How Much Barrel (weight) Can AR15 Receiver Handle?

[PBWalsh]

I have a 224 Valkyrie on a 24" barrel fluted, 6.5 twist, no muzzle device, measures .856" at the muzzle.
Its on a standard AR Areo upper, trued, glued, bolt carrier centered.
Capable of .5" 5 shot groups...note: with 3 shots through the same hole, with 95 gr SMK.
So....standard, forged, milspec recievers, work just fine, on bull barrels, no need to go high dollar billet, unless ya care to...
Your coin, your gun.

No one is denying a standard reciver is inaccurate, the debate is POI shift going from bipod/bag to a tripod/barricade.

Take that same upper that is obviously accurate in whatever position you shot that group in, and then test it in alternate positions. I'm confident you'll see a shift.

Now, a shift is not nessesarily a bad thing as long as you understand it and compensate for it in your data.

 

[roostercogburn98]

Take that same upper that is obviously accurate in whatever position you shot that group in, and then test it in alternate positions. I'm confident you'll see a shift.

What’s your opinion of how much that “shift” is shooter related and not firearm related? Just out of curiosity for my knowledge?

 

[Denver_AR]

I have a 224 Valkyrie on a 24" barrel fluted, 6.5 twist, no muzzle device, measures .856" at the muzzle.
Its on a standard AR Areo upper, trued, glued, bolt carrier centered.
Capable of .5" 5 shot groups...note: with 3 shots through the same hole, with 95 gr SMK.
So....standard, forged, milspec recievers, work just fine, on bull barrels, no need to go high dollar billet, unless ya care to...
Your coin, your gun.

My AR will also shoot about 1/2 MOA groups... it's just the POI shifts when changing from bipod to bagged positions.

 

[PBWalsh]

What’s your opinion of how much that “shift” is shooter related and not firearm related? Just out of curiosity for my knowledge?

My personal example:

I shot a group from bipod/bag and POA = POI. Moved to a tripod/bag and the center of that group was ~.4mil low. I shot a third group on the tripod/bag while holding .4mil high and found that by me holding .4mil high, the group centered around the POI.

My tripod shooting is ~4moa (I suck), but the group clearly shifted.

Here is the picture of what I'm talking about. As you can see, there is definitely shooter error, but a clear POI shift.

 

[45-90]

Forgings are generally stronger than billet recievers and tests have been done on burst chambers, and overloads.
ARs are temperamental in all ways of holding and maneuvering them for a shot... the gun likes everything the same, as the preceeding shot...exactly the same.
Just the way it is.
I never shoot them off the bench, always in the prone, and get on it...but with the same amount of pressure. Everyone has to find what works for them, but with consistency.

 

[Denver_AR]

I got an Aero enhanced reciever and handguard in for testing. Should test next week.

Oh, and www.sgtofarms.com makes enhanced Arca rails for the Aero M4e1 upper.

AR-15 15.5" ARCA Handguard | Sgt of Arms

This handguard is one of the most versatile handguards on the market. It has full M-Lok capabilities on both sides and the bottom but also has a full ARCA Swiss Rail on the bottom. The ARCA rail is great for locking into a tripod or being able to move your bipod to any point on the handguard...

www.sgtofarms.com

Whelp, you planted a seed that eventually took root. I also picked up an Aero enhanced receiver and the Sgt Arm Arca rail.
I've used it once at a local match but only had time for limited sight-in. Early results seem to indicate only slightly less POI shift between bipod and bagged shooting positions.
I convinced this shift is an inherent limitation of the ARs design; pressure on the handguard will always deflect the barrel to some extent.

 

[PBWalsh]

Whelp, you planted a seed that eventually took root. I also picked up an Aero enhanced receiver and the Sgt Arm Arca rail.
I've used it once at a local match but only had time for limited sight-in. Early results seem to indicate only slightly less POI shift between bipod and bagged shooting positions.
I convinced this shift is an inherent limitation of the ARs design; pressure on the handguard will always deflect the barrel to some extent.

Mine that you quoted shows a .2 mil shift low. I am curious to know if this is standard across all handguard length with the M4e1 upper or if a longer handguard would produce a larger shift. I have the 10" handguard with a 12.5" barrel. Curious about the 15" rail shift.

 

[rpoL98]

Mine that you quoted shows a .2 mil shift low. I am curious to know if this is standard across all handguard length with the M4e1 upper or if a longer handguard would produce a larger shift. I have the 10" handguard with a 12.5" barrel. Curious about the 15" rail shift.

longer rail would be a longer lever-arm. more applied torque. just like using a breaker bar.

 

[ut755ln]

Mine that you quoted shows a .2 mil shift low. I am curious to know if this is standard across all handguard length with the M4e1 upper or if a longer handguard would produce a larger shift. I have the 10" handguard with a 12.5" barrel. Curious about the 15" rail shift.

longer rail would be a longer lever-arm. more applied torque. just like using a breaker bar.

rpoL98 nailed it. It is an aluminum upper and there is always some flex. To me the issue is if it is repeatable.

 

[Rocketvapor]

Flex is complicated.
I have a 28" bull barrel hanging on a BCA side charge upper.
Just holding near the receiver and the barrel hangs there and I'm sure it sags.
Like a Tripod near the rifle balance point. All the rifle weight is hanging, front and rear.
(that's a downward barrel sag).

Set the rifle with a 28" barrel. 15" Free Float on a V block, 2X4, Bipod, or Rest with the same support point out close to the end of the handguard the barrel will still sag but the weight on the receiver joint will flex the receiver UP. It's the contact point that determines if the sag is compensated by upward flex. Change the contact point, change the amount and direction of receiver flex.

