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The following is a list of modifications that may enhance the function and reliability of your .22 caliber converted firearm. These include modifications to the drum, the host firearm and 22cal conversion. A&D ENTERPRISES and Bazooka Brothers offer these modifications as possible solutions that have worked in our firearms and assume no liability or responsibility for you or your firearm and if you choose to do any modifications it is solely at your own risk.

Drum Modifications

For all of you that have questions as to what can be done to the drums that are being used on the A&D Enterprises,LLC adapters for .22 conversions in the AR15/M16 series and the HK G3/91/51 we offer the following;  Because this drum operates upside down as compared to how it was originally designed and because it is feeding up against gravity instead of with gravity, there are a few things that can be done to enhance the function and reliability of this unit . It is also noted that this drum has the basic parts of; a flat plate, a domed unit that contains the cartridges, 5 springs, a circular follower,  and external parts of screws and a circular threaded ring. additionally there is and external winder, either geared or ungeared. We recommend the ungeared winder do to simplicity and durability.

Any additional friction that can be eliminated inside the drum will improve the function of the unit, so it is 1st necessary to disassemble the drum by removing the 4 screws and setting the flat plate aside.before removing the next piece; the round follower. Notice the position of the springs underneath and how they fit into small recesses in the follower. It is important that when the unit is reassembled that the springs are positioned properly in relation to the follower. Also note that the follower does not rotate separately but goes up and down by spring pressure and cartridge additions or removal. Note that the follower has several small extended radius areas on the inside of the follower that ride up and down in the splines on the inside of the dome where the nose of the bullets are on this inside edge and close to these will be some small round circles that were part of the molding process. Oftentimes these small round circles have plastic slag on the the top of them which can provide friction during function.

Next the round follower is removed. These small round areas in step 2 are then lightly sanded down, finishing with 800-1600 paper. Sand until these areas are glass smooth. The top and bottom of the edge of the domed part of the drum where it contacts the flat plate is sanded and smoothed the same way. Powered graphite may be used on the drum as is used in a "beta mag" drum. If used it must be sparingly. Also, after the surfaces have been properly prepared they may be waxed and polished with a quality auto wax that leaves no residue. This will slick the surfaces. The drum must be cleaned every 1000 rounds do to the excessive wax and dirty powder from the minimags. Use hot soapy water and a tooth brush or a baby bottle brush to clean. Do not use solvents as these can and will damage the drum and the adapter. A metal top is also available from e and l that will fit on the lexan dome in place of the lexan flat plate. It does provide a slicker surface when used with a lexan dome than the standard lexan flat plate but is more costly. The inside of the drum needs to be broken in by just running the drum in the gun. It takes several runs of the drum to help smooth out the sharp edges of the inside where the noses of the cartridges ride an the outside  slots where the rims of the cartridges ride.

AR15/M16.22 Conversion Modifications

Polish every surface that has moving contact with another surface. A dremel type tool with a good polishing compound works fine. If your kit has a parkerized or oxide type finish it will tend to collect dirt and fowling very fast and will gum up the kit prematurely. Polished surfaces will help with this problem and reduce friction but will easily rust if stored without a light coat of oil.
  1. Rail Surfaces - Polish any surface that is guiding the bolt and anti bounce weigh
  2. Bolt Rail Slots - Polish the inside of the slots where the guide rails slide through
  3. Anti Bounce Weight - Polish all surfaces so that this weight will slide back and forth freely inside the receiver when assembled.
  4. Rear Of Bolt - Polish the surface where the hammer makes contact when the bolt is retracted.
  5. Hammer Face - Polish the hammer face where it will contact the back of the bolt.
  6. Chamber Insert Feed Ramp - This area is where the nose of the bullet will slide before entering the chamber.
  7. Underside of the Bolt - Polish the entire rib where the bolt would ride over the cartridges still in the magazine or drum adapter body, when the bolt is retracted.
  8. Recoil Spring Guide Rod - Polish the entire rod so that the spring and rod slide smoothly inside the bolt.
  9. Extractor Face - Polish the leading portion of the extractor that makes contact with the chamber insert. For the best results, drive out the pin that holds the extractor in place and polish the sides as well. The extractor must move freely inside of the bolt in order to hold the rim of the cartridge correctly.
  10. Check Extractor Headspacing - What is this? This is the gap the extractor creates in front of the bolt face to allow the rim of the cartridge to rest firmly in the face of the bolt.  This is the 1st step in controlling ejection of fired empty cases. How do I check it? Remove your kit from your rifle and disassemble it so that you have the bolt in your hand. Place a .22 cartridge in the pocket that is milled into the face of the bolt. There should be no slop between the front of the rim of the cartridge and the extractor claw. In other words, make sure the extractor is "pushing" the round to the side and holding the rim inside of the little pocket. If the gap is excessive, the round will tend to fall out of this pocket and not be contacted properly when the ejector hits it during operation. Another easy check is to hold the bolt up to the light and see if there is any gap between the face of the bolt and the back of the extractor face; there should be none. How do I fix this? Make a note of the amount of excessive gap that is needed to be taken up. Drive the retaining pin out of the bolt that is holding the extractor in. Place the extractor in a silid vice with smooth jaws. Gently bend the end of the extractor inward to close up the excessive gap. The extractor is soft material and can be bent easily. Reassemble the extractor and recheck the gap. The firing pin should be polished and the pocket and spring cleaned regularly.
  11. Ejector Tab Buildup - Once in awhile on some units the ejector tab does not stick out into the bolt far enough to contact the empty case sufficiently. This area will need to be built up with a tig welder and reshaped. With a properly gapped extractor and a strong ejector tab, a spent case flies right out with very little effort.
  12. Excessive Fowling in the Chamber - A poor seal of the chamber insert in the chamber often results in wasted gas bleeding by the insert and blowing back into the action. 9/16 X 3/4 " Neoprene O Rings stacked in series inside the locking area of the barrel will prevent this. When the chamber insert is inserted it seals itself inside of the .223 chamber. The O Rings help stop forward and aft movement of the chamber insert which also robs bolt inertia. We do not recommend lubing these units except for storage. If you choose to lube your unit use only a couple drops of a light oil and wipe off the excess.
  13. Recoil and Hammer Springs - A very common problem is that there is excessive pressure in a stock hammer spring and often the recoil spring is not of ideal tension. Either or both of these can hinder ideal function of the .22 unit especially with the drum adapter. Lakeside Guns produces theses springs.

