Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login
Posted: 12/18/2002 6:56:26 AM EDT
[Last Edit: 12/18/2002 7:33:23 AM EDT by AR-fan]
The reason I ask is there is a 10mm Oly owner that modified a colt magwell conversion to allow Uzi 41AE mags to be used with his Oly upper and also be able to use the regular mag catch. I believe he had to squeeze the front of the mag to allow the 10mm round to fit -- but the point is he got the magwell conversion to work with the Oly upper (10mm upper) and he can use the standard AR mag catch.


I don't own an Oly right now but I wondered if this could be done for the 10mm Oly could this also be done for the 9mm? Maybe something similar to the Colt-sten magwell conversion?

nordicg3k.tripod.com/bren10mmautomainpage/id9.html
Link Posted: 12/18/2002 2:15:50 PM EDT
I don't have one, but yes it can be done with the Uzi mags. In order for the Colt 9mm mag block to work with the Oly upper you need to remove the ejector and last-shot hold open tab from the mag block. You'll also need to grind down the ears on the steel feed ramp a bit. Other than that you just need to cut the appropriate notch in the Uzi mags. Take your time and do it right because once it's screwed up it's screwed up for good and you've just wasted a preban mag body. I scribed the hole on the side of the mag body, drilled a 3/16" hole in the middle of it and then squared up the hole using a jeweler's file. If I ever do this project again I think I'll do it with a Oly .40 S&W upper and mate it to a black Cav Arms lower. With the .40 S&W or 9mm you don't have to open up the mag well in the mag block or mess with modifying the mags (other than cutting the notch). Oh yes, one other thing... On my 10mm there's nothing to keep the mag from being inserted too high. If the bolt is locked back and I'm trying to insert a fresh mag it can be difficult to get it to lock in place. As long as the bolt is closed though the bolt itself acts as a stop and ensures that the mag locks in place correctly.
Link Posted: 12/18/2002 7:30:25 PM EDT
Originally Posted By NordicG3K: I don't have one, but yes it can be done with the Uzi mags. In order for the Colt 9mm mag block to work with the Oly upper you need to remove the ejector and last-shot hold open tab from the mag block. You'll also need to grind down the ears on the steel feed ramp a bit. Other than that you just need to cut the appropriate notch in the Uzi mags. Take your time and do it right because once it's screwed up it's screwed up for good and you've just wasted a preban mag body. I scribed the hole on the side of the mag body, drilled a 3/16" hole in the middle of it and then squared up the hole using a jeweler's file. If I ever do this project again I think I'll do it with a Oly .40 S&W upper and mate it to a black Cav Arms lower. With the .40 S&W or 9mm you don't have to open up the mag well in the mag block or mess with modifying the mags (other than cutting the notch). Oh yes, one other thing... On my 10mm there's nothing to keep the mag from being inserted too high. If the bolt is locked back and I'm trying to insert a fresh mag it can be difficult to get it to lock in place. As long as the bolt is closed though the bolt itself acts as a stop and ensures that the mag locks in place correctly.
View Quote
I'm extremely curious abou this project. I was also thinking about putting a Colt-style mag adapter with a 9mm Oly upper (in my case using STEN mags), but was told by a couple of very knowledgable gunsmiths that it would not feed properly, due to the extra length the cartridge would have to travel from being picked up by the bolt mid-mag well to the front of the mag well into the Oly upper forcing cone. Now you come along and say you've done it with a 10mm! Perhaps the 10 works OK in this setup because of the longer 10mm case as opposed to the 9mm case? Please elaborate on your project and venture a guess as to how it would translate to 9mm or (even more interesting) .45ACP? Thanks!
