Hello all, this is my first topic so I apologize if it is in the wrong sub. I didn’t see an LMT industry forum so I thought here may be appropriate.

I am currently building an LMT stripped MARS-l lower. I have built only a few lowers before, and have been mostly successful in completing them with only very mild cosmetic damage relating almost exclusively to roll pins. Besides the Ambi controls, one of the draws of the MARS lower is that the (dreaded IMO) bolt release roll pin is already installed.

This is the first “nice” lower I have built, and I was getting ready to install a trigger guard when I started to develop a worsening dread that I would disfigure my lower with the roll pin install, or worse snap one of the ears off (which it should be noted I have managed to avoid doing so in prior builds).

My question is whether anyone has tried the Rainer Arms modified trigger guards in the MARS lower and whether it fits. This trigger guard has two button screws similar to an anti walk pin. I have heard some trigger guards (such as the KAC) require modification to fit, and was worried this may be true of the Rainer piece. Also I am wondering if any of you have suggestions on other trigger guards that avoid roll pin hell. I know the advice here may be just to get better at the install or pay someone else to do it, but I was hoping there may be a simpler/easier solution I could accomplish myself.

I have the Rainier Enhanced Trigger Guard on my MARS-L and both my MARS-H lowers.  Fits perfect.

ETA:  I think it's 2A Armament that has one similar to the Rainier, but it has a gap between the end of the trigger guard and the grip.  I used an Ergo gap filler to fill them.

Get the right tools.  Bench block to hold the receiver, roll pin holder, roll pin punch.  No need to complicate things.

put a strip of duct tape on the left side of the lower in front of the bolt catch area. This will prevent any scratches while trying to install the roll pin.
use a wooden swab stick as a slave pin inserted from the rear. This will keep everything aligned as you carefully install the roll pin. Wood will absorb the shock and not fly out.
Use a roll pin starter punch and a proper roll pin punch to complete.

Firstly, thanks everyone for the advice. I do use a bench block, a roll pin starter,  and generous tape but I’ve still managed to mar the a small rim of the anodizing around the roll pin. I guess I have poor coordination, bad technique, or both. I really appreciate the tip on the 2a product, as ranier seems Out of stock. I’ll report back on how it works out. Thanks!

This is what I use:

https://www.littlecrowgunworks.com/store1/RPP-Roll-Pin-Pusher-p106089763

Aero Precision also sells a neat trigger guard that installs with small Allen head screws.

I have used a couple and they look good install easy. Last I looked they were available in a couple different colors.

Ill second. This is fabulous.  Add some electrical tape around the backside of the device.

No tapping anything, just turn a knob.  Still might have ever so slight of an anodizing loss right at pin entry due to chafing of pin pusher pin during final seating.

Have used to drift out and install.