6mm creed or 6.5 creed?

[Creedmoor shooter]

Hey guys, I've been running a criterion 6.5 creed barrel for awhile now. Roughly 1200 rounds down the pipe. I had it threaded at about 1050-1100 rounds and it hasnt been the same. I thought I had it figured out but I just cant get this thing to shoot to save my life. It went from sub .5 moa groups to over moa just about over night. I'm thinking he got the barrel too hot when he threaded it. I'm hoping to take it back to him tonight and see what he thinks. If a new barrel is in order I'm thinking about jumping over to 6mm creed. I just used up the last of my 6.5 bullets so I'm starting from scratch anyway. Im sure we could chop some of the barrel off but I dont know what that is going to cost and since I'm halfway through the barrel life as it is I'm not sure it's worth it. This rifles main purpose is targets and occasionally whitetail hunting. I shot to 1450 yards with my 6.5 barrel so I'd like to be able to shoot atleast that far. I'm also hoping to get into prs next summer time and money permitting. What do you 6mm guys usually see for barrel life? Pros and cons of each? Tell me what you guys think. Is it worth jumping over to 6mm?

 

[BrianID]

I have both. I think either will work fine for what you are trying to do. 6mm will shoot slightly faster/flatter and may have slightly less recoil. Powder, brass and bullets are going to be about the same price. You are going to spend extra money for new dies if you switch to 6mm. 6.5mm will have the option of slightly heavier bullets. 6mm will have more options for varmint bullets.
Is it possible that the stock and barrel alignment changed after it was threaded? If the barrel was not damaged when it was worked on, it is possible it is something else. Just a loose screw on one of my stocks caused the groups to open way up. After tightening the screw it went back 1/2 MOA.

 

[Creedmoor shooter]

I have both. I think either will work fine for what you are trying to do. 6mm will shoot slightly faster/flatter and may have slightly less recoil. Powder, brass and bullets are going to be about the same price. You are going to spend extra money for new dies if you switch to 6mm. 6.5mm will have the option of slightly heavier bullets. 6mm will have more options for varmint bullets.
Is it possible that the stock and barrel alignment changed after it was threaded? If the barrel was not damaged when it was worked on, it is possible it is something else. Just a loose screw on one of my stocks caused the groups to open way up. After tightening the screw it went back 1/2 MOA.

I have bushing dies so all I'd have to do is change the bushing on my resize die then by a seater die or change the seating steam on my 6.5 seater die. My action screws are torqued to 60in lbs and I double checked them.

 

[Frog4aday]

You had it threaded...for what? A suppressor? Are you running a suppressor on it now? Did you have it threaded and then...there is nothing on it? Is it wearing a thread protector? A muzzle-brake? I'm asking because it all matters.

If you had it threaded and you are just shooting it that way (threads on end of barrel, nothing on them) you've taken away weight and changed the harmonics of the barrel. If you have a thread protector on there, if it is not TIGHT, it can cause groups to open up because (again) the harmonics are varying with every shot. If you have a suppressor on there, the barrel is definitely reacting differently due to the extra weight and it might just be a matter of finding the 'new', right load. Or, perhaps, the bullets are nicking a baffle due to slight misalignment; just enough to throw things off. And muzzle-brakes are the same. Alignment, direction of ports, tightness of the brake on the muzzle...variables that can all effect how the barrel reacts to a bullet going through it.

If you just want to go back to where you where, lop off the threaded portion, recrown your barrel and move on with life. You can even buy the tools from Brownells and do it yourself if you are so inclined.

Final thought is that during the threading process, your crown got compromised in some way. That might be the simplest, most logical explanation. Perhaps the crown just needs to be 'touched up' to get things back on track.

 

[Creedmoor shooter]

You had it threaded...for what? A suppressor? Are you running a suppressor on it now? Did you have it threaded and then...there is nothing on it? Is it wearing a thread protector? A muzzle-brake? I'm asking because it all matters.

If you had it threaded and you are just shooting it that way (threads on end of barrel, nothing on them) you've taken away weight and changed the harmonics of the barrel. If you have a thread protector on there, if it is not TIGHT, it can cause groups to open up because (again) the harmonics are varying with every shot. If you have a suppressor on there, the barrel is definitely reacting differently due to the extra weight and it might just be a matter of finding the 'new', right load. Or, perhaps, the bullets are nicking a baffle due to slight misalignment; just enough to throw things off. And muzzle-brakes are the same. Alignment, direction of ports, tightness of the brake on the muzzle...variables that can all effect how the barrel reacts to a bullet going through it.

If you just want to go back to where you where, lop off the threaded portion, recrown your barrel and move on with life. You can even buy the tools from Brownells and do it yourself if you are so inclined.

Final thought is that during the threading process, your crown got compromised in some way. That might be the simplest, most logical explanation. Perhaps the crown just needs to be 'touched up' to get things back on track.

Sorry should have clarified that. It is wearing a muzzle brake. I've shot it with the brake on and off no difference. I've tried brand new load work ups, different bullets, powder, you name it I've done it. The crown looks ok to the naked eye.

