The First Thousand Shots

[GetReal]

I'm told by reliable industry sources that rimfire bbls really don't "wear" ... at least anything comparable to CF bbls.

I dunno.

Most CF bbls seem to be kaput under 6,000 rounds. Rimfires seem to go well over 10,000. Typically much, much more.

I do know I've gotten repeated match winning results long b4 1000 rounds from both of my Vudoos. And the rifles I've bought that shot average or crappy at 250 rounds (CZ 455 / 457) continued to do so after 1,000 rounds.

Is my 4 rifle sample indicative of the entire industry? I dunno. My experiences maybe entirely unique to me. But somehow, I doubt I got magic unicorn rifles.

 

[justin amateur]

Yep, had that discussion multiple times.
Opinions range from it's all due to improper barrel cleaning, to rimfire lasts forever.
I haven't found any publications documenting 22lr barrel wear over time, just reports of worn out barrels.
What causes the wear? The lead alone? Unlikely. Aluminum oxide on the cleaning rods? Possible.
I've been sent links to pics and videos showing worn rifling after long term usage with 22lr.
It all occurs in first few inches of the barrel. So something is chewing up the steel.
I'm not seeing heat discoloration or burn cracking/pitting like centerfire, only linear abrasion patterns.
So far the only things I've found to cause scratching of the steel surface, is burn residue from primer/powder.
Mostly primer residue, with silica particles being the probable culprit.
Images captured show the bore of this barrel is being smoothed out.
Tool marks and hammer forging chatter patterns are being worn away.
I was told it doesn't happen, but from the images recorded, sure looks like it does.

Images collected in sequence, starting at the leade, ending at the crown.
4 images taken at referenced intervals, 90 degrees clockwise, starting at the bottom of the bore
Links to the hosted image folders, so the number of pics won't crash the thread.
Take a look, decide for y'erself if wear is occurring.

Bore images - from the factory

Bore images - After 100 shots

Bore images - After 200 shots

Bore images - After 300 shots

Bore images - After 400 shots

Bore images - After 500 shots

Bore images - After 600 shots

Bore images - After 700 shots

 

[GetReal]

Friction / wear always happens in every mechanical device. I just don't see any magic happenning at 1,000 rounds (or thereabouts)

I've had rifles shoot well at 250 rounds, that shot the same after 1,000 rds..... and rifles that shot average at 250 shot average at 1,000 + rounds.

 

[justin amateur]

Can't argue about that GR. Can't fix a poorly made barrel. It could be any number of problems.
Poorly cut crown or chamber, uneven bore diameter, fissures in the rifling, bore not straight.
I'm most interested in finding out how much difference there is between as-shipped and after 1000 shots.
Does the 2 brick's sent before testing for accuracy work? It was recommended in another thread
as part of the to-do list before sending the rifle in to the factory test facility.

Vudoo 1000 rounds before Lapua testing. Bulk or match ammo?

What did everyone use to break in their Vudoos? Part of me says burn a bunch of cheap bulk but the boojie part of me says put nothing down the pipe but higher end match ammo. Give me your thoughts.

www.snipershide.com

 

[Rimdenter]

Can't argue about that GR. Can't fix a poorly made barrel. It could be any number of problems.
Poorly cut crown or chamber, uneven bore diameter, fissures in the rifling, bore not straight.
I'm most interested in finding out how much difference there is between as-shipped and after 1000 shots.
Does the 2 brick's sent before testing for accuracy work? It was recommended in another thread
as part of the to-do list before sending the rifle in to the factory test facility.

What make is the barrel ?

 

[justin amateur]

CZ 455 Varmint 22lr, not a custom match grade barrel.
Hydraulic lapped, not hand worked,

 

[Rimdenter]

What's the magnification of your scope?

 

[justin amateur]

Mueller 8-32X44 target reticle

 

[Rimdenter]

I meant bore scope fixed or adjustable

 

[justin amateur]

Teslong 26" rigid USB, fixed

NTG100H 26-inch Rigid USB Borescope

TESLONG NTG100H 26-inch long rigid rifle borescope is an ideal gunsmith tool that helps verify how well your rifle barrel has been cleaned. Go to Teslong for all your gun barrel inspection and digital borescope needs.

teslong.com

 

[GetReal]

I'm most interested in finding out how much difference there is between as-shipped and after 1000 shots.

In my admittedly limited expereince, not much difference.


In my limited experience extended break in isn't needed with 22rf. Things calmed down after about 200 rounds with my 2 Vudoos. Cheaper / rougher bbls might could take more rounds to settle down.


