Added Troy's MRF-M Mid-length FF. What I've read about installing the FF hand guard should have been easy but turned out be a real bitch. I dremeled off the delta ring. No problem. Pulled off the weld spring with some pliers. No problem. Getting that damn snap ring off with pliers. Little harder. I installed the upper rail and tightened the hand guard clamp. (following Troy's instructions) Easy so far!

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The instructions say to cover the receiver and barrel. I really should have covered my barrel.
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Place the lower rail onto the upper hand guard slightly forward of the locking position and press down and slide back to lock the hand guard into place ( See Figure # 5 )
No friggin way this baby is going in!

This is what I believe.  The upper rail gets milled with ½ circles where the lower rail ½ circle tabs fit into these holes, then the lower slides back to the receiver to lock into the upper rail detent pin. (I was to pissed off to take pic's sorry)
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During the manufacturing of the rail, little ledges (very small) were left in the first few holes of the upper rail. The taps on the lower rail would get caught up on these very small ledges which caused the lower rail not to seat properly.

I took the upper rails assembly off, and tried to fit the lower rail. I could get the two rails to seat together if I flexed the lower rail inwards and over the little ledges in the upper rail. I took out my dremel (I know what your thinking) and smoothed the ledges in the upper rail. Put the upper rail back on the AR and still couldn't get the lower to fit. I had a 3in thick piece of hard foam padding. FSB was off the pad but above the floor. I could put all my weight using my knee on the lower rail and still not get the lower to fit.

Off with the upper rail again. Cleaned up the little ledges a little more. Smoothed out the lower tabs. I still have some problems getting the two pieces to fit correctly even when they were off the AR. The lower had to snap into place on the upper rail. I snap these together a few times and noticed that if I roll the lower ever so slight into the upper they would go together a little easier.

The upper rail goes back on. Using the foam pad, knee on the lower I "rolled" the lower into the upper. Success!!! I then slid the lower up and into the detent pin. The upper and lower rails are rock solid.  I took my time on all these steps so I didn't do any damage to the upper receiver, barrel, or the MRF

Conclusion: The milling of the upper rail ½ circles left behind the ledges which caused the lower not to fit and the lower rail was wider than it should have been. Independently or together, these were the factors in the difficult installation. I’m still happy with the way it turned out.

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I had a similar issue, but I just pounded the bottom half on with a rubber mallet and had no problems whatsoever.

I had a similar problem with a Troy rail. If the lower half wasn't completely straight and level with the top half it just wouldn't go together. Not to start any crap but I did not have the same problem with a Samson rail.

What length rail did you guys install?  I just ordered the MRF-C and this has me wondering. . .

I used a 10" rail system.

Rifle length (12")

I installed the MRF-M Mid-Length 9"

Quoted: What length rail did you guys install?  I just ordered the MRF-C and this has me wondering. . .

just installed mine,' its a car length' and had no probelems,,,, use a rubber masllet and on it goes,,,

just make sure you cover and tape everything before cutting, it gets messy


Hanna

After installing the MRF-C, I have play from side-to-side.  Is this normal with a FF rail?

<<-- Newbie

ETA:  Nevermind, I went back and took my skirt off. . .all's good.