AR15 Ejector Roll Pin

[MRockwell]

Hey all,
So I am doing my first ever AR build, picked up an INGO lower on the second group purchase. I sourced the parts from different places: BCG from Palmetto State, 23Wylde barrel from Spinta Precision, etc.

From all my research and reading, I decided it was wise to check the headspace. So my headspace gauge arrived late last week and I went about removing the ejector pin to do a check. Then I ran into a problem: I couldn't get the ejector roll pin back in. More research and I decided to buy a new roll pin. Couldn't get that one in either. The 1/16" roll pin was getting shaved off on the side.

Called Palmetto State on Monday, asked them what size roll pin they used. They couldn't answer my question, but I could send the BCG back and they would take a look at it. Looking at two weeks for that process, and I have a fun shoot I'm going to this weekend.

So, would I be wrong if I used a 1.5mm roll pin? Both of my 1/16" pin punches fit in the hole, but they are not .0625"(one is .055, other .053).

 

[Tactically Fat]

Free bump in hopes someone can answer!

 

[gmcttr]

I suspect a 1.5mm roll pin will not provide the intended compression/hold. Will it work? Maybe.

The new ejector roll pins I have measure 0.0690" at their widest point if that is of any help.

You might slightly round off the sharp edge of the roll pin hole in the bolt with 600 or finer grit 'wet or dry' sandpaper to help it not "shave" the roll pin.

A roll pin starter punch will also help.

 

[walt o]

Round over the edge of the roll pin,not the holes in the bolt .Always modify (when necessary) the cheaper part. I usually take an INDIA stone to the end going into the hole first. A .A roll pin starter punch can be made from a length of steel rod with the end drilled to except the roll pin .

 

[MRockwell]

I suspect a 1.5mm roll pin will not provide the intended compression/hold. Will it work? Maybe.

The new ejector roll pins I have measure 0.0690" at their widest point if that is of any help.

You might slightly round off the sharp edge of the roll pin hole in the bolt with 600 or finer grit 'wet or dry' sandpaper to help it not "shave" the roll pin.

A roll pin starter punch will also help.

I received some 1.5mm pins in the mail today. Of the two I measured, the smaller one was at .062"; so I used that one. I do have a starter punch, and even with that it took some effort to get it started. After it started, it went in without too much force(unlike the ones I was previously using).

I haven't had a chance to shoot it yet, so I have yet to see how it will hold up. I figure this weekend will be a good test.

 

[MRockwell]

Round over the edge of the roll pin,not the holes in the bolt .Always modify (when necessary) the cheaper part. I usually take an INDIA stone to the end going into the hole first. A .A roll pin starter punch can be made from a length of steel rod with the end drilled to except the roll pin .

Thanks for the reply Walt. I never thought of altering the roll pin.
I actually went out and bought a Wheeler roll pin install tool kit, because I was having a hard time with the bolt catch pin. Well worth it.

 

[gmcttr]

Round over the edge of the roll pin,not the holes in the bolt .Always modify (when necessary) the cheaper part...

Duh....that's what I should have said. Thanks

 

[Jerryboy]

Hey all,
So I am doing my first ever AR build, picked up an INGO lower on the second group purchase. I sourced the parts from different places: BCG from Palmetto State, 23Wylde barrel from Spinta Precision, etc.

From all my research and reading, I decided it was wise to check the headspace. So my headspace gauge arrived late last week and I went about removing the ejector pin to do a check. Then I ran into a problem: I couldn't get the ejector roll pin back in. More research and I decided to buy a new roll pin. Couldn't get that one in either. The 1/16" roll pin was getting shaved off on the side.

Called Palmetto State on Monday, asked them what size roll pin they used. They couldn't answer my question, but I could send the BCG back and they would take a look at it. Looking at two weeks for that process, and I have a fun shoot I'm going to this weekend.

So, would I be wrong if I used a 1.5mm roll pin? Both of my 1/16" pin punches fit in the hole, but they are not .0625"(one is .055, other .053).

You can squeeze the roll pin with needle nose pliers and get it started. Once its in the upper. Its captive.

 

[natdscott]

Called Palmetto State on Monday, asked them what size roll pin they used. They couldn't answer my question,

Good lord. Are you SERIOUS?!

My go-to for small parts, a la carte, is always Armalite. They're just as far as Illinois, and will happily send you small parts like that in a US Mail envelope...

...if you CALL them and ask nicely.

(800) 336-0184


Oh, and if you think you'll be doing that ejector very often, get a bolt vice. Pretty handy 3rd-hand kinda thing.

-Nate

 

[Jerryboy]

As a matter of fact. I replace many roll pins with stainless pin stock. I have several sizes and clip off as needed.

 

[natdscott]

As a matter of fact. I replace many roll pins with stainless pin stock. I have several sizes and clip off as needed.

Absolutely. At least, where you can get the correct interference fit.

-Nate

 

[Jerryboy]

Absolutely. At least, where you can get the correct interference fit.

-Nate

One day about 20 years ago I had built a new At and on its second range visit my bolt catch pin snapped in half. I continued shooting without a bolt catch and when I got it home I tapped the broken roll pin out and realized it had to be the weakest part of the assembled rifle. I replaced it with as pin stock. There's no going back. I know these pins are just that. But the rolled pin does a number on the softer forged aluminum. After a few years of hard use.you will see that your holes are wallowed out a bit. That split in roll pins acts as a cutter to the aluminum. Stainless is just a superior material to start with. Cheap too. I got a fist full of pin stock of many different size polished stock for free. I love working in factories. Haha. You can take a crappy mil spec trigger and replace the trigger hammer pins with ss. And it I.proves the crappy trigger dramatically.

 

[MRockwell]

Oh, and if you think you'll be doing that ejector very often, get a bolt vice. Pretty handy 3rd-hand kinda thing.

-Nate

I actually built my own bolt vice. It's more than pretty handy, I see it as a must have.
Thanks for the tip on Armalite.

 

[winterwolf73]

Actually that only works if you use split roll pins guys, if you use the solid stock pins that are originally made for the ar-15 then he would need to use the 1.5 mm pin with a rounded end contour and 1/16 pin punch (the ar-15 tolerances allow for that). If it still does not fit then polish the hole with 300 grit paper (one pass in and out) and it'll fit

 

[natdscott]

Actually that only works if you use split roll pins guys, if you use the solid stock pins that are originally made for the ar-15 then he would need to use the 1.5 mm pin with a rounded end contour and 1/16 pin punch (the ar-15 tolerances allow for that). If it still does not fit then polish the hole with 300 grit paper (one pass in and out) and it'll fit

Not bad advice, winterwolf, but I usually always suggest that anybody first modify the CHEAPER part.

IE: Sand the pin, not the bolt.

-Nate