Link Posted: 12/18/2002 9:28:51 PM EDT
I had looked at the Sten mags when starting this project and ended up going with the Uzi .41 AE mags instead. It's kinda' hard to see in the pictures, but there is very little material you can remove from the front and back of the inside of the Colt 9mm mag block. The Sten mag, because of the fold on the inside of the back of the mag, makes it too big front to back (if I remember correctly) to work with the Colt mag block. There are two or three other 9mm mag blocks that are similar to the Colt design that may allow more room to play with, but I couldn't say for sure. I too was a little concerned about the "jump" the cartridge would need to make since the magazine needs to sit in the middle of the mag well for the standard AR mag catch to work. This really became and issue when I had to grind down the "ears" on the steel feed ramp so that the Oly bolt could clear it and fully seat the cartridge in the chamber. In the end though it pretty much turned out to be a non-issue. I've shot the gun laying on its left side, right side and upside down and I have had zero FTFs. Out of the different chamberings available the 9mm or .40 S&W would be easiest because very little would be needed to be done to the Colt mag block. Getting it to work with the 10mm was time consuming (and a little nerve racking as I was constantly wondering if I had thrown away a couple hundred bucks trying to get it to work), but I wouldn't mind doing it again. I think doing a .45 (using Uzi mags) would be doable, but I can't give you any specifics since I've never had a chance to even look at an Uzi .45 Auto magazine. I have to say that out of all my guns this Oly 10mm carbine is my favorite as far as "pure shooting satisfaction!" Part of that is because I put a lot of work into it myself, but also it's just an awesome 50-75m gun with respectable puch (for a long gun) and almost zero recoil. [img]http://image1ex.villagephotos.com/1207453.jpg[/img]
Link Posted: 12/19/2002 3:15:50 AM EDT
NordicG3K, I get the feeling I found an article you did on your modification and I posted it here. Hope you don't mind? I did the sten magwell conversion on my Colt system Rock River 9mm and love it but I have seen posts from Oly owners saying they wished they could use the standard mag catch [u]and then I found your article.[/u] I am very interested in doing some other pistol calibers -- one of which is your favorite -- the 10mm auto. Cost wise I think it might be less expensive for me to get an Oly upper and do another magwell conversion block set. Also, The .41 AE mags -- where they easy to make a little longer front to back -- did you have to also do a little modification to the mag follower? The .41AE is a double stack -- is it a single feed? How many 10mm rounds fit in the AE mag? Hope you don't mind all the questions!
Link Posted: 12/19/2002 7:22:12 AM EDT
No problem using the article. The Uzi .41 AE mags are double-stack/single-feed mags. I picked up a number of mags and sent them to Olympic Arms for the modification to accept the longer 10mm round since they already have a "jig" for this. They charged me $5 per mag to slightly pinch the front edge of the mag body in order to bow it out slightly. The followers are also pinched to fit the new profile of the mag body, but they still needed a lot of patient tweaking to get them to function properly. Oly originally listed the mag capacity as 15 or 16 rounds (can't remember exactly), but I can get 20 in mine which is the original capacity of the .41 AE mag. One other thing is that I get much better functioning with my 10mm ammo loaded to an OAL of 1.250" rather than 1.260" which most manuals list. During function testing I found that while I could load 1.260" rounds fine, they would tend to drag against the front of the inside of the mag body and begin to tip which would jam up the mag. I think this has been a very successful project, but I don't think I quite trust it completely for defensive purposes.
Link Posted: 12/19/2002 8:01:22 AM EDT
NordicG3K, Thanks for all the information.
Link Posted: 12/20/2002 9:47:41 PM EDT
Originally Posted By NordicG3K: I too was a little concerned about the "jump" the cartridge would need to make since the magazine needs to sit in the middle of the mag well for the standard AR mag catch to work. This really became and issue when I had to grind down the "ears" on the steel feed ramp so that the Oly bolt could clear it and fully seat the cartridge in the chamber. In the end though it pretty much turned out to be a non-issue. I've shot the gun laying on its left side, right side and upside down and I have had zero FTFs.
View Quote
I'm really curious how your lower would do with a 9mm upper on it. Do you know anyone in your area that has a 9mm upper that you could stick on your lower to see if the 9mms feed with the aforementioned "jump"? I know the 9mm mags would not fit perfectly in your 10mm-modified magwell, but it might be cloase enough to detirmine whether or not the "jump" messes up the 9mm setup. Lemme know. Thanks!
Link Posted: 12/21/2002 5:21:15 AM EDT
Corvus, I'm still a little curious also. I really have no idea what the Oly Chamber opening looks like or what the bolt looks like -- I haven't seen any Oly pistol caliber uppers at the range. I can't imagine there would be any more of a jump than the Colt system has but I've seen posts from experts that say it won't work -- but then there is the article from NordicG3K! I know the larger chamber hole for the 10mm would make it a little easier for the round to make it home I just don't know what might make it [u]not work[/u] in the 9mm.
