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Page AR-15 » Rimfire and Pistol Calibers
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Posted: 10/25/2003 8:51:35 AM EDT
I am building up a 9mm and am planning to usr a RRA upper (Already have RRA lower).  I have been trying to research the best mag block.
1.  Do any other than colt hold the bolt open?
2.  I already have some RRA mod Uzi Mags.  Has anyone tried these in the ASA mag block?  ASA states they are not sure If they will work but think since both will use colt mags they should.
3.  I seem to be finding concerns about reliability.  Asside from playing I would like the the gun for home defense for my wife.  I would prefer the 9 to 5.56 due to control and penetration.  Any thoughts?
4.  Any opinions and experience would be appreciated.
Link Posted: 10/25/2003 3:05:04 PM EDT
[#1]
Radmd,

Look for my post on magblocks on the "9mm FAQ" thread that is tacked at the top of the page.  In short, Rock River, Hahn Precision, and recently Garrison manufacturing all make hold-open blcoks, but you will need $100 colt mags to make it operate.  RRA and Hahn have set screws/detents/etc. to retain them, no one has seen the Garrison blcok yet, though DrugRunR ordered one and is going to have a review on it.  That block requires a special 9mm bolt hold open be installed in lieu of the .223 one.

The simplest block seems to be the American Spirit Arms (ASA) block.  Drops in from the top, doesn't have the bolt hold-open, but very simple and reliable from what everyone here says. Aftermarket uzi mags seem to be a little tight in them, but you can get real IMI mags for about $15 each at www.coledistributing.com which is an awesome price.

I can't say I have used a weapon for home defense, but I highly recommend you check out the ammo FAQ in the ammunition threads.  
Link Posted: 10/25/2003 3:27:44 PM EDT
[#2]
On the "home defence" tip...Most colt types need some work to cycle anything but hardball 100%....Joe black has done some work this area...Me, Ive found that the SA mags feed HP's in my RRA rifle..Then agian theres allways those new'ish FMJ expanding Jobs....Other than that DAWG has it bout right(how fast we learn grasshopper!)....Also add that acording to the board members the ASA block seem to be "tighter" and only really fit IMI uzi mags..My RRA block is "Loose" and will fit everything, with the IMI uzi being a little loose and the SA's being a little tight......UNDERDOG
Link Posted: 10/25/2003 4:41:10 PM EDT
[#3]
Thanks very much for the information.  2 more questions.
1. The Uzi mags are they flat back or ridged.
2. SA stands for spirit arms?
Link Posted: 10/25/2003 4:59:05 PM EDT
[#4]
Quoted:
Thanks very much for the information.  2 more questions.
1. The Uzi mags are they flat back or ridged.
2. SA stands for spirit arms?
View Quote

Come both ways.....IMI mags are "ridge back" as you put it, and some "contract mags are "flatback"....Only real difference as it relates to AR's are that some "contract" mags are a little out of spec and fit "tighter"
SA means "south African"....These are mags made of 9mm AR's not uzis...30 rounders,That taper up to single feed
[img]HTTP://users.adelphia.net/~masine/samag.jpg[/img]
Link Posted: 10/25/2003 5:25:36 PM EDT
[#5]
Thanks again underdog.
One last question any source of SA mags you Know of?  They look excellent.

Rad
Link Posted: 10/25/2003 5:36:18 PM EDT
[#6]
At the moment the only source seems to be our very own EE...Put up a WTB ad and see who bites,Use my image if you like to make sure you get what you want,Ill leave the pic up on my host site for a while if you don't have hosting....These thing were coming out of the woodwork a couple months ago when the whole sten/colt system looked to be just around the corner,Now they've kind of dried up...I like them a lot and have told everyone who asks about them,which is probably why I cant find any more myself[:)].............UNDERDOG
Link Posted: 10/25/2003 6:02:19 PM EDT
[#7]
Quoted:
Thanks very much for the information.  2 more questions.
1. The Uzi mags are they flat back or ridged.
View Quote


Uzi mags come either way, depending on source/manufacture--- Here is a pic showing the ribbed style on left, this mag is a "star of David" military mag, and the mag on right is a "IMI" 32 round mag ([blue]see the IMI at bottom of mag[/blue]), and 25's also come flat.
[img]http://www.imagestation.com/picture/sraid73/pee055516459ede5b08a7140790742acd/fb6773d8.jpg[/img]
Link Posted: 10/25/2003 6:27:05 PM EDT
[#8]
Quoted:
I am building up a 9mm and am planning to usr a RRA upper (Already have RRA lower).  I have been trying to research the best mag block.
1.  Do any other than colt hold the bolt open?
View Quote

The Hahn block has the hold open.  But it's spendy.  I know that ASA does not, as I have an ASA block (older one).  Not sure about RRA....somone said it did once...but can't recall.


