Barrel nut (over) torque vs Accuracy

[NCHillbilly]

I'm not sure if this may be my issue, but it's the next thing on my list of things to check/address. I've been working with a 224 valkyrie that I put together, partially. The upper was already assembled, so it never occurred to me to check the barrel nut torque before assembly. I have, what should be, enough rounds down the pipe to have broken in the barrel, and I have seen my groups tighten up over time. My issue is, I have tried numerous loads that others have had good success with, but they're not working so well in my rifle. Out of probably 250-300 rounds fired, with 3 different weights of bullets, 6 different powders, 3 different primers, I've had 2, 4-shot groups shoot sub moa.
Could an over-torqued barrel nut adversely affect my accuracy that much? That's the last thing I can think of to check before considering a new barrel. All other functions of the rifle are just fine, it just seems way too finicky as far as ammo choices. I love the rifle and the round, just wish for better accuracy.

 

[S197]

What parts where used, who built the upper and tell us more about the loads? We will need more info to work on.

 

[NCHillbilly]

20" BCA stainless, 1-7 twist, lower built with BCM lpk with npt trigger. All loads were handloads. 75gr eldm with tac and cfe, 80gr eldm with varget and H4895 (the best load so far), and 88gr with 8208 xbr, and cfe. With the exception of the 80 gr, h4895 load, none of the others have ever shot better then 1.25 moa. Thought about even possibly trying Tubb's bore conditioning bullets before pulling the barrel. I know quite a few folks are having success with Ranier, WOA, and barrels from Craddock, and if need be, that's what I'll do. I just want to exhaust all options before taking that step.
I should add that I would shoot some factory loads to see if they made a difference, but finding factory ammo in that caliber around here is like finding hen's teeth.

 

[hlee]

Bear Creek barrel? Full stop. That may be a snob reply, but is likely more accurate than the barrel too...

 

[clcustom1911]

The only time I've had a POI shift with barrel nut torque was before I trued the receiver face of one of my uppers. When I slip fit the barrel in the upper, you could see just a faint sliver of light on one side of the extension/receiver interface. Minimal torque (about 25ft lb) produced one POI, torque on the high end of acceptable (40 ft lb) produced another POI about 3" away. I trued the receiver to where there was even contact between the extension/ receiver and re-torqued. Only a 1" POI difference between torque levels.

Does it matter? Well, I mean as long as the torque doesn't change, then the POI should be the POI at that torque level. Obviously, I would say clean, even contact between parts is more better.

Edit, another instance of wandering POI with barrel nut torque was when one of my budget uppers receiver was 0.003" too big for the barrel extension. I used some 0.001 shim steel and got her nice and tight.

 

[Potsy]

Vertical? Horizontal? All over the place?
I argued with my BHW for a few hundred rounds, giving the occasional promising group and then going back to crap (2-4moa).
It finally tightened up. I've long suspected something afoot at the gas port, but no real way to prove it.
I've read terrible things about BCA, but the only one I'm familiar with in person shot very well from the get go (a friend's 6.5 Grendel barrel), so no help there.

 

[S197]

20" BCA stainless, 1-7 twist, lower built with BCM lpk with npt trigger. All loads were handloads. 75gr eldm with tac and cfe, 80gr eldm with varget and H4895 (the best load so far), and 88gr with 8208 xbr, and cfe. With the exception of the 80 gr, h4895 load, none of the others have ever shot better then 1.25 moa. Thought about even possibly trying Tubb's bore conditioning bullets before pulling the barrel. I know quite a few folks are having success with Ranier, WOA, and barrels from Craddock, and if need be, that's what I'll do. I just want to exhaust all options before taking that step.
I should add that I would shoot some factory loads to see if they made a difference, but finding factory ammo in that caliber around here is like finding hen's teeth.

I would lap the barrel, true the receiver face and If you can cut/crown the barrel without any cost. If you have to put cash into any of those options, toss it and buy a better barrel.

 

[NCHillbilly]

Well, I know of the hit and miss reputation of BCA barrels, but the upper was a gift, so I had to give it a shot(no pun intended). I have watched the groups shrink from the initial rounds fired, but the loads most others are having success with just don't seem to suit my rifle. I am happy with the 80gr eldm/H4895 load that I have, but I haven't hit on a good 88gr load yet. I will try the above mentioned tweaks to see if that helps. Thanks guys.

