As mentioned by some others, lube the pilot (it will help the pilot maintain center too if it's a loose fit), apply lapping compound AFTER inserting the pilot into the receiver bore so that compound isn't pulled into the receiver. I always lap until I can just barely see the park wear away all the way around. If you have to use a rubber mallet to seat the extension into the receiver you're good to go. If the extension is a loose fit, float a film of high-temp blue loctite (246, good to 450 degrees) around the extension when installing (to bed the extension), wipe up any excess and let sit 24 hrs. This won't lock the barrel into the receiver, it will only fill any gaps around the extension. I have always done this with all my builds. It keeps the bore of the barrel in line with the receiver bore/bolt carrier assembly, prevents unequal stress on the bolt lugs by ensuring that the lugs lock up in the extension perfectly straight, and eliminates stuff like having to crank windage in to get the rifle sighted in. Every build I have done has always sighted in with the windage perfectly centered.
I mount the upper vertically in the vise to eliminate the tool from resting on the bottom of the receiver. The lapping tool should fit snugly but gravity will still make the tool tilt a few thousands, mounting the upper receiver vertically eliminates this from happening.
I prefer to do this with the work in the vertical so the weight of the drill isn't biased to gravity and lapping the down side. Another major benefit to a square face is uniform bolt lug engagement with the extension. I also apply light oil to the shaft of the tool so it doesn't deface the raceway inside the upper, then clean everything out afterwards.
I use the same tool but I put the compound on the tool not the upper, it keeps the compound from lapping out the barrel hole in the upper. so the barrel fit stays tight. if you lap out the hole you can have a looser fit and that's not the purpose of the tool. I run the tool till the ano is mostly off of the entire ring. using the ano as a guide like a body n fender guy uses diff color primer when sanding out body work. I keep the shaft of the tool compound free at all times and use a bit of lube on it so it does minimal damage to the ano and coatings on some uppers. hope this helps some folks out, thanks for the video as always.
I do mine the same way with the compound on the tool except I never use a drill, I do it by hand and feel. Also I put the upper vertical so gravity is working with me. By having it horizontal you can get uneven wear at the bottom of the barrel channel, because gravity is pulling the tool down
@@New2Kendo Either of you notice a measurable improvement in precision? I wouldn't expect much but if you're trying to get that last 1/8 moa off your groups maybe.
@@gebeme11 I haven't seen a marked improvement, mm at best. The quality amd materials of the barrel, fit of the bolt (matched is best), and the skill of the shooter is what matters most. I figure the tool isnt that expensive, it only takes a few minutes, why not do it, and there is always a chance there is a high spot on the barrel channel that could make the zero shift to an extreme.
The lapping tool was designed to not touch the "barrel hole"(your words)..that's the thin part of the lapping tool ...no part of the lapping tool makes contact where the barrel sits, only the face..
If you use a power drill, use a very low speed, and as others have said keep compound out of upper and Grease the inside of the upper, that under cut shoulder is there for a reason to keep compound away from the pilot, pull the tool out only enough to view your work, run it horizontal so compound dose not drip onto the pilot. how much metal is removed is how off the upper is. If you want to know how far off the upper is, coat the face of the tool with layout fluid (Dyekem) dry fit the tool and ever so slightly twist about 5 ° back and forth then look at tool face to identify your high spot. if you get a nice ring, no need to lap, if you get a small contact spot, lap away till you get that full ring you mentioned. great video of a performance enhancements device.
I start out like you, with a work bench that looks "fully employed". On receivers, I usually use an 80 grit lapping compound and take it pretty slow. Even with technology being as good as it is, lapping will accurize your build. I'm no expert, by any means, but lapping an upper and lapping scope mounts are standard operating procedures on my bench. Also, I generally put a little oil/lube on the shaft of my lapping tool. It glides better at the opening, making insertion in the receiver a breeze. Feel free to use that advice in any of life's applications.
Love your channel, use these tools with the upper vertical so that you don't have gravity working against you causing an uneven grind. Also, the Wheeler version has a little spring connector which you attach your drill to, that compensates for you holding the drill slightly crooked. On some uppers they are so close to true you can just turn the tool by hand as you don't need to remove much at all if you are lucky.
Whether or not it's actually helped I'm not sure. It makes me feel like I've accomplished something at least! I've even pulled complete uppers that I've bought apart to lap them. It probably really means that I need to get out more.
