AR15 .223 - Making It Accurate

[Phil3]

I recognize this forum is not really for AR15s, and is hardly a preferred choice for fine target work, but am writing here because I feel this is the best qualified group to answer some questions. Why I have an AR15 for target work is another story.

I wish this gun to be as accurate as possible. I am using top quality parts, including a Krieger barrel, .920” muzzle, 22” long. Ranges are 100, 200 and rarely, out to 300 – 600 yards. I will be handloading, and would like recommendations on twist and bullets. Krieger offers chambering in .223 or 5.56mm. Or, I can have the barrel rough reamed with finish reaming done elsewhere. I think the .223 chambering is best,?), but is there any benefit to custom reaming? I am not familiar with this process, so forgive the naïve questions. I would want whatever rounds are chambered to be pulled from the mag, so overall length can not exceed about 2.25”.

Thanks for any guidance.

- Phil

 

[people]

A quick question for you. What type of bullet are you planning on shooting? Is it going to be all mag length ammo?

If it was mine I would say go with a 1:8 twist and a wylde chamber that would allow a little for bigger bullets,77gr SMK).

 

[billmo]

PHIL, ONE OF MY RRA AR-15 RIFLES IN .223 WILL SHOOT THE SMK 69 GR. SEATED AT 2.250 AND MAG FED ACCURATE ENOUGH TO TAKE OUT POP BOTTLES AT 500 AND 600 YDS. IT HAS THE WYLDE CHAMBER, 1 8 TWIST AT 18 INCHES LONG. I HAVE TRIED VARIOUS OTHER BULLETS AS WELL AT CLOSER RANGES AND OUT TO THE LONG END THAT PROVED TO BE JUST AS ACCURATE. I HOPE THIS HELPS. BILL

 

[Phil3]

Not sure on bullet selection as I really don't know what might be optimal for 100 - 200 yard paper target precision shooting. The ammo will need to fit in the magazine, which I think keeps rounds at about 2.25' long max. Not sure on that one though.

Krieger offers barrels with twists of 1 in 6.5', 7.7', 9.0', and 12.0'.

- Phil

 

[jthyttin]

What kind of shooting,positions etc.) are you going to do? I shoot AR-15 from field positions and like it for low recoil, my biggest grief is pistol grip which is situated far from bore axis.

If you're shooting from bags,even from field positions if you're good enough) you will notice the long lock time. Geissele trigger will help you some.

As to the bullet selection, only advice I can offer is that up to 300y don't get too concerned about the BC. Custom flatbase bullets at 52gr or so may provide the most consistent results.

 

[cliffy]

In my Ruger Model 77 Mark II .223 Remington configuration, I believe David Tubb's aftermarket aluminum-shaft firing pin has cut lock-time significantly,SPEED-LOCK). I did, however, revert back to the stock firing pin SPRING for, thus far, no misfires. Experimenting makes everything better. cliffy

 

[confuzed]

I run my 77 grain sierras out of colt mags at 2.260 with good results

 

[Phil3]

Shooting positions will be primarily bench, and while unlikely, maybe some prone. I know the lock time is long, and plan on using a single stage JP Rifles trigger with lightened speed hammer. I am not wedded to either a single stage, but think I would like the single stage more than the two stage Geissele.

'Custom' bullets, as in high quality stuff from Berger, Sierra, etc. I have come to understand that at short ranges,100 and 200 yards), the .223 may shoot most accurately with flat based bullets. ??? Is there a known optimal load for the .223 at 100 and 200 yards?

- Phil

 

[jthyttin]

'Custom' as in BIB etc. BR grade bullets.

Sierra, Nosler, Berger are just factory bullets, some held to more tight tolerances than others. I doubt you'll see any difference, but if you want best possible accuracy you can as well cling to true custom bullets.

Are you building the rifle on your own? If yes, do remember that in AR there's a lot of things which affect accuracy. Go with a premium builder if in doubt.

 

[Phil3]

'Custom' as in BIB etc. BR grade bullets.

