Buying a lower

[Uncle Alvah]

Now that my recent AR re-configure is almost done, I want to buy a lower to start build my next rifle on.
I've done some searching, and my natural tendency to "buy local" comes through loud and clear for these folks:
www.usamade-ar15parts.com

Factory is just a few miles from me, and the owner is very active in promoting and supporting local AR shooters, thats worth something right there to me!
I'm wondering if others here are familiar with this operation and what your opinions might be?

[opmike]

I'm curious as that what the "10-32 accurizing screw" is; considering the lower has nothing to do with accuracy. Is it supposed to be something to reduce the slop between the upper and lower?

[Uncle Alvah]

Good question, I'll ask them and "get back to you on that, Katie";)

[organdonor]

I'm curious as that what the "10-32 accurizing screw" is; considering the lower has nothing to do with accuracy. Is it supposed to be something to reduce the slop between the upper and lower?my first thought is it is something like an accu-wedge

[RD62]

I'll bet it presses against the rear takedown lug on the upper to remove any wiggle.

-RD62

[Belmont31R]

I'll bet it presses against the rear takedown lug on the upper to remove any wiggle.

-RD62



Yes the new phenomenon in lowers is set screws to take slop out of the fit to satisfy the crowd that things their 1k dollar AR should fit together at tight as a 50k HH double gun.

[opmike]

I'm buying Belmont an Accuwedge for Christmas.

OP

I tend to stay with established names with components, as I've yet to be burned going that route. However, in my limited experience with lowers, I've found that as long as they are in spec, they are GTG. Your LPK and Upper should be higher priorities. Getting a "tight" upper and lower fit isn't necessary, and I'd probably forgoe the screw if i were to purchase one, myself.

[Rusty_Shackleford]

Didn't know it was called an "accurizing screw", my Quentin Defense lower has this feature.

http://i555.photobucket.com/albums/jj475/Cansler_Tactical/CB6.jpg

[Uncle Alvah]

I posted that question at Carolina Shooters Forum, where the company is a sponsor.
The post got several replys before the company President chimed in, including this one:


I'm not sure what screw you were originally referring to, but there is no such thing as an accurizing screw in an AR.

1. A tighter lower to upper receiver doesn't make an AR more accurate. It simply eliminates what some people consider to be excessive wobble.

2. An adjustment screw for trigger preset doesn't make an AR more accurate. It simply removes what some people deem excessive preset.

The only things that will make an AR more accurate are a good barrel, plenty of practice, and good ammo that is matched to the barrel.


Following that reply, came this one from Mr. Barnes:


You are correct sir!

We call it an "accurizing" screw , because that it is what is has always been refered to in industry ....although it is a misleading/incorrect description.
Yes ......accuracy is contributed to-controlled by upper to barrel fit...not lower to upper fit.Screw used to take up "CREEP" of trigger is also USAMTU trick..and it lessens amount you have to pull trigger to drop the hammer...so , this CAN be an accuracy improver,especially if using high magnification optics and shooting for group size.....that is elementary.
What is first thing bolt gun guys do to improve /shrink groups??They do a trigger job(reduce creep and lighten up pull...and then reduce overtravel) as well as steel bed action to stock....and freefloat barrel. Those are the most common anyway.....that produce the biggest results.

We install this feature(like other premium grade lowers have) to tighten up feel from upper to lower when assembling.Those who know better ,(and most consumers ,with all due respect ,do not)realize Uppers are made within a tolerance range and so are Lowers ...and because of this tolerancing of parts you can get an "in tolerance" machined upper or lower ...and get more play than the ones assembled yesterday...that were also well within tolerances ..IT IS tHE NATURE OF THE DESIGN!!!!!!!!!!!!!Those who say a little play is an indicator of poor /unacceptable quality ,do not understand the way the weapon works ...or how Eugene Stoner designed it /meant for it to be made.Ever heard of an ACCUWEDGE????? Why do they exist????? Because issue has been around for many years ,and they( Accuwedge) had the first commercially available product to address it .I have seen Colts (the worst) Bushmasters/DPMS/Olympics/LMT's /Stag/Rock River/ as well as a lot of no names ...and they ALL exhibited a certain amount of play/looseness. Ours are no better/no worse....because we machine to the SAME TOLERANCES.That is also why some of these very folks tell us we machine a GOOD QUALITY/IN SPEC product that is indicative of common industry players.
If you shoot a high mag scope ...reducing upper to lower play might help tighten up groups because of less wiggle of upper once on target .(your heartbeat/breathing can affect reticle movement in this situation) ...and so can loose fitting upper to lower....it can effect group size , but it is not a "direct" effect as mentioned .
Weapon will exhibit a looser feeling the more rounds you put through it ,the more you disassemble it to clean it...and this screw gives you the option of tightening it up during the life of product.It is an old USAMTU (US Army Marksmanship Training Unit )trick that gunsmiths/armorers have been doing for YEARS....but no one until the last few years ,has been including it on production models.It is a method taught by most gunsmithing /armorers courses,as well as other "steel bed" methods,as taught by Mark Hunt at Montgomery Community College.
I did not come up with the idea ....we just decided to include it as a standard feature in our lowers ...along with hole for detent pin/spring for rear takedown pin being tapped for a set screw ...so you can do stock changes with out losing /dealing with detent pin/spring.These are just two of the things that make ours a Premium grade lower receiver in many peoples eyes...and since we do not machine uppers ....yet- it gives our customers the option of mating with ANY upper in industry ,while maintaining a tight fit.
Thanks for listening.


