Are all stripped Lower Receivers Equal?

baddarryl · November 26, 2017, 07:04 PM

Are they all generally the same for the AR or there match grade etc?

turtlehead · November 26, 2017, 07:20 PM

If they're in spec, they're in spec.

zukiphile · November 26, 2017, 07:30 PM

There are ones that fit tightly to your upper, and those that don't.
There are forged and billet; if memory serves, in the 90s there were places selling cast lowers. Billlet lowers look neat, but I think they are like the outside of a car you drive - you don't really notice how it looks while you use it. Some billet lowers have unconventional features like tension screws.

I don't think a 6061 billet lower would bother me; it isn't as if a lower takes a lot of stress. Some places sell 6061 billet uppers about which I have misgivings.

marine6680 · November 27, 2017, 02:09 PM

Yes and no... That is the short answer... But it needs context to be useful.

An in spec forged lower is usually pretty comparable to any other in spec forged lower.

Now... There can and will be some differences, some minor some less. Your personal needs and goals for the rifle you want to build will come into play as to what matters and what doesn't. If all you want is a lower that is in spec and hold the parts together, then there is not any difference that matters. If you have further concerns, then they may matter more.

Some cheap lowers do not get anodized as well as other lowers, but that is more supposition based on finish durability reports I have read over the past few years. Things like, "I got a cheap Anderson lower, and it wears and scratches easier than my Colt"... Stuff like that.

Another difference is finish machining. Some take to time to smooth out the flash from the forging process... Basically what would look like a seem from the two sides of the forging die.

For example... My BCM is smooth, clean, and nicely finished, but my Colt had the flashing trimmed off a bit, but no effort to smooth the area and make a nice uniform surface. I trust the Colt to be tough and handle anything I would throw at it, but it isn't as nice aesthetically.

Similar lack of finishing steps can be in cheap lowers. Not all of the lower cost ones though... Aero tends to make a nicely finished lower.

Another difference is in the QC... The cheap lowers may not get very thorough QC, and something that is out of spec may slip through more often. Usually it's minor and primary cosmetic, but on occasion, you will get a lower with a dimensional issue. Then parts don't fit right, and the rifle won't work correctly. Higher end and higher cost lowers tend to have this issue very rarely, as they spend more time on QC.

I have heard several stories of Anderson lowers that were out of spec in some way. I have heard a few about PSA as well... Not heard any about Aero that I can recall.

With current pricing, I think Aero is the best bet for a lower at a good low price point. Followed by PSA, then Anderson is my last choice.

Beyond those, until you start getting into brands like Daniel Defense, you won't see much different than the name on the side.

If you want a certain name brand, then go with what you want.

Once you deviate from the standard forged lower receiver... Either by using an alloy other than 7075, or getting into milled receiver options... Or some of the crazy designs like the skull magwell lower...

Then all bets are off... There are too many differences and potential pros and cons to go over.

I go with standard forged myself... They work well, they have a low cost generally, and they have the best parts compatibility with aftermarket parts and upgrades.

TrueBlue711 · November 27, 2017, 02:37 PM

I've built my fair share of ARs and here's what I've seen. Matching a lower with an upper made by the same company, they fit great with little wobble. I also "Frankensteined" an AR with two different companies on upper and lower and it wobbled like crazy. Did it still go bang when you pull the trigger? Yes. But if wiggle between an upper and lower will bother you, be careful choosing two different companies.

One exception I've had with that though is with polymer lowers. I've made 4 ARs using polymer lowers (both New Frontier and Tennessee Arms polymer lowers) and there is no wobble with any upper I put on it. However, that is because they are tight...tight enough where I need to use a punch to take out the take down pins. Which I don't have a problem with since I'm not swapping uppers and lowers in the field like crazy.

444 · November 27, 2017, 02:45 PM

No, they are not all the same (as has been mentioned).

