Building a fast barrel possible?

[ELR Harry]

I have read a lot about fast for caliber barrels but have never had one until now. I have a cut rifled 4 groove that is almost 90 fps faster than a friend's button barrel in same caliber, profile, length, same cartridge, powder charge and bullet. Both barrels chamber was cut with same reamer on same lathe by us. I have set mine back once and will again in another 600 or so rounds..unless it opens up before then. When it gets too short(<26") or stays open after next set back I will retire it. Would it be possible for a top tier barrel maker to section this barrel after its too short to make velocity and figure out why it is so much faster? Thanks in advance for your feedback!

 

[ELR LVR]

I have read a lot about fast for caliber barrels but have never had one until now. I have a cut rifled 4 groove that is almost 90 fps faster than a friend's button barrel in same caliber, profile, length, same cartridge, powder charge and bullet. Both barrels chamber was cut with same reamer on same lathe by us. I have set mine back once and will again in another 600 or so rounds..unless it opens up before then. When it gets too short(<26") or stays open after next set back I will retire it. Would it be possible for a top tier barrel maker to section this barrel after its too short to make velocity and figure out why it is so much faster? Thanks in advance for your feedback!

What a killer idea!
The only thing I can think of to help with this is
Tight bore, building more pressure
Say .0001" tight
-------------------------------------------------------------
I did have one cut barrel that for some odd unknown and strange reason
Sped up exponentially after 200 rounds
needed 12 moa for 600 at first which was on the money for its velocity.
and suddenly after 200 rounds it was shooting 6 feet high with the same load and bullets
needing only 6 moa for 600 all of a sudden
and of course it was spitting bullets erratically at 600 yds
-------------------------------------------------------------
I figured the only thing that could cause it was a tight bore
so I lapped it for 2 hours with diamond compound figuring if I get it .0001" larger in the bore that would help
My theory proved correct and it acted fine after I did so
-------------------------------------------------------------
I did test along the way during the lapping process until it finally acted as it should
Shoot, still erratic, Lapped some more, shoot, erratic, lapped some more
I did not want to lap too much and cause a loose bore
once the drop coincided with what it should be for the velocity at 600 yds
Its been fine and very accurate ever since
In a way I guess you could say I "Tuned" the bore for everything to be correct as far as Velocity is concerned.
-------------------------------------------------------------
I could have sent the barrel back and Im sure they would have taken care of me
but, with waiting time, not knowing when I can get it back running again
and the fact I REALLLY wanted to experiment with my theory
Caused me to accept I may be screwing the barrel up in my experiment
I was very happy with the outcome and gained some very valuable experience in lapping my barrels with that one.
-------------------------------------------------------------
So I can in my case anyways
---- conclude the bore was slightly tight
Maybe they didnt make their final pass or cut one groove with one less pass?
The dude decided it was 5:00 oclock and time to go home will finish the last pass tomorrow
and never did
I dunnno how these things happen
--------------------------------------------------------------
But I've seen that kind of thing happen in my shop before,
Quittin time, I'll let Joe finish it for me
And Joe never gets the memo

 

[ELR Harry]

What a killer idea!
The only thing I can think of to help with this is
Tight bore, building more pressure
Say .0001" tight
-------------------------------------------------------------
I did have one cut barrel that for some odd unknown and strange reason
Sped up exponentially after 200 rounds
needed 12 moa for 600 at first which was on the money for its velocity.
and suddenly after 200 rounds it was shooting 6 feet high with the same load and bullets
needing only 6 moa for 600 all of a sudden
and of course it was spitting bullets erratically at 600 yds
-------------------------------------------------------------
I figured the only thing that could cause it was a tight bore
so I lapped it for 2 hours with diamond compound figuring if I get it .0001" larger in the bore that would help
My theory proved correct and it acted fine after I did so
-------------------------------------------------------------
I did test along the way during the lapping process until it finally acted as it should
Shoot, still erratic, Lapped some more, shoot, erratic, lapped some more
I did not want to lap too much and cause a loose bore
once the drop coincided with what it should be for the velocity at 600 yds
Its been fine and very accurate ever since
In a way I guess you could say I "Tuned" the bore for everything to be correct as far as Velocity is concerned.
-------------------------------------------------------------
I could have sent the barrel back and Im sure they would have taken care of me
but, with waiting time, not knowing when I can get it back running again
and the fact I REALLLY wanted to experiment with my theory
Caused me to accept I may be screwing the barrel up in my experiment
I was very happy with the outcome and gained some very valuable experience in lapping my barrels with that one.
-------------------------------------------------------------
So I can in my case anyways
---- conclude the bore was slightly tight
Maybe they didnt make their final pass or cut one groove with one less pass?
The dude decided it was 5:00 oclock and time to go home will finish the last pass tomorrow
and never did
I dunnno how these things happen
--------------------------------------------------------------
But I've seen that kind of thing happen in my shop before,
Quittin time, I'll let Joe finish it for me
And Joe never gets the memo