2.  I already have some RRA mod Uzi Mags.  Has anyone tried these in the ASA mag block?  ASA states they are not sure If they will work but think since both will use colt mags they should.
View Quote

I have an older ASA block.  I have found that some modified uzi mags work, others do not.  The issue that I have seen is the position of the mag catch notch.  If the notching is low, the mag ends up too high, from what I have seen, the extracting round hits the mag lip and gets flipped out before the ejector (my experiance).

Same with the South African mags.  I ran accross a bunch that were "narrow", yet others fit fine.  I fixed the narrow mags by using heating tape (not duct tape).  This is aluminum tape.  (Range mags).

I have noticed that the South African mags (which are similar to Stens) feed much better then the Colt/Uzi type.  The bullet is in a better position to load then the double stack, double feed uzi.

The only exception I have found is w/ the modified Marsden mags (curved ones).  They are double stack, double feed, but the postion of the mag catch seems to be very good.  I have a few and the ones I have tested feed 100% rapid fire.  They fit fine in my ASA mag block also...but I had to modify the bottom of the block to accomidate the curve of the mag.  Nothing "big", but figure it's worth noting.



3.  I seem to be finding concerns about reliability.  Asside from playing I would like the the gun for home defense for my wife.  I would prefer the 9 to 5.56 due to control and penetration.  Any thoughts?
View Quote

Mags!  Find mags that will unload everything rapid fire.  Use those as your "defense" mags.  Use the same ammo you will plan on using when you fuction test.  


4.  Any opinions and experience would be appreciated.
View Quote

I also have a Sten block allows notched Stens to work in Colt style 9mm's.  (Right now, it's MIA... I misplaced it...opps.)  It worked great when I had it installed.  So I'm back to using my Colt style block.....

Good luck in your project.
Link Posted: 10/26/2003 1:11:46 PM EDT
[#9]
....Other than that DAWG has it bout right(how fast we learn grasshopper
View Quote


[darth vader voice]  The circle is complete.  Now you are the student and I am the master! [/darth vader voice]

[:D]

So the SA mags are not the same as the South African mags that vector arms is selling right now?  The vector ones would be double stack feed?  Also, has nayone ever tried the straight type Madsen mags, or are the too wide?  Hmm, maybe I shouldn't challenge Underdog to a lightsaber duel quite yet!

Dawg

Link Posted: 10/26/2003 3:06:30 PM EDT
[#10]

I also have a Sten block allows notched Stens to work in Colt style 9mm's.  (Right now, it's MIA... I misplaced it...opps.)  It worked great when I had it installed.  So I'm back to using my Colt style block.....

Good luck in your project.
View Quote


[stick]

When you find it send it to me I could really use one!


Cruizer
Link Posted: 10/26/2003 3:14:28 PM EDT
[#11]
Quoted:
....Other than that DAWG has it bout right(how fast we learn grasshopper
View Quote


[darth vader voice]  The circle is complete.  Now you are the student and I am the master! [/darth vader voice]

[:D]

So the SA mags are not the same as the South African mags that vector arms is selling right now?  The vector ones would be double stack feed?  Also, has nayone ever tried the straight type Madsen mags, or are the too wide?  Hmm, maybe I shouldn't challenge Underdog to a lightsaber duel quite yet!

Dawg

View Quote

I know it's confusing bro....As you know the one's in the pic are South African Mags for the Colt SMG's......Also There's South African (SA) mags for the Uzi's(AKA) "contract" mags.....Sorry I don't have a lightsaber but will glad to square off in a Phased Plasma rifle match...In the 40w range of course
[pyro][heavy].............UNDERDOG
Link Posted: 10/26/2003 4:15:39 PM EDT
[#12]
Well, the bolt open is not special, just the factory 9mm bolt open.

