Gas block

[wetncold]

My rifle uses a pinned (2 pins) gas block with pic rail for front sight. My tube is about 3/8" too long, and my search found this issue has been addressed before. My options: trim the handguard or change to a low profile gas block and a railed handguard. So, my question is this: are the pin specs the same for all? Mine is a DPMS pattern. So, will any DPMS pattern pinned gas block work? I really don't want to install a set screw that might collapse the pin hole of the barrel. If they are standard spec, I can use a pinned low gas block, even if just one pin.

[blue109]

Problem with factory taper pin setups is that they may only work well with that original block and set of pins. Installing a different block may not be as tight. 

[Robocop1051]

Get a low profile clamp on block. YHM makes a decent one, but they are by far not the only option. I have a spare PRI with a rail, if you have a .875 Dia bbl.

I wouldn't try to reuse the taper pin holes on a second GB. There is no spec for measuring where those are drilled. They can be unequal distance apart, tilted, angled... and you'd be blindly drilling into them from the new GB. Too much room for error.

[98Z5V]

 So, my question is this: are the pin specs the same for all? Mine is a DPMS pattern. So, will any DPMS pattern pinned gas block work?

That stuff is set up with tapered reams or bits, for that gas block and that barrel, and those pins.  One-time use with that combination of parts.  They only work together...

[wetncold]

Thanks, men. I figured as much. Off to the lathe I go! 

[98Z5V]

Just for clarification, the tapered pins have a standard dimension, and should be the same, pin to pin.  The drilling/reaming of the holes, through the gas block and through the barrel - that's a one-shot deal, right there.

[Robocop1051]

For what it's worth. .. I heard, ONCE, about a guy able to fill the taper pin holes in the barrel and then re-drilled the barrel for a new set of taper pins. I neither know how he did it or how it can be done. Delicate metal repair is beyond my skill level... I'm more of a "force it" or buy a new one, kind of guy.

[wetncold]

I have absolutely no plans, present or future, of drilling pin holes for any barrel. And I'm a gunsmith. Just too much time and energy to make it worth my time. Some shops are set up to do it, but not me. I just don't have the time or desire to do it.

[mrmackc]

.

[98Z5V]

^^^  Mac bumped his post count, and didn't even say anything...   lmao...

[mrmackc]

98Z5V, I am glad you got a good laugh!  It don't hardly take NOTHING to get you to lyao

 

I did have something to say and when I went to post it the stupid thing went blank and pissed me off so I just shut the computer off and I went out to the shop and had a cold one and cleaned off my work bench and swept the floor.  It was damn near midnight too!

Probably was the right thing to do...

Edited October 2, 2015 by mrmackc

[EasyEJL]

but with the barrel drilled for those, its not like they'll interfere with a replacement block's set screws or anything right?

[survivalshop]

 I would not expect the taper pin holes to line up with the set screws on the block , but you never know .

[wetncold]

The clamp on style is the way to go, in my opinion. I took my tube to a friend who has a lathe and he was doing fine cutting it down. He thought it was going too slow, which I said that was best when working with aluminum, but he switched to trimming it down from the end. It caught on the cutter and completely destroyed the tube but it was a cheap one. $50 or so. I have ordered another one and if it needs trimming at least he knows what not to do.  LOL