So I'm thinking of building up an "budget" precision upper (.223). Now, I've pretty much decided on a WOA barrel, but I'm not sure on the upper. Now, is there really a benefit to a billet upper? Are there any issues with mating a billet upper to a forged lower? Does the Vltor MUR fall somewhere in between? I want a really high quality upper, but I don't want to get taken to the bank. Are the "lower end" billet uppers (MI) any good, or just stick with forged. If forged, are any better than others?
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Billet upper receiver vs forged
- Thread starter RichS
- Start date
Most of the billet uppers have heavier walls, and therefore have less flex and are generally stronger, which make them perfect for heavy barreled / precision rifle applications.
With that said, DPMS makes a low profile "heavy walled" upper that is forged and is probably the strongest / stiffest available, for less than $100.
DPMS Upper Receiver Stripped AR-15 Low Profile Flat-Top Matte
Both of my expensive high power match rifles (26" heavy barrel kriegers in 223 Rem and 6mm AR turbo) are built with DPMS lo pro uppers, and I couldn't be happier.
If you want to spend more coin on billet uppers you can, but they aren't going to offer any performance advantage over the DPMS lo pro.
With that said, DPMS makes a low profile "heavy walled" upper that is forged and is probably the strongest / stiffest available, for less than $100.
DPMS Upper Receiver Stripped AR-15 Low Profile Flat-Top Matte
Both of my expensive high power match rifles (26" heavy barrel kriegers in 223 Rem and 6mm AR turbo) are built with DPMS lo pro uppers, and I couldn't be happier.
If you want to spend more coin on billet uppers you can, but they aren't going to offer any performance advantage over the DPMS lo pro.
Any concern with it being extruded 7031 (not like I have any idea of what that means....but it seems for forged receivers they're always looking for 7075)?
7031 is somewhere in between 6061 and 7075 in terms of yield strength and toughness. 6061 has about double the toughness of 7075, but 7075 has a higher yield strength. 7031 is about 50% tougher than 7075, and only 10-20% less strength from the materials books I've seen.
From what my machinist tells me, 7075 is a lot nicer to machine than 6061 and is a lot more plentiful anyway, which is why 7075 is so widely used.
So to answer your question, it's not going to make one bit of difference. Pick a heavy walled 7075-T6 billet or 7031-T6 extruded, and you will be good to go.
From what my machinist tells me, 7075 is a lot nicer to machine than 6061 and is a lot more plentiful anyway, which is why 7075 is so widely used.
So to answer your question, it's not going to make one bit of difference. Pick a heavy walled 7075-T6 billet or 7031-T6 extruded, and you will be good to go.
OP, which handguard do you plan on using? The free-float tubes with the anti-rotation tabs that index on the front of the receiver may not work with a particular billet upper and definitely won't work with the DPMS extruded uppers.
Most of the important points have been hit already. Kudos.
I have both a VLTOR MUR and a DPMS slabside like the one linked above. The DPMS is a huge, heavy and solid upper. As noted, its wall thickness will prevent use of some freefloat handguards. You can use it with a GI barrel nut setup, with a Midwest Industries Generation-2 one piece handguard (SS tube or T-series quadrail), or with many older style freefloats that use a barrel nut and jam nut arrangement (most YHM, oldest Daniel Defense, various others). As long as you plan ahead, it's not a big deal.
The other drawback to the DPMS is that it doesn't have M4 feedramp cuts, which most barrels being made today have. This isn't a big deal, but it's not ideal either. You can use it just fine with a barrel that has the feedramp cuts in its extension, you will simply have a funny intersection of the upper and extension, and theoretically not get the reliability benefit of the M4 cuts.
