AR-15 Gas Block Pins Destroyed (Options?)

F

flyboy015

New member
Really boogered up the simple process of removing the gas block taper pins on my AR-15 barreled upper receiver. Mushroomed out both pins while trying to tap them from left to right side, with flat punch and 16 oz. hammer. Then tried to drill one pin out, but didn't use a drill press because I'm an idiot. I bored right through the pin at an angle, and popped out the other side of the gas block, beside the pin. :(

I know I've already learned a valuable lesson, and made a mistake I simply won't repeat. My question now is, what can I do? I was trying to remove the FSB to install a picatinny rail gas block; I bought a Nikon P223 1.5-4.5 scope and mount, and as they are currently, the front sight post obstructs the scope view. It's annoying to say the least. Could a gunsmith drill the pins out with a larger diameter bit and a drill press? Or maybe even cut the gas block off completely? Or should I accept that this will be a permanent part of my new firearm, and cut the front sight down so I can still mount my scope?

I have links to two photos posted...the forum here would not let me post them...stated a security token was missing, tried different things but nothing worked! So sorry for the external links...

http://i.imgur.com/QuubLmm.jpg?1
http://i.imgur.com/nCcAlXw.jpg?1

Please take it easy on me fellas, I know I'm a young snot-nosed idiot punk, lol. I appreciate any tips, advice, info or insults in advance!
 
Boy, you really buggered those up! Now it's going to be harder.

You have an AR-15 bench block, right?

Most are tapered pins, a few are straight. If your upper is a S&W, the pins come out left to right, the opposite way from most. If it is anything else, then right to left. As far as your gas tube pin, either direction works, 1/16" roll pin punch will move it right out.
 
Negative, I was using blocks of oak and pine to support the gas block (with room for the pins to fall out of course). Didn't want to spend the $40 for Brownells little fixture :o

All parts are Palmetto State Armory, as far as I know they should be typical left to right taper. I did try whacking them once or twice from the other side once I realized I was up S*** creek, but neither budged.
 
That's a bit of a mess.
It looks like you drilled out the small end of the one pin, and didn't try hard enough with the other.

It is difficult to explain what my next move would be, because my mind often changes depending upon tools available at the time, and minor details in the situation. ...But it would probably involve a hacksaw, if I didn't bite the bullet and just take it to someone with a mill.

---

At least you didn't drill into the bore.

I picked up a brand-new DPMS 18" barrel for $11, because the original owner tried drilling out the gas block set screws and went just 1/2" or so too far... :rolleyes:
Through one side of the barrel, and half way into the other side.

As an experiment, I clamped a gas block on upside-down and backwards, so that it blocked all holes (including the actual gas port), and ran it as a single-shot. Shot great, even without deburring the holes; and there was no evidence of gas leakage on my witness paper. :D
The long term plan is to grab some cheap hand guards and make it the new dedicated golf ball launcher (traded GBL #1 for something far better).
 
At this point I think your gas block is ruined. It might be saved, but it's probably not worth it and best to just get it off and buy a new one.

To remove it at this point without having to resort to a milling machine, use a hacksaw to saw off the bayonet lock and the ears of the sling swivel to clear the way.
Then hacksaw UP from the bottom of the gas block to the pins.
This will reduce stress on the pins, and you can un-stress it even more by using a chisel inserted in the saw cuts and tapping with a small hammer to slightly spread the cuts.
Then drive the pins out and install whatever you want.

With the cuts taking the stress off, the pins should push out fairly easy.
 
That's probably one of the jobs where a good support is imperative. Only the pins can move when you drift, or they are not coming out.

Fair to say the gas block is a goner. Slice it with cut off wheel and get it off the barrel. That what I would do.

-TL
 
Since you were going to remove and replace the gas block anyway, just cut it off. If you want to salvage the gas block, I think that could be done, but it would look like heck no matter what you do.

Jim
 
Thanks for the advice fellas. As a follow up question, is that something a gunsmith or machinist could take care of somewhat...economically? Or would they even want to, for risk of nicking the barrel? I shot an email over to a shop that specializes in black rifles, waiting on a response. I do have two Dremel tools, I would just need some cut off wheels and a new handguard plate ;) but at this point, I'd almost rather have someone else do it. I've put my own mark on this rifle already. On the other hand, I wouldn't have to deal with the embarrassment :o
 
The only economical way is to do it yourself. A gunsmith is going to charge you, probably more than normal, as you screwed it up and you are desperate.

It isn't hard. Think it through and do it slow. Don't try to cut corners before you start, and don't panic when things start going off course. Just opposite to what you did.

There is no embarrassment between you and yourself.

-TL
 
Shrug,take a deep breath. Utter a few choice words.Figure out what there is to learn...
Then let it go and move on. You are paying tuition for experience..
Sometimes,setting the project aside and having a cup of coffee is the best idea.
Here is where you MAY have been slightly screwed.There are taper pins..there are hard taper pins,and there are soft taper pins.Had PSA used hard pins,you would not have this problem. I'm not suggesting PSA owes you.But soft taper pins become rivets when you beat on them.

