Assessing Stripped Lowers

[Chance]

I'm completely new to the concept of stripped lowers. While I know what they are, two recent (https://pistol-forum.com/showthread.php?16909-Possible-PF-AR15-Aero-lower-group-buy)threads (https://pistol-forum.com/showthread.php?16894-2016-is-coming)have highlighted my ignorance of the minutia.

How do you assess stripped lowers? I've been told that MEGA receivers are awesome, so how do Aero lowers compare (I'm trying to provide fodder for conversation, and not suggest anything about the aforementioned companies; again, I'm far too ignorant to try to funnel the conversation)? If you wanted to have a lower that was amenable to 7.62 NATO, or other calibers, how would that fit into the above?

[Gray222]

MEGA lowers are awesome because (from what I've been told) they are made in house and are the direct manufacturer for many other companies that they brand for. When you order a MEGA lower you get a 100% in house item.

Rule of thumb is usually for a whatever build you can get away with cheapy lowers from who knows companies. If you want something of serious quality, you are going to pay top dollar for that lower. Prime examples are KAC, AXTS, Rainier MOD Ultramatch Billet 3, MEGA, and so on.

[Unobtanium]

MEGA lowers are awesome because (from what I've been told) they are made in house and are the direct manufacturer for many other companies that they brand for. When you order a MEGA lower you get a 100% in house item.

Rule of thumb is usually for a whatever build you can get away with cheapy lowers from who knows companies. If you want something of serious quality, you are going to pay top dollar for that lower. Prime examples are KAC, AXTS, Rainier MOD Ultramatch Billet 3, MEGA, and so on.

MEGA has the best algorithms for machining aluminum, and do so in a climate controlled environment, and many other things of a technical nature. They also have the mental/experience talent to take advantage of their technology. To honestly test a lower, run it for a few thousand rounds. I've had some that are, I suspect, slightly out of spec, that led to issues every 5-800 rounds. Just little foibles like not chambering when I press the bolt release, etc. because the round was presented at a tiny bit steep of an angle due to mag catch height, etc.

You want something you can probably count on? MEGA. MEGA is as close to "it will run out of the box without me testing it" as you can get, in my opinion, regarding dimensional stability of their products.

[Sensei]

Aero lowers are very nice. Mega lowers are very, very nice. I own both in SBR builds, and never had any problems with either. I've also used stripped lowers from Noveske, complete lowers from LMT and KAC (IWS), and blem lowers from BCM - all have been excellent.

There are a number of other reasonable options such as CMT (Cross Machine Tool) that are also high quality. In fact, I just ordered the CMT UHP15 PDW lower which is a rather unique beast for my 10.5" build. Truth be told, most forged lowers are going to be fine if you stay away from Del-Ton, Hesse, etc. Even lower parts kits are fairly uniform in terms of springs and pins with the notable exception of the fire control kit (trigger).

Bottom line: get either a Mega, Aero, or some other reasonable 7075 forged lower. Then get a LPK from DD, G&R, Rainier, PSA, etc. Try to find a LPK that allows you to upgrade the trigger group and grip (PSA and G&R do this) since these really do affect the quality of the lower performance.

[Chance]

So, these stripped lowers are going to be stockpiled in the event of a gun-pocalypse, in which case, they would not be very high round count guns. Maybe not even enough rounds to warrant a barrel change. Would it be valid to get something high quality, under the assumption that a high quality lower would last multiple hand-me-down generations under these circumstances?

[Eyesquared]

Or you could get two decent forged lowers. Either way I suspect they would last you a long long time. You will have to be a really really really high volume shooter to completely ruin a lower. Just look at the military's stocks of rifles, some of those lowers have been around for longer than many of us.

Also, if we're assuming lowers will dry up soon, I'd rather have a shit ton of decent lowers rather than one gucci lower. With a handful of normal lowers you can equip your family with long guns, sell one for ammo, etc.

