View Full Version : Thoughts on Accurizing AR?
Hey guys,
I subscribe to Guns & Ammo and I saw this article on supposedly accurizing the AR-15.
Includes: lapping the receiver, loctite the barrel extension/receiver, "tuning" the gas tube, using a tighter BCG?
Thoughts on any/all of this?
http://www.gunsandammo.com/rifles/ar-15/accurize-your-ar-15/
Best,
Hey guys,
I subscribe to Guns & Ammo and I saw this article on supposedly accurizing the AR-15.
Includes: lapping the receiver, loctite the barrel extension/receiver, "tuning" the gas tube, using a tighter BCG?
Thoughts on any/all of this?
http://www.gunsandammo.com/rifles/ar-15/accurize-your-ar-15/
Best,
Receiver lapping, a press fit between the upper and barrel extension, "bedding" the barrel into the upper with sleeve retaining compound if the fit is not optimal, and tuning the gas tube to eliminate interference with the gas key are all tricks that have been done in the high-power world for years. There are even a few videos on YouTube discussing and demonstrating some of it.
That being said, many (most?) shooters will get more mileage out of a good trigger, quality ammunition, a quality barrel, and most of all time spent working on the fundamentals of marksmanship. If a guy has crappy follow through and doesn't understand concepts like natural point of aim, bedding a barrel with sleeve retainer isn't going to do him any good.
vicious_cb
04-14-18, 17:38
His AR is pretty much a joke to begin with. He already ****ed up with a skeletonized BAD receiver set for an precision AR. Theres a reason you dont see custom precision mfgs like GAP using skeletonized anything or even guys who mass produce precision ARs like KAC using plain receivers.
Put a carbon fiber wrapped barrel on top of that now you're just putting lipstick on a pig with all your lapping and bedding.
I tell you how make an accurized AR for half the cost and none of the BS hes doing.
1. Get a quality receiver like a Vltor MUR, HDSI or BCM who hold pretty tight tolerances.
2. Get a Kreiger barrel with a matching bolt.
3. Buy literally any decent free float tube
4. Get someone who knows what theyre doing to assemble it all.
5. Put a good trigger in your lower
6. Buy some good match ammo or learn how to reload.
Hey guys,
I subscribe to Guns & Ammo and I saw this article on supposedly accurizing the AR-15.
Includes: lapping the receiver, loctite the barrel extension/receiver, "tuning" the gas tube, using a tighter BCG?
Thoughts on any/all of this?
http://www.gunsandammo.com/rifles/ar-15/accurize-your-ar-15/
Best,
Useless if you do not start with an accurate BBL.
Hey guys,
I subscribe to Guns & Ammo and I saw this article...
51521
Most people spend useless amounts of time reading magazines and chasing the elusive golden dragon when the answer is right in front of them. Get a good barrel, use good ammo and have a good optic and you have essentially cracked the code.
Of course, it actually helps to get out and shoot and see how your stuff actually performs as well.
556BlackRifle
04-14-18, 18:48
You want accuracy?
1_ If not already done, add a free float handguard.
2_ Get a decent trigger. An ALG ACT or Sionics Enhanced are a good start. Geissele SSA-E would be better.
3_ Start reloading.
4_ Invest in a good optic and mount.
It's amazing how accurate an off the shelf AR is without going to all that much trouble.
Receiver lapping, a press fit between the upper and barrel extension, "bedding" the barrel into the upper with sleeve retaining compound if the fit is not optimal, and tuning the gas tube to eliminate interference with the gas key are all tricks that have been done in the high-power world for years. There are even a few videos on YouTube discussing and demonstrating some of it.
That being said, many (most?) shooters will get more mileage out of a good trigger, quality ammunition, a quality barrel, and most of all time spent working on the fundamentals of marksmanship. If a guy has crappy follow through and doesn't understand concepts like natural point of aim, bedding a barrel with sleeve retainer isn't going to do him any good.
I agree, especially the fundamentals of taking the shot. Case in point. Today I was zeroing my rifle at 200 yds. My breathing was off, my follow through was gone, I had too much stock movement, and my groups showed it. I realized my fundamentals had blown away, started concentrating on these things and my trigger pull and finally got my rifle zeroed.
sidewaysil80
04-14-18, 20:15
Other thing that may be worth it if REALLY going down the rabbit hole is to try and find a monolithic receiver or one in which the handguard mounts to the receiver not the barrel nut. I suspect when preloading bipods on a traditional rail setup it may transfer to the barrel nut. It may not even have an effect or be quantifiable, but I’d imagine it can’t hurt. LaRue does it with their rifles as I’m pretty sure rail mounts to receiver and they are known for their accuracy.
