Gunsmithing Sniper's Hide visits Bartlein Barrels Part One: Barrel Break In

[jbell]

Not to keep this thread off track, but I deal with things like this every day. So I have a question for Turd in the Pool (and I am not picking sides although I know exactly what I believe on this topic):

How can you scientifically prove that the direction of twist of the rifling is what causes (the very few examples of barrels that have loosened) to actually come lose? How do you know that it is not some other factor like human error in machining or assembly? Either way for the few barrels that do come lose unless you are the person who diagnoses the problem and by that I mean verifies that everything is machined correctly and somehow determines that it was all assembled correctly you will simply be guessing as to the cause of failure.

 

[NXS338]

I'd certainly like to see this tested, but my premonition is the advantage wouldn't be nearly as drastic as you suggest.

Also, I wouldn't think it ideal to stop the gaining of rate of twist. I think the idea is to keep the bullet driven up against just one side of each land...no "coasting" such that the bullet ends up riding against the backside of the next land over. I fully admit I could be 100% wrong on this.

Well this I can tell you from first hand experience, I have been shooting gain twist barrels in pistols for quite some time and running lots of different experiments with them and here is what I have found to be consistent. Pressures in gain twist barrels with the same charge and bullet weight compared to conventional twist barrels are drastically lower. Reason being you dont have the steep spike when bullet goes from still to being spun at some insane RPM which causes it to stop for just a microsecond. That is only the beginning, imagine being able to run velocities from a standard case that would equal say the Ackley improved type or even faster.

As far as weather the gain should stop or not I can not tell you as I havn't got a means to build all the combinations to test, I have got 2 rifle barrels that I picked up used and both are gain twist and start at zero and go to 12. I dont know who made them and they have been shot but I cannot attest to the accuracy of them, as they have been shot out and need to be set back. I am working on doing this. They were on a Wichita Action that I picked up in a trade and chambered in .22-250 and the gain does not stop on these.

The problem that I can see with cutting the gain twist is the width of the rifling has to change as you go from straight rifling to where it starts to twist and this width of the lands and grooves changes until it stops gaining. I had an engineer show me this and started to understand why historically these barrels did not shoot well.

 

[Frank Green]

Frank, I think that fellow was referring to chamber reaming. Some chamber reamers and many throating reamers have spiraled flutes - probably with intent to cut on RH twist barrels.

Have an opinion?

In my not-so-experienced layman's opinion, I'd think the rate of twist of rifling is so minor (1:7 being a super fast rifling twist), you could all but assume the lands are actually straight when considering the approach of reamer-to-land as the leade is cut.

But what do I know?

Only have chambered the RF barrels both in RH twist and LH twist using the same reamer. Chambers cut perfectly. So if it works with these I don't see why it wouldn't work with a centerfire gun.

I've never heard of a different chamber reamer being made to chamber a LH twist barrel. That would be a new one.

The only time I would see you needing a different style chamber reamer is if you run the machine directionally wise when doing the chambering.

Later, Frank
Bartlein Barrels

 

[Frank Green]

I'm willing to buy some bs but not much and I'm not buying this;-) Granted the bullet is trying to pull the bbl away from the receiver (or the frame in the case of the 629) but it is also causing torque. I think Frank (LL) mentioned it turning the rifle to or away from your body. I don't care what anyone says. RH twist on a RH thread can only cause it to get tighter. I often question conventional wisdom but this is one issue I can't argue.
Seems like a redundancy but when Jeep made my Deuce for the Army, they put LH threaded wheel lugs on the left side. I don't think it was because the grunt manual said left side LH thread, right side RH thread;-)

NXS 338, good points. I only have to add that polygonal rifling is the only way to TRULY get there. We've got a long way to go (machine wise) accomplish that.

Call it BS call it what you want........I seen it with my own eyes on the 629 and yes the pistol got sent back to S&W and they retimed the barrel to the frame. It's not BS. Can I explain it a 100% as to why.....no but I seen it.

