AR15 .223 - Making It Accurate

[rcw3]

Phil

A couple comments:

EGW also makes a .937 clamp on gas block just like the .875' one we use on a lot of uppers.

If you buy the barrel with an extension from Krieger,which is how they will most likely be supplying it) you just have to use the barrel as it is and there's nothing you can do about extension torque, front back bolt play and gas porting because everything will be already done and the port is drilled and that precludes a lot of further tinkering,without a whole bunch of sophisticated machine and barrel work). The good news it may shoot just fine anyway.

As far as truing the receiver face we use a mandrel through the body of the receiver to spin the receiver in a lathe and a carbide cutting tool, so I cannot tell you what to buy from Brownells. The good news is that the Sun Devil uppers generally run pretty true on the face of the receiver,a lot better than most).

Good luck!

Robert Whitley

P.S. Just got back from the range testing the new just released Berger 6mm 100 gr BTHP bullets,shooting slow prone with a sling). These bullets are awesome, .475 B.C. and with 30.3 gr of RL15 they're running around 2910 fps out of a 6mmAR Turbo 40 Imp chambered upper - shoot fast, flat and accurate! The one picture shows a 10 shot group, the other shows a dime placed over the group.

 

[jkl]

Robert,

I just picked up 100 Berger for my 6MM AR any thoughts on load? I was going to start with 28.5 gr RL15. Robert's gun is amazing and it will out shoot the shooter most days.

John

 

[billmo]

Phil

A couple comments:

EGW also makes a .937 clamp on gas block just like the .875' one we use on a lot of uppers.

If you buy the barrel with an extension from Krieger,which is how they will most likely be supplying it) you just have to use the barrel as it is and there's nothing you can do about extension torque, front back bolt play and gas porting because everything will be already done and the port is drilled and that precludes a lot of further tinkering,without a whole bunch of sophisticated machine and barrel work). The good news it may shoot just fine anyway.

As far as truing the receiver face we use a mandrel through the body of the receiver to spin the receiver in a lathe and a carbide cutting tool, so I cannot tell you what to buy from Brownells. The good news is that the Sun Devil uppers generally run pretty true on the face of the receiver,a lot better than most).

Good luck!

Robert Whitley

P.S. Just got back from the range testing the new just released Berger 6mm 100 gr BTHP bullets,shooting slow prone with a sling). These bullets are awesome, .475 B.C. and with 30.3 gr of RL15 they're running around 2910 fps out of a 6mmAR Turbo 40 Imp chambered upper - shoot fast, flat and accurate! The one picture shows a 10 shot group, the other shows a dime placed over the group.

HEY ROBERT, JUST WONDERING IF YOU WERE SHOOTING AT 100 YDS? THANKS, BILL

 

[Phil3]

Phil

A couple comments:

EGW also makes a .937 clamp on gas block just like the .875' one we use on a lot of uppers.

If you buy the barrel with an extension from Krieger,which is how they will most likely be supplying it) you just have to use the barrel as it is and there's nothing you can do about extension torque, front back bolt play and gas porting because everything will be already done and the port is drilled and that precludes a lot of further tinkering,without a whole bunch of sophisticated machine and barrel work). The good news it may shoot just fine anyway.

As far as truing the receiver face we use a mandrel through the body of the receiver to spin the receiver in a lathe and a carbide cutting tool, so I cannot tell you what to buy from Brownells. The good news is that the Sun Devil uppers generally run pretty true on the face of the receiver,a lot better than most).

Good luck!

Robert Whitley

P.S. Just got back from the range testing the new just released Berger 6mm 100 gr BTHP bullets,shooting slow prone with a sling). These bullets are awesome, .475 B.C. and with 30.3 gr of RL15 they're running around 2910 fps out of a 6mmAR Turbo 40 Imp chambered upper - shoot fast, flat and accurate! The one picture shows a 10 shot group, the other shows a dime placed over the group.

Robert,

The EGW site does not list the .937 gas block. only .625', .750', and,875'. I had sent an inquiry to EGW earlier, but never heard back. I'll try again.

Krieger does provide the barrel with extension and gas block, but not installed. $340. To install the extension, gas block, chamber, and headspace is $100.