Thanks, was thinking bore ID could be the reason but only accurate way to measure that i think would be air gauge, which we do not have. Forgot to mention case capacity...I neck size and bump with Forster BB Die, but my friend FL sizes with a SAAMI spec FL die so his case volume is a little less...less case volume should increase pressure, right? We both seat the bergers .002 in from stick point.

 

[ELR LVR]

I might also add here
One of my friends has a 6.5 Creed that

Thanks, was thinking bore ID could be the reason but only accurate way to measure that i think would be air gauge, which we do not have. Forgot to mention case capacity...I neck size and bump with Forster BB Die, but my friend FL sizes with a SAAMI spec FL die so his case volume is a little less...less case volume should increase pressure, right? We both seat the bergers .002 in from stick point.

Yes, less case volume increases pressure.
And I dont know much about air gauges
I have watched vids on them
I was thinking of getting one myself
But from my understanding so far is
They more or less measure DIFFERENCES in the bore ID as you move them through
such as reading a tight or loose spot since more or less air will escape past the exit hole in the gauge.
Someone can correct or further shed light on this if they wish since as I said
I have never used an air gauge myself
so dont know if they actually measure ID to the gnats ass
an air reading may correlate to an ID I would think though
once you got everything calibrated and compared to a known.
----------------------------------------------------------------------------------------
You could force a bullet through,
shoot a bullet through with a light load etc
I have used like 3.5 grns Titegroup for this
I think 3.2 grns sticks a bullet in the bore halfway
So doing something like that, then pounding it out the rest of the way....
then recover bullet
and measure that way
-----------------------------
As a side note, My buddy has a Tikka Tac A1
6.5 Creed
I was going to recommend to him to have me rechamber it as a 260 Rem for more speed right
Come to find out
He is launching 140's at like 2850
which is 260 velocity anyway
So he def has a fast barrel.
------------------------------
I would suppose barrel internal finish also plays a part here.
(Rough hammer buttoned vs. Cut and lapped)
So simply measuring bore ID may not be all the pieces of the puzzle

 

[Jonnyofalltrades]

I would bet that if you slug both barrels, yours would be tighter.
Anything that is manufactured has tolerances. Not terribly long ago, many manufacturers used a tolerance of +-.001" on bore diameter(Sorry, can't remember the book that's referenced from right now. I'll update if I can.).
I know that modern tolerances are tighter than that. Each maker probably has their own standards.

Tighter equals higher pressure.
Higher pressure equals higher velocity, all else being equal.

 

[Tangent]

-----------------------------
As a side note, My buddy has a Tikka Tac A1
6.5 Creed
I was going to recommend to him to have me rechamber it as a 260 Rem for more speed right
Come to find out
He is launching 140's at like 2850
which is 260 velocity anyway
So he def has a fast barrel.
------------------------------
I would suppose barrel internal finish also plays a part here.
(Rough hammer buttoned vs. Cut and lapped)
So simply measuring bore ID may not be all the pieces of the puzzle

How many rounds does your buddies Tac A1 have on it? I have noticed my 260 Rem suddenly needs less elevation for the same load. I am at just under 200 rounds and not chronographed it for a couple of sessions. Wondering if it has sped up?

 

[L.Sherm]

Not all barrels like the same powder even in the same cartridge, same reamer etc.
theres alot of variables that can contribute to FPS in a barrel from one manufacturer to the next i would be more concerned about accuracy.

