Aero M5 'Project' - Sub MOA Made Simple

Accidental bump firing off a pair of rounds is a legitimate risk with super light triggers on 308 gas guns. It’s not a malfunction of the trigger, but rather an artifact of heavier recoil and a light trigger. It can be mitigated with things that reduce recoil like brakes or heavy rifles. But the risk is real and has been brought up by KAC employees.

Glad yours has been good though.
While not 308, i did have similar issues with a Geissele SD-3G trigger in my 5.56 using the lighter of the two springs. Swapped it out for an MBT-2S LaRue.
 
Accidental bump firing off a pair of rounds is a legitimate risk with super light triggers on 308 gas guns. It’s not a malfunction of the trigger, but rather an artifact of heavier recoil and a light trigger. It can be mitigated with things that reduce recoil like brakes or heavy rifles. But the risk is real and has been brought up by KAC employees.

Glad yours has been good though.
You can say that like it’s a bad thing 😊
 
The House Donks and a handful of traitor RINO's just passed that horrible AWB bill and Mass is already a hard place to find key components for Legos guns, so last weekend I sought out my next AR-308 lower. Didn't take long to get responses to my WTB ad. My favorite FFL at the Freedom Mill happened to have a complete Aero M5 lower with the PRS stock, so Mrs. Mountain and I made the road trip.

Project in 'quotes' because I'm totally cheating and being lazy on this one. As mentioned I started with the locally sourced complete lower. Ordered the upper+barrel from California of all places. Rest of the parts I ordered from a couple online vendors or grabbed from my parts pile. Everything delivered by end of week even with the cheap shipping, so I slapped it all together last night. Very simple build:
  • Though the lower and upper were ordered separately and that lower was older stock (pre you-know-who?[rofl]), they match perfectly for color and fit.
  • Barrel is a Ballistic Advantage Premium Series heavy taper fluted. Even with the flutes it's damn heavy, but that's what you need if you want a precision shooter. BA is owned by Aero, though I was acquainted with BA's owner before he joined forces with Aero.
  • Hand guard and nitrided BCG also Aero.
  • Stock and grip are Magpul, came with the lower.
  • Trigger was OK but single stage, so I swapped in a RRA National Match 2-stage trigger. It's good but not my favorite. Pull is ~5.5 lbs with the springs in it now.
  • Brake is a VG6 Epsilon. I'm a fan of their stuff and they come with a convenient little hole on the bottom for us pin and weld fags.
  • Borrowed the scope from my 6.5 ManBun AR - Leupold Mk3i LRP with max power of 14X. It's bottomed at my zero stop for the 6.5, so that's why the groups are high and left.
View attachment 646914

I gave the barrel a good douching before calling it a night then went to the range this morning. 100 yard 5-shot groups off the bench. First group was from my grab bag of misc leftover reloads. Basically a few 'fouling shots' for the barrel, so why waste the primo stuff. Next 5 shots are my basic 168 SMK & Varget loads. That's a .86 MOA group. The 4 shots in the clover leaf are .29 MOA.

View attachment 646915

The one shot above the cluster is probably my bad. That's it for now- those are the very first and next 5 shots out of this rifle. I don't like to take a lot of shots through a new barrel without giving it a good cleaning and a few passes of JB bore paste to slick up the surface after the initial shots.

I would have been happy with 1.5 MOA and hoped for 1 MOA. Looks like this is only a great trigger and maybe more powerful glass away from hitting .5 to .75 MOA all day long. I'm sure I can keep it sub-MOA as is. Not a lot of magic in getting this done- just use the right parts, especially the barrel and BCG. FWIW, I think the BA 'Premium Series' AR barrels are grossly underrated and can hang with Douglas, Krieger, Bartlein, etc. at about half the price. It's an AR, so you can spend all the money you want on a barrel but you'll only go so far in precision.
Great post. I know a guy...who's even lazier than you and mated a complete M5 upper to a complete M5 lower to create the "M5 for dummies". He chose the same BCG as you did, the same PRS and the build looks very similar. 20" barrel with the Magpul bipod and it's off to the races. It's a real peach, the only problem is the mill spec trigger. He's wondering if it will wear in with use or it would be best to swap it out for a higher quality bang switch. Looking at Geissele products. SSA-E in particular. Buy once, cry once? Lots of great info in this thread, interesting perspectives as always. Thanks NES.
 
