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the 6.5 Grendel gets one last try
- Thread starter precision308
- Start date
I was going to post the same thing as Bustin. If the barrel extension isn't true, and the barrel isn't true, with the threads cut correctly to the bore, you're on the margins as to accuracy potential. Very rarely do you see production barrels that even have a concentric bore, concentric threads, trued flanges in the extension, etc.
So I think I see where Ballista One is coming from. If you have a rack-grade barrel from Dirtier than Cheap, el bueno barrel extension that is on cock-eyed, an off-concentric bore, off-center threads, and a generally low-dollar job, don't expect miracles from lapping the receiver face. I agree 100%. You still should do it and lap the bolt lugs so they won't break.
For those of us that start with medium to high-end barrels, a trued receiver should be a starting point. If you dropped a mid-to-high-end barrel into a no-name, rack-grade upper, then truing the face is in your best interests.
As I have been truing the faces of several generic square forge code uppers in preparation of installing some Lilja Grendel barrels, none of them have been true. I checked an AA upper that I'm putting a Lilja barrel into, and it was dead-on, and anodized after being machined true. It also has a very tight barrel extension tunnel. For the amount of effort that goes into truing even a discount blem upper, the consumer might consider ordering the best they can buy for an accuracy nazi AR15.
So I think I see where Ballista One is coming from. If you have a rack-grade barrel from Dirtier than Cheap, el bueno barrel extension that is on cock-eyed, an off-concentric bore, off-center threads, and a generally low-dollar job, don't expect miracles from lapping the receiver face. I agree 100%. You still should do it and lap the bolt lugs so they won't break.
For those of us that start with medium to high-end barrels, a trued receiver should be a starting point. If you dropped a mid-to-high-end barrel into a no-name, rack-grade upper, then truing the face is in your best interests.
As I have been truing the faces of several generic square forge code uppers in preparation of installing some Lilja Grendel barrels, none of them have been true. I checked an AA upper that I'm putting a Lilja barrel into, and it was dead-on, and anodized after being machined true. It also has a very tight barrel extension tunnel. For the amount of effort that goes into truing even a discount blem upper, the consumer might consider ordering the best they can buy for an accuracy nazi AR15.
Here were my results..........
The grendel had no change in accuracy after lapping the receiver. I did not locktite anything on it. I plan on locktiteing theb barrel and the gas block and we will see how it goes. Now on the other hand I have a 204 I was never happy with. I lapped the receiver on it which was way off and I locktited the barrel and the gas block. It brought a one inch gun down to 1/2 in. I shot three quick groups with it and the largest group was just under .6 ".
The grendel had no change in accuracy after lapping the receiver. I did not locktite anything on it. I plan on locktiteing theb barrel and the gas block and we will see how it goes. Now on the other hand I have a 204 I was never happy with. I lapped the receiver on it which was way off and I locktited the barrel and the gas block. It brought a one inch gun down to 1/2 in. I shot three quick groups with it and the largest group was just under .6 ".
Interesting results with the .204 Ruger. Glad it worked out for you with that one. I know AA beds the extensions on 20" and longer barrels, as well as the gas blocks being red loc-tited, and that's starting with a trued receiver with tight tunnel for the extension.
Ya I'm happy too. I used blue loctite. Ill update my results on the grendel once I get them done. I ll get it bedded done thisweekend but won't get to the range untill early next week.
I have no problem whatsoever with facing the extension as part of a comprehensive package of modifications on a quality build. Pride in the finished product ends with a machinist or manufacturer stamping their name on it. GAP, as an example, has complete control over the parts that are used on every rifle they build in the form of quality assurance. Their rifles aren't more accurate because they faced the upper receiver and bedded the barrel. They're more accurate because they take the time to assure the quality of every part before a rifle is built. Any part that doesn't meet their expectation would be returned to the manufacturer for one that does. Their time is better spent spent building quality rifles, not fixing problems.
Why would anyone blindly purchase a tool to modify their upper receiver before taking the time to verify the receiver is out of spec? The answer is simple, because they can't. That being said, I take issue with blind assertions by forum members that facing the receiver and bedding the barrel extension improves accuracy when they couldn't prove it has any effect on a bet. If they performed the operations and they believe their accuracy is better, good for them. They are a proverbial sample of one and Pete Brownell is $50 richer.
Here is something to think about. If a receiver is on the short end of the illustrated spec, you are going to set the barrel extension back into the upper receiver by removing material. If you are going to argue that its less than a thousandth then there is absolutely no point in the facing operation. If it's a few thousandths of an inch, the barrel extension is going to create a lip in the action that will impact reliability and potentially accuracy.