Also when a guy brings me a rifle at a match and starts telling me the rifle doesn't shoot and it's the barrels fault and I pick up the rifle to look at it and the barrel was loose on the receiver (this was just a few years ago). I could turn it with my hand (i.e. no wrenches). Why was it loose? I don't think it was tightened properly on the receiver and that is all.

Later, Frank
Bartlein Barrels

 

[Frank Green]

What is the additional cost of a left hand gain twist?

Starts at $40 extra. Depends on the amount of gain twist you want put into the rifling. Sometimes we have to make a custom tool...so they're could be a tooling charge as well.

Later, Frank
Bartlein Barrels

 

[Frank Green]

The true benefits from a gain twist barrel are only seen when the twist starts at zero and is increased to whatever it needs to be to stabilize the bullet. I believe they will get this completely worked out before long. The benchrest shooters that I know who are using or have tried these barrels are not going that far. They are only using a slight bit of gain in the barrel. But if you go from say zero twist for first 6 inches and then slowly twist up for next 6 inches and then have your max twist for the last 6 inches then you would see immense gains in the added velocities alone, not to mention a much more linear pressure curve, then add the decreased damage to the jacket and you will truly see the gains across the board. I have been pushing for this for a while now and think Bartlein will be the ones who can produce it correctly soon.

I will say that starting the twist at zero doesn't work. We've made 6mm PPC benchrest barrels for a shooter who is also a harmonics/vibrations engineer. The barrels ended at 13.5 for twist when they were cut and crowned. Some bullets were going thru the target sideways. I told him I didn't think it would work but up to that point nobody had asked us for anything like that. We made two or three barrels. All started at zero twist. The rifling didn't even make one full revolution in the barrel.

We have made barrels that go from like 1-28 to 1-18 for like .30BR barrels that go from 1-13 to 1-6.5 in .338's etc...and seem to work fine.

Later, Frank
Bartlein Barrels

 

[NXS338]

Call it BS call it what you want........I seen it with my own eyes on the 629 and yes the pistol got sent back to S&W and they retimed the barrel to the frame. It's not BS. Can I explain it a 100% as to why.....no but I seen it.

Also when a guy brings me a rifle at a match and starts telling me the rifle doesn't shoot and it's the barrels fault and I pick up the rifle to look at it and the barrel was loose on the receiver (this was just a few years ago). I could turn it with my hand (i.e. no wrenches). Why was it loose? I don't think it was tightened properly on the receiver and that is all.

Later, Frank
Bartlein Barrels

I have personally seen barrels that end up loose on the firing line, have seen more than just a couple at benchrest matches. The causes Im not sure about but it could be any one or a combination of many things. What Frank is saying is 100% true and fact, if you have never seen it you havnt spent that much time in this sport.

Frank, are you sure that polygonal rifling is the only way to get a true gain twist? Could it be done with increasing or decreaseing the width of the lands and grooves?

 

[Frank Green]

I'd certainly like to see this tested, but my premonition is the advantage wouldn't be nearly as drastic as you suggest.

Also, I wouldn't think it ideal to stop the gaining of rate of twist. I think the idea is to keep the bullet driven up against just one side of each land...no "coasting" such that the bullet ends up riding against the backside of the next land over. I fully admit I could be 100% wrong on this.

A uniform twist or a gain twist even if a slight gain twist. This is what I've come to know and one of the reasons I say a cut rifled barrel is more consistent in performance than a button barrel is because of the uniformity of the twist. A cut barrel has a more uniform/consistent twist (talking straight twist) vs. a button rifled barrel. Button rifling can produce a uniform twist but not as consistently. Why? If the button hits a hard spot/soft spot in the steel the button can slow down, speed back up etc...what you end up with is a barrel with a non uniform twist. To me this makes the barrel more temperamental as to what it likes for loads etc...