Bulders I trust have said the same. If anything, over - cleaning causes more wear than anything.

 

[Rimdenter]

I'm just captivated by some of the finishes down in the grooves and in the lead area. People think because a barrel was button rifled by a carbide button it should be slick. That's not the case lack of luberacant pressure and filter break down are the results of what I see. Proably the guy buttoning the barrels is honeing them after the gun drill opp. He probably takes the barrel out of the hone. Slaps it in the buttoning machine, washes his hand off under a bypass hose putting diamond grit in the button luberacant. Hits cycle start mean while the diamond grit is getting ironed out in your grooves by the button. The linear scratches , the gauled spots are lack of lube or friction shedding the grit has or something has created a surface imperfection on the outer portion of the button which would be the groove it could have been dropped in the floor. nobody but him knows this

 

[justin amateur]

Break-in with a 22lr isn't anything to worry about.
Especially with a custom barrel, hand lapped to a satin finish.
With an assembly line, hammer forged, production barrel, all that's happening
is knocking down the minor imperfections in order to find out what the barrel is actually capable of.
Will it produce sub-moa and be an assembly line gem, or barely capable of 2 moa as expected by the manufacturer?

 

[pete_f]

I'm told by reliable industry sources that rimfire bbls really don't "wear" ... at least anything comparable to CF bbls.

The temperature and pressure that occur in the .22lr is significantly lower than in center fire so you do not get the same "wear" that you see in a center fire barrel but they do wear, it just takes a lot of shots to wear one out. While I have seen some barrels made by a well regarded US based custom barrel manufacturer loose accuracy to the point that they were replaced in under 40,000 rounds, most go well over 100,000. The highest reliable round count that I know of was 210,000 before the barrel needed to be replaced. I will suggest that this is the main reason there is no published information available on the subject. Also, competitive shooters are probably, up to now anyway, the only folks likely to shoot a barrel enough to wear it out and then, most don't care why it stopped shooting, they just want it replaced so they can be competitive.
In my experience, Justin is correct in his thoughts on the bullets pushing the debris down the barrel causing wear. If you section a high round count barrel, there are several things that you will see. Some of the wear that occurs is the corners of the lands start to wear and round off which by itself is probably not that bad, there have been several successful rifling forms that used rounded land profiles but I think the bore also gets uniformly larger as well. The throat will also wear, predominantly starting at 6 oclock. Extreme cases of this wear can be seen in high use guns such as shooting galery or club guns where a depression like a golf divot forms just forward of the chamber. Another thing that you see is the bore surface starts to become pitted, most likely from the bits of abrasive/carbon/unburned powder/primer bouncing around in there behind the bullet. This condition generally starts at 6 oclock just in front of the chamber and will progress down the barrel. As the round count increases it will progress both down the length of the barrel and up the sides.
I should note that my experience is predominantly with dedicated competition rifles and barrels though I think what I have said above will apply to any .22lr barrel.

 

[Rimdenter]

I totally agree with your statement gravity alone helps produce the wear in the bottom or 6 oclock position of the throat or lead.

 

[Rimdenter]

In your honest opinion! Do you truly believe the barrels of today particularly 4140c are of the quality of steel they were in the say 1950 to 1960's ?

 

[pete_f]

In your honest opinion! Do you truly believe the barrels of today particularly 4140c are of the quality of steel they were in the say 1950 to 1960's ?

If you are asking me, I would have to start with I only had 2 semesters of metallurgy in school so I am only qualified to guess. I would guess that, like most things, there have been advancements in the steel production industry so steel produced today should be equal to or better than what was produced 50 years ago.
I will also point out that the majority of competition grade barrels produced today are some version of 416 stainless, not 4140.
I will also say that I do not think that the custom barrels available today are better (or of lesser quality) than those available 50 years ago.

 

[Rimdenter]

You just seem like a wise older man who had seen the good years come and go.That had spent alot of time staring across a open space predicting your bullets impact by that last glance at a distant flag. I had 2 years metallurgy as well as numerous years heatreating all types of alloys working 20 years in the aircraft and aerospace industry warps a person's mind those people got some imaginations. I can say the quality workmanship has vanished from production guns when you look at a all steel pre 64 model 70 or a A H Fox SxS compared to today's simular guns.

 

[Gleedus]

Was going through some data here on my Rim X.
It would appear that I've gained approximately 10 fps in 3000 rounds from a new barrel. Same lot# of course.