Sierra, Nosler, Berger are just factory bullets, some held to more tight tolerances than others. I doubt you'll see any difference, but if you want best possible accuracy you can as well cling to true custom bullets.

Are you building the rifle on your own? If yes, do remember that in AR there's a lot of things which affect accuracy. Go with a premium builder if in doubt.

I will be buying factory bullets, not making my own.

I am building my own rifle. The things that seem to affect accuracy are not all that many that I can find, but here is what I am focusing on,besides ammo).

Barrel length, twist, diameter, chambering.
Squareness of barrel to receiver and bolt.
Heavier bolt assembly,delays unlocking a bit).
Low pull weight quality single stage trigger.
Hi-speed, low weight hammer.
Adjustable stock.
Free float handguard,no strain on barrel).
Quality scope.
Proper tools to assemble and measure.

- Phil

 

[jthyttin]

Most people don't roll their own custom bullets. E.g. BIB which I mentioned is manufactured by Randy Robinette:

http://www.bibullets.com/

When building AR, be very careful with the upper receiver. If you're not building upon custom made billet receiver, you need to select a receiver which is bored true enough,compared to front and rear pin), true the receiver face to the receiver bore, check the gas tube hole so that gas tube is not binding etc.

 

[Phil3]

I have read considerable info on building ARs, and believe I am well prepared. While you can just screw on a barrel and go,many do), I am going further than this. Brownells has a tool to square the receiver face,end of receiver barrel threads) to the bolt bore. I also bought a tool specifically for aligning the gas tube. I will be checking headspace,even though most say it is not necessary with an AR). I am using torque wrenches and proper tools at every step. I even bought a special holding fixture for the upper receiver, which by way of its design, largely eliminates twisting of receiver when undergoing barrel nut torque. Since the gas tube holes rarely line up once proper torque is achieved, I am buying a set of shims which will permit proper torque and gas tube aligment. I am making every effort to do this right. Expensive, but if not done right, why do it all?

My biggest challenge now is getting parts and believe it or not, some specialized tools, which are also sold out. Some parts are now 4 months away, and for my AR-10 project,which I may abandon), it is now over a year for some items.

I am hopeful I can make this AR shoot very accurately. Now, I just need to make ME, as a shooter, work as well!

- Phil

 

[boltman13]

Why you want to use the AR platform to shoot from the bench is a mystery to me, but it's your money so knock yourself out. Getting an accurate AR-15 is no mystery. There are thousands out there that group inside 0.5' at 100 yds, sometimes even down close to 0.3' on a good day. Insisting on mag length and 'factory' bullets may make it a little harder but still possable. The best upper and lower receiver combo is Rock River. Expect to wait a long time for your's to be made. Other ones I can recomend are Wilson Tactical, and White Oak. DPMS isn't bad as is Bushmaster, but the tightest is Rock River. If you want the fastest lock time then get a Geissele, don't screw around trying to make a lesser trigger work faster, it may not be reliable. A Kreger barrel is as good as they get, have it cut to a wyelde chamber. A 1:9 twist should give you a wide selection of bullets to try. If you want to go with longer ones go to 1:8. I have had good luck personally with Hornady 60 gr V-max, and 63 gr HP's. Boat tail ones I like are the 69 gr Sierra MK. The AR forend does not lend itself to shooting off the bench, and it takes practice to get comfortable using a scope with the A-2 stock. There are special risers and butstocks to help in this regard if you want to spend the money. Best of luck with your project.

 

[Phil3]

Why an AR15 at the bench? Good question. Short answer? California. One's natural reaction to threats to take something away, is to obtain it. Secondly, I live in the San Francisco bay area, and shooting off a bench is about all that is available. Lastly, the AR is easy and fun to work on, with lots of options for improvements. And it can be cheap.

As stated above, I am building the rifle, and creating my own upper assembly, as no upper assembly found matched what I wanted in terms of barrel length, twist, diameter, bolt assembly, forward assist,not), handguard, and gas block.