On the VLTOR MUR, for the most part I think it's awesome. It's forged, it's heavy duty, it has M4 feedramp cuts, and the ones made since 2010 or so have the profile adjusted at the barrel nut area so they will work with 99% of all handguards, including the ones with indexing tabs that overlap the receiver. The only small issue I've had with the MUR is finding that it won't fit easily with some of my lowers - ironically a Noveske lower in particular (ironic because Noveske has actually used the MUR on some of their rifles). The MUR is theoretically in wonderfully perfect dimensional spec, but I can't explain why it interferes with some lowers while most of my mil-style uppers do not. Still, this wouldn't keep me from buying one again.
I have both a VLTOR MUR and a DPMS slabside like the one linked above. The DPMS is a huge, heavy and solid upper. As noted, its wall thickness will prevent use of some freefloat handguards. You can use it with a GI barrel nut setup, with a Midwest Industries Generation-2 one piece handguard (SS tube or T-series quadrail), or with many older style freefloats that use a barrel nut and jam nut arrangement (most YHM, oldest Daniel Defense, various others). As long as you plan ahead, it's not a big deal.
The other drawback to the DPMS is that it doesn't have M4 feedramp cuts, which most barrels being made today have. This isn't a big deal, but it's not ideal either. You can use it just fine with a barrel that has the feedramp cuts in its extension, you will simply have a funny intersection of the upper and extension, and theoretically not get the reliability benefit of the M4 cuts.
On the VLTOR MUR, for the most part I think it's awesome. It's forged, it's heavy duty, it has M4 feedramp cuts, and the ones made since 2010 or so have the profile adjusted at the barrel nut area so they will work with 99% of all handguards, including the ones with indexing tabs that overlap the receiver. The only small issue I've had with the MUR is finding that it won't fit easily with some of my lowers - ironically a Noveske lower in particular (ironic because Noveske has actually used the MUR on some of their rifles). The MUR is theoretically in wonderfully perfect dimensional spec, but I can't explain why it interferes with some lowers while most of my mil-style uppers do not. Still, this wouldn't keep me from buying one again.
Interesting. I had both of my DPMS slick side uppers built up for me by a gunsmith, so maybe they modified them, but they both have the m4 feed ramps.
Cool info, thanks guys. As to the handguards/rail I'm thinking less is more. All I really need is provision for a bipod. I like the ALG defense 13" rail. Maybe something like a VTAC or a JP. I'd like one that's light, rigid, tough, and well.......inexpensive.
If you are going for accuracy, get a better upper receiver. Most of the DPMS uppers I have used for builds didn't have a tight barrel extension fit and the faces were not square. The extension fit can be fixed with loctite and a lathe can square the face. Check out a Mega or Vltor if you want a upper with good specs.
As mentioned some of the billet uppers may not allow some handguards to fit due to the bigger area around the front. If you do decide to go billet, check with the maker to see if the handguard you want to use will fit.
As mentioned some of the billet uppers may not allow some handguards to fit due to the bigger area around the front. If you do decide to go billet, check with the maker to see if the handguard you want to use will fit.
Mega makes a great billet upper. The gun I built last week with a Mega billet upper had an extremely tight barrel extension fit, so much so that I had to use the barrel nut to seat it all the way as I couldn't press it in by hand. It's TIGHT! I'm sure partially why the gun shoots lights out...
Yup, having used several brands, Mega seems to be the best for tolerences, fit and finish. My barrel seating method is using wood block on the muzzle end and a mallet, then tighten bbl nut.
This issue was bugging me, so I looked at mine - I have one fully built, and two more as parts bin - and none of those three have M4 feedramp cuts. I also looked in the DPMS catalog online and found only this:
Flattop Lo-Pro Upper Receiver
Which does not list M4 feedramps. I am wondering if maybe DPMS makes versions with and without M4 feedramps, and it's up to the dealer to decide which one to order? All three that I have were purchased from MidwayUSA, but over the space of two years or so.
I will echo all the positive comments on Mega. I've had zero problems with anything they've made since 2009 or so, and trivial problems with a lower receiver made before then (slightly tight magwell and slightly tight pin holes).
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