Osprey OPS-416 installation issues

Finally got the last parts I was waiting for to install my OPS-416 kit.
Aero upper, DD 18" midlength barrel, standard barrel nut and round hanguard cap, Yankee Hill steel clamp on picatinny rail gas block (nice solid part, a good pick for this application) and an Osprey OPS-416 midlength kit.

Everything went together fine, but when I installed the Osprey BC, it protruded from the rear of the upper by .024" (nearly 1/32") and the op rod was tight. I took the op rod out and reinstalled the BC, and it was still proud by .006", which I would consider acceptable if not optimal. In effect, the piston/rod mechanism was holding the BC off of the barrel extension by .018" which means the buffer spring would be slamming the pisten mechanism into the gas block every shot. This can't be the way it was designed to work. Note that there is nothing to adjust the preload unless I wanted to shim the hanguard cap off the gas journal shoulder on the barrel... again, a band-aid. Given how poorly the hanguards fit (I'll get to that), I was not interested in exacerbating that issue.

I called Osprey looking for guidance, but they left for the weekend, so I decided to fix it myself. My solution was to face .020" off the op rod in my lathe. Now there is the slightest bit of play in the op rod (.002") and the BC seats on the barrel extension. The BC is still .006" proud of the upper but it fits on my lower and charges/ejects perfectly (on the bench).

Now, on to the handguards. The bosses on the front of the hanguards are an odd shape, neither round or triangular, but I suspect it was chosen to work with either a round or triangular hanguard cap. It's not very tight in the round cap, although it does work. The halves of the guard are somewhat warped so there is a gap where they meet and no amount of manipulation is going to get them to line up. I'm hoping that Osprey will send me replacements, that remains to be seen.





Anybody else have similar issues installing an Osprey kit?

Joe

Also, if you look close, you can see the extended takedown pins I made.
They feature a little extension on the right side of the rifle so you can pull them out.
Since I currently only have 1 lower but 3 (and soon 4) complete uppers, I will end up doing a lot of taking down.

I made them out of 303 stainless. The other day I went looking for bluing products and the stuff sold by Birchwood Casey does not work on stainless

Joe

I suspect your gas block is out of position. The Osprey oprod should move freely with you tip the rifle back and forth.

Bolt carrier should be flush with the rear of the upper receiver. The bolt will start to rotate and unlock too soon if not. And if too far out of the receiver may not fully lock at all. The firing pin length is only long enough to reach the primer with the bolt fully retracted into the carrier.

–– Chuck

Interesting points, but I don't think so, and I'll tell you why.
The gas block presses up against a shoulder on the barrel, with the handguard cup squeezed in between.
If it could be out of position, it could be forward, not back, creating more clearance, not less.
As for rotation (as in being clocked in to the upper) it is less than.001" per inch out of "level" with upper.
If you want to know how I measured this, I can detail the technique I used, which I learned when I was building plastic injection molds (you could say I was a tool & die maker but that would almost be an insult).
That is all assuming that DD did not make the barrel out of spec or Aero did not screw up the upper.
As for the BC not being flush with the upper, the BC bottoms against the barrel extension and the bolt is fully rotated in... first thing I checked when I noticed the BC was proud of the upper.
The bolt is rotated and locked into the barrel extension 1/32" before the BC bottoms on the barrel extension.
I guess it's tolerance stack up.
Compared the BC length to a DI BC (Windham Weaponry) and it's .002" longer.
Maybe the barrel extension is a few thousandths too long and the upper is a few thou short, but it all works together.
Looking forward to discussing with Osprey on Monday.

I shot the weapon today.
Ran like a champ.
No light strikes (Wolf WPA ammo) so the firing pin reach is okay, too.
The gas piston recoil is different than DI. Felt like the recoil pulse ramped up, less of a sharp leading edge than DI.
I shot a DI upper right after the Osprey, one that I put together this week. That ran well, also. A lot of that has to do with the Magpul anti-tilt followers I put in the GI mags.
The Osprey upper is still nice and clean (I don't think I even lubed the BC). I like it. The hanguard mismatch is an aesthetic issue only, but I'd still like to have it resolved.
I predict this may become my favorite shooter. It has a nice character (if guns have character)

Joe

Talked to the GM at Osprey this morning.
Confirmed that my op rod was within tolerance.
That means the deviation is in the barrel (gas block shoulder to barrel extension dimension) or practically any of the other parts in the Osprey kit (piston, "cylinder"/spigot, or BC).
Joe (the GM) agreed that for functional purposes as long as I've got clearance in the op rod when the BC is in battery, it really doesn't matter what is out of spec.

In fact, the kit is designed with approx. 1/16" of clearance built in... so somewhere I'm coming up .080" short.

I really don't feel like tearing the build down to find the offending part so I'm just gonna shoot the crap out of it!

Osprey is sending me a new handguard, no questions asked.

Great company to deal with.

I bet I'll be doing another gas conversion soon. I would not hesitate to buy another Osprey kit, although an AA kit looks pretty cool, too (for some variety).

Joe

I love Osprey Defense. I'm planning on another kit here soon.

Osprey sent me another set of handguards already.
Now that's good customer service.
Unfortunately, the new set has the same mismatch as the originals.
Since the top and bottom are asymmetrical, they distort differently when they come out of the mold.
I ordered a Magpul MOE for it, should fix it right up.

Osprey is still tops in my book.

Anybody need a set of huge bad fitting midlength drop in handguards?

Joe

Today the mailman brought me a present, midlength MOE handguard and a 5" rail section.
A little trimming of the heat shield and some flat black paint to hide the alteration, now I have a nice looking, functional, tight fitting handguard.
I know they're only plastic but what a good value.
I could see replacing all my drop in handguards with these, maybe even stepping out a little with FDE instead of black.
Problem there is my wife will notice a different color... years ago I replaced my mountain bike every year with a bike of the same color and she never noticed


I'm gonna have to wait until Monday to shoot it, though

Joe

Win

Copyright © 1996 - 2013 :: AR15.Com LLC :: All Rights Reserved.
Any use of this content without express written consent is prohibited.