I would only put the compound on the tool so that none gets inside the upper. Also, lube the part of the tool that goes into the upper. I did a PSA and a Sig upper and neither was true. I could never get the PSA to hold a tight group but after I did this process it shot like a champ. The Sig was not as bad as the PSA, but I saw a little improvement on it too.
If the barrel extension is machined before heat treat then it is also not true, which is likely. The upper reciever most likely started life as a cast forging where the picatinny was machined first and then used for work holding while everything else was machined true to the rail; in short that mating surface you’re lapping is probably pretty true to the rail, even more so on billet uppers which do exist but are for more rare. Now, type 3 anodizing isn’t the most even surface finish and perhaps that’s what you’re seeing however, most likely what you’re seeing is the runnout of that cheap dewalt drill chuck along with uneven pressure from a poorly fitting pilot and the human imperfection of applied pressure.
Nope. Those uppers are always just a hair untrue. The point is for the face to be true to the axis of the bolt and bolt carrier. That means the bolt, bolt carrier, receiver and barrel are all facing the same direction.
Thanks for sharing your knowledge, really appreciate it. Truing is important to accuracy. I appreciate that you show us the real work bench situation, real life warts and all. Very honest, as always.
The problem with this type of video is in order to show the benefits of lapping a receiver, you really need to first build the rifle and shoot it on paper with several different loads like you typically do and then disassemble the upper and lap it, then reassemble the upper and take it back to the range and re-test with the same ammo. Most people are not going to benefit from the lapping because there are so many other factors that go into accuracy from a rifle. One of the biggest components is the quality of the barrel itself and unless you spend a good chunk of change on it lapping the receiver hoping that's going to solve your accuracy problems is a non starter. Just my opinion from someone whose built a good many Quality Ar's.
BAT machine sells match barrel extensions that are oversize. You can measure your receiver and order the exact size or buy bigger and turn it down. If you have slop between barrel extension and receiver, a piece of .001 or correct size shim stock wrapped at least 3/4 around the extension and secure the two with brown locktite. You check a built up receiver without removing the barrel by brushing some solvent in the lug area and wiggle the barrel, if you see bubbles then there is some play. We have been doing the shim stock trick for highpower for over 10 years and bat machine co just started selling match barrel extensions. Have fun and good shooting
Good video accept you should throw some light lubrication on the pilot area of that tool that goes into the receiver so there is some lubrication going on inside between the steel tool and aluminum receiver.
A cluttered work bench may be a trigger to some, but for me it indicates that someone actually uses their tools. I'd rather have a cluttered bench than an empty one.
Lap and polishing will make a wold of different in 224 Valkyrie. Especially if you're shooting and 88gr. or 90gr hunting round. Helps with the scuffing of the longer ballistic rounds during loading. Love your channel. You and Who Tee Who should do a colab. He has a shit load of 15s and 10s with different length barrels that shoot great from the factory, but I think y'all could make them shoot on a dime from 100yards on a budget for a bunch of hunters. Keep on keepin' on!
One thing I would suggest is to - A. put some lube on the pilot, and B. put the lapping compound on after inserting the pilot onto the tool face. The way you did it runs the risk of pushing some of the compound into the receiver with the pilot (not sure that would really hurt anything, but still :)) Also to note- you only want to remove a very few thousandths off the face, otherwise the risk of head spacing issues begin to rise (some people may get a little overzealous)
Wouldn't the barrel only be able to go into the upper to the extent the barrel extension pin fits into the index slot? Never done a lapping job, but I would think that the lapping wouldn't affect the receiver index slot. Not saying to not use caution, obviously, but figured that the index slot and pin would save you from some unintentional headspacing issues.
Head space isn't affected by the receiver in the way you think it is....it has almost nothing to do with the head space and ar 15 chambers are self headspacing.
I agree completely on your first point of applying the compound to the receiver after the pilot is in as well as lubing the pilot . Lubing the pilot would seem self evident . If you get lapping compound inside the receiver you are going to lap what ever area it is touching just as much as it did the face , be it just inside or deeper into the receiver where the BCG rides . It how ever will have no effect on headspace do to it being fixed by the barrel extension and not set by how deep the barrel sits in the receiver . Another thing you can do with that tool is allow for proper indexing of the barrel nut if you can get it torqued right to where you feel indexing to clear the gas tube will be to tight and backing it off will be to loose . You can lap just a little off the face and that will allow you to index the barrel nut just that little more you need .