 

[NCHillbilly]

Vertical? Horizontal? All over the place?
I argued with my BHW for a few hundred rounds, giving the occasional promising group and then going back to crap (2-4moa).
It finally tightened up. I've long suspected something afoot at the gas port, but no real way to prove it.
I've read terrible things about BCA, but the only one I'm familiar with in person shot very well from the get go (a friend's 6.5 Grendel barrel), so no help there.

All over the place. The one glimmer of hope came from a load workup using 80gr eldm's with H4895, cci 450's, and hornady cases. shot a decent group at 22.3 grs, shot a great group at 22.6 grs, and a good group at 22.9grs. I'm gonna further develop from 22.3-23.2, but would really like more than one decent load for this thing.

 

[bfoosh006]

No offense intended at all... but ... if you have fired over a few hundred rounds of .224 Valkyrie trying to make your BCA barrel shoot... that means "X" dollars spent .. or wasted trying to make that mediocre barrel shoot .

Some BCA barrels can shoot... others can't.

Step back and buy a better barrel. Your money will be better spent, on a proven , from a respected barrel manufacturer.

You have enough proof that your BCA barrel isn't shooting to your expectations. Any lapping or such... might also be wasted time and ammo.

IMHO, A better barrel is a huge bargain now-a-days.... especially considering current ammo costs.

Again , not trying to be rude at all.

 

[NCHillbilly]

No offense intended at all... but ... if you have fired over a few hundred rounds of .224 Valkyrie trying to make your BCA barrel shoot... that means "X" dollars spent .. or wasted trying to make that mediocre barrel shoot .

Some BCA barrels can shoot... others can't.

Step back and buy a better barrel. Your money will be better spent, on a proven , from a respected barrel manufacturer.

You have enough proof that your BCA barrel isn't shooting to your expectations. Any lapping or such... might also be wasted time and ammo.

IMHO, A better barrel is a huge bargain now-a-days.... especially considering current ammo costs.

Again , not trying to be rude at all.

No offense taken. I am well aware of hidden costs of "intensive" load development, money and time-wise. If I had built this from the ground up, I would have bought a nicer barrel, but like I said, the upper assembly was a gift, so I gave it a shot. I still have a few loads already made up, so I'll probably try them before I give up. I truly do enjoy a challenge, and have a hard time admitting defeat. I will try the few (possible) fixes mentioned earlier before I throw in the towel, but at some point, this thing is gonna shoot or it's getting replaced.

 

[svxwilson]

If you pull the barrel and lap and square the receiver face you should also thermofit the barrel to the receiver.

Things you will need to thermofit are .001 or .002 shim stock, sharp scissors, rubber band and a heat gun or torch. Heat the receiver extension area and then quicky slide the barrel into the receiver with the shim and rubber band wrapped around the barrel extension. Either quickly cut the band or burn it off and give the receiver a smack with a rubber mallet to get it to go all the way together. Then boom rock solid barrel and receiver connection, sword in the stone .

Those 2 steps are the best way to get the most you can get from a barrel/receiver combo. They are the steps several high end AR manufacturers use to get the most accuracy out of a setup.

 

[Triple D]

Toss that BCA and just buy a Rainier Ultramatch. They flat out hammer with the 80 eld’s and H4895.

 

[NCHillbilly]

Believe it or not, it's that combo that is shooting very well out of my current set-up. The only sub-moa groups I've shot were 22.6 and 22.9 grs of H4895 with 80gr eldm's, hornady cases, cci 450's at 2.285, running 2665fps.

I would like to find an 88gr load that shoots as well, I also got some 90gr smk's to try as well.

 

[bobke]

No Valkyrie experience to offer, but Brownells has JP barrels of one configuration on sale now at very reasonable price. Concur with a better barrel, as others have noted.

 

[bigjake83]

The only time I've had a POI shift with barrel nut torque was before I trued the receiver face of one of my uppers. When I slip fit the barrel in the upper, you could see just a faint sliver of light on one side of the extension/receiver interface. Minimal torque (about 25ft lb) produced one POI, torque on the high end of acceptable (40 ft lb) produced another POI about 3" away. I trued the receiver to where there was even contact between the extension/ receiver and re-torqued. Only a 1" POI difference between torque levels.

