The First Thousand Shots

[justin amateur]

What happens to the bore of a new barrel during the first thousand shots?
I believe it takes 2 bricks of 22lr downrange through a new barrel,
before you can confirm the capability of the barrel to produce predictable results.
Problem....as was pointed out, all I'm basing my opinion on is anecdotal evidence.
It's true, no documentation of barrel wear during what we refer to as break-in.
How to accomplish that, eh?

New year, new project....document the effects of the first thousand rounds
through the bore of a brand new 22lr barrel, using a borescope.

Purchased a 26 inch rigid Teslong USB 5 mm borescope.
Ordered a brand new CZ 455 Varmint barrel in 22lr.
Instead of offering an opinion, I'll offer images of target results and the interior of the barrel.
We can draw our own conclusions based on what can be seen.

Started by building a jig to hold the barrel and borescope
so as to be able to duplicate image capture locations.

The rod of the borescope is marked at 1/4 inch intervals.
Images are captured at referenced intervals, down, left, up and right, inside the bore.
That way a comparison can be made of the same spot at different times in the process.
96 images documented, each time, before and at 100 shot intervals for 1000 rounds.

Here are a few before images...

The leade, reamer cut marks visible

Deposits of some sort left in the barrel from the factory

Rough edges left on the lands

Circumferential patterns left from the hammer forging of the barrel

Link to the entire 96 images taken of the bore as shipped from the factory,
after cleaning with Hoppes 9, patches and a nylon brush.

Barrel Break-In, Before

96 new items · Album by just another interested amateur

photos.app.goo.gl

 

[BullGear]

I'm not sure if you're asking a question or sending date from an experiment. But I think the type of ammo you're shooting will skew your results.

 

[justin amateur]

Does barrel polishing occur shooting rimfire ammunition,
does it improve accuracy over time, if polishing does occur
how many shots does it take to show that improvement?

 

[oldfatguy]

Will be interesting. Thanks in advance.

OFG

 

[AGrizz]

Great Justin. Looks like you have a nice little CZ barrel there so let her roll. What I have learned is there is a very minute build up of residue in the groove that is like glass in a short time. This seems to act almost like an accuracy enhancing deposit. Every time I have removed this the build up must return to get the accuracy back again. The CZ barrels are one of the few you are able to see this.

The other barrels look like someone used a grub hoe to make the grooves. Don't believe me, get a bore scope. Scare the hell out of most people. The factory barrel looks good from the end looking down it. Bore scope it and you will pee your pants.

Any more the only ammunition I run has a good lubricant on the bullet. No Thunder duds, nothing copper plated. Today it is only Lapua and SK based ammunition. No, no Eley either. Learned the hard way. Works in some and not others.

 

[steve123]

Would you use all Lapua Xact please/JK

 

[Aftermath]

Good idea. I have notifications set up.
How are you planning to compare accuracy during these 1000 rounds? Shooting from a sled or something?
How often do you plan to clean that barrel? Please do before/after barrel cleaning photos and target comparisons,e tc.

 

[justin amateur]

X-Act? Steve, really?

Not much difference in price currently, between hi end Lapua and bulk CCI.

I plan on using SK Biathlon Sport from the brick that did the best at 200 yards.
First box, fifth, tenth, fifteenth and twenty-first will be shot for accuracy at 50 yards off heavy bags.
This is an eight year old rifle, been used with a variety of barrels.
CZ 455 Varmint, single set trigger, pillared, bedded, barrel is free floated,
Mueller 8-32X44 target reticle, set trigger breaks at 10 ounces.
All targets shot will be posted including pics of setup and ammo.
Barrel wear and results with the SKBS are the important parts.
The rest is just letting cheap ammo drag powder/primer residue down the bore.

