Proof barrel Issue

[Barehandlineman11]

I bed every action the same and still get them now and again where i redo it. But i have a setup i built and set dial indicators on it. If it moves at all i re do it. And my bed jobs dont look flawless but i dont care as long as theres no stress

 

[FullCurl8]

My Smith installed the the barrel on the first rifle, verified the accuracy with the 5 round groups (before the hornady you groups are too small podcast) and then removed it. There are some extenuating circumstance that ended up with me getting the barrel but they had nothing to do with it not shooting. Otherwise I totally agree, if it seems too good to be true it probably is. I have tested it (although not as extensively) with gmm and it behaved similarily. I will do a cold bore test with the GMM. I will also verify all the action screws and everything else is torqued. If I get teh same results I will fully cede that it is the barrel.

Yes he machined the outer diameter of the shank down to fit the tikka action. I think he had to take down a bit of the carbon as well to smooth out the transition.

Regarding barrel torque? And I'm suggesting over tourqued for a Carbon barrel that's been turned down. It's common to over torque barrels now, when they really need 1/2 as much. You're getting all the right suggestions and ideas here, but since those don't appear to be the answer, I am going with the barrel. Machining the OD on a Carbon barrel is something I would not have done. And Hornady suggestion on group sizing sounds like a great way to sell bullets lol

 

[Shane Lindsey]

And Hornady suggestion on group sizing sounds like a great way to sell bullets lol

Yupp. On a hunting rifle, I don't care what the tenth shot of a 100 shot string does. Where is number one and may, hopefully not number two...


When was the last time this barrel was cleaned back to bare steel? How fast are you shooting this CF barrel, mirage coming off the barrel makes mine open waaaay up after about five shots within 5 minutes. Any load development has had to be very slow to get good, true hunting type conditions.

I have a 20" carbon fiber 308 Win and it doesn't like to shoot fast. Maybe the loads are a bit fast, if you reload, try lower velocity and see if it will group when you switch to the chassis. Also, try a lighter bullet. I love short barrels, but not convinced the 308 harmonics likes the short carbon, with the bigger pills, but I don't know nothing.


Edit...also on the if it shot, why did they give it away wagon....

 

[gerpwaller]

Here's an update on the TA accuracy. We tested 20 rounds each through our target rifle which are known to be very accurate with multiple factory loads. Half moa five round groups are common 1 moa 20 round groups. The TA shot 2" for 20 rounds with about 75% of rounds clustered into 1-1.25". Next up will be the cold bore groupings with the gmm.

 

[gerpwaller]

Yupp. On a hunting rifle, I don't care what the tenth shot of a 100 shot string does. Where is number one and may, hopefully not number two...


When was the last time this barrel was cleaned back to bare steel? How fast are you shooting this CF barrel, mirage coming off the barrel makes mine open waaaay up after about five shots within 5 minutes. Any load development has had to be very slow to get good, true hunting type conditions.

I have a 20" carbon fiber 308 Win and it doesn't like to shoot fast. Maybe the loads are a bit fast, if you reload, try lower velocity and see if it will group when you switch to the chassis. Also, try a lighter bullet. I love short barrels, but not convinced the 308 harmonics likes the short carbon, with the bigger pills, but I don't know nothing.


Edit...also on the if it shot, why did they give it away wagon....

These are factory loads, the TA measures 2600 fps over a lab radar and the gmm around 2650. I'm doing cold bore testing at the moment as that's where the accuracy issues seem to be so I'm only shooting 2 shots per day. From the few times I've shot the gun enough to get it warm/hot it seems to do much better with heat in the barrel (shrinks the groups in half). That's the part I'm struggling to understand. I will check it for stress as has been suggested and then also check it in the strike nuke chassis to verify that it is not a bedding issue. Thanks to everyone for their suggestions. I will clean the barrel before starting the gmm groups. It has roughly 60 rounds through it since it was last cleaned so it shouldn't be too bad yet.

 

[cm1021]

You have something that is a tolerance issue somewhere. Otherwise it wouldn't show when it heats up. When you're heating the barrel you're getting thermal expansion, so therefore everything is growing. I don't believe that it's just a barrel that won't shoot or necessarily the wrong ammo.