On a Factory COLT setup, the bolt open is different between the 9mm and the 223.

I went with the Garrison block because it was the cheapest and with the slotted verson, it is most like a standard COLT version.
It drops in from the top and it looks just like the ASA block.

If you want something easy then go with the HYTECH block.  You don't have to modify the UZI mags.

I would rather have something that was factory looking so I went with Garrison block.

Link Posted: 10/26/2003 4:25:58 PM EDT
[#13]
Drugrnr
Where did you get the Garrisin Mag block?  I have their site bookmarked and dont see it.

Thanks for the info Rad
Link Posted: 10/26/2003 4:52:43 PM EDT
[#14]
Radmd,

Garrison Mfg just started selling them on the Equipment Exchange on Oct. 22, IIRC.  They sell an unslotted (i.e. ASA style) and a slotted block.  With the slotted, you need their 9mm bolt catch (and probably another punch pin when you remove the one holding the .223 bolt catch).  

FYI, the guy at Garrison said it becomes a dedicated 9mm lower with the 9mm bolt catch, as .223 mags won't seat and function with the 9mm bolt catch installed.  

(If and) when I get my 9mm together, I think the ASA is probably the best way to go- too many extra problems/cost for bolt hold open function from what I have learned.

Damn, Underdog was right.  I do spew out a lot of info for someone who doesn't own a 9mm AR!  [%|]
Link Posted: 10/26/2003 4:56:55 PM EDT
[#15]
Quoted:
Radmd,
Damn, Underdog was right.  I do spew out a lot of info for someone who doesn't own a 9mm AR!  [%|]
View Quote

Never meant to imply that bro,...Knowledge is power,knowing is half the battle....Yada,yada,yada..........UNDERDOG
Link Posted: 10/26/2003 4:58:57 PM EDT
[#16]
Quoted:
On the "home defence" tip...Most colt types need some work to cycle anything but hardball 100%....Joe black has done some work this area...Me, Ive found that the SA mags feed HP's in my RRA rifle..Then agian theres allways those new'ish FMJ expanding Jobs....Other than that DAWG has it bout right(how fast we learn grasshopper!)....Also add that acording to the board members the ASA block seem to be "tighter" and only really fit IMI uzi mags..My RRA block is "Loose" and will fit everything, with the IMI uzi being a little loose and the SA's being a little tight......UNDERDOG
View Quote


[knowledge sponge mode] Underdog, does that RRA block need a special bolt catch, or once you mount it in, does it us a transfer bar or some other dohickey to all the bolt hold-open to work with the standard .223 bolt catch? [/knowledge sponge mode]

Link Posted: 10/26/2003 5:08:55 PM EDT
[#17]
Yeah the RRA block uses a "Transferbar dewhicky" type setup to hold open the bolt...Mag pushes up on transfer bar which pushes up on the standard .223/5.56 hold open which hold the bolt open.....Having said that I cant tell you how well its works because I'm to cheap to buy any colt mags(Got a corona habit to support ya know) Anyway I've been working on a few ideas to make uzi mags operate the hold open...Have some working prototypes but nothing as yet that would be "legal"....Must still work in an Uzi as you know.............UNDERDOG
Link Posted: 10/26/2003 8:53:00 PM EDT
[#18]
Underdog,

Not to hijack this thread, but I had a thought when discussing uzi mag bolt hold-open with Drugrunr a couple of days ago.  What if you were cut a notch in the back of the uzi mag maybe 1/2" deep and then have a peice of spring steel that flips out.  The spring lever would only have to project enough to activate the transfer bar, which would be as much as the bump-out in the back of the Colt mags. It could be in a vertical postiion with the attachment point at the bottom, flip out horizontal.  pulling the mag out would at worst force it back vertical, a dn the action of loading the mag would stow it.  Depending on the uzi magwell and the way you  mount it, it proabably would still work.

Anther thought would be to actually use a modified snap cap with a post on the primer portion that would pop out at the backside notch.  That would mean your mags would hold one round less, but that you could remove the contraption and still use the mag for uzi's

I'll see if I can't post a sketch of what I am thinking in a day or two here...