Geiselle triggers are excellent, but they are two stage, and I prefer single stage. Still, for a gas gun 2 stage may be best. I worry about transitioning between a single state on a bolt gun and 2 stage on the AR. Perhaps not a concern, maybe so?

I spoke to Compass Lake who like White Oak, makes custom barrels,and complete uppers). They said the Wylde chamber and the 5.56 NATO chamber would have sharply reduced barrel life vs their own custom chambering. I understand Krieger's 5.56 Match is quite a tight chamber and am considering it or the Compass Lake,or White Oak) barrel. Most are pushing me towards a 1:8' twist,bullet and barrel makers). Krieger has 1:9' and 1:7.7'. As an aside, Krieger does not offer the Wylde chamber. Your bullet recommendations will work fine in the 1:7.7'.

I wrestled with the stock choice, and made note of the scope eye relief for my scope, where my head was, etc. If the scope is mounted at an ideal location, I have no need for an adjustable cheek piece. I much prefer the adjustable butt plates, like a TUBB, rather than the adjustable tactical stocks, which are very expensive. They look tactical, but functionally, I did not find them any more useful than the much cheaper A2.

I very much know the AR is not a benchrest rifle. And it won't be in a benchrest bag,using a bipod - more challenging I know). I came to this forum because I did not think any group would know more about accuracy than the people here. I always somewhat wanted an AR, but they are severely threatened in CA, already restricted in some ways,10 round mags max, tool to remove mag), and needed to act now,like everyone else). I'd like to shoot in more varying circumstances, but in my area, it is basically bench at 100 yards. 200 yards on Fridays only. Any further means a 4 hour round trip to another range. After that, an overnight trip somewhere. Can't wait to move!

- Phil

 

[rcw3]

I wish this gun to be as accurate as possible. I am using top quality parts, including a Krieger barrel, .920” muzzle, 22” long. Ranges are 100, 200 and rarely, out to 300 – 600 yards. I will be handloading, and would like recommendations on twist and bullets. Krieger offers chambering in .223 or 5.56mm. Or, I can have the barrel rough reamed with finish reaming done elsewhere. I think the .223 chambering is best,?), but is there any benefit to custom reaming? . . .
- Phil

The Krieger 7.7' twist is a universally great twist for a .223. If everything is going to be magazine feed, it's hard to beat the Sierra 52 gr bullets at 100 yards, and further out, the Sierra 77's. Both of those bullets can jump and shoot well. Berger Bullets has some great magazine feed bullet offerings too. As far as chambering, there are a number of different .223 reamer designs out there. I would stay away from the 5.56mm,I assume you mean NATO) as that is a long throated military type chambering designed to deal with some military concerns. For match rifle use, the .223 Wylde chambering is very popular. Some of the plain .223 reamers have a very short throat which has pluses and minuses. If you are saying you want to shoot xyz bullet at 2.250' OAL and only be off the lands .010', then you are going to need a custom chambering, probably with a custom reamer. My suggestion is that unless you know what you are doing on chamberings, stay with one of the recognized well proven match chamberings like the Wylde.

I cannot honestly say Frank White's .223 chambers yield a longer barrel life than a Wylde chambering,and I have had and shot them both). The whole barrel life discussion is somewhat subjective because the issue is really accuracy and 'accurate barrel life' and I know of no body of information to suggest because Frank White may use a different throating than a Wylde reamer does, that this would necessarily mean a longer accurate barrel life. In truth, no matter whose chambering you go with, after 3000 rounds or so you are on borrowed time with a barrel for top accuracy. Heck, some of the top shooting teams consider around 2500 rounds to be a cutoff point for relegating an AR-15 match barrel to practice use or re-barreling.

If you want to rifle to be as accurate as possible then using unspecified 'top quality parts' may or may not be helpful. For example, if you are using a military style flat top upper receiver, you will using a receiver that was designed for a carry rifle and had all the metal stripped off of it so it would be light to carry. These receivers are thin walled and somewhat flexible and are not ideal for an accuracy build up,i.e. heavy walled rigid upper receivers are better for an accuracy build up). The standard military style receivers do well for what they are and considering their design, but receiver rigidity is helpful to accuracy.