 

[Rimdenter]

Was going through some data here on my Rim X.
It would appear that I've gained approximately 10 fps in 3000 rounds from a new barrel. Same lot# of course.

What's your current barrel and length your running.

 

[Gleedus]

IBI 1-16 calfee 4 at 26" I wont be cutting till warmer weather.
In comparison to a couple of 18" I have most ammo is the same velocity. SK and Lapua are the slow ones.

 

[Rimdenter]

IBI 1-16 calfee 4 at 26" I wont be cutting till warmer weather.
In comparison to a couple of 18" I have most ammo is the same velocity. SK and Lapua are the slow ones.

And this is the barrel your seeing unexplanable group growth at 200 yds ? or longer ?

 

[Gleedus]

And this is the barrel your seeing unexplanable group growth at 200 yds ? or longer ?

Past 300 it starts to open up. Was out to 338 in a 10-15 mpr wind on 12" square plates tonight. 373 gets illusive... that data shared in the other thread is this barrel

 

[Rimdenter]

Past 300 it starts to open up. Was out to 338 in a 10-15 mpr wind on 12" square plates tonight. 373 gets illusive... that data shared in the other thread is this barrel

Was it a prefit or did you spin it up ?

 

[Gleedus]

Prefit. First I've had. No complaints. Fit perfect head space was in spec.
I dont have a 22 reamer. Yet... have to learn more first.

 

[Gleedus]

Next one Will be a IBI with a barrel nut. Then I can mess with head space and see what I find out.

 

[Rimdenter]

Prefit. First I've had. No complaints. Fit perfect head space was in spec.
I dont have a 22 reamer. Yet... have to learn more first.

So you cant say or know if the barrel is indexed you'd have no way to check it ?
Correct

 

[Gleedus]

So you cant say or know if the barrel is indexed you'd have no way to check it ?
Correct

If you referring to indexing the curve of bore it would be easy to do when I put in the lathe to shorten.
I'm not sure how that would affect long range performance other then where I would zero??

 

[Rimdenter]

If you referring to indexing the curve of bore it would be easy to do when I put in the lathe to shorten.
I'm not sure how that would affect long range performance other then where I would zero??

Not the bore curve but mass curve its twice the work but worth the effort after cutting the barrel shape and tenon I put the barrel in 2 vee blocks on my surface plate. I set my indicator up in my height gauge and run indicator across the top of barrel to find high point. I stop there then I slowly rotate the barrel in the vee blocks till I see max run out has been rotated to top 12 o clock,then I sweep the entire top of barrel to find the highest point I put a scribe mark here. I move the vee block at muzzle to the scribe mark the muzzle will now be low. I move my indicator to the muzzle then rotate barrel till high point comes up. I install my vee block clamps and lock the barrel in place and slowly turn it over onto a set of 123 blocks I remove the indicator and put my carbide scribe in height gauge and pick up barrel center. This is simply done I set the blade on top of the 1.200 dia. at the tenon shoulder the drop down 1/2 dia. .600
I scribe a mark here at shoulder this is 12 o.clock top muzzle mass. We know a barrel makes a circular motion when a bullet is fired down it hence the need for tuners and weights. It's easier for the barrel to replicate the same circle with the mass at TDC if the bend is down the mass is harder to raise if it's off to the side it will whip with inconsistency. Professional Rod builders use the same theroy . Now back to the lathe I have a 4 screw spider in the chuck and on the outside spindle the 1/2 13 set screws have a perfect radius on the end that touches the barrel this way theres no lateral stress put on the surface of the barrel using a coaxle indicator I line up breach and muzzle to .0002 or less. Since I have a rimx action I set it in the vee block like the barrel and pick up center then rotate action till the scribe is centered on the front dowel pin location of rail I scribe the front shoulder of action this is TDC action. I take the action to the lathe and slowly install it on barrel till I see where the Mark's are to each other. Rimx threads are 1.06 x 20 the action will move forward .050 per revolution the total circumference of the 1.2 dia. Rounded up is 3.770 I cut the shoulder till the mark on receiver is within .175 at 11.00 to the mark on barrel the 70 ft lbs of tork will bring it up I finish the breach face to 1.6855 +.0005 chamber then lap and polish the chamber and lead. Its alot of work but you will have a far more consistent shooting barrel and the pros know just ask a few. Man I'm tired now!

 

[IdealJoe]

I line up breach and muzzle to .0002 or less.