Now we know!!!!:)

[rat31465]

I'm curious as that what the "10-32 accurizing screw" is; considering the lower has nothing to do with accuracy. Is it supposed to be something to reduce the slop between the upper and lower?

Ummm, this is very far from accurate. You need a solid lower as a platform for the upper. The lower also contains the Trigger which is vital to accuracy as well....so you can see that the lower does effect accuracy.

[Failure2Stop]

Here's the Cliff Notes on Mr. Barnes' grammatically creative reply:

"Beacuse some people think it's neat."

[ALCOAR]

Here's the Cliff Notes on Mr. Barnes' grammatically creative reply:

"Beacuse some people think it's neat."

LOL...why the hell did the Cliff Notes come after the long, boring story. Heck, your a mod....you got secret powers and stuff:D

[Failure2Stop]

Ummm, this is very far from accurate. You need a solid lower as a platform for the upper. The lower also contains the Trigger which is vital to accuracy as well....so you can see that the lower does effect accuracy.

Eh, it depends on what you mean by "accuracy".
The lower will have no impact on mechanical accuracy unless something in the lower is really messed up and impacts consistency.
If you ate talking about the individual's ability to be consistently precise, a good trigger will definately help, but less than precision optics will help, or to ake it in another direction- the most significant issue will be individual skill. Since these things are nigh impossible to qualify and have little to nothing to do with the individual items one is throwing cash at, we tend to limit the discussion topics to those things that do directly apply to mechanical precision and consistency, things like barrels, handguards, barrel nut torque, trueness of the face of the upper, and things like that.

[opmike]

Ummm, this is very far from accurate. You need a solid lower as a platform for the upper. The lower also contains the Trigger which is vital to accuracy as well....so you can see that the lower does effect accuracy.

Umm, no, I'm not seeing it. Please, elaborate on how an in-spec lower contributes to the mechanical accuracy of an AR-15.

[rat31465]

Does a loose or sloppy fitting lower add to accuracy?

I wasn't necessarily limiting my comments to strictly Mechanical accuracy and I understand where your statements are coming from.

These firearms are not mounted arms and few are probably going to see a Benchrest outside of sighting in and or load development.

On a side note I admit that my experience with the AR platform is somewhat limited as the majority of my shooting experience with one has been Varmint hunting.
That said I have never seen or handled an accurized AR with a sloppy Upper/Lower.

[opmike]

Does a loose or sloppy fitting lower add to accuracy?

Define "accuracy" here.

Lower receivers that are in spec and have the wiggle common to every AR-15 I've handled will neither add nor detract from the mechanical accuracy of the rifle.

Elements beyond the mechanical that make things easier on the "shooter" are highly subjective and dependent largely upon the "shooter" in question, assuming we're dealing with quality components at the onset.

I'm simply not seeing how a good shooter's groups on paper will change between a standard fitting lower and one that's been modified to fit more tightly, all other things being equal.

If anyone has some data to the contrary and the testing procedure used, I'd like to see it.

[shootist~]

No data and no testing on AR platforms, but it stands to reason that anything that changes the way the rifle recoils from shot to shot could affect accuracy. If the horizontal slop bears left on one shot and right on the next, it stands to reason that the path of the bullet is affected to some degree.