Whatever you do, enjoy your AR - they're fun to shoot!

Robert Whitley
www.6mmAR.com

 

[rcw3]

. . . I also bought a tool specifically for aligning the gas tube. . . . Since the gas tube holes rarely line up once proper torque is achieved, I am buying a set of shims which will permit proper torque and gas tube alignment. . . .

- Phil

There is no tool I am aware of that can do as good of a job aligning a gas tube properly as a good set of hands and a critical eye that knows what to look for. Save your money on that tool.

The shim solution to get the barrel nut hole to line up at a reasonable torque is a 'jury rig' solution at best and I would never use it on the uppers we build. That's no place to put a paper thin shim. Depending on the hand guard and barrel nut set up you have there are other options to accomplish what you want to do. If you are truing the face of the receiver, then you have control of that issue by how much metal you remove from the face of the receiver,just don't remove too much or your barrel extension will sit inside the receiver too far and leave a lip that can cause feeding issues). Just bear in mind too that the hard coat anodizing on the face of the receiver can do a good job wrecking cutting tools.

Robert Whitley
www.6mmAR.com

 

[rcw3]

A few parting thoughts - some of an AR-15 accuracy build up is not only what you do to make it accurate but what you don't do to harm accuracy.

Gas Block: Avoid the slip on type with set screws underneath as the screws put all the pressure right in one spot of the barrel and can actually deform the bore, but gluing them on is not ideal either because they cannot be adjusted easily after they set. A clamp on gas block is the only way to go, not only for accuracy, but for ease of assembly and adjustment, gas tube alignment, servicing of the rifle, etc.

Gas Porting - Don't over port the rifle. If you need carrier weights or some special heavy buffer to slow down your cycling, it's most likely because your rifle is over ported. These weights are a retrofit to try to resolve something that was not right in the first place,i.e. the gas port being too big). If a rifle is ported correctly in the first place you don't need weights to delay the cycling of the action. Adding weights is like making it so you seat your rounds in the chamber by hitting them with a heavier hammer - not good - there's the downside of weights too that nobody talks about,i.e. hammering the, bolt, cartridge, action and rifle on loading)!

Placing of Gas Port - Don't believe the often stated theory that the best location for a port is in the groove - plain and simple it's not - in fact it's probably the least appropriate place for it. If I can, I will take the port half in the land and half in the groove every time over one in the groove. What proof is there that drilling into the groove is best other than internet chatter and people just repeating what they have heard? After bore scoping many barrels that have been shot for a while I am sure the port half through a groove and half into a land is best. Over time, the 'in the groove' ports exhibit much more barrel disruption and erosion of barrel metal forward of the gas port than those bisecting a land/groove half and half. The 'in the groove' ports are like a big deep pothole right in the middle of a flat stretch of road you hit squarely with the wheel of your car at high speed - WHAM! The half and half ports do not exhibit any where near the barrel disruption and erosion as the 'in the groove' ports. There's a reason why this is so, but the explanation is a little lengthy for this post.

Barrel Extension Torque - It is important to have a correct amount of torque on the barrel extension. After examining some commercial barrels,even big names in accuracy barrels) it is clear some assemblers in their shops don't know what is correct and what is not correct for barrel extension torque. If an extension comes off with 25 ft lbs of torque, that's bad & you probably won't have an accurate rifle and this can be the cause. If it takes 250 ft lbs of torque to come off that's bad too.

Front/Back Bolt Play - Most chambered barrels from commercial sources have a front/back bolt play of around .015' which is sloppy and allows the bolt to seat the cartridge less consistently. That may be fine for a military rifle where they expect it may get dirt and a build up of grunge in there, but for a match rifle accuracy build up you should be working with much less,i.e. like .003') for a number of reasons, accuracy being one of them.

Free Float Hand Guard - While a free float hand guard is good, some of them are not rigid and are bouncy. These are usually composite or thin aluminum or of a multiple piece design that leads them to flex. This is not good for accuracy and rigidity is important.

