If building a reasonably accurate to very accurate rifle, will a billet upper or any other type upper make any real difference in your accuracy with a long and heavy barrel?

Unless you generally shoot .5" groups with every rifle you own, you probably won't notice a difference.

I've been meaning to do an "accurate AR" build comparing receivers, FF/non-FF, barrel contour etc - that is, using the same barrel throughout - but I've been having technical difficulties with some of the test products.

So, in other words, I think it might make a small difference, but I have no data to back that up.

Some uppers like the DPMS lo-pros and I think the sun devil and mabe fulton armory have heavier wall thickness that should theoretically better support the heavy barrel. Since the DPMS is cheaper than a standard one, I'd at least give it a look....PK has 'em.

I believe that the FF vs. non-FF has been proven ad nauseum. It generally makes a measurable difference.

The only claims I have ever seen are by the people making and/or selling them.  Take that for what it is.

Do they add accuracy, no. They do however give the potenial for more accuracy.

I wouldn't spend an additional penny for a billet upper or lower.

YMMV.

what's more important is the lock up between the barrel and the upper receiver, if this is good and the barrel nut has been tightened correctly then either will produce good results - if the barrel is concentric to the receiver then the bolt will be concentric to the barrel extension.

They increase the accuracy of the manufacturer's target date to retire a wealthy man.  (from all the money he makes claiming that they increase accuracy.)

I'll never buy one, its a waste of money.

That's the post of the day

ETA But they do look tacticool.

good point.  But I was actually thinking how the pull of a sling, position or use of a bipod, or position of support hand could flex the barrel to upper connection or the upper in relation to the line of the scope.  I should have said reduce POI shift rather than increase accuracy.

This man is wise beyond his post count.

I don't know that this is actually true.  The Remington 40's and FN M98 400's came in single shot or mag. fed.  Claim was they were stiffer.  I don't really know.  Since it seems as if any bolt could be locked into battery and fired (remotely) sans receiver.

I'd think a barrel nut with a much larger bore for a receiver that was heavier, some (not me) might see more accuracy.

I'd thought of building a Space Gun with a really heavy billet.  Until I thought out the barrel nut, recever relationship.  Then I sobered up.  I don't know.
458

So, lets say a round is chambered,  And the aft end of the receiver were to be cut off.  Bolt still holds the round in battery, right?  Could it not be fired remotely via a strike to the firing pin?  The receiver has no effect on the round once it's in battery right?

 This is not something I thought up but comes from Frank Newhouse book (Bolt Action Rifles).  I realize a gas gun is not a bolt action, but the cartridge is held in place by the bolt. Until relieved by the gas system right?  

 Would I advise any of the above?  Not only no, but HELL NO.  

 Sorry, should have ask what part you didn't understand. I assumed it was the above.
458

I understand that.    My AR's have  eight lugs.  So if each lug, two or 20, is engaged when in battery, in concept the receiver is not needed.
Could it be fired?
458

i don't think you quite get it.  most bolt action rifles lock up in the receiver not the barrel in which case the rigidity of the receiver is of upmost importance as it controls headspace.  with the ar, the lock up is bolt to barrel via the barrel extension.  it is critical that the the barrel extension and receiver interface are in true alignment otherwise, while the bolt will still lock into battery, it is not concentric to the barrel meaning that when the round fires, the bolt flexes to a greater degree effecting headspace.  consistant headspace is the key to accuracy.

Negative to the thread question!

From what I've been able to find out, it sounds like a good forging is the strongest.

not if you bother to read my earlier reply.  the receiver construction is imaterial to accuracy which is the question the op asked.

Thanks for that.
Bigbore

I don't know what difference it makes, if any... all I know is the one billet AR I own is real accurate. Alot more so than the forged one I have. Could be the barrel, the reciever or the combination of the two. There are claims that it's a bit stiffer than forged, but your getting way beyond my paygrade with that.

"imaterial" = ????

Again NO it will not add accuracy.

The question has been asked and answered, but I'll weigh in anyway since there's some discussion here:


*IN THEORY* a stiffer reciever will help. The problem is that, with a system where the bolt locks directly into the barrel extension, as Bigbore and others have pointed out, as long as there's a mechanism to hold the assembly steady during firing, the particulars of the reciever do NOT matter. It's only jobs are to a) provide a space in which the action operates, and b) hold the barrel tightly in relation to the optic's mount.

In other words (again, as has already been pointed out) if the reciever is holding the barrel fixed in relation to the optic (this implies a solid optic mount, a solid optic, and a firmly tightened barrel nut ) and providing a path within which the action can operate, it's doing its job, adding another inch or more (exaggerating for the sake of illustration) to its thickness isn't going to change anything. The only 'wild card' would be the degree of flex in the action that would cause a shift in alignment between the barrel and optic mount. With a standard AR upper and the forces at work in a cartridge the size of a 5.56 or other round, this flex is negligible.


As for changing POI due to sling tension, this is irrelevant with a FF handguard system (if the sling is on the handguard); with non-FF systems, no amount of thickness in the reciever is going to stop tension from being applied to the barrel.

IOW, billet recievers look nice, ARE nice, but contribute NOTHING to the function of the rifle in terms of accuracy or anything else.

apologies for incorrect late night spelling "immaterial", perhaps "of no consequence" would have been a better choice?

Yup. Either way it does not add accuracy.