BTW, no offense taken, meant that as a bit of a joke.  AR15.com is the best class I have ever had! [:)]
Link Posted: 10/26/2003 9:11:35 PM EDT
[#19]
I've tried the spring steel idea....The spring steel has to be very stiff to operate the hold open,Don't have any pics of what I did but Ill try to s'plain....I cut a slot in the uzi follower and stuck the spring steel out,if you just tack it on the back it will bind the follower....I've gotten the idea to work and I figured that you could allways switch the follower for a stock one to use in an Uzi and I figured that would be legal,But what I think is legal and what the batf thinks....Well...Email me and ill send you some pics off the colt follower and mag body,Maybe It'll give you some idea's.........I haven't pursued this I'm a little while,figured id just wait till after the ban..........BTW I Think We've already hijacked this thread..........[:)].........UDOG
Link Posted: 10/27/2003 2:46:55 AM EDT
[#20]
Which block depends on what you gonna do.

If you are going with a dedicated lower or not.

If you go the ASA route you can just use your 223 lower and be fine.
If you go with the Garrison block then I would go with a dedicated lower.

I went with a post ban RRA upper so I will just spend the money and get a postban lower and have a COMPLETE 9mm setup.
I hate swapping stuff around.

I also am gonna play around with getting the bolt hold feature to work with UZI mag but I figure that if the people that make the adaptors can't get the mag catch to work with non-colt mags then it will not happen.

Today I will get my upper in and I hope on weds I will have my mag block.
I got a flat-top upper and I went ahead and got a carry handle from tapco($50 del) so I can shoot the weapon without haveing to spend the money on optics just yet.

CHARLES
Link Posted: 10/27/2003 5:47:40 AM EDT
[#21]
Quoted:
Underdog,

Not to hijack this thread, but I had a thought when discussing uzi mag bolt hold-open with Drugrunr a couple of days ago.  What if you were cut a notch in the back of the uzi mag maybe 1/2" deep and then have a peice of spring steel that flips out.  The spring lever would only have to project enough to activate the transfer bar, which would be as much as the bump-out in the back of the Colt mags. It could be in a vertical postiion with the attachment point at the bottom, flip out horizontal.  pulling the mag out would at worst force it back vertical, a dn the action of loading the mag would stow it.  Depending on the uzi magwell and the way you  mount it, it proabably would still work.

Anther thought would be to actually use a modified snap cap with a post on the primer portion that would pop out at the backside notch.  That would mean your mags would hold one round less, but that you could remove the contraption and still use the mag for uzi's

[:)]
View Quote


I have also been playing with a few ideas but I am not anxious to get to involved until I see what the crime bill does.  I think it is completely possible to come up with a mofidied follower to use in an UZI mag that could be made to interact with the AR-15 bolt catch.  I have been using the Armalite AR-10 follower as inspiration...

The problem is that you will need to make a custom follower that will also need a custom mag block and if the crime bill dies it will cost me more to modify each UZI style mag then to just buy Colt style 9mm mags.
Link Posted: 10/27/2003 9:51:42 AM EDT
[#22]
Regarding the bolt hold open with Uzi mags.  I mentioned months ago that Mike Maguire (mmag) made at least one prototype that I handled and watched it work with live ammo firing it and it held the bolt back fine.  It was a custom solid aluminum follower that had a spring loaded plunger in the back of it that held the bolt open.  He was going to start producing them but decided not to bother.  I know he must still have the CNC program.  He is busy working on another large bore project.

Regarding the mag blocks.  I have a TacBlock (crossfire clone) and recently switched to the bottom loading Hahn Block.  I have a few friends that have the Colt/RRA block also.  I have a friend that has no Colt mags and he is using the top loading Hahn Block.
Of all the ones mentioned above, I believe the Hahn block to be the best.  No Colt mags - get the top loading - impossible to fall out.
If you have Colt mags like me get the bottom loading Hahn block.  It has a nice roller that you adjust with an allen wrench when the block is in the mag well and it will not fall out.  It also has the nicest shaped flared opening for fast mag changes.
Link Posted: 10/27/2003 9:24:17 PM EDT
[#23]
Who sells the Hahn blocks, in particular the bottom loading one?
Link Posted: 10/27/2003 10:45:04 PM EDT
[#24]
Quoted:
Who sells the Hahn blocks, in particular the bottom loading one?
View Quote


Check Brownell's.  They had it in the latest catalog (or check online).
Link Posted: 10/28/2003 5:57:44 AM EDT
[#25]
[url]http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=1548&title=AR-15+9MM+CONVERSION+BLOCK[/url]

Link to Hahn block so no one has to search all over.