Fitting and Selection of Parts - Despite the best and highest quality parts, many times things need to be stoned or fitted to assure the best function and accuracy. There's no playbook here except an eye to recognize a potential issue and the experience to know how to deal with it best. If you only have one set of parts and the stacking tolerances on that set are bad, you're out of luck and you have to work with what you have. Most AR builders have an advantage here because they have an inventory of parts and a bit of know how on how to stone and fit parts.

I have other items on my website 'info page'

Robert Whitley
www.6mmAR.com

 

[Phil3]

I wish this gun to be as accurate as possible. I am using top quality parts, including a Krieger barrel, .920” muzzle, 22” long. Ranges are 100, 200 and rarely, out to 300 – 600 yards. I will be handloading, and would like recommendations on twist and bullets. Krieger offers chambering in .223 or 5.56mm. Or, I can have the barrel rough reamed with finish reaming done elsewhere. I think the .223 chambering is best,?), but is there any benefit to custom reaming? . . .
- Phil

The Krieger 7.7' twist is a universally great twist for a .223. If everything is going to be magazine feed, it's hard to beat the Sierra 52 gr bullets at 100 yards, and further out, the Sierra 77's. Both of those bullets can jump and shoot well. Berger Bullets has some great magazine feed bullet offerings too. As far as chambering, there are a number of different .223 reamer designs out there. I would stay away from the 5.56mm,I assume you mean NATO) as that is a long throated military type chambering designed to deal with some military concerns. For match rifle use, the .223 Wylde chambering is very popular. Some of the plain .223 reamers have a very short throat which has pluses and minuses. If you are saying you want to shoot xyz bullet at 2.250' OAL and only be off the lands .010', then you are going to need a custom chambering, probably with a custom reamer. My suggestion is that unless you know what you are doing on chamberings, stay with one of the recognized well proven match chamberings like the Wylde.

I cannot honestly say Frank White's .223 chambers yield a longer barrel life than a Wylde chambering,and I have had and shot them both). The whole barrel life discussion is somewhat subjective because the issue is really accuracy and 'accurate barrel life' and I know of no body of information to suggest because Frank White may use a different throating than a Wylde reamer does, that this would necessarily mean a longer accurate barrel life. In truth, no matter whose chambering you go with, after 3000 rounds or so you are on borrowed time with a barrel for top accuracy. Heck, some of the top shooting teams consider around 2500 rounds to be a cutoff point for relegating an AR-15 match barrel to practice use or re-barreling.

If you want to rifle to be as accurate as possible then using unspecified 'top quality parts' may or may not be helpful. For example, if you are using a military style flat top upper receiver, you will using a receiver that was designed for a carry rifle and had all the metal stripped off of it so it would be light to carry. These receivers are thin walled and somewhat flexible and are not ideal for an accuracy build up,i.e. heavy walled rigid upper receivers are better for an accuracy build up). The standard military style receivers do well for what they are and considering their design, but receiver rigidity is helpful to accuracy.

Whatever you do, enjoy your AR - they're fun to shoot!

Robert Whitley
www.6mmAR.com

I have to say, I was very surprised,and pleased), to see a message from Robert Whitley. One of the reasons I decided to dive into ARs, besides those I cited earlier, is the diversity of things you can do with an AR, specifically, the 6mmAR, and the 20 Practical. I am very familiar with www.6mmar.com, and already have taken some cues from it,EGW bag rider, clamp on gas block), and intend on building future ARs using components from the site. In any event, I am extremely thankful to have access to your AR knowledge.

On to your comments. I should have been more clear about Krieger's options. Krieger’s offering is not called “5.56 NATO”, but rather “5.56 Match”. I don’t know enough about chambers to know what that really means for my needs. There is no Wylde offering. Besides '5.56 Match', the only other alternative is “223 Remington”. Regarding if I know what I am doing with chamberings, the answer is “no”, but the above are the only two offered by Krieger, and in 1:7.7” twist, the only choice is 5.56 Match. I am not sure where this leaves me, except maybe to find another barrel maker using a Wylde, assuming the 5.56 Match from Krieger is not optimal for top accuracy.