Good information. Wish you made a video of a built upper showing groups, then disassemble and true it, reassemble and see what accuracy difference the work made.
@@Mrgunsngear @mrgunsngear Thanks for the short and sweet DIY and making the job look simple even for us amateur enthusiasts. Have you at all noticed, if not from objective observation/scientific methods, in your subjective/anecdotal experience, any differences in accuracy before and after? Keep up the great work sir! ! We enjoy you on Full30 also!
I have a brand new M&P 15 sport 2 that I noticed never seemed quite right. I did a free float hand guard and put iron sights on it and then it was apparent. Even with a bore laser you could see the barrel was slightly angled to the right and down quite a bit. So far off I could not even get the Iron sights to fix it. They shipped the gun with a red dot lol. I know why they did now. Use this upper that should be thrown in the garbage and toss a red dot on it and sell it. :(. I may have to get one of these tools to true the face up and see if I can fix the problem.
I hadn't even thought about lapping an AR upper. I've been thinking about building my AR uppers (instead of buying them complete). I may add the lapping tool to my kit.
Hey Mr Guns And Gear, thanks for all you are doing for 2A! I'm reaching out in response to all the anti gun legislation that is taking place currently. You are one of the largest youtube channels with a very loyal and patriotic fanbase, including myself. You have a voice that is heard and respected in the 2A world. I am wondering if you, along with other youtube channels can help us gun owners get organized and have a March for our 2A rights. I am willing to do anything I can to make this possible, but we need folks like yourself to help as you can reach so many people who will listen and act on this. Could you please use your power to help us get this organized? Could you reach out to other gun channels and folks in the 2A to organize something like this? Thank you once again for all you do. United we stand, divided we fall. All respect brother!
Quick tip for your vice, I noticed the one screw underneath the flat table portion of your vice is loose...Try drilling the hole with a drill bit so you can fit a bolt up from underneath the table, that way you can use a bolt, nut and washer to get it nice and snug to the table..Makes its alot better when you have a snug vice....take care
Either way works but if you do it with the reciever vertical you can use a level to make sure theres no cant to it and just use weight of drill without off center input. (Splitting hairs I know)
Just wanted to let you know about a upper receiver "block" that's really much better then the standard two half type, and it's not expensive at all. It's from NCStar. Yea I know the company isn't known as a quality Company, but the concept is different and doesn't mark the receiver. It's anodized blue and I bought it off Amazon. It is definitely worth checking out.
I would advise to do it by hand, no drill. Aluminum against steel, if you're not careful you can take too much material off and the upper would be out of MIL-SPEC. Take your time and be patient.
A y non moron can tell you to not do it at all. Whst a joke you think a drill will somehow make your crap more round. Lmao. Don't use either. It's a scam
Tool doesn't need to be true. It's spinning so any high spot on the tool will be the part that laps the receiver face..kinda like when you machine something, the part that removes material is a sharp point, same idea here. That's why you lap until roughly 85% of the anodizing is wore off, not 100% because now you're taking off too much material.
This was a very interesting video. Speaking of OCD; do you think doing this with a drill press would be a more accurate option vs. doing it with the hand drill that could move or does the tool make it so it doesn't really matter?
@@douglass56A drill press might hold it too ridgid and put unequal pressure on it. The shaft that goes into the receiver forces it to line up perfectly. No chance for human error to cause misalignment.
Also takes off any high spots inside receiver where bolt carrier rides without removing significant metal, lending to smoother operation of BCG. Yeah, I see many benifits.
@@openmythirdeye a caveat to those stand alone barrel extensions... They are meant for new barrels being custom fabricated and not as a retrofit to existing Barrels with extensions already. The issue is it's almost impossible to time correctly the new extension with respect to the existing gas port hole. I learned the hard way, plus I also talked to the gentleman in the recommended video. He's fabricating a couple of custom Barrels for me...