I suppose I could ask Krieger to chamber but not install the extension. But, I don't know that I have the expertise to install the extension and manage the dimensions associated with this process. I'd like to learn and do it, but know it must be done right.

Brownells offers two receiver face truing tools. One is a 1' mandrel with a shoulder. Driven by a drill, it spins inside the receive,lube needed, but this worries me), while the shoulder contacts the receiver face. With lapping compound, the face is trued.

The other tool is a cutting tool with flutes on it that is guided by a mandrel such as above. I much prefer spinning the receiver as you described, but I have no access to such tools.

Well, you are further convincing me to opt for the 6mmAR on the next AR15. Reminds me of the 20 Practical groups. Truly outstanding.

- Phil

 

[rcw3]

Robert,

I just picked up 100 Berger for my 6MM AR any thoughts on load? I was going to start with 28.5 gr RL15. Robert's gun is amazing and it will out shoot the shooter most days.

John

John

Sounds good to me at 28.5 gr of RL15. You will probably be able to go another .5 gr to 29 gr. but I am not sure about 29.5 gr. in the 6mmAR. Work up and see.

Robert

 

[rcw3]

HEY ROBERT, JUST WONDERING IF YOU WERE SHOOTING AT 100 YDS? THANKS, BILL

Yes, 100 yards - this was not off a rest or a bench, it was prone with a sling so there is pulse and body movement in the group.

Robert

 

[rcw3]

Robert,

The EGW site does not list the .937 gas block. only .625', .750', and,875'. I had sent an inquiry to EGW earlier, but never heard back. I'll try again.

Krieger does provide the barrel with extension and gas block, but not installed. $340. To install the extension, gas block, chamber, and headspace is $100.

I suppose I could ask Krieger to chamber but not install the extension. But, I don't know that I have the expertise to install the extension and manage the dimensions associated with this process. I'd like to learn and do it, but know it must be done right.

Brownells offers two receiver face truing tools. One is a 1' mandrel with a shoulder. Driven by a drill, it spins inside the receive,lube needed, but this worries me), while the shoulder contacts the receiver face. With lapping compound, the face is trued.

The other tool is a cutting tool with flutes on it that is guided by a mandrel such as above. I much prefer spinning the receiver as you described, but I have no access to such tools.

- Phil

Phil

I know EGW has the .937 blocks, you would need to call them.

Keep in mind, Krieger makes great rifle barrels but they do not make AR-15's or uppers. The barrels themselves are excellent, but the machine work they do for AR-15 barrels is more in line with commercial production specs. vs custom match barrel specs. For our build ups we only use contoured blanks and do everything else ourselves,i.e. threading, chambering, fitting of extension, gas block area, gas port, etc.). It's the only way to have control over these items and keep tolerances very tight.

To do any serious barrel work you would need a lathe, the tools, and the know how, so I think you have to buy what you can get already made.

The thing that I am unsure of with Brownells tool is what guarantees that the mandrel fits tight into the inside of the receiver so that you pick up the true line of the carrier hole through the receiver? It seems to me,and I might be wrong here because we don't do it like that) if the mandrel that is supplied by Brownells tool does not fit tight into the receiver the tool cannot true the face correctly because it can move around and cant because it is loose in there. If you have a tight fitting mandrel that's good but it also cannot be tight because it has to spin inside the receiver. Maybe I just don't understand their tool. With our set up the receiver is mounted tight on a mandrel and the mandrel and the receiver both spin in the lathe so that just the face can be trued with a cutting tool. Bear in mind again, the Sun Devil receivers have generally been very good for trueness right out of the box so maybe you should just pass on the tools and use the receiver as is. I am not telling you what to do but that might be a better play under the circumstances. What happens if the Brownells tool doesn't make things better but there is a problem or things go bad and with the tool you make things worse? Then you are really in a fix. If I were you I would probably save the tool money and use the receiver as is. Loctite your barrel with extension in the receiver and put it together and go with it.

Robert

 

[Phil3]

Robert,

The EGW site does not list the .937 gas block. only .625', .750', and,875'. I had sent an inquiry to EGW earlier, but never heard back. I'll try again.

Krieger does provide the barrel with extension and gas block, but not installed. $340. To install the extension, gas block, chamber, and headspace is $100.