Compass Lake made it clear using Wylde or 5.56 would substantially shorten life, but if any of the barrels last 3000 rounds, I am OK with that. Compass Lake also said they use a 1.5 degree taper in the chamber vs the standard 3.0 degree. I do not know the significance of that, or whether that is the only change to the chamber over some other chamber. But, your point is understood. One question, when you say “rebarreling”, do you mean shortening the barrel and reaming the chamber again? Does the rifling ever wear out?

I failed to define “top quality parts”, and understand your point. The parts list is as follows.

SunDevil upper and lower receiver
Rock River Arms lower parts kit
JP Rifles single stage 3.0 – 3.5 lb. trigger
Non-rotating trigger pins
JP Rifles hi-speed hammer
Young Manufacturing National Match Chrome bolt assembly
Rock River Arms charging handle
Krieger bull barrel, 22’ long, 1:7.7” twist. 5.56 National Match chamber?
JP Rifles free floating handguard. 2.0” diameter
EGW Gas Block. But, Krieger gas block diameter is .936”. EGW goes to .875”. ???
A2 stock
EGW rear bag rider
Harris bi-pod
Bushnell 6 – 24 x 50 4200 series scope. Model 426245T.
Scope mount,to be determined after I evaluate fit of rifle and scope)

Anything you would change here? I would love those tiny groups the 20 Practical shot!

It looks like to me that on www.6mmar.com, the billet upper with side charging option is SunDevil. It sure looks the same and SunDevil is billet.

I very much appreciate your help!

- Phil

 

[Phil3]

. . . I also bought a tool specifically for aligning the gas tube. . . . Since the gas tube holes rarely line up once proper torque is achieved, I am buying a set of shims which will permit proper torque and gas tube alignment. . . .

- Phil

There is no tool I am aware of that can do as good of a job aligning a gas tube properly as a good set of hands and a critical eye that knows what to look for. Save your money on that tool.

The shim solution to get the barrel nut hole to line up at a reasonable torque is a 'jury rig' solution at best and I would never use it on the uppers we build. That's no place to put a paper thin shim. Depending on the hand guard and barrel nut set up you have there are other options to accomplish what you want to do. If you are truing the face of the receiver, then you have control of that issue by how much metal you remove from the face of the receiver,just don't remove too much or your barrel extension will sit inside the receiver too far and leave a lip that can cause feeding issues). Just bear in mind too that the hard coat anodizing on the face of the receiver can do a good job wrecking cutting tools.

Robert Whitley
www.6mmAR.com

Robert,

Thanks for your comments. The gas tube alignment tool is little more than a steel rod. You’re right, no real need, just trying to ensure I was using correct tools. The tool was $5.

OK, will not use the shims. I had not ordered those. These were found at http://www.ar15barrels.com/data/barrel-nut-index.pdf.

What best approach is there to lining up the gas hole? I am using the JP Rifles handguard.

http://www.jprifles.com/instructions/Rifle/JPHG.pdf

Brownells has two kinds of receiver facing tools. One cuts with an abrasive compound,your selection), and the other uses hardened steel flutes. Both are guided by a mandrel within the receiver body,1”).

- Phil

 

[Phil3]

A few parting thoughts - some of an AR-15 accuracy build up is not only what you do to make it accurate but what you don't do to harm accuracy.

Gas Block: Avoid the slip on type with set screws underneath as the screws put all the pressure right in one spot of the barrel and can actually deform the bore, but gluing them on is not ideal either because they cannot be adjusted easily after they set. A clamp on gas block is the only way to go, not only for accuracy, but for ease of assembly and adjustment, gas tube alignment, servicing of the rifle, etc.

Gas Porting - Don't over port the rifle. If you need carrier weights or some special heavy buffer to slow down your cycling, it's most likely because your rifle is over ported. These weights are a retrofit to try to resolve something that was not right in the first place,i.e. the gas port being too big). If a rifle is ported correctly in the first place you don't need weights to delay the cycling of the action. Adding weights is like making it so you seat your rounds in the chamber by hitting them with a heavier hammer - not good - there's the downside of weights too that nobody talks about,i.e. hammering the, bolt, cartridge, action and rifle on loading)!