On FALs upper/lower slop has a major affect on accuracy. I've tightened up more than a few and the results have always been positive *for me*. This is easy to understand with the irons since the the rear sight is on the lower receiver - but I see similar results when an optic is used. (I replaced the barrel on one rifle five times before I discovered the problem was in excessive horizontal slop between the upper and lower receivers.)

One would think that moving the sighting system to the upper receiver would immediately solve the problem, but that was not my experience.

[byrdman]

Hey Uncle

I have one of the lowers with a S&W upper in my very, very little experience (outside of the Corps) it is GTG I don't see any problems with it and there are no malfunctions. The main man at BPM will give you a tour of the facility and show you them being made if you would like (thats what he offered to do for me when I questioned about my lower) My lower came with the gun in a trade.

[Uncle Alvah]

He's offered me a tour as well, and I fully intend to take him up on the offer! Andrew is a stand-up guy and very supportive of local shooters and shooting scene.

[Arnoldi13]

Hello everyone, I am brand new to the site and really have no idea how forums like this are suppose to work. Anyway, I am looking to build and my question is mating uppers and lowers. I am looking at getting a colt le6920 lower that is brand new. I am new to the build scene and I was wondering if you can put together different brands of lowers and uppers like the colt that I am planning to get. I know that the trigger control group pins are a different size than most but that shouldn't have anything to do with putting the two together, right? Thanks for any insight you might have.

[Eric D.]

I commend you on your ability to search and dig up a thread relative to your question. You should have no problem mating in-spec uppers and lowers of different brands. Also, depending on when the lower was made, it may in fact have the normal 0.154 DIA. trigger/hammer pins.

[Arnoldi13]

Thanks for your help! I have figured out all the specs that I want everything to be at I am just not sure what some of the good brands are, I know this is probably a huge debate in taste, style or personal opinion but I from a smaller part of the country and don't have a whole lot to work with here. Plus by the time i spend upwards of 1500-2500 to build i just want to make sure that im using tried and true parts and brands. thanks

[Eric D.]

Care to post the specs that you want?

You're on the right track with the 6920 lower and you have the right mindset on buying quality the first time. I don't know if you're aware but a quality rifle can be had/built for roughly $1k. That's why I'm curious about your specs because $1500-$2000 is a lot to work with.

I get being from a small area but most local shops aren't going to have the selection of quality brands or competitive price of online retailers.

Read through the stickied threads at the top of each subforum. They explain what the quality brands are and what makes them that way.

[Arnoldi13]

Sorry that original figure was a little high, but my plan is to hopefully get a complete colt le6920 with the leo markings and more or less a lot of the bells and whistles that i am looking for. I am a firm believer you get what you pay for and more often then not the more expensive something is the better quality it is (of course with all the research of materials and specs used to build, with all the research it takes to make a educated decision). then i hope to get another colt le6920 lower with the same marking both brand new and then finding a really good upper to put on it with a rifle gas system so then i will have a really nice carbine and really nice rifle system. plus the leo markings and all that are pretty sweet and more or less a novelty haha.

[DeltaSierra]

The trigger pins are of the 'normal' size (.155) on all the new manufacture Colt lowers, not .170.

Go to Grant @ G&R Tactical - he has Colt lowers for sale, as well as complete rifles.

http://www.gandrtactical.com/cgi-bin/commerce.cgi?display=home

As far as the LE markings, just get a new model 6920. Really, the LE markings are not something that you want to go out of your way to buy.

[Arnoldi13]

@ eric, i just barely caught that you wanted to know what my specs were. my dream guns consists of a lot of nit picky stuff it seems but i've got plenty of time to figure out exactly what i want; i just want some opinions of people who have much more knowledge than i do on the subject. I would like:

*either a 4150 steel chrome lined barrel or a cold hammer forged barrel that is MPI'd and in 20"
*a chrome lined chamber and bore in probably 556 because the tolerances are just a little looser and since i don't want to shoot match grade ammo but would rather just load my own brass and try and find what works for the 1:7 twist rate, it seems they handle the heavier rounds and loads better.
*m4 extended feed ramps (the good ones)
*a rifle sized gas system (m16 sized)
*f marked fsb
*a3 flat top (im not much for the carry handle and all that jazz and optics seem to work better on the flat top not on top of the carry handle).

I already am planning on purchasing a complete colt le6920 carbine and then i found another colt le6920 lower that is brand new and not fired that i want to implement all the above specs on and keep the complete carbine probably the way i bought it minus putting new free float hand guards and some sort of optic on. other other good accessories and what not i should look for or beware of?