 

[ELR LVR]

How many rounds does your buddies Tac A1 have on it? I have noticed my 260 Rem suddenly needs less elevation for the same load. I am at just under 200 rounds and not chronographed it for a couple of sessions. Wondering if it has sped up?

He doesnt have many rounds through it,
I'd say approx 200 rounds (300 Max)
He recently bought it to shoot long range
and hasn't shot it much except for with me learning long range
-----------
I was impressed with his choice of rifle when he asked for recommendations of what to get for a factory rifle to start out with. ( I didnt even mention that one)
The Tikka Tac A1 is a very nice package so to me he showed he did some research to go above and beyond with his rifle choice.
Unfortunately he hasn't gotten into reloading yet, but he is seeing the need to in order to get the most out of his rifles accuracy.
(however nice all its features are, it does not come close to competing with a custom barreled rifle I can say that) Which he is also learning now.
I keep telling people if youre going to spend above a grand
---"Get a rifle BUILT"
The cost can be very close to a high dollar factory rifle such as the Tac A1 or a Ruger Precision but accuracy will be better with a custom
------------
A very nice budget build might only cost $2k - Minus choice of Scope

 

[Tangent]

I can't argue with custom. Unfortunately over here you'll be paying £5k+ for a custom rifle. You have much better options in the US, I'm not jealous though

 

[Steve Donlon]

I have a new barrel , 6.5, that did the same thing, same reamer from the same smith. First one was a button rifled and the new one is a Bartlein. Same heavy varmint profile. I'm down almost 2 moa @ 1000 yards and more accurate. I was told that this happens with button rifled barrels with faster twist rates. It might just be better barrel now. It also takes hotter loads without showing pressure. That's one reason why I have less moa at 1000 yards and every where else. But with the same loads, it's still faster.

 

[ELR Harry]

I have a new barrel , 6.5, that did the same thing, same reamer from the same smith. First one was a button rifled and the new one is a Bartlein. Same heavy varmint profile. I'm down almost 2 moa @ 1000 yards and more accurate. I was told that this happens with button rifled barrels with faster twist rates. It might just be better barrel now. It also takes hotter loads without showing pressure. That's one reason why I have less moa at 1000 yards and every where else. But with the same loads, it's still faster.

Guys, our barrels are chambered in .264 Demille modified... or as many would say 65 needmore, lol. The reamer is significantly different in multiple dimensions than SAAMI but I am sworn to secrecy about the details. The accuracy node for this barrel is 41.9 gns of H4350 @ 2830 fps. and NO pressure...I have gone up to 42.2 @ 2850 but it wouldn't group. My previous barrel was 1" shorter but the same HV profile and would barely hit 2700 but that was back when 4350 was like hens teeth and I had to run 4831sc to get acceptable accuracy...staball and other ball powder would give more velocity but would not group and this barrel is on my 1000 yd light gun. 742 rounds on it so far. I would be happy to donate the barrel to science when it's done if anyone is interested.

 

[Alex Wheeler]

Its known what makes a fast barrel. Barrel makers have to work within saami spec and try to stay on the tight side of that. Contrary to what you may think, tighter barrels are not faster.

 

[Steve Donlon]

Guys, our barrels are chambered in .264 Demille modified... or as many would say 65 needmore, lol. The reamer is significantly different in multiple dimensions than SAAMI but I am sworn to secrecy about the details. The accuracy node for this barrel is 41.9 gns of H4350 @ 2830 fps. and NO pressure...I have gone up to 42.2 @ 2850 but it wouldn't group. My previous barrel was 1" shorter but the same HV profile and would barely hit 2700 but that was back when 4350 was like hens teeth and I had to run 4831sc to get acceptable accuracy...staball and other ball powder would give more velocity but would not group and this barrel is on my 1000 yd light gun. 742 rounds on it so far. I would be happy to donate the barrel to science when it's done if anyone is interested.

My old barrel was showing pressure signs above 40.5 and my new barrel is good at 41.5. That's all I know. The same old barrel only lasted 700 rounds before it was throwing flyers way off. I talked about this barrel in the past. I figured it was me shooting to many long strings without letting the barrel cool off. But obviously I'm no expert.

 

[dellet]

Lots of variables here.
Not only two different barrels, but two completely different lots of steel and manufacturing processes.