Try this:
Pull the rear pin. Set the rifle in a rear bag and move the forward contact point back and forth.
There will be a location that will keep the action closed (Bipod forward ?).
A location that will tend to open the upper/lower (Bipod back ).
And, a location that will balance the load on the receiver set.

 

[LRRPF52]

I like what Hk did with the upper receiver and longer barrel extension.

Only thing is it’s external piston-operated, which does not help with accuracy or precision.

 

[PBWalsh]

longer rail would be a longer lever-arm. more applied torque. just like using a breaker bar.

That is my assumption.

Be real cool if Aero made a steel M4e1 upper, real cool. I'd buy it at double the standard price if it meant zero flex. Yes I know the RD-15 exists.

 

[45-90]

There is no such thing as zero flex...
An all steel complete upper would be really heavy. A steel upper reciever would also be heavy.
A thicker aluminum upper reciever could be more stiff than a regular sized steel reciever.
Areo enhanced recievers have more material for rigidity, than the standard mil-spec reciever.

 

[PBWalsh]

There is no such thing as zero flex...
An all steel complete upper would be really heavy. A steel upper reciever would also be heavy.
A thicker aluminum upper reciever could be more stiff than a regular sized steel reciever.
Areo enhanced recievers have more material for rigidity, than the standard mil-spec reciever.

A standard stripped upper is 6.9oz. The M4e1 is 12.4oz. Steel is approximately 2.5-3 times the weight of 7075 aluminum. So we are looking at a 20.7oz or 37.2oz reciever. It'd definitely add some weight, but I am curious to see what the net result would be in performance.

 

[45-90]

A standard stripped upper is 6.9oz. The M4e1 is 12.4oz. Steel is approximately 2.5-3 times the weight of 7075 aluminum. So we are looking at a 20.7oz or 37.2oz reciever. It'd definitely add some weight, but I am curious to see what the net result would be in performance.

Probably not much increase in performance, compared to the extra weight....aluminum recievers have shot 5 shot groups as small as 1/4" so I'm not interested in the idea at at this time...but you and others may be, and could pursue it.

 

[rpoL98]

Noveske has an AR-15 upper receiver that has a beefed up snout, not sure if it's Gen 3 or Gen 4. I think though it's billet, not forged. Pricey.

and BCM has their Mk2. they sold just the stripped upper for a short while, but the internet keyboard commandos criticized it for its' different appearance, incompatible with Geissele Mk16, etc. Those idiots didn't understand its' purpose. Morons. It has a beefed up snout for more stability, thicker at the front end. Yeah, it's different. $130 in 2019. So BCM took the stripped upper off the market, after it sold out in a couple weeks, never re-listed. Now, you can only buy it as part of an assembled upper. This is why we can't have nice things.

 

[PBWalsh]

Probably not much increase in performance, compared to the extra weight....aluminum recievers have shot 5 shot groups as small as 1/4" so I'm not interested in the idea at at this time...but you and others may be, and could pursue it.

So the purpose of the assumed steel reciever is not pure accuracy, but mitigating POI shift in other positions.

Yes, this would not be for everyone, but I'm betting a few would buy it to make a small batch worthwhile for a manufacturer.

 

[45-90]

So the purpose of the assumed steel reciever is not pure accuracy, but mitigating POI shift in other positions.

Yes, this would not be for everyone, but I'm betting a few would buy it to make a small batch worthwhile for a manufacturer.

I could build a steel receiver in the Bridgeport mill, but not intrested in a steel reciever.
But being a machinist and former CNC programmer / machinist this is very easy to do. A manufacturer already has the programs in the system, along with any fixtures used.
Using the same size steel blank.

Just copy and change program, changing machining parameters to meet the steel used feeds and speeds. Change the cutting tools to steel cutting carbides and end mills. All this entered into the tool library, along with lengths, diameters, number of cutting teeth, etc.
Rename program, for Steel recievers.
Check program, clean out machine of aluminum chips, adjust or change coolent as per company protocol.
Should be ready to go in about 1 hour with all these tasks.
First part passes inspection, let it rip.
Full CNC production of Steel recievers.

 

[AR shooter]

I have a 24 inch 22 Nosler White Oak on a Aero enhanced receiver and a 24 inch 204 Shilen on a standard Aero receiver both bull barrels and get no POI shift at all. The enhanced is definately stronger though.

 

[Bravo6niner]

Tagging @unclemoak Didn’t you do a “longish” barreled AR

 

[unclemoak]

This barrel weighed 8.2 lbs. basically a 1.2” straight contour that’s 27” long.

This is how well it shoots.

 

[Bravo6niner]

Yep that’s the one !!!

 

[supercorndogs]

Just point this thread down tracks again. This thread is about POI shift with depending on how the rifle is supported.

A stiffer upper reciver also has the advantage of not letting the barrel whip around as much, making the low pro gas blocks hitting the inside of the handgaurd less of a problem. Or less likley with the same amount of clearance.

 

[Cascade Hemi]

Noveske has an AR-15 upper receiver that has a beefed up snout, not sure if it's Gen 3 or Gen 4. I think though it's billet, not forged. Pricey.

and BCM has their Mk2. they sold just the stripped upper for a short while, but the internet keyboard commandos criticized it for its' different appearance, incompatible with Geissele Mk16, etc. Those idiots didn't understand its' purpose. Morons. It has a beefed up snout for more stability, thicker at the front end. Yeah, it's different. $130 in 2019. So BCM took the stripped upper off the market, after it sold out in a couple weeks, never re-listed. Now, you can only buy it as part of an assembled upper. This is why we can't have nice things.

Mega reinforced the entire side of the receiver. When the A2 carry handle is remove, the receiver buckles at the ejection port. Material thickness needs to be added to the entire side of the receiver to make up for the ejection port.