Just spitballing here, but I'm wondering if maybe the barrel tenon was cut a little loose, as you're firing and warming it up, it's expanding and tightening up the barrel to action fit. Just trying to think outside the box.

I am fairly confident it's something that has more play than need be, and as you shoot and warm up the barrel it's expanding and tightening up. With a free barrel you don't really have anything to lose and worse case you're back where you started, no barrel.

I have a proof 7SAUM that is shooting lights out, so I'm hesitant to say that it's the barrel. I'm really leaning towards something was machined a little more than needed to be.

 

[Small Lady]

My Smith installed the the barrel on the first rifle, verified the accuracy with the 5 round groups (before the hornady you groups are too small podcast) and then removed it. There are some extenuating circumstance that ended up with me getting the barrel but they had nothing to do with it not shooting. Otherwise I totally agree, if it seems too good to be true it probably is. I have tested it (although not as extensively) with gmm and it behaved similarily. I will do a cold bore test with the GMM. I will also verify all the action screws and everything else is torqued. If I get teh same results I will fully cede that it is the barrel.

Yes he machined the outer diameter of the shank down to fit the tikka action. I think he had to take down a bit of the carbon as well to smooth out the transition.

I openly admit to being a newbie, but this doesn't sound like a good idea to me.
A barrel maker who makes a barrel a certain thickness, must have had a reason to do so. Not so that it was extra thick to later be turned down on a lathe.
Again yes I'm new, but a barrel that would have fit seems like a better idea.

 

[cm1021]

I openly admit to being a newbie, but this doesn't sound like a good idea to me.
A barrel maker who makes a barrel a certain thickness, must have had a reason to do so. Not so that it was extra thick to later be turned down on a lathe.
Again yes I'm new, but a barrel that would have fit seems like a better idea.

I think you have probably hit the nail on the head. I have been thinking about this all morning for some reason lol.

I'd be curious to know how much was taken off to make it fit the new action. I'm betting the chamber diameter and tenon diameter difference might be a little thin. This is why he's getting more thermal expansion and allowing the barrel to tighten up to the action.

All in all it was a free barrel, so he's not out anything unless he paid the smith to fit it to his action. If that's the case and the smith didn't say this might not work, I'd be requesting a refund.

 

[ShtrRdy]

I think you have probably hit the nail on the head. I have been thinking about this all morning for some reason lol.

I'd be curious to know how much was taken off to make it fit the new action. I'm betting the chamber diameter and tenon diameter difference might be a little thin. This is why he's getting more thermal expansion and allowing the barrel to tighten up to the action.

All in all it was a free barrel, so he's not out anything unless he paid the smith to fit it to his action. If that's the case and the smith didn't say this might not work, I'd be requesting a refund.

I know what he is saying about reducing the barrel diameter to fit a Tikka. Last year I had a Tikka Varmint barrel replaced and learned that the front of a Tikka receiver has a little radius machined in. To match up to that radius the barrel diameter at the breach end has to be about 1.150" diameter. Most barrel blanks in the US are 1.200" or 1.250". So, to make it look like the barrel matches the receiver you have to reduce the diameter on a new barrel by up to 0.1". That would be 0.050" on each side.

A different approach some people use is to cut off the radius on the front of a Tikka receiver. This would shorten the threaded section holding the barrel on and possibly introduce some misalignment between the barrel and bolt bore.

 

[gerpwaller]

Regarding barrel torque? And I'm suggesting over tourqued for a Carbon barrel that's been turned down. It's common to over torque barrels now, when they really need 1/2 as much. You're getting all the right suggestions and ideas here, but since those don't appear to be the answer, I am going with the barrel. Machining the OD on a Carbon barrel is something I would not have done. And Hornady suggestion on group sizing sounds like a great way to sell bulle

I think you have probably hit the nail on the head. I have been thinking about this all morning for some reason lol.

I'd be curious to know how much was taken off to make it fit the new action. I'm betting the chamber diameter and tenon diameter difference might be a little thin. This is why he's getting more thermal expansion and allowing the barrel to tighten up to the action.

All in all it was a free barrel, so he's not out anything unless he paid the smith to fit it to his action. If that's the case and the smith didn't say this might not work, I'd be requesting a refund.

The barrel was free and the work was free so from that standpoint I can't complain too much. My Smith readily admitted it may work and it may not.