<a href="http://s1363.photobucket.com/user/BallistaSystems/media/OFFICE-PC/Drawings/UpperReceiver_zpse4dc2d21.jpg.html" target="_blank"><img src="http://i1363.photobucket.com/albums/r704/BallistaSystems/OFFICE-PC/Drawings/UpperReceiver_zpse4dc2d21.jpg" border="0" alt=" photo UpperReceiver_zpse4dc2d21.jpg"/></a>
Why would anyone blindly purchase a tool to modify their upper receiver before taking the time to verify the receiver is out of spec? The answer is simple, because they can't. That being said, I take issue with blind assertions by forum members that facing the receiver and bedding the barrel extension improves accuracy when they couldn't prove it has any effect on a bet. If they performed the operations and they believe their accuracy is better, good for them. They are a proverbial sample of one and Pete Brownell is $50 richer.
Here is something to think about. If a receiver is on the short end of the illustrated spec, you are going to set the barrel extension back into the upper receiver by removing material. If you are going to argue that its less than a thousandth then there is absolutely no point in the facing operation. If it's a few thousandths of an inch, the barrel extension is going to create a lip in the action that will impact reliability and potentially accuracy.
<a href="http://s1363.photobucket.com/user/BallistaSystems/media/OFFICE-PC/Drawings/UpperReceiver_zpse4dc2d21.jpg.html" target="_blank"><img src="http://i1363.photobucket.com/albums/r704/BallistaSystems/OFFICE-PC/Drawings/UpperReceiver_zpse4dc2d21.jpg" border="0" alt=" photo UpperReceiver_zpse4dc2d21.jpg"/></a>
This is a gross example but illustrates what LRRPF52 points outs out in post #52 above. A gallon of blue Loctite and 0.003 of an inch won't fix this one. The woble at about :26 is nothing short of amazing. Turn the volume down or you'll be looking for the business end of a shotgun before the video is finished.
Accurizing the AR-15: Barrel Extension to Receiver Fit - YouTube
Accurizing the AR-15: Barrel Extension to Receiver Fit - YouTube
If you don't want to do it then don't do it, I don't think anyone cares how someone else builds their own rifles. I can tell by the way you talk and try to explain this you have never done it. As far as the .003 you talk about when people square the receivers it only takes .001-.005 off one side the other side is in the same place. If the extension doesn't cause a ledge before squaring it will not after an NO extension is within .001 of the ledge on the inside of the receiver. We have done thousands of receivers like this over the past 5 years and it causes no hangover issues.
For everyone else reading this train wreck. I have an old cast receiver from the late 80s. It was loose as a goose. After squaring the receiver and bedding the extension the barrel was as tight as any receiver made. The connection is rigid between the barrel and receiver. It would shoot just as accurately as my Megas or Vltors.
If you want to return every upper receiver that is not square you will return almost every single one. The bore of the receiver is what everything else must be aligned on, you can't change it. With a Mega or Vltor receiver the barrels need to be tapped into place, squaring would do no good. That makes a rigid connection and holds the barrel extension square with the bore of the receiver that the carrier rides in and controls the bolts squareness with the extension.
The scope is attached to the top of the receiver. The barrel is attached to the front of the receiver. You want the scope to be as rigid as possible in relation to the barrel. The receiver is the bridging between the two. If the barrel extension is square with the bore of the receiver the bolt will be square with the extension lugs.
Op- a few other things. Be sure to clean all of the copper out of the barrel and inspect the crown to be sure it isn't damaged or worn.
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I would also point out that those DPMS and PRI upper receiver holding fixtures with the cross pins are a quick way to snap off the pivot pin and take-down pin lugs, especially when removing a barrel nut that has been torqued heavily or with loc-tite.
I've never used them, but have a box with uppers in it people have given me after destroying theirs using that tool. I recently even saw a high-dollar .308 that had the rear lug broken by the manufacturer after going back and forth with the customer because of reliability issues.
A female shooter was firing it, when the rear lug finally separated and the gun went full auto on her, with the upper slightly out of alignment with the lower. The manufacturer accused the customer of tinkering, when he doesn't even own tools to work on the gun.
I've never used them, but have a box with uppers in it people have given me after destroying theirs using that tool. I recently even saw a high-dollar .308 that had the rear lug broken by the manufacturer after going back and forth with the customer because of reliability issues.
A female shooter was firing it, when the rear lug finally separated and the gun went full auto on her, with the upper slightly out of alignment with the lower. The manufacturer accused the customer of tinkering, when he doesn't even own tools to work on the gun.
Order a 6.5 LBC Lesbaer upper and be done. 1/2 MOA guaranteed like any other AR they do.
