AR Rails...

pdm

pdm

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I suck. I attempted to move the rails (Troy MRF-DI) from my old post-ban AR (DPMS A3 upper) to my new (to me) pre-ban AR (Oly A2 upper).

Yeah, that didn't work.

The little ring behind the FSB just won't let the top half seat. Liberal application of WD40 and curse words did not help. Rubber mallet didn't work either. My next step would be flame and/or a grinder. Am I fighting a losing battle or is fire truly the answer?
 
I've never used those rails but can you put them side-by-side and compare lengths: Troy rails vs. the A2 handguards you removed? Are the rails longer, thicker, wider? If so maybe you do have to do some fitting.

Is one designated top and one bottom? Also, new AR's can be a real bitch to get the guards on and off. You may need the hand guard removal tool or at least a second pair of hands.

good luck
 
Have the tool, and the only difference between the metal rails and the old plastic ones is that the plastic ones have a little notch. The bottom rail has a little angled corner and it fits just fine. A gunsmith I am not, apparently.
 
I'm not going to bash Olympic Arms, (okay, I am just a little bit), but they are among the most out-of-spec manufacturers on the planet earth...It is highly likely, that your front ring was either made by monkeys, or ordered by Olympic to those specifications to fit an out of spec barrel...Or I suppose, they could have bought a batch of bad front rings and "coerced them into working"... Either way, I don't see the harm in grinding down the ring a bit, (little by little) and test fitting as you go - you could also replace it. Those rails should literally just drop into any ring set up that's in spec...
 
MassMark said:
I'm not going to bash Olympic Arms, (okay, I am just a little bit), but they are among the most out-of-spec manufacturers on the planet earth...It is highly likely, that your front ring was either made by monkeys, or ordered by Olympic to those specifications to fit an out of spec barrel...Or I suppose, they could have bought a batch of bad front rings and "coerced them into working"... Either way, I don't see the harm in grinding down the ring a bit, (little by little) and test fitting as you go - you could also replace it. Those rails should literally just drop into any ring set up that's in spec...
Click to expand...

I don't really want to rip apart the FSB and get the ring off and then try to put it all back together. I don't have all the punches and crapola. Especially since it's my plan to buy a shorty upper for this at some point (aka, whenever my bank balance recovers).
 
Whew, finally got around to breaking out Ye Olde Dremel(e). Tried taking down the endcap stays a little, that wasn't working due to the angle while it's attached. So I angled off the ends of the top half of the rail just a little bit. I figured it wasn't a bad thing, since the bottom half has a 45deg angle where it goes onto the endcap. One little love tap from the rubber mallet and... I didn't quite believe it was together for a bit. Jammed the bottom half on and now I wait for my replacement buffer tube kit from BCG. Effing out of spec "milspec" buffer tube. Do I need to loctite the castle nut or can I just torque that sucker down?
 
pdm said:
Whew, finally got around to breaking out Ye Olde Dremel(e). Tried taking down the endcap stays a little, that wasn't working due to the angle while it's attached. So I angled off the ends of the top half of the rail just a little bit. I figured it wasn't a bad thing, since the bottom half has a 45deg angle where it goes onto the endcap. One little love tap from the rubber mallet and... I didn't quite believe it was together for a bit. Jammed the bottom half on and now I wait for my replacement buffer tube kit from BCG. Effing out of spec "milspec" buffer tube. Do I need to loctite the castle nut or can I just torque that sucker down?
Click to expand...

If you can, stake it....
 
pdm said:
Stake the end plate or the nut?
Click to expand...

The castle nut...There's an armorer, (real-deal battlefield armorer), over on M4 Carbines, that will tell you to stay far, away from LocTite on your buffer tube area. 23-35lbs of torque is all you need, but without staking the castle nut, you will need to regularly snug it up - especially with shooting higher round counts...By the way, his handle is "Iraqgunz" and he's in theatre now, but will respond to PM's if you give him time. His posts are pretty informative...
 

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