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2theXtreme
02-01-12, 13:33
I noticed a few difference in my 2 DDM4's today when I was cleaning them one after the other. Figured I would come here to see if anybody could shed some light on them. The older one I bought compete and the newer one I put together myself. But everything Daniel Defense was bought directly from them. Both weapons function flawlessly.

1st I noticed that the newer of the 2 has a rubber o ring on the extractor spring and the older one doesn't. Is this a more recent addition or did I lose this piece somewhere along the way?
http://img.tapatalk.com/46ad09fc-9144-12e0.jpg
New

http://img.tapatalk.com/46ad09fc-915d-8338.jpg
Old

2nd thing I noticed were the different shapes stamped on the upper. The newer one is a square and the older is a key hole shape. Is this just showing the time difference in manufacturing? Or something else?

http://img.tapatalk.com/46ad09fc-91e6-5f65.jpg
New

http://img.tapatalk.com/46ad09fc-91f7-6bc0.jpg
Old

3rd one is just that there is a number, I am assuming is the serial, on the bottom of the older lower but not on the newer.

http://img.tapatalk.com/46ad09fc-928a-0af0.jpg
New

http://img.tapatalk.com/46ad09fc-92a9-ce68.jpg
Old

Thanks to anyone that can help. I am not really concerned about any of these things. I am more so just curious.


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wahoo95
02-01-12, 13:40
Looks like the factory built one has the Serial # marking on the upper to ID it as a factory built rifle. As for the different forge marking....I'm sure DD like most companies source many parts from differen suppliers. My BCM upper and DS Arms upper both have the square marking indicating they come from the same place.

No clue on the bolt....outside of them probably just adding the O-ring to newer bolts.

markm
02-01-12, 14:03
1. Toss the Oring out. It's never an acceptable patch. EVER!

2. As stated... different forgings... completely irrelevant. It's the finish machining that matters. They're both 7000 series forgings.

3. No idea... the factory build makes sense though. Never saw a DD complete in person before.

TehLlama
02-01-12, 14:07
If it bugs you, pick up the $3 enhancement kit from BCM (not sure how much they still are), but if they're both running, I wouldn't worry about it.

duece71
02-01-12, 14:13
My DDM4V3 has the keyhole on the upper (so does my Colt) and no o ring for the extractor. There is not a serial number on the lower in the spot in your pictures either. When did you buy/build your 2 DDM4s??

2theXtreme
02-01-12, 15:16
1. Toss the Oring out. It's never an acceptable patch. EVER!

2. As stated... different forgings... completely irrelevant. It's the finish machining that matters. They're both 7000 series forgings.

3. No idea... the factory build makes sense though. Never saw a DD complete in person before.

What do you mean it is not an acceptable patch? That's how I got it.


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2theXtreme
02-01-12, 15:18
My DDM4V3 has the keyhole on the upper (so does my Colt) and no o ring for the extractor. There is not a serial number on the lower in the spot in your pictures either. When did you buy/build your 2 DDM4s??

I can't pinpoint exactly when I got the first one but I finished the 2nd about September or October some time. I probably got the 1st one 5 or 6 months before that maybe more...


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markm
02-01-12, 19:44
What do you mean it is not an acceptable patch? That's how I got it.


I understand that.... get rid of it quick, MAMA!

2theXtreme
02-01-12, 20:01
I understand that.... get rid of it quick, MAMA!

Mark, are you intentionally trying not to make sense? Haha! Why do I need to get rid of it quick!? What's so bad about it?


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Bluedreaux
02-01-12, 22:01
How do you like your V7? I haven't had my hands on one, but it seems like what I need. I'd just rather have a fixed front sight. How flexible is the rail?

2theXtreme
02-01-12, 23:06
I absolutely love my V7. It compliments my first one nicely (being that my 1st one weighs about as much as a cinder block slung over my shoulder). The rail is solid. I haven't had the chance to push it to it's limits but I have run a few comps with it and it handles beautifully!

On another note. If a fixed front is what you want the new Troy rail may be a good idea. I can't for the life of me remember the one that is slick and has the cut out for the fixed front. I'll report back with that.

ETA: The Modular Troy Delta BattleRail is the one I was thinking of. It's pretty sweet. That's tough for me to say being a Daniel Defense guy.

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warpedcamshaft
02-02-12, 00:37
Looking at a very recently manufactured DDM4, I found no O-ring installed, just the spring and the buffer.

The rifle is a factory built unit.

Amicus
02-02-12, 06:16
Mark, are you intentionally trying not to make sense? Haha! Why do I need to get rid of it quick!? What's so bad about it?


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I think markm, in his way, is indicating a school of thought that the O-ring part is designed to supplement the force of the extractor tension spring. Actually, it masks the weakness of the spring when the spring wears out. The proper remedy is to replace the spring, which will do the job if properly maintained.

Some people believe that the O-ring will make extraction failures more likely due to the overpressure on the extractor, until the O-ring "wears in." Using just the spring will not cause this.

globeguy
02-02-12, 07:38
I absolutely love my V7. It compliments my first one nicely (being that my 1st one weighs about as much as a cinder block slung over my shoulder).

What version of DDM4 is your first one? Is the weight savings on v7 coming from lack of rails that noticable?

markm
02-02-12, 07:51
The o ring is absolute NONSENSE. If a gun needs one to function, it's time to get a NEW GUN. Plus, excess extractor tension introduces its own set of problems.

I can't believe we have to cover this again on this site. :jester:

Hitech50
02-02-12, 10:47
Not that it probably matters much after what has been posted but I have a RRA upper that has the same little square on it.

Doc Safari
02-02-12, 10:57
Not that it probably matters much after what has been posted but I have a RRA upper that has the same little square on it.

Whose mark is it?

2theXtreme
02-02-12, 14:23
What version of DDM4 is your first one? Is the weight savings on v7 coming from lack of rails that noticable?

It is the v2. It's not necessarily the quad rails that gives me the weight savings but the stuff I have hanging on them and and to mention my Redi-Mod. Here is a pic of the 2.

http://img.tapatalk.com/44687e77-f05d-5e07.jpg

There is a Surefire scout on the other side of the v2. It's not unbearably heavy but very very noticeable when compared to my v7.


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2theXtreme
02-02-12, 14:25
I think markm, in his way, is indicating a school of thought that the O-ring part is designed to supplement the force of the extractor tension spring. Actually, it masks the weakness of the spring when the spring wears out. The proper remedy is to replace the spring, which will do the job if properly maintained.

Some people believe that the O-ring will make extraction failures more likely due to the overpressure on the extractor, until the O-ring "wears in." Using just the spring will not cause this.

Consider it gone! Thank you for clearing that up!


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tonyxcom
02-02-12, 14:42
My DD V5 LW Upper came with that o-ring on the extractor.

My LT Stealth did not.

2theXtreme
02-02-12, 14:47
My DD V5 LW Upper came with that o-ring on the extractor.

My LT Stealth did not.

My best guess is that Daniel Defense does not manufacture their own bolts (somebody correct me if I am wrong) and one company DD gets them from puts the o ring on and one doesn't.

Again. Totally a guess.


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Noodles
02-02-12, 15:25
The keyhole upper on the old. That's the mark of Superior irrc. Very few companies make their own forgings, the newer one looks like a D, so they probably spec'ed their own.

nml
02-02-12, 16:20
Mark possibilities:
http://www.baforging.com/
http://www.cerrofabricated.com/
http://www.ar15armory.com/forums/FORGE-MARKS-Upper-Receiv-t52833.html