I’m NOT saying this is necessary for an accurate AR at all, but it can’t hurt if building from scratch for that purpose.
(Waiting for Iraqgunz thoughts on the matter)
My recommendation to anyone wanting to "accurize" any weapon is to ensure they can shoot well enough to realize the benefits.
How to make an AR more accurate:
Start with a quality rifle
1. Buy ammo meant to be accurate
2. Buy an optic to facilitate precision shooting
3. Learn to properly utilize your system
4. Practice and log your results
5. Repeat step 4
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Achilles11B
04-14-18, 20:50
My recommendation to anyone wanting to "accurize" any weapon is to ensure they can shoot well enough to realize the benefits.
Truth.
vicious_cb
04-14-18, 21:56
My recommendation to anyone wanting to "accurize" any weapon is to ensure they can shoot well enough to realize the benefits.
Why try and learn to shoot well when you can just buy a lead sled and shoot of the bench all day. Show everyone your pristine bad ass looking AR and the tight groups it can shoot. :p
ginzomatic
04-14-18, 22:48
Most guns are more accurate than the person shooting them. Start there.
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Okay, firstly thanks for the replies. I was just trying to find out if these techniques were valid, but I guess I really asked for the whole ammo, trigger, free float, you suck at shooting thing -which I have read about a billion times on the forum. Appreciate you guys.
Achilles11B
04-14-18, 23:11
I have no doubt the techniques are valid, but it appears many here doubt their necessity. I understand it was for an article, but who is the intended audience? I dare say most shooters have access to more than four loads, and the techniques seem drastic to all but the most dedicated bench shooters who are trying to chase every bit of accuracy possible. If you’re in this category, it may be worth looking into the techniques in the article.
They are all valid, and work. I had never heard of the bossed BCG but you learn something new everyday. Now I am trying to figure out creative ways of tightening up BCG tolerances, thanks man.
Okay, firstly thanks for the replies. I was just trying to find out if these techniques were valid, but I guess I really asked for the whole ammo, trigger, free float, you suck at shooting thing -which I have read about a billion times on the forum. Appreciate you guys.
The techniques in regard to the barrel, upper, and gas tube are valid. As everyone has been saying, whether the juice is worth the squeeze depends a lot on the individual shooter and the application they intend to use the rifle in.
Here's one of the YouTube videos I was thinking of earlier. Joe Carlos, a gunsmith who specializes in building match grade ARs for Service Rifle competitions talks about barrel to receiver fit, including a couple of ways to improve it. He mentions that he has seen group size improve by as much as 30% when a loose barrel to upper fit is corrected. But again, his clientele are probably better than average shooters to begin with. IIRC Joe is a MSG (Ret) and was an armorer for the Army Reserve Marksmanship Team for about 10 years. I think he also held the Inter-service 1000 yard Service Rifle Record for a number of years.
https://youtu.be/pJL-IscH_jo
There are several other videos from the same interview that also make for an interesting watch.
Excellent video Tx Aggie. Mr. Carlos did a great job of explaining the problem and solution.
Okay, firstly thanks for the replies. I was just trying to find out if these techniques were valid, but I guess I really asked for the whole ammo, trigger, free float, you suck at shooting thing -which I have read about a billion times on the forum. Appreciate you guys.
You got your answer early on...high power shooters have been using those techniques for quite a while. But this forum really doesn't cater to that particular sport, neither does it cater to the sport I like, 3gun. I don't remember anyone saying you suck at shooting, but we did re-enforce that good shooting for any of us begins with good shooting practices with whatever rifle you're using, be it a highly worked over accuratized AR or a $500 basic model.
Eurodriver
04-15-18, 09:23
I hate the internet.
I hate the internet.
There are days when I think I should cancel my internet and use the money to go shooting instead.
I hate the internet.
I felt the exact same way yesterday.
Thanks for everyone's replies.
I used to lap the receiver face, etc. Then, a well distinguished high power shooter said that either the USMC or AMU stopped the practice as they saw no real benefit to the practice.
