can be hard to come by but I was luck to find one in stock at J&T Distributing. A lot of folks like the Hahn but I still prefer a block that used the standard 5.56 bolt catch to hit the BHO actuator on the mag block. The 9mm specific bolt catches have been known to break.

A lot of folks like the Hahn but I still prefer a block that used the standard 5.56 bolt catch to hit the BHO actuator on the mag block. The 9mm specific bolt catches have been known to break.

I don't follow this. I know that non AR15 bolt catches have been known to break but thge Hahn top loading block uses the standard bolt catch. Well actually, the magazine pushes up on a "lever" in the Hahn block which in turn actualtes the stock AR bolt catch. There is zero chance of the Hahn lever breaking.

Bomber

Quoted: A lot of folks like the Hahn but I still prefer a block that used the standard 5.56 bolt catch to hit the BHO actuator on the mag block. The 9mm specific bolt catches have been known to break. I don't follow this. I know that non AR15 bolt catches have been known to break but thge Hahn top loading block uses the standard bolt catch. Well actually, the magazine pushes up on a "lever" in the Hahn block which in turn actualtes the stock AR bolt catch. There is zero chance of the Hahn lever breaking.

My mistake then. I apologize for the misinformation.

I vote for Hahn too. I like mine very much and compared to otheres I am very happy with my choice.

Quoted: A lot of folks like the Hahn but I still prefer a block that used the standard 5.56 bolt catch to hit the BHO actuator on the mag block. The 9mm specific bolt catches have been known to break. I don't follow this. I know that non AR15 bolt catches have been known to break but thge Hahn top loading block uses the standard bolt catch. Well actually, the magazine pushes up on a "lever" in the Hahn block which in turn actualtes the stock AR bolt catch. There is zero chance of the Hahn lever breaking. Bomber

What actually causes the bolt catches to break is that the Colt style 9mm bolt is blowback and is shorter than a 5.56 bolt/bolt carrier.  The 9mm bolt overtravels into the buffer tube about .75" past the bolt catch, whereas the 5.56 bolt/bolt carrier only have about 1/8" of overtravel.  When the bolt catch is activated, the 9mm bolt basically slams into the bolt catch.  When using a 9mm style bolt catch, it takes the beating all by itself and has failed for some.  The 5.56 bolt catch takes less abusive battering from the 9mm bolt because there is an actuator to absorb some of the battering.  Nonetheless, there have been a couple of reports of people breaking 5.56 bolt catches also, just far fewer than reports of broken 9mm bolt catches.  If you put a spacer at the back of the buffer tube to take up about .5-.6" of the overtravel or use Slash's extra long super heavy 9mm buffer, you can reduce the overtravel inherent in the Colt 9mm set-up and reduce/eliminate any chances of bolt catch breakage with either the 9mm or 5.56 bolt catches.

I use a top load Hahn block with a 9mm bolt catch and put a .5" spacer behind the buffer and spring in conjunction with a standard 5.5 oz. 9mm buffer and have not broken a single bolt catch.  With as good as the standard and dedicated top loading Hahn blocks are, I can't think of any reason why anyone would want to pin a block in place anymore.  The top load blocks cannot fall out and do not have any movement once the upper is closed onto the lower.  Save the money you would pay for the pinning job and buy some Colt mags instead.

Spacer for what? Were you reffering to a rifle receiver extension or CAR receiver extension?

ETA: I thought the CAR receiver extension does not call for a spacer.

RRA once again has available the "colt clone" one piece block.  I'm sure it could be pinned in place.

Is the Hahn block steel or aluminum?  Steel blocks are pretty heavy, and would be harder to drill through for pinning.

With the advent of modern technology there is zero reason to pin adapters in place......ATF doesn't like folks drilling holes in AR-15 receivers anyway.

Slash has heavy buffers in a couple variations and Hahn Precision makes a heavy one with a longer head/shorter stroke just for pistol calibers.

Quoted: Spacer for what? Were you reffering to a rifle receiver extension or CAR receiver extension? ETA: I thought the CAR receiver extension does not call for a spacer.

The 9mm spacer you are referring to would be needed if you wanted to use a CAR buffer in a rifle length tube.  There is still going to be overtravel of the bolt though because a 9mm bolt is shorter than a 5.56 bolt/bolt carrier.  You would still need an additional spacer to prevent the possibility of bolt catch breakage.

The spacer I was actually referring to is one that you would have to make yourself to reduce the amount of overtravel the 9mm bolt has regardless of what stock is used.  This overtravel is inherent in the design, since the blowback design of the 9mm bolt doesn't have a separate bolt/bolt carrier and is shorter than the 5.56 bolt/bolt carrier.  If you don't want to make a spacer to reduce/eliminate 9mm bolt overtravel and the potential for bolt catch breakage, you can always buy one of Slash's extra long and extra heavy 9mm buffers.  I believe they are available in the EE or from Hahn Precision direct.

If you can't visualize what I am talking about, you may need to have a 5.56 AR and a 9mm Colt-style AR in front of you so you can actually compare the 9mm bolt to a 5.56 bolt/bolt carrier and see how far each can be pulled back behind the bolt catch when assembled.

I appreciate that people are telling me I don't need to pin a block in place, but I want to.

Quoted: I appreciate that people are telling me I don't need to pin a block in place, but I want to.

There are occasionally real Colt 2 piece blocks for sale on the EE here, get a set of those and IIRC M60Joe can correctly drill the holes in the magwell for the blocks.