Amphibian, could you post some pics of the bottom loading Hahn block?  Curious as to the roller mechanism that retains it.  Also, I take it that the block is pretty solid and doesn't shift around (like the RRA supposedly does) when you lock it in real good?
Link Posted: 10/29/2003 3:04:45 PM EDT
[#26]
Below is a pic that I got from some site that was selling it.
Note that you can adjust the block when it IS installed in the mag well so it can be adjusted so it will NOT come out.  You use an allen wrench to adjust a set screw that presses on that roller.
[img]http://home.cfl.rr.com/c3stuff/m16/hahn.jpg[/img]
Link Posted: 10/30/2003 6:44:03 AM EDT
[#27]
Awesome pic, thanks!

Anyone have a pic that good of the RRA block?  I am curious to see exactly how/where it is secured (I know, set screws, but a pic would help me undestand why the Hahn is better!)



Link Posted: 10/30/2003 8:17:51 AM EDT
[#28]
Here is a link to an ad that has a small pic of the RRA block:
[url]http://www.ar15sales.com/rraparts.htm[/url]
You can see from the pic that the RRA block has a small pin on the middle front side of the block.  There is a pin on both sides of the block that gets pushed out when you tighten the set screw at the bottom.
As I mentioned before, I have friends that have the RRA/Colt and the Hahn.  Both blocks will not fall out when they are tightened.  What did it for me was that the Hahn block has a nicely flared mag well both on the front and back and has the feed ramp grooves cut into the feed ramp.
Link Posted: 10/30/2003 9:24:48 AM EDT
[#29]
Quoted:Below is a pic that I got from some site that was selling it.
Note that you can adjust the block when it IS installed in the mag well so it can be adjusted so it will NOT come out.  You use an allen wrench to adjust a set screw that presses on that roller.
[url]http://home.cfl.rr.com/c3stuff/m16/hahn.jpg[/url]
View Quote



I just ramped a 9mm bolt and he sent his mag well adapter with the bolt for me to look at.  The adapter is this same exact one.  Very, very nice, but, the ejector is held in by two pins (same two pins that hold the bolt hold open arm in place)and it's very sloppy.  I was able to put a .008" feeler gage between the ejector and the wall it locates on.... The ejector tip, tip that makes contact with the cartridge, wiggles around 1/8".  Is that a problem? I don't know..... I had to bend my ASA to rub the bolt....... That much slop makes it hard to bend over so it rubs (almost rubs) the bolt.... He's going to let me know how it runs.
Link Posted: 10/30/2003 10:16:01 AM EDT
[#30]
For the record, I never had a problem with the RRA block "falling out"....Understand that the block secures VERY tightly in the mag well..The problem I had was that the block would eventually move upward under recoil and sooner or later rub against the bolt slowing the bolt down and giving failures....the Hahn block look to be susceptible to the same problems....UNDERDOG
Link Posted: 10/30/2003 10:59:19 AM EDT
[#31]
Excellent information.  It seems the ASA and the Hahn to be the most logical.  I got my hands on a RRA at the Gun show.  It seemed very loose in the receiver.  I understand the set screws tighten this up but it seemed like they would have to extend a long way to tighten up.  This is probably not fair as I have not gotten my hands on the other 2.  Is the ASA or topload Hahn loose in the mag well ie does it rattle? or are there set screws to tighten it up?
Also the hold open on the hahn bottom loader does it only work with colt mags?
Link Posted: 10/30/2003 11:08:09 AM EDT
[#32]
Joeblack.  The 3 Hahn blocks I've seen didn't have ejector slop but come to think of it my tacblock has a little but it still functions 100%.
Radmd, I don't know about the ASA block but both the bottom loading and toploading Hahn block have the same set screw that tightens the roller in the front.
Yes, all mag blocks that have the bolt hold open feature only work with Colt Factory mags or if you have a special follower like I mentioned Mike Maguire making that 1 prototype.
I think the issue of being loose or tight all depends on the receiver of course.  I have a friend with a EA RR and his is tighter than either of my RR Colts.
Link Posted: 10/30/2003 2:07:52 PM EDT
[#33]
Quoted:
For the record, I never had a problem with the RRA block "falling out"....Understand that the block secures VERY tightly in the mag well..The problem I had was that the block would eventually move upward under recoil and sooner or later rub against the bolt slowing the bolt down and giving failures....the Hahn block look to be susceptible to the same problems....UNDERDOG
View Quote