He shoots better in his feet than I do in the prone.
ETA: stupid phone submitted my post before I was done typing.
Parts have gotten better, if you buy good parts. In the last ten rifles I've assembled using DD, BCM, and a couple ARP 6.8 barrels. All using Aero uppers, I have pretty much had to resort to a plastic mallet to get the barrels into the uppers. No shim stock is going to fit in there, and I don't really see any need to loctite them either. I also seriously doubt that I could much improve on the barrel's grouping through gunsmithing. I see far better results from proper load development. All of which is a waster of time if you can't make a good wind call, or don't have good shooting fundamentals.
HelloLarry
04-15-18, 15:35
Use a hair drier or a heat gun on those tight uppers to get the barrel in.
That being said, many (most?) shooters will get more mileage out of a good trigger, quality ammunition, a quality barrel, and most of all time spent working on the fundamentals of marksmanship. If a guy has crappy follow through and doesn't understand concepts like natural point of aim, bedding a barrel with sleeve retainer isn't going to do him any good.
Best advice given.
sidewaysil80
04-16-18, 06:20
Use a hair drier or a heat gun on those tight uppers to get the barrel in.
Why???
Expands the receiver just enough to accept the barrel extension and when it cools it will tighten up on it. This of course only if the receiver is a tight fit/oversized barrel extension.
Scroll through for science post:
https://diy.stackexchange.com/questions/90392/if-metal-expands-when-heated-how-does-heating-a-bolt-loosen-it
Fatorangecat
04-19-18, 08:42
In my experience chasing tiny groups there are measurable gains in accuracy and there are theoretical gains in accuracy. A match barrel and trigger will result in measurable gains in accuracy, All the other voodoo is theoretical. For example if we took a stock M4 and swapped out the barrel with a Krieger it would shoot measurably better. If you took the same M4 and did nothing but swap the receiver for a thicker MUR would it shoot measurably better?
Grant's recipe for success;
*NOTE, assumptions are made that the builder will be using KNOWN, QUALITY barrels, receivers, etc.
1. Tight fit between barrel extension and receiver.
A. You can use loctite, but assume that if Green is used, you probably won't get it back apart.
B. Just use a BCM or VLTOR receiver as they specifically undersized the barrel extension hole (tight fit).
2. Check that the upper receiver M1913 rails are square and true.
A. We use a Tru-Stone from Starrett to verify.
3. Barrel nut is at or under 40lbs.
A. You can use shims if the barrel nut design doesn't allow for correct timing at that poundage.
4. FH/MB is timed (5 O'Clock position) so as not to put to much pressure on the end of the barrel (which causes "trumpeting").
A. Use shims to time.
5. Fit bolt to barrel extension. J. Noveske taught me this (along with ranges for each barrel length and gave me the gauges he had made).
6. Square and true the barrel and then re-crown (30 degree).
7. Be a good shooter! Use a good trigger! Use good ammo! Use good glass! Well, Duh! ;-)
C4
That's a whole lotta work for basically nothing gained over a properly built AR with high quality parts like the barrel. I've extensively evaluated a DD, LMT, Sionics, KAC, BCM, Colt, and several others. All of those barrels will be around 1-1.25MOA using true 10rd groups (if we were doing three 5rd groups like the article, then these barrels would print around .75 MOA with exceptional trigger control, and shooting technique given you add three things imho.....
If you want "turn key" accuracy potential out of any, and every quality AR made (lets assume the barrel is FF).....it only requires three things:
NF Compact optic 2.5-10x models (fill in your 2/3-9/10x variable powered optic)
Geissele 2stage trigger......SD-E is my pick (A KAC 2 stage will work fine, but a G trigger will give complete control on the second stage wall)
Atlas V8 (or updated) bipod .... In prone position, with a slight load....this bipod is truly a game changer....or was when it came out and hadn't been copied by everyone. Out of the knockoffs, the KAC seems to be the next best option imo. Even a Harris BRMS will do fine, especially if you upgrade the tilt/cant knob.
Obviously we're using ammo as a control...but if not, three loads will usually tap an ARs potential out given the Indian is present...
1. Hornady 55gr. Vmax. IMHO the finest factory ammo to shoot 10rd half dollar groups out at 100yds. Honestly never seen an AR that didn't absolutely love this loading. Sure it's a paper tiger terminal ballistic wise, but damn if it's not bughole accurate.