Is this alignment to the bore or the barrel OD? I first assumed the bore, but your index measuring did not seem to include the bore location. I could imagine if finishing your barrel tenon while indicated to the bore, this could possibly change the mass location index. Do you account for bore curve or concentricity to the OD in your setup? Thanks.

 

[pete_f]

The wise part is debatable, and only semi old, early 60's. I have spent a bit of time looking at a wild flag or two, started competing in my teens and still at it. I have all ways been just a competitive shooter so never paid much attention to sporting guns so I can not comment on those but I do think that a lot of the skilled craftsmanship that produced those kind of things has been lost. The bright side of that though is manufacturing techniques and equipment have improved so generally, we make better stuff now. The sad part of this, for me, is that society has lost the appreciation for that skill and craftsmanship.

That is an interesting perspective that you have on barrel indexing. There has been a fair amount of research and experimenting done on indexing and I have never seen your ideas regarding the offset mass noted. The general consensus is that the curvature of the bore should be oriented in the vertical plane, with the 6 oclock orientation generally being accepted as preferred. I index the barrels that I fit and the experimenting that I have done agrees with this. There is also the subject of indexing the rifling to the chamber, something that is rarely discussed. For .22lr, there is a school of thought that says there should be a land oriented at the 6 oclock position, any thoughts on this?

 

[Rimdenter]

I diminish as much ID to OD. run out as possiable during the barrel profiling operation. I line up the I'd on both ends and make qualifieing cuts, I single point cut my center champer in the muzzle end for tail stock. I've even used ultrasound equipment from 1 job I had and presses to bring everything perfect. It seemed that the mass run out played a larger effect on repeated shot dispersion. I did see problems with barrels that I had straightened that had high round count they slowly stress relieved back close to their original bend within 20%. I do not reccomend this over free machining with a end to end '0' normally on my finished barrel the ID.to OD. at muzzle and breech is less than .0002 tir. Is the bore ie. rifling perfect to the od. the entire lenght NO I've ran precision mandrel rods the entire lenght of a barrel blank and finished barrel only because I had access to the technology they did alot of deep hole gun drilling and roller burnishing . You will never get everything perfect. I index the highest point of bend of barrel od to 12 oclock the exit point of muzzle is there also with in .0001 tir I'm not worried if the bullet is .002 low 14" from exit. I'm interested in RETURN OF MUZZLE upon exit ,tuners and weights balance harmonics to return the muzzle to a zero condition upon bullet exit .
Hope this helps

 

[justin amateur]

A minor deviation from the ongoing discussion...

Well that was unexpected.
Sent 4 rounds into the poly-fil bullet trap.
Recovered immediately.
Used one as a slug and aligned it with the rifling at the leade and pushed it through.
Yep, snow plow effect. Everything is caught at the leading edge of the drive bands.
The burn residue comes out wet. Black mud, not dry ash.

Give that a thought.
What effect would that have on a bullet passing through the bore?
Wet burn residue and bullet lubricant...less friction?
So a dry bore is the cause of the cold bore flyer?
It's not a cold bore flyer, it's a dry bore flyer?
No wet gsr and lube to allow the bullet to ease through the rifling?
Following bullets will be running through a wet surface?

Hmmmmmmm....

 

[Rimdenter]

I can not substantiate the land orientation this I have not delved into heavely does this consensus apply to all configurations 2,3,4,5 thru 12 land rifling?

 

[pete_f]

The number of lands does not matter, just that one is at 6. I think that there are 2 sides/reasons to do this, one is accuracy and the other, more specifically relating to .22lr is barrel wear just forward of the throat.

 

[pete_f]

A minor deviation from the ongoing discussion...

Well that was unexpected.
Sent 4 rounds into the poly-fil bullet trap.
Recovered immediately.
Used one as a slug and aligned it with the rifling at the leade and pushed it through.
Yep, snow plow effect. Everything is caught at the leading edge of the drive bands.
The burn residue comes out wet. Black mud, not dry ash.

Give that a thought.
What effect would that have on a bullet passing through the bore?
Wet burn residue and bullet lubricant...less friction?
So a dry bore is the cause of the cold bore flyer?
It's not a cold bore flyer, it's a dry bore flyer?
No wet gsr and lube to allow the bullet to ease through the rifling?
Following bullets will be running through a wet surface?

Hmmmmmmm....

