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View Full Version : Stag lowers and compatability with other brand uppers


Solidsnake87
08-22-2006, 11:22 AM
I'm looking into buying a stag lower receiver for a project gun. I know that all AR parts are supposed to be interchangeable but that is not always the case. I was wondering if the stag lowers work effectively (as in fit perfectly) with uppers from armalite, dpms, bushmaster, rock river arms, or olympic arms? I plan on making a target match type rifle with a 24" barrel so this is a pretty important detail before I start shelling out $700 for a 24" upper.

bwiese
08-22-2006, 11:26 AM
All uppers and lower should fit OK. There's relatively little variance in lowers, and any quality brand of lower should work. If you have your heart set on a Stag, get it.

There are some variations in uppers but most should be OK. I'd stay away from Rock River Arms uppers unless you had an RRA lower - there are multiple reports of tight fits w/RRA uppers on non-RRA lowers.

blkA4alb
08-22-2006, 11:29 AM
Also know that the lower to upper fit does not affect accuracy. All the accuracy is in the upper and optics. A tiny gap of light showing through the back of the upper and lower is not a big deal.

Sugarfoot47
08-22-2006, 12:00 PM
All uppers and lower should fit OK. There's relatively little variance in lowers, and any quality brand of lower should work. If you have your heart set on a Stag, get it.

There are some variations in uppers but most should be OK. I'd stay away from Rock River Arms uppers unless you had an RRA lower - there are multiple reports of tight fits w/RRA uppers on non-RRA lowers.
You're certainly correct about this. I have an RRA 9mm upper on my registered Bushy lower and it was pretty tight at first where the front receiver pin is. After a while it loosened up a bit, but it's still a snug fit.

JOEKILLA
08-22-2006, 12:12 PM
I just put my upper and lower together, both Stags. Really tight fit. I need to tap the td pin in and out.

rorschach
08-22-2006, 12:22 PM
I just put my upper and lower together, both Stags. Really tight fit. I need to tap the td pin in and out.

+1 I just picked up a Stag upper from CWS at the Costa Mesa show, and it is TIGHT on a Stag lower. I've hand twisted a 1/4" drill bit through the upper and lower holes, and have worked the pin a bunch of times and I still have to tap the pin with a punch to get it out.

bwiese
08-22-2006, 12:31 PM
+1 I just picked up a Stag upper from CWS at the Costa Mesa show, and it is TIGHT on a Stag lower. I've hand twisted a 1/4" drill bit through the upper and lower holes, and have worked the pin a bunch of times and I still have to tap the pin with a punch to get it out.

Let's also not confuse tightness with misalignment.

Sometimes an extra thick moly/phosphate coating can make pins hard to insert & extract until it wears down a bit. Other times there's physical blockage of pin travel because the center-to-center distance btwn the upper's pin holes (pivot and takedown, that is) differ from those of the lower.

PIRATE14
08-22-2006, 12:50 PM
Well as you guys are putting these together......bring in your lower for a fit check, doesn't hurt.

I have an assortment of rear take pins and parts or can let you know what is slightly out of spec if any, I know we are very busy but if you gotta few minutes......

There are a lot of parts that have an excessive amount of finish, they leave them in solution to long...etc. This with tight tolerances can cause headaches but don't fret.

On the opposite spectrum, you hand somebody a LMT rifle and they want to know why it's loose......not loose just made like they were intended to.

We are pretty much victims of the majority of folks thinking that loose isn't correct or right....the manufactures have responded and so you're getting some variations on the spec, nothin that usually can't be dealt with 15 minutes of tweaking........

Solidsnake87
08-22-2006, 2:23 PM
I've decided on a target match 24" stainless upper from olympic arms. Will it fit a stag lower just fine then? Has anyone had a lower that did not fit an upper or visa versa (besides rock river arms)??? Will a Rock river Arms stock assembly and lower parts kit fit a stag lower ok?????

grammaton76
08-22-2006, 3:11 PM
Also, if you're being annoyed by it being a little bit loose, and you're doing a gripless build, use an accu-wedge to tighten it up a little. Mine was just a little loose for my tastes, and now it isn't. Details/pics below:

http://thegunwiki.com/view/Gunwiki/ProcInstallAccuWedge

FreshTapCoke
08-22-2006, 3:31 PM
I'm using a low serial Stag Lower with a DPMS 20inch upper. No problem with fitment; I just have to squeeze the upper and lower together tightly when inserting the retaining pin. Seems to fit nice and snug that way.

Mudvayne540ld
08-22-2006, 3:37 PM
I just started on my new AR. I now have the 20'' fluted Bushmaster Upper. (I think it is a predator, but im not sure >_<)

I am also gunna get a Stag for it. Ordering from Eagle Firearms. $104 shipped to dealer is about best it will get. (I e-mailed em and they said they would ship to CA as long as an FFL would accept :cool:)

Solidsnake87
08-22-2006, 4:14 PM
Well now I know that the DPMS upper will fit but will a Rock River Arms lower parts kit work ok on a stag lower?

blkA4alb
08-22-2006, 4:17 PM
Well now I know that the DPMS upper will fit but will a Rock River Arms lower parts kit work ok on a stag lower?
Any LPK that is to spec will fit in any to spec lower. The only exception is for the colts with larger pins. Your's are standard size, .154", the Colts measure .170".

James R.
08-22-2006, 6:21 PM
Also know that the lower to upper fit does not affect accuracy. All the accuracy is in the upper and optics. A tiny gap of light showing through the back of the upper and lower is not a big deal.

My BS detector is pegged well into the red on this statement. It absolutely matters how tightly the upper and lower receivers fit together. The entire upper receiver pivots on the front pin. The rifle begins to recoil before the projectile has even left the bore. So I don't see how you can think that if the upper receiver is allowed to recoil back onto the lower somehow magically the accuracy isn't going to be affected. What's worse is the buttstock is fitted to the lower receiver, not the upper. When you fire from the bench you're supporting the buttstock with your off hand or with a bag while the fore end of the rifle rests on a bi-pod or bench rest. When you fire that gun the upper receiver will rotate back onto the lower counter clock wise viewed from the ejection port side. This will cause the muzzle to be up some very small amount which will degrade the accuracy of the gun.

I shot a 0.318" 5 shot group a while back with my Remington 700 and out of curiosity calculated how accurately the rifle had to be aimed to create that spread at 100 yards. It worked out to something like +/- 0.0015 degrees. You going to tell me that an upper and lower that have play in them are going to hold the center axis of the bore to within 1/1000th of a degree or less?

May not matter on a battle rifle, but on a target gun I'm gonna say it matters a lot.

Regards,

James R.