2. Hornady 5.56 TAP T2 75gr. For ranges past several hundred yards. Don't waste this stuff unless its at distance, and you really require extreme accuracy as it's rare, and costly.
3. BH red box 5.56 77gr. OTM SMK ( MK262 ) For max effective range accuracy....if you gotta fly to 1000 and buck transonic, this is the round for the job.
Examples.....
My HD rifle sits 99% of the time like this ready for the boogie man....A DD 14.5" LW pencil barrel/BCM FA BCG with BCM CH/Geissele proto MK1 13"/KAC micros/T-1
(absolutely no voodoo or secret sauce was applied...as in no "accurizing" besides building it from scratch according to military type specs, I.E. torque values, staking nuts, using the right grease on barrel threads, etc.
https://i.imgur.com/cY4HKBJ.jpg
Now here is same rifle pushing the absolute envelope of it's accuracy performance with the turn key items added. At a bit less than 750yds, it recorded a true 10rd group measuring 1.1 MOA IIrc. Note only things added are the turn key pieces of kit minus the bipod ( attach it once at the range)......NXSc 2.5-10x24 Geissele SD-E Atlas bipod & TAP T2 ammo in that vid
https://i.imgur.com/nyG8tF0.jpg
https://www.youtube.com/watch?v=H_cIuMw0_R0&t=1s
Group from vid
https://i.imgur.com/Sm39YFn.jpg
https://i.imgur.com/9kmmsXk.jpg
EzGoingKev
04-19-18, 16:41
Grant's recipe for success;
5. Fit bolt to barrel extension. J. Noveske taught me this (along with ranges for each barrel length and gave me the gauges he had made).
C4
Can you provide more info on this process?
...
I always enjoy reading your posts. That's some great shooting, and a really nice rifle.
Thanks for taking the time to post.
I always enjoy reading your posts. That's some great shooting, and a really nice rifle.
Thanks for taking the time to post.
It's my pleasure friend, and I always appreciate your words of encouragement.
Photobucket ruined so much of my threads on here that I haven't really been active posting wise, however now that I found Imgur, and finally am getting to shoot quite frequently again...I hope to change that. My close by range had a oil and gas explosion that rocked all of central Alabama and closed the range for 6 months....some dude right by the range dug with a backhoe, and you can guess his fate.
I just got into M1 carbines the last cpl. months, and am so far down that rabbit hole its not even funny. I wish I could share more on those on M4C, but I'm not sure folks are into 70yr old carbines.
Can you provide more info on this process?
Sure. You take a bunch of bolts. Remove the ejector from them. Put the one of the gauges (for that barrel length) into the barrel. See if the bolt will lock. Repeat till you find one that does.
C4
............................I just got into M1 carbines the last cpl. months, and am so far down that rabbit hole its not even funny. I wish I could share more on those on M4C, but I'm not sure folks are into 70yr old carbines.
I having been shooting M1 Carbines for several years and would be interested in your observations and tips if you started a thread.
HelloLarry
04-21-18, 12:33
Sure. You take a bunch of bolts. Remove the ejector from them. Put the one of the gauges (for that barrel length) into the barrel. See if the bolt will lock. Repeat till you find one that does.
C4What? Are you sticking a rod with a stop down the barrel?
What? Are you sticking a rod with a stop down the barrel?
Not Grant, but think what he meant was he was setting the minimum headspace by picking a bolt that would lock on a specific gauge in the chamber. The gauge mimics a chambered round, so no need for rod in barrel.
Mark
Not Grant, but think what he meant was he was setting the minimum headspace by picking a bolt that would lock on a specific gauge in the chamber. The gauge mimics a chambered round, so no need for rod in barrel.
Mark
Bingo.
C4
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Sure. You take a bunch of bolts. Remove the ejector from them. Put the one of the gauges (for that barrel length) into the barrel. See if the bolt will lock. Repeat till you find one that does.
C4
How does barrel length change the desired head space?
TacticalFun
04-22-18, 11:21
Im not sure about the rest of it but we have been pressing hanson premium 18" barrels into bcm uppers and head spacing the bolt on our newer competition rifles. Paired with ssa-e and the new ssp triggers our shooters are shooting consistent 1/2 moa.
