By my measurements, it looks like they are intended for a close to exact fit.
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This is the third or fourth thread I've seen mentioning short taper pins on DD uppers (even after fully seating since they come loose from factory).
My DD upper is the same way, even after pounding them in they are not flush on the smaller side. That being said, I can't see them going anywhere anytime soon and I've decided to leave well enough alone.
I'm installing a rail later this month and at that point, since it will be apart anyway, I may go ahead and put new pins in during reassembly.
Right now my plan is to shoot it this weekend with my son, see what happens. It should function fine. I am also mildly curious to see if it has any "special" qualities.
(Don't get me wrong. I come from a science and law background, and they are pretty logical and unforgiving disciplines. But, every so often, you run into situations where you are in the presence of something unexplainable and mysterious. I've seen this with weapons, autos, musical instruments, occasionally with old watches -- things that can create a fairly intense meaning to the user. I have hopes for this rifle, but I won't bet the farm on it.)
You mean "Special qualities" like turning lead into diamonds? :D
I'd like a gun with qualities like that. I'd just shoot it into a barrel of water all day long... ;)
In all seriousness, if the pins are indeed inserted correctly (which I believe they are), your rifle should be fine, aside from a slight cosmetic issue that will only be apparent upon close inspection, and should have no effect on the function of the weapon itself.
Just a quick update. The upper has been in DD's hands for about two weeks, and I expect that they will take care of any "issues." I am glad they were so friendly about it, but I never expected anything else.
Part of the reason I sent it back to DD was that I thought they might benefit from taking a look at the barrel. The pins were not the only aspect of the barrel that I did not like (but, I won't go into that).
I felt that I had reached the limit of my competence, and I should learn to take stock of the situation before attempting my own work. I will get a reamer (or two) before I try this again, and now I know another thing to look out for. Since this was my seventh build, I thought I knew what I was doing. Ha!
Wrench: I haven't forgotten that I was going to PM you. I do have a few questions, but I haven't quite figured out what they are.
Seems like this post is timely for several here...me included. I'm putting my FSB back on tomorrow after shaving it down today. Fun project to do actually. I was considering replacing the pins as it seems like those are a one-time-use-only type of thing. Is this something that would benefit from a bit of loc-tite prior to driving the pins in or does it really not matter? While I've never seen on pop out during use mind you, I just have a habit of adding it to items like that.
https://lh6.googleusercontent.com/-Z...2616.JPG?gl=US
Taper pins are cheap enough that it's a good idea to replace. With the beating that they take going in and out, they're bound to suffer some deformation. The result may be that they wont fully seat because the trailing end has flared out, or they may cause the gas block to have a slight wobble. The wobble was a result of the pin on the right in the picture. The old pin was a DD taper pin, and didn't hold up to repeat installation. I get hardened steel taper pins from a local source for about .60ea and trim them after installation, leaving about 1/8" exposed. A little chemical blackening and we're good to go.
I will just throw this out here after replacing to many damn press fit bearing that I cant count any more.
Put the Damn pins in the freezer for a couple of hrs or better yet over nite before you try to drive them in.;)