The question is, does this matter ?
I would say that you can buy pretty much any lower, and shoot it heavily for a lifetime and it will be perfectly fine at your funeral. IN MY OPINION, most of the stuff people talk about when discussing the pros and cons of the various lowers are largely solutions in search of a problem, gilding the lilly, taking things way too far..................

FWIW: I have owned an AR15 since the early to mid-1980s. I have probably owned 20 of them over the years. I have put a lot of them together. I have finished 80% receivers................. Knowing what I know now, if I didn't own an AR and wanted to put one together, I would probably not only buy the cheapest lower available, but it would absolutely be the part that I put almost zero thought into my selection. I would care deeply about the fire control parts, I would care deeply about the barrel..........My experience is that the lower is something that I wouldn't spend a moment thinking about other than availability, price, and where I was buying it.

DMK · November 27, 2017, 02:58 PM

Quote:

Originally Posted by 444

I would care deeply about the fire control parts, I would care deeply about the barrel.

I'll add Bolt Carrier Group to that list, but otherwise agree completely.

Most folks nit pick about cosmetic things regarding receivers. (Like upper/lower fit)

zukiphile · November 27, 2017, 03:23 PM

Quote:

Originally Posted by TB711

One exception I've had with that though is with polymer lowers. I've made 4 ARs using polymer lowers (both New Frontier and Tennessee Arms polymer lowers) and there is no wobble with any upper I put on it. However, that is because they are tight...tight enough where I need to use a punch to take out the take down pins.

That's my experience too. I prefer the feel of my polymer receivers over the regular ones because of the low thermal mass.

I built my first lower on a New Frontier stripped lower. It allows lots of mistakes that would be ugly gouges on anodized aluminium.

As much as I like them, they are a tough sell in a world of $35 7075 lowers.

Sevens · November 27, 2017, 05:40 PM

This actually brings up a good question-- where I am located, Anderson lowers are growing on trees. I own four but have only built a rifle on one of the four. That rifle runs fine, zero problems.

Curious as to how Anderson would handle a problem if I build a rifle on another lower years down the road. We'd be talking anout a new and never-used stripped lower from them, and one I purchased new from a dealer, but YEARS back.

Has anyone dealt directly with Anderson? Is it no big hassle for a no-cost swap out on a defective lower?

I'm just not a hard core rifle guy. I truly have no way of knowing if my lowers are all in-spec and good to go unless/until I were to find years down the road that they are not.

Nimble1 · November 29, 2017, 02:22 PM

Just finished a build with a Anderson lower and PSA upper. The lower went together fine and fits the upper tightly. The color matches great also. Couldn't ask for more.

Metal god · November 30, 2017, 04:58 AM

I think marine6680 pretty much nailed it . I have several milspec lowers ( PSA , Spikes , Frankfard arsenal , Anderson ) They all seem to work well . The mag well on one of my PSA lowers seems a little tighter then the others when using P-mags . It still works fine but there's something about the way they fit that is different .

kraigwy · December 1, 2017, 10:05 AM

Except for the trigger, it doesn't matter about what lower is used. The Accuracy is in the Upper.

I have three ARs. I can put my White Oak Service rifle upper on any of my AR lowers and the accuracy doesnt change.

But IMO the trigger is critical.

hdwhit · December 4, 2017, 12:21 AM

Quote:

baddarryl wrote:
...or [are] there match grade etc?

There are no "premium", "gold" or "match grade" receivers, but there is a difference in quality between manufacturers.

In this respect, consult marine6680's post on the issue which is a very good treatment of quality amongst manufacturers supposedly manufacturing identical products.

MagnumWill · December 4, 2017, 08:32 AM

I find very little difference in lowers when bought from reputable companies. I think the only difference i’ve seen (mentioned above) is that my Bushmaster lower’s anodizing is starting to scratch/chip a little bit at the bottom of the mag well where i’ve been whacking magazines against it. Fit and function have been 100% however.

November 26, 2017, 07:04 PM	#1
baddarryl Senior Member Join Date: March 29, 2011 Location: Cape Fear! Posts: 1,683	Are all stripped Lower Receivers Equal? Are they all generally the same for the AR or there match grade etc?