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EzGoingKev
04-22-18, 12:07
Joe Carlos, a gunsmith who specializes in building match grade ARs for Service Rifle competitions talks about barrel to receiver fit, including a couple of ways to improve it. He mentions that he has seen group size improve by as much as 30% when a loose barrel to upper fit is corrected.
He talks about swapping the barrel extension out for an oversized one to tighten up the fit. It kind of comes across as spin the extension off and just spin the oversized one on. I would think that it is more involved then that as the barrel extension's pin needs to be in phase with the gas port.
I used to lap the receiver face, etc. Then, a well distinguished high power shooter said that either the USMC or AMU stopped the practice as they saw no real benefit to the practice.
I do not think lapping the receiver base increases accuracy. I do think it squares the barrel extension to the bolt face so the lugs are all loaded evenly instead of being biased to one side.
Use a hair drier or a heat gun on those tight uppers to get the barrel in.
A cup warmer works good for stuff like that too. Place the receiver face down on the cup warm and let it sit a while.
I've used BCM blem/demo stripped uppers for north of a dozen builds, using barrels from various sources - green mountain and ballistic advantage mainly.
The extensions fit snug in the receivers, but I've never had to freeze the barrel or heat the receiver.
Do you think it is because the receivers have been previously used on demo rifles?
TacticalFun
04-22-18, 12:47
I've used BCM blem/demo stripped uppers for north of a dozen builds, using barrels from various sources - green mountain and ballistic advantage mainly.
The extensions fit snug in the receivers, but I've never had to freeze the barrel or heat the receiver.
Do you think it is because the receivers have been previously used on demo rifles?Yes. Usually you either need to sand the inside of the bcm or heat it. I actually made up a jig to press the barrels in.
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HelloLarry
04-22-18, 13:50
From what I understand, one of the nice features of the Joe Carlos/Shilen barrel extensions is that they are cut with a thread that begins at the same spot on all of them so they are truly interchangeable.
EzGoingKev
04-22-18, 14:01
From what I understand, one of the nice features of the Joe Carlos/Shilen barrel extensions is that they are cut with a thread that begins at the same spot on all of them so they are truly interchangeable.
If you are Shilen and you are making your own barrel and extensions I can see that being the case.
Maybe I am wrong about this but I do not see that happening 100% of the time when using a barrel from company A and an extension from company B.
I would love to hear from someone who has actual experience swapping these things out.
I've used BCM blem/demo stripped uppers for north of a dozen builds, using barrels from various sources - green mountain and ballistic advantage mainly.
The extensions fit snug in the receivers, but I've never had to freeze the barrel or heat the receiver.
Do you think it is because the receivers have been previously used on demo rifles?
I’ve built several uppers using bcm receivers and had to heat every one. I’ve used Krieger Direct, a CLE Bartlein, Lothar Walther, a few ARP’s, Colt, and Ballistic Advantage barrels. A heat gun or propane torch gets it done. I haven’t used the blem uppers.
Grant's recipe for success;
*NOTE, assumptions are made that the builder will be using KNOWN, QUALITY barrels, receivers, etc.
1. Tight fit between barrel extension and receiver.
A. You can use loctite, but assume that if Green is used, you probably won't get it back apart.
B. Just use a BCM or VLTOR receiver as they specifically undersized the barrel extension hole (tight fit).
2. Check that the upper receiver M1913 rails are square and true.
A. We use a Tru-Stone from Starrett to verify.
3. Barrel nut is at or under 40lbs.
A. You can use shims if the barrel nut design doesn't allow for correct timing at that poundage.
4. FH/MB is timed (5 O'Clock position) so as not to put to much pressure on the end of the barrel (which causes "trumpeting").
A. Use shims to time.
5. Fit bolt to barrel extension. J. Noveske taught me this (along with ranges for each barrel length and gave me the gauges he had made).
6. Square and true the barrel and then re-crown (30 degree).
7. Be a good shooter! Use a good trigger! Use good ammo! Use good glass! Well, Duh! ;-)
C4
As someone who is not particularly knowledgeable but pretty good at following instructions, this summary seems like a great opportunity to build out an article or (if you’re into it) a step by step video. Not that it’s needed, but I would find it helpful to “see” these things done.
Reply to original post. Quality ARs and army issued M4s do their part better than the shooters do. This is true for they army, if you want to, not just hit a silouette at 300 meters, but hit it between the eyes, you need to get a sniper rifle. A quality AR is already accurate.
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