Great post. I know a guy...who's even lazier than you and mated a complete M5 upper to a complete M5 lower to create the "M5 for dummies". He chose the same BCG as you did, the same PRS and the build looks very similar. 20" barrel with the Magpul bipod and it's off to the races. It's a real peach, the only problem is the mill spec trigger. He's wondering if it will wear in with use or it would be best to swap it out for a higher quality bang switch. Looking at Geissele products. SSA-E in particular. Buy once, cry once? Lots of great info in this thread, interesting perspectives as always. Thanks NES.
If he's banging decent size plates at up to 200 yards and not much else, stock trigger is OK. They don't really break in that well but there are some youtubes about 25 cent trigger job or something similar. I've done this and used JP reduced springs and netted a halfway decent trigger. If anyone is trying to do more precision shots requiring something ~1.5 MOA or less, you have to spend the money on something at least as good as a 'National Match' type trigger. The RRA is a good example. Spec to meet competition rules mandates over 4.5 lbs pull, but that can be dropped a little with reduced springs.

If you don't mind spending the bucks, IMHO the Geissele SSA-E is the best AR trigger, period. That's what's in my 6.5 Manbun AR.
 
blasphemy!
there ain`t better triggers than TriggerTech and the Diamond is the name of it!

very good note about some rules to be set for triggers be at #4.5 min.
I still put Larue in everything, good price and I like the consistency between rifles
 
Great post. I know a guy...who's even lazier than you and mated a complete M5 upper to a complete M5 lower to create the "M5 for dummies". He chose the same BCG as you did, the same PRS and the build looks very similar. 20" barrel with the Magpul bipod and it's off to the races. It's a real peach, the only problem is the mill spec trigger. He's wondering if it will wear in with use or it would be best to swap it out for a higher quality bang switch. Looking at Geissele products. SSA-E in particular. Buy once, cry once? Lots of great info in this thread, interesting perspectives as always. Thanks NES.
No brainer in my opinion to upgrade the trigger. Short money compared to the overall cost of the gun
 
I still put Larue in everything, good price and I like the consistency between rifles
I also have a LaRue and thought it a very good trigger for the money. Probably will put one in my next project as I don't need a Geissele.
 
blasphemy!
there ain`t better triggers than TriggerTech and the Diamond is the name of it!

very good note about some rules to be set for triggers be at #4.5 min.
Preach brother preach

Trigger tech all the way

I get the competition one that's fixed 3.5 lb for my "serious" rifles
 
i posted in classifieds my aero 6.5CM complete upper with bolt/handle - will probably be relevant till beginning of the summer, then i will turn it into some other caliber.
 
hey ar10 guys, i need advice. shot a around 100 rds 308 through my m5 aero ar10 the other day, the pin on hammer keep on sliding out, causing a lot of problems, is there a special pin that i can buy to fix this? any other small parts that i need to stock up for that gun?
 
the pin on hammer keep on sliding out,
IF you use a traditional trigger - the pin there is supposed to have a groove and the hammer spring is supposed to be sitting in that groove preventing it from sliding out.
if you use a drop in trigger - it may be a sign of other issue - where you did not tighten up 2 bolts in the body of the drop in trigger that was supposed to keep all pins under enough tension to prevent sliding out.
and, of course there are a non-sliding anti-walk pins for triggers, a rather fugly solution, but, in some cases it is the only way if the lower is old and holes are in less than ideal condition.
that is NOT the case for any new m5 aero lower.


don`t forget to loctite them - the bolts on those pins.
 
+1 that if you have a traditional trigger, the hammer spring 'legs' should be sitting on the grooves of the trigger pin. Sorry the res is bad on first pic, but between that and the second pic you should get the idea:

1679336709294.jpeg
HammerSpringLegs-1024x768.jpg
 
+1 that if you have a traditional trigger, the hammer spring 'legs' should be sitting on the grooves of the trigger pin. Sorry the res is bad on first pic, but between that and the second pic you should get the idea:

View attachment 733971
HammerSpringLegs-1024x768.jpg
nice pics, my gun trigger assembly look exally like the one in your gun.trigger pin on mine is fine , it the pin on the hammer keep on sliding out. i will buy that anti walk trigger pin mr paul73 got in his post above,it cheap . and old guy at work said he will bring me his spare trigger pack.i really like the ar10, hitting steel plate at 300 yard is nice,lot nicer that the sks.

Armaspec Anti-Walk Trigger/Hammer Pins w/Hex Keys ARM136-SS Color: Stainless Steel, Fabric/Material: Stainless Steel, 23% Off
 
nice pics, my gun trigger assembly look exally like the one in your gun.trigger pin on mine is fine , it the pin on the hammer keep on sliding out. i will buy that anti walk trigger pin mr paul73 got in his post above,it cheap . and old guy at work said he will bring me his spare trigger pack.i really like the ar10, hitting steel plate at 300 yard is nice,lot nicer that the sks.