As you noted.....and I agree a barrel with a gain twist even a slight gain it will act like a mechanical choke. The bullet cannot get sloppy in the bore/go to sleep call it what you want. The rifling will always be putting a fresh bite on the bullet as it goes down the bore.

I'll quote Pope here again with his comments on GT barrels....

1st.) The twist being less at the breech, gives less friction to the bullet; there fore starts easier and quicker, giving the powder less time to burn on in front of the chamber, which there fore fouls less than in a barrel of uniform twist at the same necessary muzzle pitch (twist).

2nd) The slight change in angle of the rifling, in connection with choke bore (lapping choke into the bore of the barrel), effectually shuts off any gas escape of gas and prevents gas cutting, which is another case of imperfect delivery.

3rd.) it holds a muzzle loaded bullet in position much better than a uniform twist.

With what Pope says above I agree with most of it but I feel it applies to a lead bullet shooter more than a jacketed bullet shooter (my opinion). Remember back when Pope made a lot of his barrels was in the time when Schuetzenfest shooting was at it's peak and they all shot lead bullets. Pope did make barrels as well though for guns in .30-06 etc...for the Olympic teams in the 1920's and the .30-06 guys were shooting jacketed bullets. I feel it won't hurt a jacketed bullet shooter at all though.

Later for now....

Frank
Bartlein Barrels

 

[Edds]

There was a "subtle to extreme" reference made about gain twist. Where do you draw the line? Is a 7mm that goes from an 11 inch twist to an 8 inch twist subtle or extreme?

 

[Frank Green]

I have personally seen barrels that end up loose on the firing line, have seen more than just a couple at benchrest matches. The causes Im not sure about but it could be any one or a combination of many things. What Frank is saying is 100% true and fact, if you have never seen it you havnt spent that much time in this sport.

Frank, are you sure that polygonal rifling is the only way to get a true gain twist? Could it be done with increasing or decreaseing the width of the lands and grooves?

Polygonal rifling is different than conventional/standard rifling (English style rifling). Also Polygonal rifling is different than 5R style rifling. Are you thinking polygonal and 5R are the same thing? Just want to understand you correctly that's all.

When we do gain twist rifling we are not changing the width of the groove/land etc...the width stays the same. We are just basically speeding up the rate of the twist from where it starts.

Later, Frank
Bartlein Barrels

 

[Frank Green]

There was a "subtle to extreme" reference made about gain twist. Where do you draw the line? Is a 7mm that goes from an 11 inch twist to an 8 inch twist subtle or extreme?

Good question and I don't have an exact answer. If you want my personal opinion? I would say going from a 11 to a 8 would be extreme. Doing a one full twist (11 to 10j twist) or less would be subtle to an extent. Why do I say extent....it would depend on the barrel length and twist rates you want.

Doing a 7mm barrel that is a 32" finish length and going from a 11 to a 10 twist will have less of a gain per inch vs. a 7mm barrel that has a 11 to 10 twist but the barrel is only a 22" finish length. The shorter barrel the gain twist per inch of barrel length will be more aggressive.

Also some GT barrels made over the years and still being made are not a uniform gain twist. They start out slow and after a certain distance will ramp up very fast and then slow down but still have a gain to them. This is the case with the 20mm barrels and I want to say the 30mm cannon barrels our military uses.

My Pope barreled Ballard that was converted from centerfire to rimfire is a gain twist barrel as all of Popes barrels were. As close as I can check it the twist starts out at 1-18 and ends at 1-16.5. Barrel finish length is 30". Also if I recall correctly Popes barrels were not a uniform gain but very hard to measure. The gun shoots extremely well and this with the barrel being made back around 1905. Here is a picture of the rifle that I've posted on other threads.



Later, Frank
Bartlein Barrels

 

[NXS338]

Polygonal rifling is different than conventional/standard rifling (English style rifling). Also Polygonal rifling is different than 5R style rifling. Are you thinking polygonal and 5R are the same thing? Just want to understand you correctly that's all.