Two different loads, based on methods.

Likely two different lots of powder

If I understood correctly, one new barrel, one that has been shot enough to need setting back.
Is The other new? Is it even broke in? Not uncommon to have velocity rise over the first couple hundred rounds. Or shot out, reasonably close round count for comparison would be part of any evaluation.

A custom chamber, how many barrels has this reamer cut to establish a base line for expected velocity?
Maybe yours isn’t fast, his might be slow.
I would say that expected velocity +/- 50 fps between barrels isn’t uncommon. You need a baseline.

First thing I would do is shoot each others loads and check velocity. Accuracy isn’t the question, only speed. Might answer your question right right there.

If you want to know why there is a difference now, the time to conduct the test is now.

 

[SKWERLZ]

Its known what makes a fast barrel. Barrel makers have to work within saami spec and try to stay on the tight side of that. Contrary to what you may think, tighter barrels are not faster.

Tight gets more speed for a same charge to a point, a bit loose let’s you stuff more powder into case and get more speed without hitting pressure so soon is my monkey brain reasoning.

Kinda like the case volume scenario.

 

[farmerjohn]

Hey Fellers, the barrel makers ought to speak up on this one. I know a little about friction vs pressure by trying to maintain 135lb of pressure on an irrigation rig. You start at the pump with 150lb on a 8" pipe. As you add 30' sticks the pressure starts dropping, how much it drops depends on the interior finish of the pipe and the restrictions at the end. If you go far enough with the same size pipe the pressure will go to zero on an open hole leaving interior friction as the only factor, this tells me that friction is what would determine the speed of the bullet.... farmer logic and I may be way off base..... John

 

[ELR Harry]

Hey Fellers, the barrel makers ought to speak up on this one. I know a little about friction vs pressure by trying to maintain 135lb of pressure on an irrigation rig. You start at the pump with 150lb on a 8" pipe. As you add 30' sticks the pressure starts dropping, how much it drops depends on the interior finish of the pipe and the restrictions at the end. If you go far enough with the same size pipe the pressure will go to zero on an open hole leaving interior friction as the only factor, this tells me that friction is what would determine the speed of the bullet.... farmer logic and I may be way off base..... John

I would bet lunch that Mr Wheeler knows and that is a good point about about manufacturers staying within SAAMI specs. Dellet has a good point about defining a baseline, unfortunately I could not make an apples to apples comparison with my old barrel or my buddies due the large variance in round count. We have chambered 4 barrels with the reamer so far but my buddy shoots a lot more than I do so his current barrel has well over 1000 rnds on it by now...and we don't clean the same...he uses way too much IOSSO and JB in my opinion...I would think his barrel is not as tight due to this.

 

[Clancy]

I’m sure Alex is right and that manufacturers know what makes a barrel fast.

I don’t think I’d have even wondered over 90 fps. How do they each shoot? Are you concerned that yours is slower or just curious?

I’ve had a bunch of 6BRA barrels cut with my Reamer. All of them were Krieger 4 groove 237/243 and all of them shot 30.1 grains of H4895. None of them were the same speed. Oddly enough, even amongst 24/25/26” barrels, my 20.5” hunting barrel is the fastest.

I’ve never concerned myself with why.

 

[StumpGrinder]

Hey Fellers, the barrel makers ought to speak up on this one. I know a little about friction vs pressure by trying to maintain 135lb of pressure on an irrigation rig. You start at the pump with 150lb on a 8" pipe. As you add 30' sticks the pressure starts dropping, how much it drops depends on the interior finish of the pipe and the restrictions at the end. If you go far enough with the same size pipe the pressure will go to zero on an open hole leaving interior friction as the only factor, this tells me that friction is what would determine the speed of the bullet.... farmer logic and I may be way off base..... John

Nothing wrong with farmer logic, more inventions have come from that than you can count. As to friction being a major factor, I agree.

I have three examples, on is shooting related and one is not.