Underdog,

have you considered using a dremel and grinding a small "dimple" or recess at each point in the lower where the RRA posts/screws fix against it?  I would suspect that would make it very hard for the block to work its way up, and would guarantee the same seating point every time. Probably even 1/16" depth would do the job.

Of course, this involves using a dremel on the inside of your lower, but it wouldn't affect using the lower for .223 mags.
Link Posted: 10/30/2003 3:12:15 PM EDT
[#34]
I am gonna send JoeBlack my bolt to get ramped.
I will also send my Griffin block for him to look at also.
I have played with the block more today and I like it.
The ONLY drawback is that you must use a factory style 9mm bolt hold open if you are gonna use the bolt hold feature.
That means the if you are not using a dedicated lower you will have to swap out your bolt hold because the 9mm one is not compatible with the 5.56mm one.

CHARLES
Link Posted: 10/30/2003 3:19:13 PM EDT
[#35]
Quoted:
Radmd, I don't know about the ASA block but both the bottom loading and toploading Hahn block have the same set screw that tightens the roller in the front.
View Quote



ASA is drop in (snug slip in) from the top and no holding screws, clamps, pins, levers, or buttons
Link Posted: 10/30/2003 4:00:48 PM EDT
[#36]
Joeblack,
I would still argue that the toploading Hahn is superior to the ASA toploading.
Yes, the Hahn has an adjustable roller but you don't have to use it.  As you know, not all lowers are same.  It is nice to have options.  
Link Posted: 10/30/2003 4:55:35 PM EDT
[#37]
Quoted:
Joeblack,
I would still argue that the toploading Hahn is superior to the ASA toploading.
Yes, the Hahn has an adjustable roller but you don't have to use it.  As you know, not all lowers are same.  It is nice to have options.  
View Quote


No arguing from me.  I e-mailed the person who sent me their bolt and Hahn mag well adapter today and stated that it was constructed very well.  I don't like the sloppy ejector but other than that seems very nice.  

ASA is tight in the receiver mag well and mags are snug in the mag block.  I like them tight!! I've had 6 72 round Vector drum dumps in a row with out any issues, I think it's because of the mag well adapter and the mags repeating location do to the nice slip fit.

FWIW, I don't convert mags like ones I've seen. I mill the mag catch slot in the UZI mag's .005 over the catch width. I've seen mags converted .025 and wider than the catch. Way, way too much slop.
Link Posted: 10/30/2003 11:31:14 PM EDT
[#38]
Quoted:
Quoted:
For the record, I never had a problem with the RRA block "falling out"....Understand that the block secures VERY tightly in the mag well..The problem I had was that the block would eventually move upward under recoil and sooner or later rub against the bolt slowing the bolt down and giving failures....the Hahn block look to be susceptible to the same problems....UNDERDOG
View Quote


Underdog,

have you considered using a dremel and grinding a small "dimple" or recess at each point in the lower where the RRA posts/screws fix against it?  I would suspect that would make it very hard for the block to work its way up, and would guarantee the same seating point every time. Probably even 1/16" depth would do the job.