November 26, 2017, 07:30 PM	#3
zukiphile Senior Member Join Date: December 13, 2005 Posts: 4,451	There are ones that fit tightly to your upper, and those that don't. There are forged and billet; if memory serves, in the 90s there were places selling cast lowers. Billlet lowers look neat, but I think they are like the outside of a car you drive - you don't really notice how it looks while you use it. Some billet lowers have unconventional features like tension screws. I don't think a 6061 billet lower would bother me; it isn't as if a lower takes a lot of stress. Some places sell 6061 billet uppers about which I have misgivings. __________________ http://www.npboards.com/index.php

November 27, 2017, 02:45 PM	#6
444 Senior Member Join Date: November 20, 2000 Location: Ohio Posts: 3,968	No, they are not all the same (as has been mentioned). The question is, does this matter ? I would say that you can buy pretty much any lower, and shoot it heavily for a lifetime and it will be perfectly fine at your funeral. IN MY OPINION, most of the stuff people talk about when discussing the pros and cons of the various lowers are largely solutions in search of a problem, gilding the lilly, taking things way too far.................. FWIW: I have owned an AR15 since the early to mid-1980s. I have probably owned 20 of them over the years. I have put a lot of them together. I have finished 80% receivers................. Knowing what I know now, if I didn't own an AR and wanted to put one together, I would probably not only buy the cheapest lower available, but it would absolutely be the part that I put almost zero thought into my selection. I would care deeply about the fire control parts, I would care deeply about the barrel..........My experience is that the lower is something that I wouldn't spend a moment thinking about other than availability, price, and where I was buying it. __________________ You know the rest. In the books you have read How the British Regulars fired and fled, How the farmers gave them ball for ball, From behind each fence and farmyard wall, Chasing the redcoats down the lane, Then crossing the fields to emerge again Under the trees at the turn of the road, And only pausing to fire and load.

November 27, 2017, 05:40 PM	#9
Sevens Senior Member Join Date: July 28, 2007 Location: Ohio Posts: 11,756	This actually brings up a good question-- where I am located, Anderson lowers are growing on trees. I own four but have only built a rifle on one of the four. That rifle runs fine, zero problems. Curious as to how Anderson would handle a problem if I build a rifle on another lower years down the road. We'd be talking anout a new and never-used stripped lower from them, and one I purchased new from a dealer, but YEARS back. Has anyone dealt directly with Anderson? Is it no big hassle for a no-cost swap out on a defective lower? I'm just not a hard core rifle guy. I truly have no way of knowing if my lowers are all in-spec and good to go unless/until I were to find years down the road that they are not. __________________ *Attention Brass rats and other reloaders:* I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.

November 30, 2017, 04:58 AM	#11
Metal god Senior Member Join Date: April 10, 2012 Location: San Diego CA Posts: 6,875	I think marine6680 pretty much nailed it . I have several milspec lowers ( PSA , Spikes , Frankfard arsenal , Anderson ) They all seem to work well . The mag well on one of my PSA lowers seems a little tighter then the others when using P-mags . It still works fine but there's something about the way they fit that is different . __________________ If Jesus had a gun , he'd probably still be alive ! I almost always write my posts regardless of content in a jovial manor and intent . If that's not how you took it , please try again .

November 26, 2017, 07:20 PM	#2
turtlehead Senior Member Join Date: October 20, 2015 Location: Phoenix, AZ Posts: 1,203	If they're in spec, they're in spec.