So,now you have two 1/2 holes across your skinny barrel.You see,cutting a complete hole through a gas block and barrel assy works.Cutting 1/2 hole is pretty hard. It takes a mill and some skill.

I'm not sure the setscrew type gas block is the answer.The setscrews might end up in the taper pin cuts.

One more thing. BEFORE you do anything...Is this all about getting the front sight gone?
You can still look real close at what you have,and saw the sight part off.

Grind and shape what you have into a lo profile "gas block". Fill up your holes with JB or equivalent,use a Birchwood-Casey touch up pen on it,and shoot it.
It will work fine.
If you replace the gas block,

I'd consider the kind of gas block that has clamp screws and goes around the barrel. Those transverse cuts with no support won't help accuracy. Maybe a clamp on gas block will act as a "splint".

Maybe Yankee Hill has something.

In any case,all is not lost. You can always buy a new barrel!!
And then, realistically assess your skills and tools. Sometimes,if you don't know what you are doing...don't!! Not everyone is a surgeon,not everyone is a gunsmith.

IF you decide to do your own work, :-) study references,know procedures,and you have to make or buy proper tools.

Ask questions BEFORE you hose it up :-)

Trust me on this,I have made and fixed or scrapped a lot of mistakes.
Having a cup of coffee....
 
Last edited:
The only economical way is to do it yourself. A gunsmith is going to charge you, probably more than normal, as you screwed it up and you are desperate.
Click to expand...
The stereotype is live and well.

Case in point: there's a gunsmith that works out of the back of my preferred LGS.
Near his lathe (out of view of 99% of people that would be offended), there's a sign reading:

"Cost is not determined by how easy it is to fix. Cost is determined by how badly you [messed] it up before deciding you needed help."​

And he does live by that standard. Bring him something for modification, he charges reasonably. Bring him a botched garage gunsmithing job, and he doubles the rate.


We all make mistakes. Some are less expensive than others.

Another case in point: About a month ago, that gunsmith had a guy come in with a rifle that had JB-Welded scope bases. ...Because the guy couldn't find the right ones, so he just epoxied something 'close' on.
$300 to chisel off the bulk of the material (said it popped right off - poor surface prep), drill the crap out of the holes, and chase with a tap.
Then another $90 for (correct) cheap Weaver bases and re-mounting the scope.
 
Most do, but I don't. I'm a part-time smith, doing the work mostly for fun. I just charge by the hours. There will be more hours to right the wrong for sure.

-TL
 
Just cut it off with a dremel. If you bugger the barrel up more, buy a new barrel. A gunsmith is gonna want good money for this. If you decide to go the gunsmith route, just pay them to replace the barrel with one you want.
 
Just cut it off with a dremel. If you bugger the barrel up more, buy a new barrel.
Click to expand...
Yeah, sure. Just screw the whole thing up, then buy a new barrel and a new gas block. Why not? New gas block= $40, new barrel= $150-ish.
A gunsmith is gonna want good money for this.
Click to expand...
And a gunsmith will only want about $100 to fix it. That is a lot less than a new barrel and gas block cost. And if you hadn't buggered it up to begin with, it would be about $40 total.
:rolleyes:

If you don't know how, DON'T!
 
New gas block = $10 and new barrel= $80.
Gunsmith = $100/hour.
Problem is the capability of the OP is already in question and most likely, he lacks the proper tools to replace the barrel.
Would I do this job myself? Absolutely, but then I wouldn't have mucked up driving the pins out, either. At this point, some careful Dremel work won't really hurt as long as the depth of cut is managed. I'd cut into the already ruined gas block from the bottom to relieve tension on the pins.
 
Again, thanks for the input everyone. When I get off work this afternoon, I'll pick up some more cut off wheels for the dremel, and be sure to take my time. If I have any doubts about the integrity of the flat top gas block I purchased when I bought the rifle, I'll just get a clamp-on type and sell or give away the DPMS flat top. I'd like to see clearly through the scope, but also...the MOE SL handguard I bought to replace the standard style will only fit on a round handguard cap, whereas the PSA cap is triangular. And a new 1-in-8 16" barrel from PSA is only about $80 with free shipping. So off the FSB comes.
 
So I'm thinking then, a few good ideas would be to have more lighting than I need, tape off the barrel between and on either sides of the gas block barrel rings just as cosmetic insurance, mark the gas tube length at the delta ring so I know how far into the upper to reinstall it. Start off by punching the gas tube pin with a roll pin punch, spin up the dremel and slice off the bayonet and sling lugs, then cut upward just to the very bottom of the pins, smack said pins out with unnecessary fury.

Any other tips or things to be aware of?
 
I did the same thing with my S&W........
14973949226042359613.jpg
Had to cut it with a dremel because when driving the pins out the wrong way it flares the barrel
IMG_20170408_172940_1.jpg
I used a flat file to remove the high spots where the pins damaged the barrel and finished it off with some emery cloth until the new gas block fit. touched it up with some super blue. It still shoots 1.5 MOA like it did when it was new.
 
You must log in or register to reply here.
Back
Top