When we do gain twist rifling we are not changing the width of the groove/land etc...the width stays the same. We are just basically speeding up the rate of the twist from where it starts.

Later, Frank
Bartlein Barrels

Frank, yes i understand the difference between polygonal rifling and standard rifling. Have you guys or can you produce a barrel that goes from zero twist to say a 10 twist in say 24"? Giving a straight section of rifling in the beginning?

 

[steve123]

@Turd in the Pool,

spare us your half assed wisdom, seen RH twist barrels come loose, had one happen at the SHC years back, a 7WSM. So clearly your rule of thumb has no merit. There is also an instance in one of the TR threads with a loose barrel from them.

As noted which you conveniently ignored, as you side show types tend to do, is Mark Chanlynn barrels which are left twist. Several use them without issue. Including smiths on this site. So again please spare us your clueless ramblings.

Good work done by competent smiths, left or right will stay on. A 175gr bullet is not unscrewing a 9LBS barrel torqued to 100ft lbs... Your logic makes less sense than you're trying to poke a hole in. In fact I would say, it's guys like you that cause more Bullshit than you purport to point out. Last time I checked, every car on the street has the same thread on both sides, how do we avoid dodging all the cars with loose lug nuts. Maybe call NASCAR and tell them what will happen at 200MPH.

Gotta go with Frank on this.

I've had two RH standard twist barrels come loose on me. One on the M700 and one on a AR, yes the extension came loose. This can be extremely frustrating! Subtle POI shifts over time and getting worse as the barrel gradually loosens enough for the problem to become obvious.

 

[Frank Green]

Frank, yes i understand the difference between polygonal rifling and standard rifling. Have you guys or can you produce a barrel that goes from zero twist to say a 10 twist in say 24"? Giving a straight section of rifling in the beginning?

O.K. wasn't sure what you were asking on the polygonal.

Yes we have made barrels that started at a zero twist. Go back about 4 posts.

Starting at zero twist doesn't work. Bullets will not be stable. Only did a few that way and the bullets were going thru the target sideways at a 100 yards. If they were not going thru the target sideways it looked like a shotgun pattern. The bullets were not stable at all. So I feel starting at zero twist is just asking for problems.

Later, Frank
Bartlein Barrels

 

[NXS338]

O.K. wasn't sure what you were asking on the polygonal.

Yes we have made barrels that started at a zero twist. Go back about 4 posts.

Starting at zero twist doesn't work. Bullets will not be stable. Only did a few that way and the bullets were going thru the target sideways at a 100 yards. If they were not going thru the target sideways it looked like a shotgun pattern. The bullets were not stable at all. So I feel starting at zero twist is just asking for problems.

Later, Frank
Bartlein Barrels

Frank, yes this seems to be the consensus on this is the bullets does not stabilize. When I asked a person who was much smarter than me (there are plenty out there) and explained all these parameters and what I was trying to do we came to the conclusion it was due to the groove in the bullet jacket becoming so wide. This is where we came to the conclusion that the lands would have to start extremely narrow and get wider as it gained in twist. Do you think this is at least on the right track or is it something you guys have looked at? I have pistol barrels that go from zero to 32 and 24 twist in 5 and 6 inches, the first inch or so being straight and they shoot extremely well. If this can be done in that short of space for a pistol cartridge it should also work in a rifle is my thinking. Thank you for giving us your insight on this subject.

 

[Frank Green]

Frank, yes this seems to be the consensus on this is the bullets does not stabilize. When I asked a person who was much smarter than me (there are plenty out there) and explained all these parameters and what I was trying to do we came to the conclusion it was due to the groove in the bullet jacket becoming so wide. This is where we came to the conclusion that the lands would have to start extremely narrow and get wider as it gained in twist. Do you think this is at least on the right track or is it something you guys have looked at? I have pistol barrels that go from zero to 32 and 24 twist in 5 and 6 inches, the first inch or so being straight and they shoot extremely well. If this can be done in that short of space for a pistol cartridge it should also work in a rifle is my thinking. Thank you for giving us your insight on this subject.

