I think it has to do with the incremental benefit that you are getting relative to incremental cost. If you want a basic AR that is fairly reliable and reasonably accurate, then a $500 AR will accomplish that goal. Actually right now more like $450, pending any potential rumblings out of Pelosi, Hillie, and company. If you then say, hey let me change that gun into a competition worthy tack driver, you might want a new trigger. But a $240 trigger, which increases your investment by 50%, will only give you so much accuracy improvement until you also switch out the barrel and a few other parts.
I think the general thought here is that if you are going for that tack driver weapon, you are better off buying a higher end AR in the first place, or better yet building one from the start with all higher end parts.
Then again, I personally have installed $200 triggers in Glocks, so I'm not one to criticize if someone wants a $240 trigger for their DPMS AR.
I've seen folks who could shoot sub MOA with handloads in a $500 AR with a good trigger. The "higher end parts" in an AR are things like barrel steel, or HPT and MPI bolts... things that don't necessarily add to accuracy. My BCM is higher quality than my Sport, but it really isn't more accurate in my use... both rifles shoot 2 to 3 MOA with typical range fodder ammo.
Hey, spend your money however you see fit. I spoke in general terms. The heart of an AR15 are the barrel, and the bolt carrier group. If you have a $400-$500 AR15, you don’t have a match grade barrel, or a match grade BCG. It’s not junk, but it’s not a match grade rifle. What Soccerdad1995 said about incremental cost benefits is spot on. If it makes you happy to put a $238 trigger in a $500 gun, be my guest. It does
make for a nicer shooting experience. But you won’t realize as much accuracy improvement as you would if you spent the same money on a barrel upgrade. This is not just truth for ARs....this is truth for rifles
. A better barrel and bolt lockup will yield a better accuracy result than a better trigger alone. If you’ve already got the better barrel and bolt lockup, then the better trigger will take it to the next level.
I have three aftermarket Timney triggers, one in a Remington 700 precision rifle, one in an AR15, and one in a SCAR 17. The Remington and the AR15 are both match-grade precision weapons. The trigger is the final piece (optics not included) to creating a weapon that shoots precisely. The Timney that’s in the SCAR is there just to improve the shooting experience - as the SCAR’s EOM trigger is way too heavy (8 lbs) out of the box. But that Timney in the SCAR doesn’t really add to its accuracy. It was a very accurate rifle out of the box from day one - so far as battle rifles go - but it is stil just a battle rifle. The trigger makes it a lot nicer to shoot, but not any more accurate than it was before.
So I’m not saying not to put a nice trigger on your rifle if you want to. It will make for a a nicer shooting experience. I’m just saying that it isn’t going to be the primary thing that upgrades your rifle’s accuracy. Your BCM and your S&W both shoot 2-3 MOA with standard fodder because they are are not made to match tolerances. BCM makes fine rifles. In fact, I’m looking at building my next AR - a 20” A4 replica - on a BCM gov’t profile barrel and receiver. I don’t expect better than about 2 MOA out of it, because that’s the limit of the barrel. Changing the trigger won’t change that. OTH, I have a 16” carbine with match grade barrel, with 5R polygonal rifling, which the barrel manufacturer guarantees sub MOA with match ammo......and it DOES shoot that well. It shoots about 1-1.5 MOA with non-match ammo. Again, the barrel is the heart of the beast, followed by bolt lockup, followed by trigger locktime and reset.