Justin, in my opinion, you are correct on the cold bore thing, it is not about a "cold" bore as much as a dry bore. And a wet bore is not good either, if you leave oil or solvent in there, the first shot will be loud (higher velocity) and not go where you aim.
The "wet" component of the "mud" is water, a byproduct of combustion. Under ideal temperature and humidity conditions, I have seen water droplets spit out of the bore of a .22lr when fired. This is the principal reason that I give when asked the clean/don't clean question, why would you leave a wet mud mixture of water and the assorted acids and such found in combustion byproducts?
On another subject, it would be good if you could accurately measure the length of the fired bullets and post that, possibly as a separate thread. I think it would help clear up a lot of the difficulty folks are having with the various ballistics calculators they are using.

 

[Rimdenter]

The number of lands does not matter, just that one is at 6. I think that there are 2 sides/reasons to do this, one is accuracy and the other, more specifically relating to .22lr is barrel wear just forward of the throat.

Well when my new barrel comes in I'll take that into account on land timing .

 

[justin amateur]

Recovered fired bullet lengths as requested.

0.4675 inches
0.4665
0.4630
0.4695
0.4660
0.4470
0.4370
0.4510
0.4620
0.4610
0.4585
0.4515
0.4730 inches

No two alike from the samples measured.

 

[pete_f]

What ammo are those bullets from?
What were they shot out of?
It is interesting that there is that much variation in the length.

 

[justin amateur]

Fed 36 grain cphp
CCI SV
Eley Action 40 grain

Lilja EPS chamber 21.5 inch barrel

I've ended a couple of discussions at the local range by setting up the poly-fil trap.
Captures fired bullets in soft polyester fibers, no damge on impact.
Allows for examination of the fired bullets to check what is happening.

 

[pete_f]

It would be interesting to look at how consistent the fired lengths of say 10 rounds of each ammo type are. This may (probably would) have something to do with longer range performance?

 

[justin amateur]

I can do that, after I finish this project.

 

[pete_f]

I think most folks have no idea what the actual, as fired bullet form and size ends up being. The topography at one range where I shoot prone matches is such that the grass catches and stops bullets shot at the 50 yard targets at about 90 yards so the ground ends up covered in them right in front of the 100 yard targets so I have seen undamaged fired .22lr bullets but never looked at how consistent they were. I also shoot Palma and long range. One of the things that we look at carefully for those games is the consistency of length of any lot of bullets that will be used in a match.
It will be interesting to plug your length numbers into a Twist rate stability calculator.

 

[justin amateur]

800 sent, pics captured

What do you think?
Is that leade showing signs of wear?

Bore images - After 800 shots

 

[pete_f]

Do you record the clock position of your photos? Showing the same clock position photo in order of shot count progression would make for a good comparison of surface condition. the 6 oclock orientation would be a good place to start.

 

[justin amateur]

I knew that question would arise sooner or later.

A is the 6, B is 3, C is 12 and D is the 9 o'clock position.
First number of the pic identifier is the number of shots.
Second number is the distance from the case mouth up the bore.
So 800 shots at 0.3 inches from the case mouth at A, B, C or D.

I was thinking before I started, eh?

 

[justin amateur]

I was pointed at a couple of publications for further reading.

Calfee in his book on rimfire accuracy states the need for 2 to 4 thousand rounds fired
before the barrel/leade is seasoned enough to produce consistent results.
That would be pages 104 and 105 of "The Art of Rimfire Accuracy".

Geoff Kolbe commented...

When you look at a newly cut chamber, there are the inevitable small tool mark rings visible running circularly around the chamber and leade. When you look at the same chamber when a few thousand rounds have gone down the barrel, the radial rings in the leade have been replaced with fine longitudinal abrasive marks as the lead bullet and powdered glass from the primer have worked on the leade. It is about now that the barrel starts giving of its best.

 

[oldfatguy]

Have been following your project since 1st post. Thank you for your efforts. So has there been any improvement in group size?

OFG

 

[justin amateur]

OFG, shots 750 to 800 weren't produced under worthwhile conditions.
Pre-front, northerly winds huffing and swirling over the left side berm.
I was caught multiple times mid-squeeze by gusts and turbulence.
Can't blame the ammo or rifle for the results, all on me.

 

[1813Benny]

The number of lands does not matter, just that one is at 6. I think that there are 2 sides/reasons to do this, one is accuracy and the other, more specifically relating to .22lr is barrel wear just forward of the throat.

Pete
I can confirm that orienting the barrel with one land at the 6 o'clock position was a standard practice by Karl Kenyon. I recall that he mentioned this as one of the operations he did when installing a new barrel.

Regards,
ken