Shooting pistol rounds/pistol bullets vs. a rifle round/rifle bullets are two different things. Pistol rounds with those short fat bullets need a lot less twist and operate at less pressures than rifle rounds do. I've seen damaged pistol barrels shoot as good or better than one that looks like brand new. Even worn out pitted pistol barrels can shoot pretty well but a rifle barrel that has any significant amount of wear or damage is a killer when it comes to accuracy.

We don't have the ability and I don't know of anyone at this time that does. That can change the width of the lands/grooves over the length of the barrel.

Our cutting tools are made to a specific width. You would need different width tools to make the grooves a different width and change the tools thru out the manufacturing process and also you would have to be able to control the timing/twist of the tool as it goes down the bore in order to cut the grooves to a different width etc....off hand the only way I could see this getting done right now would be by hammer forging the barrel. You would have to have a mandrel made that will be mimicking what the bore is suppose to be/come out as but then I would think you would have trouble getting the mandrel out of the barrel once it's been rifled (I might be wrong on that but seems logical). If either process could do it I for see high tooling/manufacturing costs that the average guy will not want to pay or could afford.

Just my .02.

Later, Frank
Bartlein Barrels

 

[Punisher29073]

Im sorry. Were you saying something? I was mesmerized by that beautiful thing sitting there on that bar stool.....

Ryan

 

[Das Capitolin]

On a lighter note, I enjoyed hearing them discredit the often repeated "barrel break-in process" that make up 100+ threads here on Snipers Hide. So you mean I shouldn't prematurely wear down my expensive custom barrel with repeated cleanings the very first things I get it? Dumb people drive the economy.

 

[MarinePMI]

All this talk of rifling widths and gain twist leaves me wondering if they have gotten a laser engraving unit small enough to go down a bore? It would certainly make changing the width and rate of the rifling twist possible...multiple passes to deepen the grooves?...changing the width of the beam to change the width (and depth) of the rifling...

Just thinking out loud here...

 

[Luvman]

As to making a GT barrel with varying width grooves, does the machinery exist that could rotate the barrel at the same time the tool is being rotated?

Example: the tool is made to the minimum groove width at the muzzle. Machine is programmed for tool to cut from 0 twist to 10 twist over 24". After the initial groove is cut the final operation rotates barrel a few tenths of a degree positive as the cutter starts into blank, as the cutter travels to muzzle the barrel rotates back to zero. When that side of the groove was complete the machine would rotate a few tenths of a degree negative as the cutter starts into blank. It would again rotate the barrel back to zero degrees as the cutter reached the muzzle.

I hope my explanation makes sense.

Would this not make the grooves wider at the breech and narrower at the muzzle?



Sent from my iPad using Tapatalk

 

[richidaho]

Thanks for the Video.

 

[Lowlight]

I have another one rendering now, so the Barrel Rifle Machines is almost ready

 

[Lowlight]

I will start a new thread too, but here is Part Two

Bartlein Barrels Rifling Machine - YouTube

Rifles Machines and how they operate

 

[Geno C.]

Simple way to test and explain why a rh barrel is trying to loosen a barrel every time a bullet get forced down the bore.

Take a barrel a press it against something like live center of a lathe. Then lube up your hand like you're about to go to town... Hold the barrel with that hand. With your other hand take a very tight fitting patch on a non rotating cleaning rod and force it down the barrel...

Bet it wants to turn left in your self loving hand.

Turd you're one of those guys that I just love to run into at a bar. You sit there and talk about all kinds of things that you think you know. I smile and nod. When you leave I get to look like the smartest guy in the world to everyone there because I set the record straight with the simple things I actually do know.

I know you like to think of yourself as a very smart person but look up inertia. Look very carefully and apply that to a bullet that does not want to be spinning but a barrel forces it to turn right. Which way to you think the bullet is trying to force the barrel to go.

 

[Geno C.]