To the OP I'm not gonna bother with reading The whole thread but @clcustom1911 is correct Even though his torque values are a bit on the light side. The only time you're going to see accuracy degradation in relationship to barrel torque is if the receiver face is not square, It also depends on the type of receiver too. As long as it's a traditional receiver you should aim for 35-55 ft lbs, I find the sweet spot to be around 50. As others have stated it's probably the barrel, But it never hurts the check in case somebody did gorilla fuck the barrel nut. Also and actually just as important as everything mentioned here check your gas tube alignment, If your gas tube is binding/pushing up in the gas key of the BCG you no longer have a free floating barrel.

 

[clcustom1911]

Thanks. I knew my torque values were off. I was feeling lazy and didn't want to look up the book values. Thanks for the correction.

To the OP I'm not gonna bother with reading The whole thread but @clcustom1911 is correct Even though his torque values are a bit on the light side. The only time you're going to see accuracy degradation in relationship to barrel torque is if the receiver face is not square, It also depends on the type of receiver too. As long as it's a traditional receiver you should aim for 35-55 ft lbs, I find the sweet spot to be around 50. As others have stated it's probably the barrel, But it never hurts the check in case somebody did gorilla fuck the barrel nut. Also and actually just as important as everything mentioned here check your gas tube alignment, If your gas tube is binding/pushing up in the gas key of the BCG you no longer have a free floating barrel.

As an aside: standard Shellback here. When I was a FMF Corpsman on the 13th MEU back in 2005 we were only a couple hundred miles away from being Golden Shellbacks from what some of the crew told us. So close!

 

[UpSideDown]

Are you shooting your rifle like an AR or like a bolt gun? Precision shooting with AR's is kind of the opposite. Hang onto that bitch. It needs to not move before the round leaves the barrel, and the bolt coming back is going to make it want to move.

Also you're starting with a real sketchy barrel and asking for sub-MOA out of an AR, that's a dead giveaway.

 

[bigjake83]

Thanks. I knew my torque values were off. I was feeling lazy and didn't want to look up the book values. Thanks for the correction.

If you ever have any questions brother feel free to ask.




As an aside: standard Shellback here. When I was a FMF Corpsman on the 13th MEU back in 2005 we were only a couple hundred miles away from being Golden Shellbacks from what some of the crew told us. So close!

 

[NCHillbilly]

Are you shooting your rifle like an AR or like a bolt gun? Precision shooting with AR's is kind of the opposite. Hang onto that bitch. It needs to not move before the round leaves the barrel, and the bolt coming back is going to make it want to move.

Also you're starting with a real sketchy barrel and asking for sub-MOA out of an AR, that's a dead giveaway.

I have achieved sub-moa with an 80 gr load, I'm trying to get that with an 88-90 gr load now. This caliber is more finicky than anything I've ever messed with, but I have a glimmer of optimism because it has shot one load well.

 

[NCHillbilly]

Are you shooting your rifle like an AR or like a bolt gun? Precision shooting with AR's is kind of the opposite. Hang onto that bitch. It needs to not move before the round leaves the barrel, and the bolt coming back is going to make it want to move.

Also you're starting with a real sketchy barrel and asking for sub-MOA out of an AR, that's a dead giveaway.

It's definitely not like my 308. That thing shoots everything well.

 

[CrabsandFootball]

When you use cheap parts you are playing the lottery with poor odds. You just found out.

 

[NCHillbilly]

When you use cheap parts you are playing the lottery with poor odds. You just found out.

I get that, but if you were given an assembled upper, would you have immediately dis-assembled it, or tried it out? Hell, anybody can make a $1200.00 upper shoot. I take it as a challenge to see if I can make this one work.

 

[NCHillbilly]

When you use cheap parts you are playing the lottery with poor odds. You just found out.

See post #20

 

[CrabsandFootball]

I get that, but if you were given an assembled upper, would you have immediately dis-assembled it, or tried it out? Hell, anybody can make a $1200.00 upper shoot. I take it as a challenge to see if I can make this one work.

If it was junk parts i would have sold it or thrown it in trash.

Waste of time and money to dick around with shitty gear. The outcome is predictable.