I've got the 9mm AR project almost done.  It is built on a Century C15 forged lower receiver (just has their name, they didn't make it), modified JRW magwell adapter to use Sten mags and the rest (upper, stock, lower parts kit) is Rock River Arms.  As you can see by the below picture, it sports some very sexy green furniture

I have a few more questions before I'm ready to finish it.  They are ...

1. 9mm Stock Spacer - does this go in the stock before the buffer spring, or after the buffer spring and buffer?  In other words, what should be touching the bolt-carrier, the buffer, or the spacer?



2. The mag well isn't quite tapered enough to allow the "bumps" on the sides of the mag to fit through.  I tried squeezing one mag, but it still doesn't want to fit at the bumps.  Would it be okay to "mill" a couple notches in the receiver to accommodate the mag bumps?



3. When installing the front mag block, should I insert it until it touches the bolt, and then back off a hair?  The back block is caught by the mag catch, so there's really no guess-work there.  I'm thinking that I need to give as much feed-ramp lift as I can.  I already had to shave off some metal from the top of the ramp sides to keep from scraping the bolt.



4. Should I notch just one or two mags to start with and then wait until I take it to the range before doing the rest?  I'm afraid the range trip might require some more fitting or tweaking and I'd hate to have all the mags notched improperly.  Never mind, this question answers itelf.

Well, I think that's about all I have for now.  I appreciate any advice or information you can give.

Thanks,
LL

Don't know the answers to the other questions, but I do know that the stock spacer goes into a rifle length buffer tube first, then the CAR length spring, then the heavy 9mm buffer last.
Sluggo

That would probably be fine.  I just shoved the hell outta mine, and they fit in.  It dinged up the magwell where the bumps hit, but who cares?


That's probably the best way to do it, or you could just install the front block so that the top of the block BODY is flush with the top of the magwell.  Either way, you want it low enough so that the feed ramp sides don't rub on the underside of the bolt.

[b]ABSOLUTELY[/b].  Best way to notch the mags (at least how I did it) was to remove the mag catch, shove a mag up there (with the block installed) high enough to hit the bolt.  Then scribe the mark in the mag catch hole, onto the mag.  It is better to cut the mag catch too LOW on the mag body than too high.  Once you cut it too high, you've lost the mag (unless you can weld the cut up, and try again.)  Once you get the right position oh the mag, you can copy the position onto other mags.  The important thing to remember is, since Sten mags vary a little in all their measurements, you have to measure from the HIGHEST point on the mag, down to the TOP of the mag catch hole.  The highest point will be the topmost part of the feedlips.

Good luck, and keep us updated!

Sweet.  

Gloftoe covered it all....

[url]http://www.quarterbore.com/ar15m16/colt2stenmags.html[/url]

The "Word" file is being hosted as HTML now... not sure if you saw/have this version.

Thanks for the info.  Let's see ...

1) LL quietly puts the spacer in the BACK of the stock ... DOH!

2) I ended up with a little of both.  I notched the magwell a little, and for mags that are too tight, I squeezed them just a hair.  They should still function just fine as Sten mags.

3) In order to get the feed ramp up a little higher, I took some metal off of the top and tapered the sides a little.  It now rides just a little higher than flush.

4) I have successfully notched two mags using a drill, Dremel and some filing.  Looks a little crude, but effective.  Both mags lock in nice an tight, yet drop free when released.

Below is a picture of my finished mag block.  Because I had a small milling machine available, I was able to do some detailed work.  The two most noticeable differences on my block are:
1) I left the "wings" on the front block to stabilize the mags.  The fit is perfect.
2) I left the feed ramp intact (although I took some metal from under it to make it flush with the block).

I did some minor testing with snap-caps, but they wouldn't shoulder properly in the chamber and would get stuck.  So, being the daredevil that I am, I loaded up 5 live rounds, went out to the back yard, aimed into the mulch and dropped the bolt.  1st round chambered.  Pulled back, eject, let loose, 2nd round chambered.  I then went through all five rounds and they chambered and ejected perfectly.  The second notched mag also functioned perfectly.  Of course, I didn't shoot it in my back yard, just function checked it.

I'll post a range report as soon as I can get there.  My favorite outdoor range is an hour away so I have to do some planning.  Hopefully in a few weeks although I might brave the indoor range just enough to function test and sight it in.

[banana] LL [banana]

[img]http://photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=15319[/img]
{Note: If you find it useful, feel free to use this photo for the web site as an alternate example.)

SWEET!!!!!