[Sensei]

So, these stripped lowers are going to be stockpiled in the event of a gun-pocalypse, in which case, they would not be very high round count guns. Maybe not even enough rounds to warrant a barrel change. Would it be valid to get something high quality, under the assumption that a high quality lower would last multiple hand-me-down generations under these circumstances?

The standard forged lowers from the likes of Aero and Mega run you $100-130. These are are the types of stripped lowers (and complete lowers from BCM, LMT, and KAC) that I'm stocking up on because they are the least likely to give me problems mating with quality LPKs and uppers. Forged lowers also tend to be stronger than their billet counterparts (although billet tend have nicer esthetics), but I've personally NEVER seen a decent quality lower break - forged or billet. Like SIRTainly said, there are plenty of 70's and 80's era lowers running strong with tens of thousands of full auto rounds through them. Even lower tier / no-name lowers generally don't break; they do have higher incidence of compatibility issues due to out of spec construction.

[Unobtanium]

So, these stripped lowers are going to be stockpiled in the event of a gun-pocalypse, in which case, they would not be very high round count guns. Maybe not even enough rounds to warrant a barrel change. Would it be valid to get something high quality, under the assumption that a high quality lower would last multiple hand-me-down generations under these circumstances?

No, it is valid to get a high quality lower because of dimensional accuracy that will insure reliable function. Even the crappiest 6061 lower is "strong" enough to last "forever". It's dimensional accuracy that is at play, here.

[Unobtanium]

The standard forged lowers from the likes of Aero and Mega run you $100-130. These are are the types of stripped lowers (and complete lowers from BCM, LMT, and KAC) that I'm stocking up on because they are the least likely to give me problems mating with quality LPKs and uppers. Forged lowers also tend to be stronger than their billet counterparts (although billet tend have nicer esthetics), but I've personally NEVER seen a decent quality lower break - forged or billet. Like SIRTainly said, there are plenty of 70's and 80's era lowers running strong with tens of thousands of full auto rounds through them. Even lower tier / no-name lowers generally don't break; they do have higher incidence of compatibility issues due to out of spec construction.

...but then you get into hand-forged lowers. Those have the dimensional accuracy of billet, with the compressed grain structure of a forging. I believe this was what Noveske's Gen II lowers were, and why they were so expensive (extra machine-time/wear).

[rob_s]

MEGA has the best algorithms for machining aluminum, and do so in a climate controlled environment, and many other things of a technical nature. They also have the mental/experience talent to take advantage of their technology. To honestly test a lower, run it for a few thousand rounds. I've had some that are, I suspect, slightly out of spec, that led to issues every 5-800 rounds. Just little foibles like not chambering when I press the bolt release, etc. because the round was presented at a tiny bit steep of an angle due to mag catch height, etc.

You want something you can probably count on? MEGA. MEGA is as close to "it will run out of the box without me testing it" as you can get, in my opinion, regarding dimensional stability of their products.

How do you know?

[Chance]

Thanks guys.

[Malamute]

How are the Smith & Wesson M&P lowers for quality? I recall somebody using them some and thinking the complete guns were acceptable in general. Pat Rodgers?

I like the traditional S&W logo on the side more than many of the stripped lowers available.

[Sensei]

How do you know?

The same way that I know LMT produces lowers of comparable quality to Colt - there is now a N of tens of thousand problem free units in the hands of end users. That and the fact that multiple people have toured their Washington facility and documented what they are capable of producing: http://www.megaarms.com/2011/10/mil-spec-monkey-visits-mega/.

[rob_s]

The same way that I know LMT produces lowers of comparable quality to Colt - there is now a N of tens of thousand problem free units in the hands of end users. That and the fact that multiple people have toured their Washington facility and documented what they are capable of producing: http://www.megaarms.com/2011/10/mil-spec-monkey-visits-mega/.

And so a similar number of people have toured the facilities of the competitors to know that anything Mega is doing is somehow out of the ordinary or special?