Straight out of high school, 40 years ago, I purchased this stuff called System 48 Plus. It was along the same lines as Slick 50. It was supposed to bond to the metal parts of your engine at a molecular level and reduce friction by up to 70%. I bought a case of the stuff and proceeded to put it in every vehicle I bought after that. My best confirmed results was in a Toyota Camery, 4cyl, 5 speed. It went from 35 mpg to 40 mpg. Years went by and I continued to use it and share with friends. One example was a friends Ford Ranger had some loud valve knocking. For this to work you were to warm the engine, add the stuff and then run for 20 minutes. He did that and during the 20 minute run time he was driving to his sister's house. Halfway there the engine git so quite that he thought it had died. He pulled off the road to see what was wrong and realized the engine was still running.....His words, not mine! The company is now out of business but I still have a little stashed away for the next vehicle.

Now for the guns, there is a similar product for guns make the same claim. It's called Teyra Gun Lubricant and claims to condition the bore on a molecular level. Since my success with the System 48 I thought this was a great idea and I now run it through every barrel after cleaning. I have never tested this in a before and after but I just recently got a Labradar so maybe I'll do that.

And finally, a couply of years ago I bought 2 Blackhole Weaponry 24" barrels and found out that they claim their rifling technique reduces pressure and increases velocity by reducing friction. I think it is polyagonal rifling so it grips the bullet rather than cutting groves in it. This is not a new concept, I've seen it in other barrels. I believe the Desert Eagle has it and also the Glock. Anyway I believe the claim because out of my 25-45 Sharp's barrel I'm getting 3000 fps from an 80 grain ttsx with 27 grains of Tac over a cci 41 primer with absolutely no pressure signs. Rounded corners on primers, no cratering around firing pin and easy extraction. This is a 5.56 Lake City case opened up to .257". I physically can't put anymore powder in this case so I don't know when pressure might occur. I will try other powders eventually but for now this is a great deer load.

 

[ELR Harry]

Nothing wrong with farmer logic, more inventions have come from that than you can count. As to friction being a major factor, I agree.

I have three examples, on is shooting related and one is not.

Straight out of high school, 40 years ago, I purchased this stuff called System 48 Plus. It was along the same lines as Slick 50. It was supposed to bond to the metal parts of your engine at a molecular level and reduce friction by up to 70%. I bought a case of the stuff and proceeded to put it in every vehicle I bought after that. My best confirmed results was in a Toyota Camery, 4cyl, 5 speed. It went from 35 mpg to 40 mpg. Years went by and I continued to use it and share with friends. One example was a friends Ford Ranger had some loud valve knocking. For this to work you were to warm the engine, add the stuff and then run for 20 minutes. He did that and during the 20 minute run time he was driving to his sister's house. Halfway there the engine git so quite that he thought it had died. He pulled off the road to see what was wrong and realized the engine was still running.....His words, not mine! The company is now out of business but I still have a little stashed away for the next vehicle.

Now for the guns, there is a similar product for guns make the same claim. It's called Teyra Gun Lubricant and claims to condition the bore on a molecular level. Since my success with the System 48 I thought this was a great idea and I now run it through every barrel after cleaning. I have never tested this in a before and after but I just recently got a Labradar so maybe I'll do that.

And finally, a couply of years ago I bought 2 Blackhole Weaponry 24" barrels and found out that they claim their rifling technique reduces pressure and increases velocity by reducing friction. I think it is polyagonal rifling so it grips the bullet rather than cutting groves in it. This is not a new concept, I've seen it in other barrels. I believe the Desert Eagle has it and also the Glock. Anyway I believe the claim because out of my 25-45 Sharp's barrel I'm getting 3000 fps from an 80 grain ttsx with 27 grains of Tac over a cci 41 primer with absolutely no pressure signs. Rounded corners on primers, no cratering around firing pin and easy extraction. This is a 5.56 Lake City case opened up to .257". I physically can't put anymore powder in this case so I don't know when pressure might occur. I will try other powders eventually but for now this is a great deer load.

Clancy
A little more than just curious....started shooting 1000 yard benchrest a couple years ago and got hooked last year after my light gun printed a 1.5" "four" shot group..lost the last shot 4" low...anyway, this 26" HV barrels best accuracy is at 2830 fps with SD and ES nobody would believe....I am 65 and would happily give my left nut for another barrel or three just like it. After the current throat erodes and it opens up i might just send it to Bartlein or Krieger and ask them to cut same land and groove dims in the new barrel...couldn't hurt to ask!