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View Full Version : Trouble mating upper to OLL


MB38
05-18-2010, 10:50 PM
Hey folks,

I have a Spike's OLL that I'm connecting to a DDM4v2. When attempting to connect them, I'm not able to get either breakdown pin to engage. The front pin doesn't want to go through at any angle between the upper and lower. If I assemble the upper and lower without the pins in place, it seems that the upper isn't able to slide far enough back for the holes to line up. That said, it appears pretty uniformly flush in the gap between the upper and lower.

Anybody run into this problem before?

Noah3683
05-18-2010, 10:54 PM
pics? sounds strange

technique
05-18-2010, 10:54 PM
Push back?

One at a time? Try the front first, then try the back first if the front fails.
Hammer is down? Mag out?

reidnez
05-18-2010, 11:12 PM
Sometimes they're tight and do not want to push in by hand, I've experienced that. There's nothing wrong with grabbing a hammer and giving it a few LIGHT taps. If that doesn't work, you know there is a genuine problem and should seek a gunsmith at that point. It's not unheard of for either an upper or lower to be out of spec; once you determine which it is, contact the company and get a replacement.

Richie Caketown
05-18-2010, 11:15 PM
Do your pins fit through the upper at all? Try fitting your pins throught the upper when its off

asme
05-18-2010, 11:15 PM
I heard through the grapevine that Spikes had a batch of lowers not too long ago where the takedown pin and trigger holes were too far back by a little.

If you do determine it's the lower, call Spikes, they'll take care of you.

MB38
05-18-2010, 11:24 PM
The front bit a bit, but I was able to swing down the rear and get it to bite as it should.

It looks like the handguard is too close to the receiver so it's not letting the fronts line up. I've been wearing back the metal a bit with this trying. I'm going to remove the handguard tomorrow and figure out a new method. It looks like the barrel nut is a little too tight so the handguard isn't able to move far enough away from the upper.

stitchnicklas
05-18-2010, 11:26 PM
firing hammer down,push back set rear first,do not hammer it!!!!!! if you force it and it is out of spec you might lose-out with spike saying you damaged it........patience is a virtue

SJgunguy24
05-18-2010, 11:27 PM
If they are trying to mate, try some wine and maybe candles. A little Luther Vandross wouldn't hurt.

shark92651
05-19-2010, 8:41 AM
The front bit a bit, but I was able to swing down the rear and get it to bite as it should.

It looks like the handguard is too close to the receiver so it's not letting the fronts line up. I've been wearing back the metal a bit with this trying. I'm going to remove the handguard tomorrow and figure out a new method. It looks like the barrel nut is a little too tight so the handguard isn't able to move far enough away from the upper.

Is it a Yankee Hill free-float? If the jam nut is not rotated forward 1 1/2 turns from the end of the barrel nut there may not be enough clearance to mount the upper on the lower (been there, done that).

CHS
05-19-2010, 9:27 AM
Also, is it a Samson rail like on a Stag 2HT?

I had to deal with this same problem yesterday. I just loosened the 4 bolts on the Samson rail, tapped everything forward, and tightened them back up. Upper dropped onto the lower with no issues.

rogtac
05-19-2010, 10:43 AM
i have a couple Spikes lowers and they mate fine with my DDMV, but they are real tight with my LMT CQB MRP.

Noah3683
05-19-2010, 1:15 PM
It says ddm4v2. So I'm assuming he wouldn't take off the DD rail to place a samson or yhm on there

Nessal
05-19-2010, 1:18 PM
I had an issue like this with a CMT upper mating to my KD lower. I had to get a new upper receiver.

MB38
05-19-2010, 11:41 PM
Yeah, it's the rail that was preventing the upper and lower from connecting properly. I could either send it back or just machine out about 1/16th of an inch from the rail to make it all fit. I'm thinking I'll get in contact with Daniel Defense.

shark92651
05-20-2010, 7:06 AM
Yeah, it's the rail that was preventing the upper and lower from connecting properly. I could either send it back or just machine out about 1/16th of an inch from the rail to make it all fit. I'm thinking I'll get in contact with Daniel Defense.

I've never had an issue with a Daniel Defense rail getting in the way of mounting an upper. Which model is it?

ar15barrels
05-20-2010, 10:22 AM
The front bit a bit, but I was able to swing down the rear and get it to bite as it should.

It looks like the handguard is too close to the receiver so it's not letting the fronts line up. I've been wearing back the metal a bit with this trying. I'm going to remove the handguard tomorrow and figure out a new method. It looks like the barrel nut is a little too tight so the handguard isn't able to move far enough away from the upper.

:useless:

Pictures would REALLY help.

Is the metal thickness the same all the way around the front pin on the lower, or is the metal thinner above and below the pivot pin than directly forward from the pin?

MB38
05-22-2010, 12:19 AM
I'll take pictures tomorrow. It's a DDM4v2. It also didn't ship with the vertical front grip... d'oh! Gotta call them about that.

mhho
05-26-2010, 7:11 PM
I had the same problem with the Spike's Tactical OLL and DD handguard upper. I called DD and the tech that helped me said that he has seen this before on some Spike's lowers. He recommend that I either file the handguard to make room for the lower or file the lower to make room for the handguard. He said I could also send it in to DD and they can do it for me. I did not want to deal with shipping so I chose to do it myself.

I chose to file the upper handguard to make room because I did not want to touch the lower. So after some filing and fitting, it fit in the assembled position. But when I removed the rear pin to break the two halves open, I could not pivot the upper all the way. It turns out that the lower protruded too far in the front and now it is hitting the underside of the upper. I bit the bullet and filed the front portion of the lower forward of the pivot pin where it was interfering with the underside of the lower. After filing and fitting, the upper with the DD handguard fit and pivoting fully about the pivot pin. I tried with a 2nd Spike's lower and same problem. Same problem and same fix. The 2nd serial number is only a digit off from the first one. 3rd lower: same thing. Serial number about 10 after the 1st 2. Other than that the Spike's lowers are great.

A trick that I discovered while doing this is to use a tiny strip of paper to detect where the interference was. Like using a dollar bill to test if the barrel is free floating, use the paper strip when the upper and lower is stuck to see where the two halves are touching and needing filing. In the end, I was able to pass the piece of paper around the lower pivot tab and not get stuck anywhere. Good luck.