I've got an old RRA upper that I'm going to re-barrel to Grendel & was going to lap the upper to make sure it's nice & true. BUUUUT, alas Wheeler has put that one single item on my order list on backorder with no immediately available eta.
Based on the level of experience & knowledge base on this site, have y'all found RRA to be pretty dang good about their uppers being true, or do they tend to be a little "off"?
I wanna build this one right & don't want to have to re-do it just to lap in a month when I finally get the tool. Other side is, I also don't wanna wait a dang month either! lmao
I've got an old RRA upper that I'm going to re-barrel to Grendel & was going to lap the upper to make sure it's nice & true. BUUUUT, alas Wheeler has put that one single item on my order list on backorder with no immediately available eta.
Based on the level of experience & knowledge base on this site, have y'all found RRA to be pretty dang good about their uppers being true, or do they tend to be a little "off"?
I wanna build this one right & don't want to have to re-do it just to lap in a month when I finally get the tool. Other side is, I also don't wanna wait a dang month either! lmao
Appreciate advice from the wiser Horde!
I believe most uppers are cast and not lapped before assembly for mass production guns or complete uppers that most companies offer. I would suggest canceling that item and ordering it through another vender that has it on the shelf. Amazon has them and you can have it in a couple of days
Part of my concern is the dang "black Friday weekend" sales, even Wheeler showed in stock on their site until I inquired after placing it. BUT, sounds like my "concern" is valid and means I either need to wait or see if they'll let me cancel that part of my order.
2nd what clove8 said,....between, brownells, midway, and amazon someone will have it in stock if you have to have it now.
Saying that i have 2 RRA uppers i bought factory direct, a 20" Coyote and a 18" ATH both in .223 wylde. They are both shooters, proably .75" moa average with handloads. I haven't had a reason to tear them apart yet,..after having them 10-12 years. Don't know if they take any additional steps when assembling uppers? Hope that helps?
You might be able to tell how square the upper receiver face is by standing it on a piece of glass, smooth granite table top or other smooth surface. Use a light to see if there is a visible gap and the top of the receiver is level. If the previous barrel was centered and square into the upper you probably didn?t need but a couple of clicks of windage when sighting in the irons or optic.
I’ve moved a place holder scope between various AR-15’s and it is easy to tell which uppers have been lapped because the scope needs so little adjustment. Put the scope on an unlapped upper and you have to crank in significant windage and elevation.
Good idea Vascar, hadn't thought about that trying that.
I did call wheeler today after a God awful hold time got someone who "claims" they got more in & will get the rest of my order shipped "asap" which means I'll see it in Jan lol.
Will you the surface check for sure. My current 12" does the job, but I have new toys that I'm dying to put to use!
Eh, I tried it and found the project to be pretty much a waste of time. I'm not convinced those who experience improvement didn't benefit as much from just rebuilding and re-torqueing associated with the tear down, then the actual lapping. Beware that you can mess things up with this, if you aren't careful. You can erode out your upper and actually make your fit more loose. And if you do it horizontally (which many people will without knowing better), then the heavy rig will wear the bottom more than the top - potentially making the mating worse, not better. In my experience, it really didn't do much, and to me - the whole thing is an unnecessary waste of time. But others swear by it; so this is just one guys opinion.
I lean towards the camp of if you are going to do it have done properly on a lathe, removing the human element and the loose fit of the hand held devices.
Clove8 Wrote:I believe most uppers are cast and not lapped before assembly for mass production guns or complete uppers that most companies offer. I would suggest canceling that item and ordering it through another vender that has it on the shelf. Amazon has them and you can have it in a couple of days
Upper receivers are either forged and finish machined, or machined from billet aluminum, then anodized.
The boring and face-cutting operation is done so that there should be no way for the face to be out of square....however, once anodizing is done, it can create a face that is no longer square due to non-uniformity in the anodizing process (a common headache in the anodizing process).
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12-13-2019, 05:11 PM (This post was last modified: 12-13-2019, 05:19 PM by Wheelhorse.)
LRRPF52 Wrote:Upper receivers are either forged and finish machined, or machined from billet aluminum, then anodized.
The boring and face-cutting operation is done so that there should be no way for the face to be out of square....however, once anodizing is done, it can create a face that is no longer square due to non-uniformity in the anodizing process (a common headache in the anodizing process).
This is 100% fact. Anyone who doesn't believe it is just lucky to have never encountered an upper that isn't square because they do exist and the reason just given is the only thing that makes sense.
I've seen two.
I’ve installed barrels without lapping the face of the upper receiver without ever having a problem.But,once I discovered the lapping tool,it made sense to use it.For around $30,you will be sure that the face of your upper receiver is true.
Most of them are close enough as they are but occasionally you'll get one that's a real problem child. I couldn't figure out how they could be off until I heard the explanation about the uneven thickness of the coating.
I don't know that it does much for the group sizes, but I've never had a sight anywhere but in the center of the adjustment range with any I have lapped.
A couple of weeks ago I took apart my 6.5 & started to do a lap job on the upper. I mounted it in my vise vertically to manually lap the receiver face. It was quite obvious that the face was already true after about only 20 hand-rotations of the lapping tool. In this case I didn't need to true the face but I think it is something I'll do whenever I do a new build. I'm happy with the accuracy of my other ARs so I don't think I'll be dis-assembling them to see if they need truing.
I refuse to be victimized by notions of virtuous behavior.
Clove8 Wrote:I believe most uppers are cast and not lapped before assembly for mass production guns or complete uppers that most companies offer. I would suggest canceling that item and ordering it through another vender that has it on the shelf. Amazon has them and you can have it in a couple of days
Do we have (or should we try to develop) a list of manufacturers whose uppers were good/true out of the box and whose improved after lapping? (specifically in my mind, BCM, but curious about others). Just curious which uppers are most likely to benefit from this vs which are a waste of time. (This might be more appropriate as a separate thread)
redhat Wrote:Do we have (or should we try to develop) a list of manufacturers whose uppers were good/true out of the box and whose improved after lapping? (specifically in my mind, BCM, but curious about others). Just curious which uppers are most likely to benefit from this vs which are a waste of time. (This might be more appropriate as a separate thread)
They are all inspect as per measurements of the material that is used to make them from. It's the surface coatings that put them out of spec.
I lapp all my uppers but it's more of a need to have a square face for even bolt lock up and getting the max bolt life.
I have found that barrel nut, gas block and muzzle device torque has more effect on groups then a lil out of spec reciver face.
But I also don't buy bottom of the barrel priced barrels and bolts and I don't buy no name anyone's guess to chamber spec barrels either.
If it ain't made are sold by AA,PF or the group buy/six5arms my money isn't and won't ever be spent on it.
Here are a couple shots of one I did last Friday. It wasn't as far off as the last one I did, but you can tell in the first shot that it is slightly uneven. The second shot is closer, but still not completely even. I didn't get a shot of the finished upper before the barrel was installed.
I definitely think it's worth taking the time to do. I grease up the lapping tool shaft and use a drill while holding the upper in my hand to reduce lateral loading.
