What to look for in buying a used complete AR15 lower?
- Thread starter ZBill
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14427H
Member
Assume you know what caliber and talking basic .223/5.56 type.
Rule one; know who put it together and what was "upgraded. Look it up on the web. Name brands are easy, most others will list specs.
Unless something exotic, the aluminum lower basically just holds the parts. As long as it is in spec, it’s just the same with different markings and they are made mostly by the same manufactured and just finished and marked. There are options to the trigger group, the stock assembly and the grip. For example, Mil Spec buffers and stock on carbines usually are premium. You can look up the trigger groups etc. Of course Bubba can screw up anything, overworked triggers, messed up assembly etc.
Plastic lowers...well I have one and it's interesting and seems to be in spec. I'd stear clear for the first one.
Rule two; buy the gun not the story.
Rule one; know who put it together and what was "upgraded. Look it up on the web. Name brands are easy, most others will list specs.
Unless something exotic, the aluminum lower basically just holds the parts. As long as it is in spec, it’s just the same with different markings and they are made mostly by the same manufactured and just finished and marked. There are options to the trigger group, the stock assembly and the grip. For example, Mil Spec buffers and stock on carbines usually are premium. You can look up the trigger groups etc. Of course Bubba can screw up anything, overworked triggers, messed up assembly etc.
Plastic lowers...well I have one and it's interesting and seems to be in spec. I'd stear clear for the first one.
Rule two; buy the gun not the story.
Tex4426
Member
Forged aluminum lower..manufacturer doesnt really matter its what is inside that does..what trigger...i.e. is it 2 stage is it standard is it a aftermarket singlestage with a light pull. ..as far as the buffer mil spec is a little bit higher in price but for your average person commercial is just fine...just know which is which if u want to change the stock..what grips does it have...hogue...magpull ..ergo or factory...that pretty much the main stuff i can think of...generally its cheaper to build your own unless you get a good deal on a used on...if you might be interested on building one check out itstactical.com and they have step by step videos on how to put it together..its super easy
madcratebuilder
Member
Check the trigger for pull, creep and reset. Not all LPK's are equal and it's very difficult to determine what is really installed in the lower.
Check for wear in the FCG pin holes. Check the threads for the RE. If possible put a complete upper on it and make sure the bolt pushes the buffer back as it closes. Some lowers have the buffer retainer pin hole out of spec. Check the mag well, the more bevel the better. Some lowers can have a tight mag well and mags well not drop free without assistance.
Check if the RE is mil-spec or commercial diameter.
I'd check the trigger group to make sure that it works. Being sure not to let the hammer hit the mag well, I'd cock the hammer and (with my thumb restraining the hammer so it doesn't hit the magwell) squeeze the trigger letting the hammer release. Keep the trigger pulled. With the trigger to its rear most position, recock the hammer and then let go for the trigger. The hammer shouldn't fall.
I'd also check the pin holes for the trigger group. Check for a good fit between the holes and the pins and that the hole are round and not egg shaped.
Now this may or may not be an issue, but I have, on occassion, come across a couple of lowers that turned out to be made of 6061 aluminum from lesser known manufacturers/distributers. Most are made of 7075 and I'd confirm that the one I was getting is made of 7075. If it is one of the better know names, it won't be a problem.
I'd also check the pin holes for the trigger group. Check for a good fit between the holes and the pins and that the hole are round and not egg shaped.
Now this may or may not be an issue, but I have, on occassion, come across a couple of lowers that turned out to be made of 6061 aluminum from lesser known manufacturers/distributers. Most are made of 7075 and I'd confirm that the one I was getting is made of 7075. If it is one of the better know names, it won't be a problem.
adelbridge
Member
I have seen the buffer detente get whacked and the hole oblonged but that is pretty rare. Unless you are getting a screaming deal it might make sense to go new. I regularly see stripped lowers for $69-$99.
Tex4426
Member
i would go new as well..that way you know what you are getting and if you order a complete upper new if somethings messed up they will usually fix it
adelbridge does hit on a good point. A lower, even a complete lower, would have to be pretty darned cheap before I'd consider buying one. Lowers are cheap to start with.
If you wind up buying it and then, say, replacing the trigger, most of the saving will go out of the window anyway.
I've built a couple of ARs on AERO (I believe) lowers and they worked out just fine. I was told that they were purchased for something around $60 or $70 a piece. One of those and a Stag lower parts kit with a tube and stock and you're rolling.
If you wind up buying it and then, say, replacing the trigger, most of the saving will go out of the window anyway.
I've built a couple of ARs on AERO (I believe) lowers and they worked out just fine. I was told that they were purchased for something around $60 or $70 a piece. One of those and a Stag lower parts kit with a tube and stock and you're rolling.
madcratebuilder
Member
Just seven months ago I was buying Aero Precision lowers for $49 ea in three packs. Shipping and FFL fees pushed that to about $62 each, prices keep creeping up as we get closer to Nov 6th.
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