I suppose I could ask Krieger to chamber but not install the extension. But, I don't know that I have the expertise to install the extension and manage the dimensions associated with this process. I'd like to learn and do it, but know it must be done right.

Brownells offers two receiver face truing tools. One is a 1' mandrel with a shoulder. Driven by a drill, it spins inside the receive,lube needed, but this worries me), while the shoulder contacts the receiver face. With lapping compound, the face is trued.

The other tool is a cutting tool with flutes on it that is guided by a mandrel such as above. I much prefer spinning the receiver as you described, but I have no access to such tools.

- Phil

Phil

I know EGW has the .937 blocks, you would need to call them.

Keep in mind, Krieger makes great rifle barrels but they do not make AR-15's or uppers. The barrels themselves are excellent, but the machine work they do for AR-15 barrels is more in line with commercial production specs. vs custom match barrel specs. For our build ups we only use contoured blanks and do everything else ourselves,i.e. threading, chambering, fitting of extension, gas block area, gas port, etc.). It's the only way to have control over these items and keep tolerances very tight.

To do any serious barrel work you would need a lathe, the tools, and the know how, so I think you have to buy what you can get already made.

The thing that I am unsure of with Brownells tool is what guarantees that the mandrel fits tight into the inside of the receiver so that you pick up the true line of the carrier hole through the receiver? It seems to me,and I might be wrong here because we don't do it like that) if the mandrel that is supplied by Brownells tool does not fit tight into the receiver the tool cannot true the face correctly because it can move around and cant because it is loose in there. If you have a tight fitting mandrel that's good but it also cannot be tight because it has to spin inside the receiver. Maybe I just don't understand their tool. With our set up the receiver is mounted tight on a mandrel and the mandrel and the receiver both spin in the lathe so that just the face can be trued with a cutting tool. Bear in mind again, the Sun Devil receivers have generally been very good for trueness right out of the box so maybe you should just pass on the tools and use the receiver as is. I am not telling you what to do but that might be a better play under the circumstances. What happens if the Brownells tool doesn't make things better but there is a problem or things go bad and with the tool you make things worse? Then you are really in a fix. If I were you I would probably save the tool money and use the receiver as is. Loctite your barrel with extension in the receiver and put it together and go with it.

Robert

OK, will call, and order the .936' gas block.

You understand the Brownells tool correctly. The looser it is, the worse the alignment will be. One individual has reported, the fit on one of the tool is quite snug, requiring good lubrication to prevent galling or marring. Your method is superior, and would have that done if I could.

Given your comments on Krieger's AR machining work outside the barrel itself, it would appear having someone like Compass Lake Engineering provide a custom barrel they make from a blank is best. Compass Lake can obtain Krieger blanks and does their own machine work. The process is here.

http://www.compasslake.com/barrels.htm

I still don't know about Compass Lake chambering, other than it using a 1.5 degree taper, but will ask more about this tomorrow.

Compass Lake had sent me the following message.

We don't stock 1-9 twist barrels and Krieger tends to run on approximately 16 weeks for delivery. A 1-7 twist, or 1-7.7 or a 1-8 twist barrel will shoot 59 gr bullets up to 80 gr and be a more versatile barrel.

We use our own Compass Lake chamber, particularly for Krieger barrels. It is similar to SAMMI spec, but has a 1.5 degree taper rather than the sharper 3 degree taper. It was designed by Frank and the folks at JGS to optimize life of the barrel and accuracy. The primary reason for buying a Krieger barrel is because it is a cut-rifled barrel and the life tends to be greater than other barrels. I'd suggest if you want a Wylde or NATO chamber, to go with a Douglas barrel. You're going to lose a lot of the barrel life when you cut those two chambers and the accuracy of the Douglas barrel is excellent.

Any other suggestions to optimize tight groups are welcome.

Thank you.

Phil

 

[rcw3]

Phil

I really don't understand Frank White's comments in regard to the Wylde chamber vs his chamber and the suggestion that somehow his chambering will give you better barrel life. Many reamers use a one and a half degree throat angle and I have Wylde reamer prints with a one and a half degree throat angle. For what it's worth I also have an old Wylde reamer print with approximately a one and a quarter degree throat angle. I have not seen any match rifle 223 reamer prints with a three degree throat angle,I suspect there is a SAAMI print out there for a .223 Rem with a three degree throating but I have not seen that in use for 223 match rifle reamers). The strange thing is that with reamers in general, many feel a three degree throat angle lasts longer and does not wear forward as fast as a milder throat angle. I suspect the wording of the e-mail you received is not the best and perhaps he means, although he does not say it directly, that his reamer throating is shorter. The Wylde chamber throating on the longer side,and so is the 5.56 NATO).

