Some of you guys may already have this or know about it, but if you dont,,it works wonders on the roll pins while assembling your stripped lower.(bolt catch and trig guard)

I picked up a couple of spring loaded center punches from harbor frieght. I removed the punch from the assemble as to machine the end so that it has a nipple to fit inside the roll pin to guide and center for installation into the lower reciever. i also magnitized the punch to help hold it. I have 2 of these spring loaded center punchs, 1 for the bolt catch roll pin and 1 for the trigger guard roll pin. It makes easy work of installing the roll pins and wont scare/mar/scrap the reciever if done correctly.

Whats the benefit of spring loadedness?

Hey, that might work pretty good.  Push, bang, the pin moves a little bit.  So you're saying you've used them (more than once) and they're driving the pins into position with only a few strokes?

Like I said, if it works that's a good (great) idea.

Need more info.

I think it means that you don't risk smashing your lower or your fingers with a hammer.

If you are smashing fingers and lowers...You're not doing it right.  Hammers and punches have been used to assemble rifles for a while, and they are very viable means of assembling a lower.  Other means may work for other people, and I do not condemn them for doing such things (taped vice grips/auto center punches/C-clamps) - They work.  However, if they can't use the "sort of" standard means of tools, then maybe they should seek some help and learn how to use them correctly.  I hope they aren't using a short sledge hammer, standard weight ballpeen, etc.  Although, I guess this could explain the shattering lowers.  It's not a race to put the nail through paneling and into the stud...It's assembling a rifle which needs care and precision.

Rob

Seems to be an idea, good or not I'm not sure.  

I like the idea of magnetizing the roll pin holder.

The spring loaded center punch will infact drive the roll pins in with total control. You can carefully and easily handle the spring loaded center punch to install the roll pins...Installation of the roll pin at the bolt catch will defently mar/scratch/scrap your new reciever if not done right. I realize you take the time to place protective tape/rag/rubber etc...on the reciever before you start installing the roll pin at the bolt catch, but if you use the center punch, your not holding a punch,  swinging a hammer, and ,if you dont have a mag block, your holding the reciever.
Ive been a certified Ford tech for 35yrs, and have learned that while disassembling/assembling manual transmissions and dealing with shift rails and  forks, its at times , not easy to remove and install roll pins at the shift rails, much less get to them. thats where I got the idea of using a spring loaded center punch to remove and reinstall the roll pins, which happen to be a heck of alot bigger than the ones on an AR-15...anyway, Ive been using the center punch as one of my specialty tools for yrs.

As far as the reciever,s roll pins. On my 1st efforts of useing the spring loaded center punch to install the pins, I "very slightly" chamfered the pins for easier installation for the pins to find center faster, after installation, i simply put a dab of blueing paste on the exposed metal that i chamfered...but being a tech...I new "its not the right way".....so I decided to take the time to machine (grind) the center punch,s end to leave a nipple (sorta speak) that would fit inside of the roll pin, not much, (especailly for the smaller bolt catch pin).It help,d center the spring loaded punch to the pin, but it didnt hold it, thats when I decided to magnitize the punch. you can magnetize anyway you see fit, you can either magnitize the pin or punch.
I decided to magnetize the spring loaded center punchs end by electro magnetizing it myself, which involves a car battery, but I cant say anymore (dont want anyone to get hurt on my account)

anyway, the punch will hold the pin stable enuff for installation. the key is getting it correctly centered. then just press the springloaded punch and a couple of snaps later, the pin is installed.


after watching a couple of u-tube vids, of some guys assembling a stripp,d lower and maring/scratching the lower, thats when i decided that there has to be a better way

yes, it only takes a few strokes, the bigger the pin,the more strokes. as you said, it only moves the pin  a couple of mm,s at a time, giving you ample time to hold completely still and double and triple ck what your doing.

I also use a left over needle brg from a drive shaft u joint which happen to be about 1 mm smaller than the bolt catch roll pin and use it as a preassmeble to hold the bolt catch into the reciever, then when Ive installed the roll pin with the spring loaded center, it simply push,s the needle brg out of the reciever and bolt catch.