AR-15 trigger mod

[bronco71]

Just wandering if anyone has done this trigger mod, heard about it today.......

Remove grip screw and use a 3/8" long 1/4-28 set screw, use it to adjust the pretravel; then use a 3/4" long 1/4-28 socket head screw to replace the stock grip screw since it will be too long.....

I know there are aftermarket adjustment screws to do this but this is easier and cheaper...if it works.

[CJ]

Just wandering if anyone has done this trigger mod, heard about it today.......

Remove grip screw and use a 3/8" long 1/4-28 set screw, use it to adjust the pretravel; then use a 3/4" long 1/4-28 socket head screw to replace the stock grip screw since it will be too long.....

I know there are aftermarket adjustment screws to do this but this is easier and cheaper...if it works.

It is very tedious and requires a whole lot of patience and attention to detail. We're talking thousandths of an inch adjustments by grinding down the screw to set the pre-travel correctly. It sounds real easy, until you realize you need to grind down the back of your trigger to intersect further into the safety mechanism to get any real results. Once you start to do this you get into unsafe territory - grind a hair too much and your rifle will fire on safety or when you bang it too hard. If that happens your trigger is trash. Keep in mind the trigger is tool hardened, it's like grinding diamonds. The heat from the grinding will temper the steel. As long as you know how to properly re-harden the trigger once you're done you should be fine.

[bronco71]

Did this to one of my complete lowers with stock,slightly polished trigger and JP springs. NO grinding is needed on the screw or the trigger, the short set screw is used to adjust the pre-travel to a point just before it interupts the disconnector (so it will still reset for next shot), the shorter than stock grip screw holds on the grip and doesn't screw in far enough to contact the set screw. Once it is adjusted and tested as working and safe I went back and put locktite on the set screw......works great and took out most of the creep!!

Decided to do this on a lower I just started building and found that the hole for the grip screw is not tapped all the way through, no big deal since the trigger is not installed yet so I tapped it all the way with a 1/4-28 tap and cleaned it out......

[CJ]

Did this to one of my complete lowers with stock,slightly polished trigger and JP springs. NO grinding is needed on the screw or the trigger, the short set screw is used to adjust the pre-travel to a point just before it interupts the disconnector (so it will still reset for next shot), the shorter than stock grip screw holds on the grip and doesn't screw in far enough to contact the set screw. Once it is adjusted and tested as working and safe I went back and put locktite on the set screw......works great and took out most of the creep!!

Decided to do this on a lower I just started building and found that the hole for the grip screw is not tapped all the way through, no big deal since the trigger is not installed yet so I tapped it all the way with a 1/4-28 tap and cleaned it out......

No grinding is needed if you leave 40% of the pre-travel. If you don't grind the trigger down in my opinion it doesn't do much. The reason I mentioned grinding down the bolt was to avoid having to tap the receiver like you did. If you don't grind the trigger down to take all of the pre-travel out you don't have to deal with much of the tedious work I mentioned like grinding down the bolt head. Most of the precise work is getting the last bit of travel out. If your goal is to just take up what travel exists before the trigger contacts the selector then it is quite easy as you described. The JB weld trick does the same thing without the need to modify anything.