Link Posted: 12/21/2002 7:31:22 AM EDT
[Last Edit: 12/21/2002 7:36:41 AM EDT by NordicG3K]
[b]WARNING: I HAVEN'T HAD MY COFFEE YET SO WHAT I'M ABOUT TO SAY MAY BE WAAAAAAAAAY OFF![/b] To my way of thinking a single feed 9mm Uzi or Sten magazine would be more reliable in that the cartridge is already in line with the chamber and so the bolt is basically pusing the round straight forward. In a true Colt 9mm system the magazine is a double-feed setup (like a regular 5.56 AR mag) and so when the bolt strips a cartridge from the mag it has to be "bumped" towards the middle in order to align it with the chamber. (I think that's why the "ears" on the feed ramp were so high.) Also, the Oly is a blow-back and so the bolt doesn't actually "lock up" like the 5.56 AR bolt. Instead it has more of a truncated cone shape to the front of the bolt. Again this is where I would think the Oly system would be more reliable because this would work similar to the forcing cone on a revolver, forcing the bullet/cartridge to align center. I know this is kinda' hard to visualize so I'll try and take some close-up shots of the Oly bolt and chamber. PS - I'm afraid I don't know of anyone here abouts with a 9mm upper in any make. I hope to pick one up some day, but that will be a while unfortunately. [url=http://www.bren-ten.com][img]http://image1ex.villagephotos.com/1211382.jpg[/img][/url] [b][i][red]10mm-aholic:[/red][/i][/b] S&W 1006, S&W 610, Colt Delta Gold Cup, T/C Contender, Olympic Arms CAR-97/10mm, Bren Ten SM, Bren Ten SFL, Ruger Buckeye, Glock 20, iAi Javelina, Bren Ten MP, Paraordnance P16.40 LTD 10mm Conversion & S&W 1086
Link Posted: 12/21/2002 7:42:41 AM EDT
[Last Edit: 12/21/2002 7:52:45 AM EDT by AR-fan]
"Nordic", I really would appreciate the pictures if you get the chance. I agree with you about single feed mags -- I use the sten mags in my RRA 9mm and they work smooth as silk. I replaced the stock front ramp with a homemade ramp that is more like the forcing cone you mentioned. When using sten mags in the Colt system the round must go up slightly and any type of ramp will work. I was hoping that the design of the Oly may actually enhance the feed from the sten mag to the chamber.
Link Posted: 12/22/2002 7:46:20 PM EDT
AR-fan, here's a couple pics of both the Oly bolt head and chamber. (Hmmmm, I don't think I cleaned it after shooting it the last time.) Hope these help. [img]http://image1ex.villagephotos.com/1226713.jpg[/img] [img]http://image1ex.villagephotos.com/1226714.jpg[/img] [url=http://www.bren-ten.com][img]http://image1ex.villagephotos.com/1211382.jpg[/img][/url] [b][i][red]10mm-aholic:[/red][/i][/b] S&W 1006, S&W 610, Colt Delta Gold Cup, T/C Contender, Olympic Arms CAR-97/10mm, Bren Ten SM, Bren Ten SFL, Ruger Buckeye, Glock 20, iAi Javelina, Bren Ten MP, Paraordnance P16.40 LTD 10mm Conversion, S&W 1086 & S&W 1076
Link Posted: 12/22/2002 10:10:10 PM EDT
Nice pics.... so that's what it looks like.
Link Posted: 12/23/2002 3:49:34 AM EDT
NordicG3K, That's a cool design -- I've never seen it before! Due to the pickup ramp on the bottom of the bolt and the matching pocket just below the chamber I can understand why people would think it won't work. It's like a little wall just below the chamber opening -- a lot more area to smack than would be found on the Colt system. Your longer rounds (1.25") are like a long shaft arrow -- I would hate to spend the money on an upper just to find out it won't work with 9mm, 40 S&W or 357 Sig. Maybe some 9mm Oly owner might try it (experiment)!
Top Top