Armaspec Anti-Walk Trigger/Hammer Pins w/Hex Keys ARM136-SS Color: Stainless Steel, Fabric/Material: Stainless Steel, 23% Off
I have only had one issue with pins walking. The pin grooves where out of spec , both grooves where very shallow. More like scratches, lol
And one grove did not get past the receiver housing. Of course it was a super budget build with the cheapest crap I could find.
Not Idea fix but a chucked the pin in a drill and filed my own new groves. Remember this was a “as cheap as f*** build” i also found out the hard way the cheap in the white barrel I got did not have the front sight pin groves cut.
So I green loctite and set screw the front sight. Someday I will get that gun back. Right now my friend has been abusing it, many thousands of rounds later and no complaints from him.
 
I have only had one issue with pins walking. The pin grooves where out of spec , both grooves where very shallow. More like scratches, lol
And one grove did not get past the receiver housing. Of course it was a super budget build with the cheapest crap I could find.
Not Idea fix but a chucked the pin in a drill and filed my own new groves. Remember this was a “as cheap as f*** build” i also found out the hard way the cheap in the white barrel I got did not have the front sight pin groves cut.
So I green loctite and set screw the front sight. Someday I will get that gun back. Right now my friend has been abusing it, many thousands of rounds later and no complaints from him.
Not to pick on anyone with 'anti-walk' pins, but I think their strongest feature is to pull money out of people's wallets. For the same price one can get the full set of spare pins for the entire lower. Even if the holes are a little off spec, the springs are going to apply pressure into the grooves just the same. From semi-high end to supposed low end lowers, I've yet to see a problem with pins walking even with the heavy calibers.

If part of a Gucci build with all the cool features one wants, I don't see any issues with using the anti-walks. Nothing wrong with having fun with AR builds and though not my thing I like seeing the high dollar custom builds that some folks assemble.
 
i fixed my gun with an "anti- walk " pin . they did not build the hammer in my gun correctly, so the original pin that come with it keep on falling out .my cell phone broken or else ill up load some pic.

nice to know that a cheap ar10 can run thousands of happy rounds lol.
 
i fixed my gun with an "anti- walk " pin . they did not build the hammer in my gun correctly, so the original pin that come with it keep on falling out .my cell phone broken or else ill up load some pic.

nice to know that a cheap ar10 can run thousands of happy rounds lol.
Probably more 'moderate' than cheap. I'd call cheap if under ~$800.

A pin with proper grooves would be held just fine via the hammer springs, though I can see the peace of mind from the extra insurance of anti-walk pins.
 
See this is why I like triggertech triggers.
You never have to worry about this stuff.
it depends.
for field stripping the drop-in stuff that needs a special wrench to be released is less reliable. for a range gun - sure, for something to be with in the forest - nope. same with anti-walk pins, it is an additional element to unscrew where it is not really needed, an extra unnecessary complexity.
 
The Aero / Ballistic Advantage barrels are IMHO an incredible value and the trick to getting such accuracy at a reasonable price. One can spend $1500 to $1800 on just an upper if you go to one of the known precision builders like Compass Lake and include a Bartlein, Krieger, etc. barrel. Aero catches some grief on the forum for not shipping direct to Mass, but they have many dealers who will. Personally, I can't find fault with a small company that avoids the risk of lawsuit from an AG who's happy to blow through our tax dollars to do it.

There's not really risk. That said.....

There's no reason to need to buy aero direct anyways, there's a network of resellers who ship here no problem. You'll get better selection at 2nd tier dist anyways.
 
it depends.
for field stripping the drop-in stuff that needs a special wrench to be released is less reliable. for a range gun - sure, for something to be with in the forest - nope. same with anti-walk pins, it is an additional element to unscrew where it is not really needed, an extra unnecessary complexity.
Yep, for a self defense or survival rifle I'll take simplicity. I'll use a pin pusher or drift for convenience to remove and install triggers, but that's only for convenience and not really a necessity.
 
There's not really risk. That said.....

There's no reason to need to buy aero direct anyways, there's a network of resellers who ship here no problem. You'll get better selection at 2nd tier dist anyways.
I liked buying barrels direct from Ballistic Advantage, before the Aero buyout. If I had technical questions or specific needs, I'd either be connected to or called back by Adam. If I need smaller items from Aero- yes, the many distributors are easy enough to purchase from. If I want an Aero lower I'm taking a short road trip to FFL nirvana.
 
LaRue.com canceled my order a few days ago for some triggers. Said they are restricted in MA 🤣 What a douche
That is a new and very sad development.
I guess local da got to them as well, finally. Very sad.

They used to ship everything here just fine. That is how those marxists win over, inch by inch. Sad. :(
 
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