While I understand your concerns about removing too much material I'll pose the question from another angle. Proof makes barrels for various actions some of which have a larger diameter than others. Tikka being one of those actions and is likely one of slimmest profile for center fire rifles. Are we thinking proof has a completely different metal core diameter for tikka than they would for other actions or would the tennon on an R700 action or custom action just be made larger to fit that action and more carbon wrapped to make it match? By turning down a thicker barrel would I just end up with what a factory tikka barrel would've been in the first place? In my thinking production costs of producing carbon wrapped barrels would be cheaper and production would be more streamlined if they always used the same sized core and then just turned down the tenon to match or used a slightly smaller blank. The actually rifles portion of the barrel would essentially be the same regardless of action. It would be great to hear someone from Proof chime in on this.

 

[nksmfamjp]

My gunsmith (the same one who installed it on the pgw in the first place) then turned the barrel down so that it fit my action

Can you ask your gunsmith exactly what this means? I doubt it means he cut the cf. Did he turn a shouldered barrel into a nut barrel? Is it fit from a larger tenon action to a smaller one? Is the shoulder just turned from 1.25" to 1.2" to fit the stock? Did he just adjust the shoulder position to correct headspace?

BTW, this is something most gunsmiths I've asked won't do because results are unpredictable. I'm guessing he did it because he did the original work.


Found this elsewhere:

https://www.practicalmachinist.com/...l-extensions-rod-henrickson-remington-700.jpg

Here is a close up view of a Tikka T3/T3X shank (above, top) and factory Remington 700 shank (above, bottom). Note the T3/T3x has a longer shank and thinner major diameter (nominally 1″ v. 1.062″). Both barrels have a thread pitch of 16 threads per inch.

Building a custom Tikka T3/T3X precision rifle

Building a custom Tikka T3/T3X precision rifle The Tikka T3 and T3X have developed a strong following in the US rifle market. Known for its short throw two-lug bolt and crisp trigger, the Tikka of…

rifleshooter.com

The key point in the second link is Tikkas need a smaller shoulder than Rem 700, so I would guess all 1.25" barrels are turned down when fitting to a Tikka.
This is not abnormal. My M70 stock barrel shoulder was 1.13 or 1.15".

 

[grouse]

I've noticed while figuring new loads with my cf that after shooting a few times it also grouped better.....but recently I dropped powder charge and it started shooting really good...has about 600+ thru it...sendero cut down from 26" to 22"...got rid of that front heavy feeling...
This is my last group....
View attachment 500985
..at 400yds...had to be the gun...I surely cannot shoot that well....65284Lapua(had to rename my rifles due to 3 65284s...

@26Reload Was this a proof that you cut?

 

[FullCurl8]

The barrel was free and the work was free so from that standpoint I can't complain too much. My Smith readily admitted it may work and it may not.

While I understand your concerns about removing too much material I'll pose the question from another angle. Proof makes barrels for various actions some of which have a larger diameter than others. Tikka being one of those actions and is likely one of slimmest profile for center fire rifles. Are we thinking proof has a completely different metal core diameter for tikka than they would for other actions or would the tennon on an R700 action or custom action just be made larger to fit that action and more carbon wrapped to make it match? By turning down a thicker barrel would I just end up with what a factory tikka barrel would've been in the first place? In my thinking production costs of producing carbon wrapped barrels would be cheaper and production would be more streamlined if they always used the same sized core and then just turned down the tenon to match or used a slightly smaller blank. The actually rifles portion of the barrel would essentially be the same regardless of action. It would be great to hear someone from Proof chime in on this.

I believe, but a call to Proof would verify, that the metal barrel cores may be the same diameter for that Caliber, but action size and tenon length which the customer orders i suspect is finalized in one pass. Once a CNC process has started production, it's rarely advantageous to place it back in a machine, as time is money. But the wrapping and curing process and continual CF fibers I assume are very important in the rigidity of the barrel. Machining it exposed and broke those fibers.
Your gunsmith had his doubts as well, so no harm no foul, it's a good experiment!

 

[nksmfamjp]

Machining it exposed and broke those fibers.

Are we sure? I believe proof barrels are under 1" where the cf starts, but not positive. How else do you fit to a Savage nut?