If I were you, I would not hesitate to have Frank make up a barrel for you. Years ago before I got into building uppers I had him make up a few for me, he did a nice job and they shot well.

Robert Whitley

 

[Phil3]

Phil

I really don't understand Frank White's comments in regard to the Wylde chamber vs his chamber and the suggestion that somehow his chambering will give you better barrel life. Many reamers use a one and a half degree throat angle and I have Wylde reamer prints with a one and a half degree throat angle. For what it's worth I also have an old Wylde reamer print with approximately a one and a quarter degree throat angle. I have not seen any match rifle 223 reamer prints with a three degree throat angle. The strange thing is that with reamers in general, many feel a three degree throat angle lasts longer and does not wear forward as fast as a milder throat angle. I suspect the wording of the e-mail you received is not the best and perhaps he means, although he does not say it directly, that his reamer throating is shorter. The Wylde chamber throating on the longer side,and so is the 5.56 NATO).

If I were you, I would not hesitate to have Frank make up a barrel for you. Years ago before I got into building uppers I had him make up a few for me, he did a nice job and they shot well.

Robert Whitley

Robert,

I suspect you are right on the e-mail not being clear, the message I quoted from Compass Lake,CLE) was in fact, a response by them to some confusion I had on an earlier response. They have a phone number, so perhaps time to call them. Talking to Frank would be best. Theresa White was the one who responded to the e-mails.

Any other custom barrel makers besides CLE. I was also considering White Oak Precision. They can also use Krieger barrels, but know nothing of the chambering they do on Krieger blanks.

- Phil

 

[rcw3]

For what it's worth, John Holliger at White Oak definitely knows what he is doing with .223 barrels, and uppers for that matter.

Take a look at the attachment.

The Compass Lake reamer has a shorter throating and a little steeper throat angle relative to the Wylde reamer,dimensions N and R on the attachment).

Robert

 

[Phil3]

For what it's worth, John Holliger at White Oak definitely knows what he is doing with .223 barrels, and uppers for that matter.

Take a look at the attachment.

The Compass Lake reamer has a shorter throating and a little steeper throat angle relative to the Wylde reamer,dimensions N and R on the attachment).

Robert

I sent John Holliger an e-mail, with some options I was considering, asking for some guidance on barrel selection. John said $460 and 14 - 20 weeks...no other feedback.

Thanks for the attachment. Very informative, and educational. The Compass Lake freebore is much shorter, and I was surprised to see a steeper throat angle vs the Wylde. Not sure what works best for me, but it may not be possible without experimentation in varied loads.

Spoke to Krieger. For up to 69 grain bullets, they recommend 1:9' twist and .223 chamber. Was told don't try to run anything heavier or longer, but the lighter bullets may shoot better in the .223 chamber. Their 223 chamber is nothing custom to my knowledge. End of June for these barrels and July if I want it chambered.

I reached EGW and ordered the .936” gas block.

Undecided on the chambering options. Greater accuracy with lighter, short range bullets in a tight chamber rules out being able to “eat anything”. I can see why the Wylde is popular…a pretty good compromise,if you need that).

- Phil

 

[AJ172SBCT]

[/QUOTE]



The other tool is a cutting tool with flutes on it that is guided by a mandrel such as above. I much prefer spinning the receiver as you described, but I have no access to such tools.

[/QUOTE]

Phil,

Do you have a link for the tool from Brownells mentioned above?
I found the one that uses the lapping compound but I can't find the cutting tool with flutes on their site.
Thanks.

Jacques

 

[Phil3]

Jacques,

Sure, the link is below.

http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=20449&title=RECEIVER%20FACING%20CUTTER%20&%20PILOTS

Not always easy to find things on Brownells, and found this by accident.

- Phil

 

[AJ172SBCT]

Phil,
Thank you for the link and your time. Much appreciated.

Jacques