I bought a magazine at the local gun show that's for a 22 version of the AK-47 -- I paid $15 for it. It's supposed to be a 20 rounder and I figured I'd try to make it work with the M261 unit. Through trial and error I desided to remove the real magazine from the AK mag shell and adapt it to an AR magazine -- it took all day but I got it working!

This is the magazine in my AR -- you can see the M261 bolt. I use this magazine along with a standard M261 mag insert setup for the .17 Mach2 round. I installed a .17 caliber liner in the AR barrel.

The mag on the left is the standard M261 mag insert in a GI 20 round mag. The mag on the right is the 20 round Hi-Cap I just built.

This is a picture of the tops of the two mags -- the Hi-Cap on the left. Looking down from the top, the Hi-Cap mag looks a little crapy -- I used an old junk AR magazine shell and kinda slapped things together.

Does it function well?  Looks like a fine job!


- BG

I ran several .17 Mach2 20 round tests through the mag with no problems -- my problem is I only bought 4 boxes of the ammo so I needed to save some for the range.

Can you provide any details on the .17 liner for the barrel?
Thanks,
Pete

I used a 1/9 twist .17 caliber liner from Brownells. The M261 barrel/chamber adapter is drilled out using a barrel liner drill to make sure the hole is centered all the way through it. The chamber is cut with a Manson .17 Mach2 reamer made for Redman barrel liners. The liner is crowned using an 11 degree crowning tool form Brownells. The liner is epoxied into the M261 barrel and then the extractor groove and spring shell holder groove are cut with a dremel.

The is the removable barrel liner setup with the drilled out GI barreled upper and the M261 unit.


This is a close-up on the M261 barrel with the liner installed next to the M261 unit.

The exact same thing can be done with a 22 caliber liner and another M261 barrel/chamber adapter. You can just slide out the .17 Mach2 liner setup and slide in the 22lr liner setup and shoot really cheap ammo! I have a 22lr version but it's cut shorter to work in a "M4 like" carbine setup I have.

I originally did the exact same thing with the Ciener conversion unit but the Ciener requires a little extra work to allow it to function correctly with the .17 Mach2 round.

This is a picture of the carbine with the Ciener that shoots the .17 Mach2 -- the barrel liner in this carbine is 17.5" long even though the outer barrel measures only a hair over 16".

This is really COOL. Nice job!!!!

If you can make that mag work, you can adapt a Ciener--it's the same basic magazine.

Quoted: If you can make that mag work, you can adapt a Ciener--it's the same basic magazine.

Your right about the ciener magazine and I have a couple of Ciener 30's but didn't have the heart to chop one up. Somebody here on ARFC had found a bunch of the Ciener type 30 round mags without the metal magazine adapter welded on -- I would love to find out where they came from!

The magazine part looked like this. the mag in the pic is for a PPS-50 and costs like $99!

I might just try cutting up a Ciener and make it work with the M261 -- I just hate the idea of chopping up a perfectly good mag.

by the way -- I switched back to the 22lr liner setup and ran a couple of mags worth of Stingers through it and it was a blast and the stingers were a lot easier to load than the Mach2's.

DEFINITELY let me know how these turn out.  i want one!!!

True statement, I'd like to find some too.  I think the mag is made for a bingham or some other .22.  Wouldn't it be nice to find a source for those at say $16 a pop.  I'd make a dedicated block for them and buy them by the crate.

Quoted: If you can make that mag work, you can adapt a Ciener--it's the same basic magazine.

Snake -- below is my little carbine with the original Ciener unit and 30 round mag.


The picture below is the modified Ciener mag that works with the M261 -- for both 22lr and .17 Mach2. I like the M261 better for semi-auto stuff.


Notice that the position of the Modified mag is further forward than for the Ciener.

The picture below is the top of the modified Ciener 30 round mag -- notice how far forward the main magzine is and also the ramp that I attached to the mag to help with the smooth flow of the round from the mag to the chamber.

If you find a source of those mags, please let me know. I have an AP-80 and an AP-84 that use them, and I need some. Even the 10 or 15 rounders would be welcome. In fact, I actually prefer the 15 rounders.

I wish someone with "connections" would see these threads and build a freaking hicap M261 mag in the first place.  

Quoted: I wish someone with "connections" would see these threads and build a freaking hicap M261 mag in the first place.

You are so right about that one! This is one of the reasons I did this -- to try and get somebody interested in making a hi-cap for the M261 or maybe know where there is a supply of the long 30 round mag pieces that Ciener uses or something similar! The price of the Ciener mags is around $60 so I only wanted to do one to see how it worked -- plus I have developed a real liking for the M261 unit! I remember reading that some company over in (I think) England is going to start making new M261's but I never saw any more info on it.