Well got out today and shot the gendel. After going back and locktiting the barrel and gas block ive had no increase wirh accuracy. I've contacted bhw and they told me that they would stand behind the barrel.
I'll say it again, but sum it up short. I believe 90-95%, if not more of the accuracy of any AR platform, comes from the barrel. That includes the extension and proper headspace, leade, chamber, etc. Like I said, I have a 6.5G, and it's my BEST shooting rifle, period. .33MOA! Blew me away! I had it built on basic milspec parts with a KAC FF rail and A2 stock with an RRA trigger with an ACOG at first. Since it shot so damn well, I upgraded all the parts but the A2 stock and FF rail. Put a MUCH better scope on it, and all top end parts. Still shoots exactly the same: .33MOA with the right ammo. It's a Satern 20" HBAR or whatever, came with matching bolt, and I believe it's the key to the accuracy of this rifle. That and the Nosler 120's it likes --doesn't like SMK's for some reason. Lapua and AA brass (which is Lapua) does perform best, but I have to use it since I use Forster Mic dies --they require it.
I'd venture to say your barrel is subpar. Change that out and I bet you're golden. Satern is a LOOONG wait, but there are other great barrel makers that can get you one much faster too.
BTW, I've never used anything but TW25B grease on the receiver threads when installing a barrel. Never had any problems either.
I'd venture to say your barrel is subpar. Change that out and I bet you're golden. Satern is a LOOONG wait, but there are other great barrel makers that can get you one much faster too.
BTW, I've never used anything but TW25B grease on the receiver threads when installing a barrel. Never had any problems either.
I been in contact with Black Hole Weaponry through email and so far so good. They have agreed to accept the barrel back and check it. They said that if they found something wrong they would correct it if possible and send the barrel back. if not they said that they would give me a new barrel. Seems to have good CC so far. But I decided to try one last thing. ive swapped upper receivers. I had a DPMS low pro which is not a top end receiver but ive always had luck with them before and I just happened to have one in the safe. I lapped it which it seemed to be very close anyways. I did barrel using the locktite method and plan on shooting it tomorrow. ill let you all know the results. hopefully this solves something if not the barrel will be sent back.
thanks everyone for your advise so far. The Loctite and lapping have done wonders for my 204 ruger.
thanks everyone for your advise so far. The Loctite and lapping have done wonders for my 204 ruger.
I have a Precision Firearms built custom upper. Billet receiver 22" Lilja barrel, with PRI break. I t shot 1/2 moa with Precision Firearms factory ammo which is 123 grain bullets . I load 123 Amax with 8208 and still get 21/2 to 3" groups at 500yds. It has a Stiller Preditor billet lower with a CMC trigger. Functions flawlesley. Give them a call they sort of specialize in target quality Grendals.
I switched those receivers and yesterday shot four 5 shot groups at 100yds. Group sizes were approximately .5, .7, .75,.7. I consider this acceptable. Would I like to see better. Yes but acceptable. It appears for whatever reason rather it be the stiffness of the new receiver or something was way out of spec on my other receiver it played a major role in accuracy.
Thanks for updating with the results, this was an interesting read. I am getting ready to build an AR15 myself off of a Seekins forged upper and lower and trying to decide on an accurate barrel for it.
I like to learn new things. For what I paid the barrel is acceptable and with speaking with bhw they were eager to help. It was a pain but now that I got consistanty I can work on the loads and hopefully improve on what it is already shooting. I will say from the results of my 204 I believe in loctiting andblapping the receiver. But I still want to know if that first receiver is out of spec somehow or if the stiffer receiver was thebcure.
THANKS EVERYONE
THANKS EVERYONE
Since you are able to shoot very small groups with your .204 AR15 after lapping and Loc-titing, and changing uppers shrank your BHW .264 Groups, I think your case is a good example that illustrates that the upper can play a significant role in the accuracy formula.
Hi-power shooters don't just grab any old A2 upper receiver and slap a barrel in it, and head to the range. Go look at what a DCM service rifle A2 upper costs, and then ask yourself why, excluding the match-grade and tweaked rear sight assembly. I'm talking about the stripped upper alone from one of the top smiths in the Nation, not the concealed free-float tube either.
Hi-power shooters don't just grab any old A2 upper receiver and slap a barrel in it, and head to the range. Go look at what a DCM service rifle A2 upper costs, and then ask yourself why, excluding the match-grade and tweaked rear sight assembly. I'm talking about the stripped upper alone from one of the top smiths in the Nation, not the concealed free-float tube either.
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Agreed. I will definitely pay more attention to what I build my rifles off of from nowr on. The upper made more of an accuracy issue this time than anything that I have seen in the past.
