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ARMATAC
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Posted: 8/3/2011 12:36:52 PM
[Last Edit: 8/3/2011 12:41:01 PM by ARMATAC]
I figured this might help some. The nature of the tilt is usually no big deal but I have found an upper that it is a problem with. It removed the entire opening of the mouth on the extension tube and was just intermittent with problems. It would wierdly do 149 round dumps repeatedly. Then it just got worse.
*To see if you could be having a tilt issue, take your upper only, push up on the area near the bolt like the magazine does, pull down on the rear of the carrier and cycle the carrier, if you feel it is hard to unlock compared to normally cycling the carrier you may benefit from this mod.

The TDP for the AR calls for a high tolerance near the chamber and it can be pretty far out near the rear of the receiver. Manufacturers have tightened the tolerances between carrier and bore so the tilt isn't as bad. The mass production of the TDP for the DI system makes it difficult, I think, for an all out replacement piston upper that has the added meat on the bottom rear of the carrier because it will cause a bind in certain limits of the tdp in the extension tube.
So I have really liked the looks of those anti tilt buffers. So I made one and it seems to have really helped out my situation I had with the tilting badly upper.

Here is what you need.
buffer, I used a H2
.201 drill bit
1/4-20 tap
.188 thick piece of aluminum about 5/8" square or round
1/4-20 button head cap screw
a milling machine-i know this makes it right out of the DIY but there are a few ways this could be done I just chose to mill it.

Step 1.take apart the H2 buffer,
Step 2. Make the round slug that fits very snugly into the rear of your carrier, should be about .62” in diameter but it may vary and you want a very good fit, in the step you are making the round you also put a .260 hole through the center, you can make this larger as this is for clearance and not a locator, it just needs to be larger than the o.d. of the threads and any offsets incurred. Once you have a piece with a hole in the center and a good fit with the carrier you are ready to move to the buffer head modifications.

Step 2. Find center of the buffer head,
Step 3 drill with .201 drill through the buffer head, you need to have the tapped hole as close to center as you can get it but it is not as important as the cylinder location the slug you made will go inside.
Step 4. You will need to mill a .04” deep round hole into the head of the buffer about the exact size of the slug. This needs to be concentric with the buffer as best as possible. If you do this in the same operation of the tapped hole, check for concentricity after the pilot, make the shift, then do the milling.
(This could be done differently, for example no need for milling if you get a shouldered screw, like a ¼-20 screw with a .25 shoulder on it, then you would nail your drilling and tapping on the buffer, and the hole through the slug should be roughly .251 to have a tight fit with the shouldered screw. )
Sneak up on your targets, the slug can be converted from its slug to its ideal shape very easily by holding it with a 1/4-20 screw, chucking the screw in a drill, turning it on and using a file as a turning tool to make the additional geometry. The taper on the slug really helps with installing the upper.
Look at the print and see if you can make the angled geometry to the slug, do not alter the diameter near the base, (I had to edge break the base to get a good snug fit into the buffer pocket)
Step 4. tap through the buffer head now.
Step 5. After making sure all the fits are good, screw the cap screw through the slug into the buffer. Look into the buffer and see how much is protruding. Keep taking apart and sanding the screw thread end until it is flush with the inside surface on the buffer. Take the cap screw and take a pair of pliars to screw the theads up just a little bit(this is assuming it is very easy to thread in and out after tapping) and apply red anti-seize to the theads. Now clean all the buffer internals, coat with a dry film lube if you have it(fine graphite), oils work as well.
Step 6. Install and check the action, the upper and won’t come apart with just removing the rear pin but that is nothing to complain about. When installing, rock the rear into the buffer while the front pin holes get aligned. Then install both pins and cycle. I can install and uninstall my upper whose pins are pretty free in just seconds. Any complaints about the upper-lower disassembly are overcome when you see how easy it is.

gotta get back to work..




Dawg180
Student of the Assault Rifle
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Posted: 8/4/2011 1:34:12 AM
Some enterprising guy could start cranking those buffers out and make a mint!
"I pledge allegiance to the ideal left us by men wiser than I, having the forethought to gift their children with the power of being free."
ragingyeti
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Posted: 8/4/2011 9:05:17 AM
Originally Posted By Dawg180:
Some enterprising guy could start cranking those buffers out and make a mint!


Someone did.
Bretshooter
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Posted: 8/4/2011 9:38:30 PM
Originally Posted By ragingyeti:
Originally Posted By Dawg180:
Some enterprising guy could start cranking those buffers out and make a mint!


Someone did.


And that would be the reason for the wink...
ragingyeti
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Posted: 8/4/2011 11:13:42 PM
Originally Posted By Bretshooter:
Originally Posted By ragingyeti:
Originally Posted By Dawg180:
Some enterprising guy could start cranking those buffers out and make a mint!


Someone did.


And that would be the reason for the wink...


And now I see what you did there...

I'm a tad slow when reading tone. I always tend to think literally....
Dawg180
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Posted: 8/5/2011 2:25:05 AM
LOL, that actually wasn't the reason for the wink, I assumed Armatac might start cranking them out, I had no idea someone was already making them!
"I pledge allegiance to the ideal left us by men wiser than I, having the forethought to gift their children with the power of being free."