I have been doing this for a while, I set the upper vertical so you get even lapping on the upper. What happens when you do it horizontal is gravity pulls the tool down and its never 100% true. By doing it verical gravity works with you and you get even lapping. Also I dont use a drill, I do it all by hand that way I have more control over how much is done, with a drill ots easy to overdue. I only go till there is an even silver ring showing. I have always put the compound on the tool not the upper, I am not sure there is a difference, just the way I have always done it
Fitty % has a great video on lapping the receiver face. He brought up a good point to lock the receiver vertically in your vise and level it prior to lapping. Is that necessary? Depends on your level of OCD 👀
@@Brickrider2 this was the deciding factor in me knowing this guy is a clown. I'd never recommend reaming out your ar with a inaccurate drill flopping around let alone that vice. This is the most scam video and procedure I've ever seen. Would not recommend. What was your asvab score mr sf delta Dave gunsandgear?
People lap the receiver but what if the barrel extension is not cut true with the centreline of the bore???? I haven't seen anyone check this out. If you can, please do. When a precision rifle barrel is cut everything is supposed to be trued up. Just wonder if all AR barrels are that accurate. Thank you!!!
Why would you not want to lap VERTICALLY instead of horizontally? Seems like it would be more natural to let gravity (and the weight of the lapping tool) do some of the work. You could literally hand-lap at that point...just spin it with your fingers. I only ask because I just purchased the G&G Rifleworks lapping tool and I was going to lap with my receiver mounted vertically in my vise.
Hello Mr. Gunsngear, I know this might be a little off topic of this video but I don't have Facebook to send you a message there. I am wanting to get a new build going with the Geissele URGI upper receiver and I want to make an exact or close to exact clone or replica of the actual rifle that the military will be using. Can you please give me some pointers on what basics of the rest of the parts of the build I need to get exact as possible like what lower receiver brand and the other main basic components that go into the building minus the optics and other ancillary accessories. Your help or anyone in the comments section would be a great help. I have an idea of what and how I want to set it up but I'd like to hear other input on the future build. Thanks.
@@Mrgunsngear Sir, Do you mean the AR15.com website? One quick question while I have you being so kind as to reply to my comment, I really appreciate it. Can you just clarify for me after watching your videos on your review of the Geissele URGI, I was a little confused on when you said there is a "clone" and "near clone" version I believe, I could be mistaken. Which version of the Geissele URGI upper receiver is the one closest to the specs of the real thing? Thanks again for your time I'm a big fan and watch all your videos. You put out great information. I am former military myself but I just used the basic issued gear. My name is Tony and I hope to see more great content from you in the future as always.
The messy bench top doesn't bother me because it's yours. Mine is spotless. What bothers me is the claw hammer being used to work on firearms. Claw hammers are for carpentry work. Ball peen hammers or gunsmith hammers is for working on firearms. Great short video. This is so easy everyone assembling an upper should do it. Thanks
Honestly in 2019 I feel an individual would be better of with a guage and a return label. If you buy an upper and a barrel and it doesn't snug up to where it doesn't move let alone fall out when you tip it upside down it needs to be returned after you take measurments and find out which part is out of spec. Of the 4 builds ive done with quality parts all of them have been snug and with proper installation shoot at least 1-1.5 moa as stated on the barrel guarantee
This is great. What I like is you try to leave some anodizing on the piece. The ano is actually harder than the aluminum and it supports the blow back of the barrel a bit better over the life of the gun.
I'm always going to do this from now on, my last build was not trued and the barrel aims a considerable amount to the left, the gun looks crooked and the sights are off, works fine but should have done it.
Understand the philosophy behind the lapping but when using a handheld drill like that...what ensures that you're not applying some catywompas pressure and not actually making it true?
dexon555 The ar design uses the bolt face to HS which has more than a few thousand of an inch of play. This is the amount of material this removes done properly.
My rear sight is right side by, so I'm hoping that lapping the upper receiver will bring that back toward the center. Is it a waste of time since it's still in spec? Maybe but I'm OCD that way
This procedure is commonly not described correctly in technical terms. This tool & procedure does not "true" the face. It does not fix anything in terms of being concentric with barrel bore, nor does it make the face perpendicular to bore axis. This procedure is to put the face all in the same plane (make flat) so that the extension lip can sit as flat as possible against the the upper. The final tuning is done with sights.
Ok I just tried this with my ar10. I mounted the upper vertically so the weight of lapping bar wouldnt cause it to put more pressure on the lower portion of the barrel interface. I also tried doing it by hand and it took forever........ams some of the lapping compound went down into the receiver ans marred the finish inside which looks like shit lol