I'm sorry. I should have been a little nicer but I'm not that kind of a guy.

You're an idiot.

 

[Geno C.]

Better yet, you remind me of something my dad used to say about idiots. You're nothing but an oxygen thief.

 

[Geno C.]

Frank Green, thank you for taking the time to respond to all serious questions. One of these days when I'm down by you guys I'll swing by to shoot the shit with you.

 

[sakobob]

that's the answer i was looking for mr green and hog extreme, just me over thinking things.
O btw, i have one of your barrels and it's a hammer

 

[Tommyquest]

Great videos. Learned something about barrel stress and bullet walk. I guess I know where my next 6.5CM barrel is coming from.

 

[79jeepcj5]

Simple way to test and explain why a rh barrel is trying to loosen a barrel every time a bullet get forced down the bore.

Take a barrel a press it against something like live center of a lathe. Then lube up your hand like you're about to go to town... Hold the barrel with that hand. With your other hand take a very tight fitting patch on a non rotating cleaning rod and force it down the barrel...

Bet it wants to turn left in your self loving hand.

Turd you're one of those guys that I just love to run into at a bar. You sit there and talk about all kinds of things that you think you know. I smile and nod. When you leave I get to look like the smartest guy in the world to everyone there because I set the record straight with the simple things I actually do know.

I know you like to think of yourself as a very smart person but look up inertia. Look very carefully and apply that to a bullet that does not want to be spinning but a barrel forces it to turn right. Which way to you think the bullet is trying to force the barrel to go.

Coming across Turd's post while reading this thread had me scratching my head. Thought maybe I was missing something. You nailed it Geno. Great minds think alike (and ours do too

Matt

 

[Frank Green]

Frank Green, thank you for taking the time to respond to all serious questions. One of these days when I'm down by you guys I'll swing by to shoot the shit with you.

Your welcome!

Your only a little less than 2 hours away from us! Swing in sometime!

Later, Frank
Bartlein Barrel

 

[Edds]

Simple way to test and explain why a rh barrel is trying to loosen a barrel every time a bullet get forced down the bore.

Take a barrel a press it against something like live center of a lathe. Then lube up your hand like you're about to go to town... Hold the barrel with that hand. With your other hand take a very tight fitting patch on a non rotating cleaning rod and force it down the barrel...

Bet it wants to turn left in your self loving hand.

Turd you're one of those guys that I just love to run into at a bar. You sit there and talk about all kinds of things that you think you know. I smile and nod. When you leave I get to look like the smartest guy in the world to everyone there because I set the record straight with the simple things I actually do know.

I know you like to think of yourself as a very smart person but look up inertia. Look very carefully and apply that to a bullet that does not want to be spinning but a barrel forces it to turn right. Which way to you think the bullet is trying to force the barrel to go.

If you are looking at the back end of a barrel that has RH threads on it and it is turning to the left, that is the direction that would tighten it.

 

[Geno C.]

Brain fart on my part. You are correct. 42 hours working straight will do that.

Still doesn't change what I think about turd in the pool though.

 

[Edds]

Brain fart on my part. You are correct. 42 hours working straight will do that.

Still doesn't change what I think about turd in the pool though.

Am I looking like the smartest guy in the world?

 

[Geno C.]

That would be you right now.

 

[Greg Langelius *]

I came to The 'Hide long ago with some fixed ideas in which I had some pretty firm faith.

I have been reeducated by the collective 'Hide in pretty much every aspect. These days I believe I know far more than once I did, and that I can trust in that knowledge more strongly.

After viewing the first vid, I am reminded that I always learn something from Frank's vids; even if it is simply a better way to understand what I have already learned here over years.

I have a couple of questions.

Is there a relationship between ogive shape and leade angle and can this be tuned to aid accuracy?

I have also concluded that a large portion of 'carbon' fouling derives from kernel coatings which have traditionally consisted of graphite, which was intentionally chosen for its electrically conductive property which allows static charges to dissipate harmlessly in the powder container, and prevents discharge sparks from igniting the powder in transit.