November 27, 2017, 02:09 PM	#4
marine6680 Senior Member Join Date: July 24, 2012 Location: Parker, CO Posts: 4,594	Yes and no... That is the short answer... But it needs context to be useful. An in spec forged lower is usually pretty comparable to any other in spec forged lower. Now... There can and will be some differences, some minor some less. Your personal needs and goals for the rifle you want to build will come into play as to what matters and what doesn't. If all you want is a lower that is in spec and hold the parts together, then there is not any difference that matters. If you have further concerns, then they may matter more. Some cheap lowers do not get anodized as well as other lowers, but that is more supposition based on finish durability reports I have read over the past few years. Things like, "I got a cheap Anderson lower, and it wears and scratches easier than my Colt"... Stuff like that. Another difference is finish machining. Some take to time to smooth out the flash from the forging process... Basically what would look like a seem from the two sides of the forging die. For example... My BCM is smooth, clean, and nicely finished, but my Colt had the flashing trimmed off a bit, but no effort to smooth the area and make a nice uniform surface. I trust the Colt to be tough and handle anything I would throw at it, but it isn't as nice aesthetically. Similar lack of finishing steps can be in cheap lowers. Not all of the lower cost ones though... Aero tends to make a nicely finished lower. Another difference is in the QC... The cheap lowers may not get very thorough QC, and something that is out of spec may slip through more often. Usually it's minor and primary cosmetic, but on occasion, you will get a lower with a dimensional issue. Then parts don't fit right, and the rifle won't work correctly. Higher end and higher cost lowers tend to have this issue very rarely, as they spend more time on QC. I have heard several stories of Anderson lowers that were out of spec in some way. I have heard a few about PSA as well... Not heard any about Aero that I can recall. With current pricing, I think Aero is the best bet for a lower at a good low price point. Followed by PSA, then Anderson is my last choice. Beyond those, until you start getting into brands like Daniel Defense, you won't see much different than the name on the side. If you want a certain name brand, then go with what you want. Once you deviate from the standard forged lower receiver... Either by using an alloy other than 7075, or getting into milled receiver options... Or some of the crazy designs like the skull magwell lower... Then all bets are off... There are too many differences and potential pros and cons to go over. I go with standard forged myself... They work well, they have a low cost generally, and they have the best parts compatibility with aftermarket parts and upgrades.

November 27, 2017, 02:37 PM	#5
TrueBlue711 Senior Member Join Date: March 16, 2011 Posts: 489	I've built my fair share of ARs and here's what I've seen. Matching a lower with an upper made by the same company, they fit great with little wobble. I also "Frankensteined" an AR with two different companies on upper and lower and it wobbled like crazy. Did it still go bang when you pull the trigger? Yes. But if wiggle between an upper and lower will bother you, be careful choosing two different companies. One exception I've had with that though is with polymer lowers. I've made 4 ARs using polymer lowers (both New Frontier and Tennessee Arms polymer lowers) and there is no wobble with any upper I put on it. However, that is because they are tight...tight enough where I need to use a punch to take out the take down pins. Which I don't have a problem with since I'm not swapping uppers and lowers in the field like crazy.

November 29, 2017, 02:22 PM	#10
Nimble1 Member Join Date: February 12, 2005 Location: SW Fla Posts: 54	Just finished a build with a Anderson lower and PSA upper. The lower went together fine and fits the upper tightly. The color matches great also. Couldn't ask for more.

December 1, 2017, 10:05 AM	#12
kraigwy Senior Member Join Date: June 16, 2008 Location: Wyoming Posts: 11,061	Except for the trigger, it doesn't matter about what lower is used. The Accuracy is in the Upper. I have three ARs. I can put my White Oak Service rifle upper on any of my AR lowers and the accuracy doesnt change. But IMO the trigger is critical. __________________ Kraig Stuart CPT USAR Ret USAMU Sniper School Distinguished Rifle Badge 1071

December 4, 2017, 08:32 AM	#14
MagnumWill Senior Member Join Date: March 18, 2009 Location: Central Colorado Posts: 1,001	I find very little difference in lowers when bought from reputable companies. I think the only difference i’ve seen (mentioned above) is that my Bushmaster lower’s anodizing is starting to scratch/chip a little bit at the bottom of the mag well where i’ve been whacking magazines against it. Fit and function have been 100% however. __________________ Those who hammer their swords into plow shares will plow for those who didn't...