Ball Detent Modifications

The following was an article download from AR15.com that you may find helpful.

Here's the basic step-by-step to install a ball detent anti-bounce device in a Ciener kit. This is about as easy as this type of setup can be. While I did it in a vertical mill, a drill press would work fine. All you need is a 5/32" drill and a 1/8" ball, cannibalized from a ball bearing or similar.

The concept is this: The JAC kit uses a sliding weight to help minimize bolt bounce, which is really applicable only when you have a happy switch and a FA capable Ciener kit. Bolt bounce is the phenomenon in which the bolt, upon chambering a round, bounces back slightly from the bbl face, causing light primer strikes and FTF. The sliding weight helps drive the bolt forward when it contacts the bbl. If you think it'll work in FA without the sliding weight, try removing the weight and watch what happens. It doesn't run!

By having a spring loaded ball engage a hemispherical detent when the bolt is in battery, the bolt is much happier and will pretty much NOT bounce on you. Norrell uses a similar setup, I believe, in his 10/22 FA trigger packs.

First, mount your bolt as shown in a vise. The spring and ball will ride inside the bolt, near the aft, right-hand side of the bolt when viewed from the rear. 

After spotting for ~ 0.235" from the rear of the bolt (the actual measurement isn't critical, just remember the value), I drilled a 1/8" hole to a depth of 0.200" from the bottom of the rail channel. Don't break into the firing pin hole! The 1/8" hole was followed with a 0.156" end mill, plunged straight down.

You can use 1/8" OD springs, or 0.150" OD; just be sure the spring fits and is free to compress in the hole, and the 1/8" ball won't fall into the spring's ID. The next step - we want to cut a detent into the rail for the ball. The detent will form a pocket for the ball when the bolt is fully forward and a cartridge is chambered. This is probably the trickiest part of the mod... you must position the bolt on the rail where it would be if the bolt is in battery. Locate the rear face of the bolt, and move forward on the rail the same distance as the hole in the bolt was drilled. Use a prick punch, DRO, what have you, so you can then remove the bolt and work only on the rail.

Use a 1/8" end mill, or a needle file (be careful; err on being too far FORWRD on the rail. If too far aft, the mod will be worthless.) Cut the detent to a depth of 0.040". Too much cutting will "stiffen" the action of the ball and detent. Too little and it will not be as effective. Start small, you can always open it up more. In my case, 0.040" seemed to work.The parts layed out without the bolt. Hopefully the concept will be clear at this point. 'Pictured with the bolt. The spring and ball are installed into the bolt. You can see the notch for the ball cut into the rail to the right in the picture.'

I cut a number of springs of different lengths and diameter of wire. Here's a neat trick... hate the open end of the spring after it has been cut to length? Create a mild steel post like this one. Heat it to dull red with a propane torch, and without branding yourself, press the spring onto the red-hot rod. The heat anneals the last spring element, and the spring end closes right up, perfectly! Don't let it sit there, remove the spring the moment it has been cloed up. It takes about 3 seconds only.

An assortment of springs, all closed-ended with the hot fixture.

All cutting is basically done now. Select a likely spring and install it with the ball into the bolt. Adding spring, ball, and bolt to the rail is not too tough. Note the notch in the rail as it all comes together. You can feel a distinct "chunk" as the ball drops into the rail cut.

Now this was interesting... even WITH the recoil spring, the ball keeps the bolt in the correct position on the rail! Normally, you'd have to use the sear trip stamping to keep it in this configuration. I lubed the rails, notch, and ball, and moved the bolt back and forth on the rail several times, loosening the action of the detent a bit, and checking the forces required. My original guess of a 0.040" notch, along with the spring (you can always swap springs of different strength) felt pretty good.