Of course, this involves using a dremel on the inside of your lower, but it wouldn't affect using the lower for .223 mags.
View Quote

Yes I thought of this,Problem is I think you'd have to be very precise and the "dimples" would Have be very close to the same Dia. as the "posts" in the block otherwise you'd still have room for the block to ride up..Alas my Redneck engineering isn't that close tolerance wise....Of course I'm not saying You'll have problems with block riding up,..I hope you don't...Its just something to look for.........UNDERDOG

*edited because I cannot spell at 0330....
Link Posted: 10/31/2003 5:49:06 AM EDT
[#39]


Yes I thought of this,Problem is I think you'd have to be very precise and the "dimples" would Have be very close to the same Dia. as the "posts" in the block otherwise you'd still have room for the block to ride up..Alas my Redneck engineering isn't that close tolerance wise....Of course I'm not saying You'll have problems with block riding up,..I hope you don't...Its just something to look for.........UNDERDOG

*edited because I cannot spell at 0330....
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After looking at a lower last night, I take back this idea- it looks like the side walls of the magwell are only about 3/32" or at most 1/8" thick.  One slip with a dremel and you would punch a hole right through.  Then you couldn't get the RRA block to seat at all!

There is enough "meat" however in the front of the magwell (maybe as much as 3/16" to 1/4") in the form of the two interior "ribs" that would allow you to cut a horizontal slot for the Hahn roller to engage.  There is also a lot more space to work on the front inside of the well than the sides. ctually, if the roller runs in the "slot" in the middle of the front inside of the magwell you might even be able to glue or jb weld a small stop shim in there that would not affect the insertion of a .223 mag.

It looks to me like the roller is a better configuration- more contact surface, and the placement on the front of the blcok means that as you crank it tighter, it should in theory cause the blcok to bulge out on the sides slightly which should make it grip even better.
Link Posted: 10/31/2003 5:53:22 AM EDT
[#40]
Quoted:
Quoted:Below is a pic that I got from some site that was selling it.
Note that you can adjust the block when it IS installed in the mag well so it can be adjusted so it will NOT come out.  You use an allen wrench to adjust a set screw that presses on that roller.
[url]http://home.cfl.rr.com/c3stuff/m16/hahn.jpg[/url]
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I just ramped a 9mm bolt and he sent his mag well adapter with the bolt for me to look at.  The adapter is this same exact one.  Very, very nice, but, the ejector is held in by two pins (same two pins that hold the bolt hold open arm in place)and it's very sloppy.  I was able to put a .008" feeler gage between the ejector and the wall it locates on.... The ejector tip, tip that makes contact with the cartridge, wiggles around 1/8".  Is that a problem? I don't know..... I had to bend my ASA to rub the bolt....... That much slop makes it hard to bend over so it rubs (almost rubs) the bolt.... He's going to let me know how it runs.
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Could you shim it so that it doesn't wiggle?
Link Posted: 10/31/2003 10:46:30 AM EDT
[#41]
Quoted:
Quoted:
Quoted:Below is a pic that I got from some site that was selling it.
Note that you can adjust the block when it IS installed in the mag well so it can be adjusted so it will NOT come out.  You use an allen wrench to adjust a set screw that presses on that roller.
[url]http://home.cfl.rr.com/c3stuff/m16/hahn.jpg[/url]
View Quote



I just ramped a 9mm bolt and he sent his mag well adapter with the bolt for me to look at.  The adapter is this same exact one.  Very, very nice, but, the ejector is held in by two pins (same two pins that hold the bolt hold open arm in place)and it's very sloppy.  I was able to put a .008" feeler gage between the ejector and the wall it locates on.... The ejector tip, tip that makes contact with the cartridge, wiggles around 1/8".  Is that a problem? I don't know..... I had to bend my ASA to rub the bolt....... That much slop makes it hard to bend over so it rubs (almost rubs) the bolt.... He's going to let me know how it runs.
View Quote


Could you shim it so that it doesn't wiggle?
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No, the two pins that hold the bolt hold open arm hold the ejector as well. The ejector and the bolt hold open arm rub against each other.  If I had this mag well adapter, since it splits in two (another reason I like it), I would flat head screw the ejector to the mag block. Other than needing that (IMHO) it is a first rate mag block. If I needed a bolt hold open magblock, I would buy this one......FWIW  
Link Posted: 10/31/2003 11:19:14 AM EDT
[#42]
Or maybe JB weld the mutha on nice and snug? [;)]

BTW, awesome thread guys.  I think we have a great comparison thread on all the blocks  right here.  Anyone think this is worth tacking?

Dawg
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