It is also a dry lubricant, and as such, has a direct effect on bore friction, pressure curve/burn rate, and velocity. I have refrained from using moly since I suspect that mixing graphite and moly only adds complexity to fouling management. I also suspect that moly may be finding its way into kernel coating recipes.

Does any of this make sense to anybody besides myself? Would a better knowledge of this subject add to what goes into making barrels?

Finally, rifling twist may have a torsional flex effect on barrels. As that flex unwinds, this opposite effect may be affecting the security of barrel threading counter-intuitively. My guess is that the unwinding occurs at a higher rotational velocity than that of the initial windup.

Physics is an absolute science. What the laws of physics say should occur always occurs, even if the effect are miniscule; and even miniscule effects accumulate with repetition.

Greg

 

[79jeepcj5]

If you are looking at the back end of a barrel that has RH threads on it and it is turning to the left, that is the direction that would tighten it.

I assumed that's what Geno was getting at when he said it would turn to the left. Just figured his first statement was sarcasm directed at Turd. Huh. That's what I get for assuming.

Matt

 

[Greg Langelius *]

I have a couple of questions.

Is there a relationship between ogive shape and leade angle and can this be tuned to aid accuracy?

I have also concluded that a large portion of 'carbon' fouling derives from kernel coatings which have traditionally consisted of graphite, which was intentionally chosen for its electrically conductive property which allows static charges to dissipate harmlessly in the powder container, and prevents discharge sparks from igniting the powder in transit.

It is also a dry lubricant, and as such, has a direct effect on bore friction, pressure curve/burn rate, and velocity. I have refrained from using moly since I suspect that mixing graphite and moly only adds complexity to fouling management. I also suspect that moly may be finding its way into kernel coating recipes.

Does any of this make sense to anybody besides myself? Would a better knowledge of this subject add to what goes into making barrels?

May I politely bring these questions up again?

Greg

 

[Frank Green]

May I politely bring these questions up again?

Greg

Greg, Cannot answer your questions a 100% but will give some thoughts.

I won't use moly at all. It's another variable to deal with. It does nothing for accuracy or barrel life in my opinion. It can cause pitting in the bores of the barrel if left in to long. In a good barrel I don't see it adding/extending to accuracy in between the number of rounds being fired and the barrel being cleaned. I asked one of the bullet makers one time what they seen with the moly. They said nothing. No increase in barrel life, no difference in accuracy etc...or gain in velocity etc...so I asked why are they doing it. They said they can charge another $1 per box and the demand was currently there for it. I don't think they do it anymore.

Carbon fouling from the coatings on the powder etc...this is tough. I'm not a powder maker but I will say even with the same manf. and type of powder I've seen them vary from lot to lot in how they clean at times. We've also been seeing lately where guys are not cleaning the barrels good enough that the carbon is building up in the bores and causing accuracy issues. I don't know if this a powder issue or just guys not cleaning good enough. To many variables beyond our control.

Lead angle of throats and accuracy. This is another big debate at times. I would say a 1 degree 30 min. lead throat with a parallel throat section is kind of the standard/norm for match type reamers. I have shot 2 degree 30 min. lead angles in .280 AI, .308win. Obermeyer reamers/chambers and even a standard 3 degree .223 Rem. chambers. I don't see any real difference. We also have here a AW .308win. rifle and that has a standard Saami min. spec. .308win. chamber our barrel and that gun will pound 1/4 to 1/3 moa groups so go figure. Also as you shoot the gun the throat will change/wear as well as I do believe it's been proving that the throat will change/wear to match the style of the particular bullets ogive that you are shooting. You switch bullets/ogives etc...and the throat after you fire x amount of rounds will change and conform to that bullet then.