 

[Frog4aday]

Last guy having 'mysterious' accuracy issues turned out to have a loose muzzle brake, but if you've had it on and off, that's not it. Interesting that it is not shooting well w/the brake on or off. Makes me think the crown. And the naked eye seems like it should see a problem, but it doesn't always work that way. My smith told me my crown was a mess and I thought it looked fine. He recrowned it and...the gun shot great. So I don't know what he saw or how he saw it, but apparently my visual assessment was worth the money I paid for it

I'm wondering if the gunsmith sticks a bar/guide down the barrel to ensure alignment with the bore as he gets his machines setup and indexed to cut the threads and in the process of doing all that - and cutting the threads - something got dinged or skewed along the way with your crown. There really isn't a good reason for your gun to go from shooting great to shooting badly unless the crown got compromised in the process.

Now if you said it shoots great without the brake and woefully with it on, then we'd be looking at the brake itself (alignment, size of hole in it, the indexing of it...stuff like that.) Hopefully you can convince your smith to touch up the crown for you and see if that cures the problem. If not...I'd be looking at cutting the threaded bit off, recrowning it and forgoing the muzzlebrake for that gun. At 1200 rounds through that 6.5CM, you should still have some life left in that barrel (see this URL for some idea on usable barrel life in the 6.5 CM: https://www.65creedmoor.com/index.php?topic=299.msg1753#msg1753)

It could just be that you need to firelap the barrel to clean up some erosion/roughness at the leade and it was just coincidental that problems cropped up around the time you fit a muzzlebrake? Weird things happen.

 

[Frog4aday]

I'm guessing the action was out of the stock for the threading? Could this be as simple as action screw torque needing to be sorted out again. You don't say what gun this is (Savage 110? Rem 700? Tikka?) but they all have their 'sweet' spot for action screw torque settings and the Savage 110 (apparently) likes a 'floated' tang. Just learned that on another recent thread. Do you torque your action screws to a specific amount or just do it by hand feel? Something to think about.

 

[Creedmoor shooter]

I'm guessing the action was out of the stock for the threading? Could this be as simple as action screw torque needing to be sorted out again. You don't say what gun this is (Savage 110? Rem 700? Tikka?) but they all have their 'sweet' spot for action screw torque settings and the Savage 110 (apparently) likes a 'floated' tang. Just learned that on another recent thread. Do you torque your action screws to a specific amount or just do it by hand feel? Something to think about.

I torqued it to the exact same as before. 60inlbs. It's a savage model 12. I dropped the rifle off last night and he's going to go through everything. He said there is absolutely no way his threading caused any issues. He runs at 60revs a min and only takes off a couple thousandths at a time so it's no way he got it too hot. He thinks I didnt get my headspace right when I re installed my barrel so he's going to look into that and also check out the crown alittle better. Said he was going to get to it today because it was bothering him now so he wants to get to the bottom of it as well.

 

[Frog4aday]

If it still shoots poorly, try 40 in/lbs on the front screw and 20 in/lbs on the rear and make sure the tang (very rear portion of receiver) isn't contacting the stock. Hoping you get it back and the smith fixed whatever the issue was. It is so frustrating when a gun is shooting well and then something is done to the rifle that SHOULDN'T hurt anything...but does. Keep us posted. Fingers are crossed for you.

 

[Creedmoor shooter]

The barrel is a winner. It shoots VERY well so I just hate to have to get rid of a barrel pre mature that shoots so well. These are groups of how it used to shoot, and how it shoots now

 

[Frog4aday]

Hmmm...vertical stringing. I'm really suspicious of the tang contact now, more than ever. Also, rear screw needs less torque than the front. BUT...however you had it set-up before seemed to be fine, so what really changed? I wish I had the answer for you. I'm still thinking the crown needs 'touched up' and all will be right with the world again. I don't think it was an 'over-heating' issue cutting the threads. I do think that tools going in and out and around the muzzle play a role. Just one little 'doink' up there and things get weird.

 

[Creedmoor shooter]

Hmmm...vertical stringing. I'm really suspicious of the tang contact now, more than ever. Also, rear screw needs less torque than the front. BUT...however you had it set-up before seemed to be fine, so what really changed? I wish I had the answer for you. I'm still thinking the crown needs 'touched up' and all will be right with the world again. I don't think it was an 'over-heating' issue cutting the threads. I do think that tools going in and out and around the muzzle play a role. Just one little 'doink' up there and things get weird.

It can be horizontal too. Just depends on the day

 

[Frog4aday]

Nothing like randomness to make a problem more fun to troubleshoot, ha! Vertical, horizontal, and none of it good compared to where you were before threading the barrel. Let's hope your gunsmith is able to sort out what's new (and wrong) and can get you fixed up. Should be lot's of life left in that barrel if you can just get things back to the way they were.

 

[fmuguira]

+1 on Crown. Possibly nicked during machining.