Placing of Gas Port - Don't believe the often stated theory that the best location for a port is in the groove - plain and simple it's not - in fact it's probably the least appropriate place for it. If I can, I will take the port half in the land and half in the groove every time over one in the groove. What proof is there that drilling into the groove is best other than internet chatter and people just repeating what they have heard? After bore scoping many barrels that have been shot for a while I am sure the port half through a groove and half into a land is best. Over time, the 'in the groove' ports exhibit much more barrel disruption and erosion of barrel metal forward of the gas port than those bisecting a land/groove half and half. The 'in the groove' ports are like a big deep pothole right in the middle of a flat stretch of road you hit squarely with the wheel of your car at high speed - WHAM! The half and half ports do not exhibit any where near the barrel disruption and erosion as the 'in the groove' ports. There's a reason why this is so, but the explanation is a little lengthy for this post.

Barrel Extension Torque - It is important to have a correct amount of torque on the barrel extension. After examining some commercial barrels,even big names in accuracy barrels) it is clear some assemblers in their shops don't know what is correct and what is not correct for barrel extension torque. If an extension comes off with 25 ft lbs of torque, that's bad & you probably won't have an accurate rifle and this can be the cause. If it takes 250 ft lbs of torque to come off that's bad too.

Front/Back Bolt Play - Most chambered barrels from commercial sources have a front/back bolt play of around .015' which is sloppy and allows the bolt to seat the cartridge less consistently. That may be fine for a military rifle where they expect it may get dirt and a build up of grunge in there, but for a match rifle accuracy build up you should be working with much less,i.e. like .003') for a number of reasons, accuracy being one of them.

Free Float Hand Guard - While a free float hand guard is good, some of them are not rigid and are bouncy. These are usually composite or thin aluminum or of a multiple piece design that leads them to flex. This is not good for accuracy and rigidity is important.

Fitting and Selection of Parts - Despite the best and highest quality parts, many times things need to be stoned or fitted to assure the best function and accuracy. There's no playbook here except an eye to recognize a potential issue and the experience to know how to deal with it best. If you only have one set of parts and the stacking tolerances on that set are bad, you're out of luck and you have to work with what you have. Most AR builders have an advantage here because they have an inventory of parts and a bit of know how on how to stone and fit parts.

I have other items on my website 'info page'

Robert Whitley
www.6mmAR.com

Good tips. Thank you.

Gas Block - I read your comments about the gas block set screws on the 20 Practical AR project, so set about looking for a clamp on type that could fit the .936” gas system diameter on the Krieger barrel. The only one I could find is from JP Rifles, but it is adjustable, something I really don’t need. EGW has one but it is .875”.

Gas Porting - I recognize the importance of proper porting, but how would I know if the porting is done correctly? Reputation of barrel maker or...? Or are there specs I should look for?

Placing of Gas Port - Krieger, my preferred barrel, told me they do port in the groove. Does any reputable barrel maker port “half and half”?

Barrel Extension Torque - Regarding barrel torque, not sure how I would know if this is being done correctly. I don’t think I can be set up to work with barrel extensions, unless the only unique tool is a barrel vise of some sort.

Front/Back Bolt Play - How would front/back bolt play be measured, and if it is sloppy, how is it rectified?

Free Float Hand Guard - I hope the JP Rifles handguard is satisfactory. Most people seem to think they are quite rigid.

Fitting and Selection of Parts - Understood on the stack up of tolerances working against me. If I use the JP Rifles trigger, they will fit it for me, for $40. While I would like to learn to do this myself, I think at least this time, they should do it. I am cautious, and if something does not seem to be working right, I will find out the proper way to proceed. Still undecided on single stage vs 2 stage. If the latter, I will get the Geissele.

www.6mmar.com 'info' page already read! Fact is, whole site has been read.

Thanks!

- Phil