You also have to ask what are you using the gun for and what you expect out of it for accuracy? If it's a real hard core accuracy type gun I would lean towards the 1 degree 30 min. lead and a straight parallel section as I feel this will help with bullet alignment as the bullet jumps into the rifling. You also have to contend with your ammo and bullet run out etc...again I feel there are more than just a few variables that can effect accuracy and it's not just the throat style.

Later, Frank
Bartlein barrels

 

[Greg Langelius *]

Frank;

Thank you very much for your time and your responses.

I think that one of the reasons why fouling may vary by powder type is that in addition to managing electrostatic discharge, kernel coatings are counted upon heavily as ignition retardants, and the weights of the coatings are regulated as a burn rate manager. For example, the Win ball powders seem to have a deeper coating layer and to require a primer with a greater degree of brisance, which the Win primers would appear to provide. Consequently I think they burn a lot more dirty, at least for me. I remain unconvinced that dirt from carbon is really such a detriment.

I do not seek ultimate accuracy from my firearms; rather, I limit my accuracy demands to that which is necessary to defeat a given target. 2MOA or better serves most of my needs, and less than 1MOA is only called for in the F Class courses that I shoot. My chambers are usually SAAMI spec, since I don't care to turn necks or regulate concentricity, and such considerations seem to have less relevance with the standard SAAMI neck configurations.

Right now, immediately after some load development, my box-stock savage .223 11VT is shooting about 1/2MOA in dead calm conditions at 250yd. For me, this is nothing short of a miracle. My missing mojo, gone for lo this past decade, appears to have found its way back home.

Load is F/L PPU match brass, BR-4, HDY HPBTM at 2.255" OAL, and 23.7gr Varget. It is loaded on a Dillon RL550B with a Hornady automatic powder dispenser, standard RCBS dies, and no heroically complex handloading techniques. My simple-as-possible handloading philosophy does not permit such complexities. Sometimes I get lucky, too.

Greg

 

[plh]

Also as you shoot the gun the throat will change/wear as well as I do believe it's been proving that the throat will change/wear to match the style of the particular bullets ogive that you are shooting. You switch bullets/ogives etc...and the throat after you fire x amount of rounds will change and conform to that bullet then.

Given this, can a reasonable argument be made to limit the exposure to only a single bullet? For instance, I have a moderately tight-chambered .308 set up for 185 Berger Jugg. for 1k. Would shooting 175 smk's in shorter distance scenarios have an adverse effect on the performance of the 185's for which it was primarily chambered and is its main 'diet'? (perhaps this question should be redirected to the "Stupid..." thread)
Respectfully, Pete

 

[Frank Green]

Given this, can a reasonable argument be made to limit the exposure to only a single bullet? For instance, I have a moderately tight-chambered .308 set up for 185 Berger Jugg. for 1k. Would shooting 175 smk's in shorter distance scenarios have an adverse effect on the performance of the 185's for which it was primarily chambered and is its main 'diet'? (perhaps this question should be redirected to the "Stupid..." thread)
Respectfully, Pete

Pete, Hard to say and also it's not a stupid question. The only stupid one is one that isn't asked!

Sometimes I shoot bullets that I can lay my hands on especially now with the current demand and trying to find ammo/bullets on a given day. As an example one of my .30cal. guns I shoot mostly 155 Lapua Scenars thru it but my other bullet of choice is a 175 SMK. That gun shoots so good and so consistent it will always out shoot me and I cannot tell a difference if the throat is slightly changing and it effecting accuracy. I'm running both bullets .010" off the lands.

I've shot 120smk, 123 Lapua's, 130 Berger VLD's and 139 Lapua's thru my .260 Rem. again I don't see a real difference. The gun is consistently a 1/3 moa gun. It's not a bench rifle and again the limiting factor more than anything is ME!

As the barrel/throat wears over time I think it's more important to revisit your load and check accuracy on a regular basis. You will find overtime usually you will lose a little velocity so you have to retune your load to keep the velocity and accuracy you want.

Later, Frank
Bartlein Barrels

 

[Millionaire]

Thank you for posting the videos.

I look forward to part 3 and 4.