 

[1911JMB]

It will be interesting to see what happens

 

[justin amateur]

CZ 455 Varmint, Mueller 8-32X44 Target retical, heavy bags, new factory barrel, 50 yards
SK Polar Biathlon from a tested brick, first 50 shots

ten 5 shot groups

Note the change in pattern at shots 35 to 40.
First 35 shots 1.5 to 2 moa, then submoa.
Something changed. Wasn't me or conditions.
This is a well used rifle, I understand it's quirks.


Possible answer seen after running the bore following the first 100 shots.
Before image of the crown, see the cotton fibers hung up on the burr at the crown?

Where's the burr at the same location after 100 shots?
No cotton fibers hung up at the crown after cleaning.

Note also the circumferential pattern has been worn away
and replaced with a linear abrasion pattern.
Looks like 400 grit sandpaper was run down the barrel.


Next 50 shots with a low quality batch of CCI SV.
This stuff is not CCI's best. Dents, dings, chips, bullet material over the crimp on to the brass.
Throws strays even from my Lilja and Shilen barrels.

Yeah, that's as expected, crap ammo, crap results.
All it has to do is go bang and clear the barrel.
Each bullet is dragging primer/powder residue through the rifling and polishing the surfaces.


After cleaning with Hoppes 9, patches and nylon brush,
the next 96 images of the bore after 100 shots downrange.
Bore shows a linear abrasion pattern, the deposits are gone,
tool marks still visible at the leade, still a few rough edges on the rifling.

Barrel Break-In, First 100

101 new items · Album by just another interested amateur

photos.app.goo.gl

 

[Mr. Wolf]

Very interesting thread. I too found my CZ 457 settling down after 400-500 shots but it could be due to shooting for groups with cheaper ammo and working up to the more expensive stuff.
It'll be interesting to see the correlation between the group size and borescope photos.
Thank you and subscribed.

 

[Defender32]

This is very interesting. It would be cool to do this on the Vudoo when it gets here in May. Might have to look into one of the cameras.

 

[Aftermath]

The way the barrel gets more accurate reminds me of a custom I had made by a VERY good smith. I fired it 20 rounds and it was grouping like crap. I was seriously cussing my smith. 20 rounds and really no good group. I knew it wasn't me, shooting from a real stable set of bags, zero wind, etc.
Since I was fireforming, I sort of blew off the results and shot the 100 rounds I had loaded up so I could really start load development.
About 25 rounds down the tube and it started grouping. I mean groups of under 1/4" at 100 yards. I just kept shooting many different 10 round groups until I had my 100 fire formed cases.
I have no idea what cleaned up in that barrel but it certainly did clean up. I've fired groups of near 1/10" at 100 yards many times with this rifle since. It's literally like shooting a laser all the way to 600 yards. I have not shot at anything beyond 600 that I can measure but I am certain those are also under 1/4 MOA. I am convinced that a few rounds rounds polishing that steel with copper makes a huge difference in even high quality barrels installed on actions prepared by the finest of smiths.
Your study confirms what I have been saying for decades! I am real curious how this all plays out. I'd love to see more studies of this bent with various calibers.

 

[Sgeorge]

I know this typically opens a can of worms but maybe a different cleaning method. Boretech Rimfire Blend for the bore and Carbon Remover for the chamber.

 

[justin amateur]

Hoppes 9, patches and a nylon brush look to be doing a decent job on this new barrel.
Every 100 shots, clean until patches show no discoloration, then capture images with the borescope.

Second 100 rounds sent using bulk Winchester.

The whole box at 100 yards

CCI TNT Green 30 grain jhp 22wmr rated 2050 fps CZ 455 Feddersen Fuglie Hey...why are there only 27 holes y'er asking? :confused: Well, there's a good reason for that... That's what's left of the magazine and mag well. :( Case rupture/head separation blew out the bottom of the...

www.snipershide.com

200 yards with rimfire

Keep up the good work. I will join you and your 200 yard shooting next Spring/Summer when I spend more time at my new property.

www.snipershide.com

200 rounds through the bore, still visible rough spots.
Still a few burred edges on the lands showing up.
Crown now looks very sharp and clean.

Other portions look very smooth, almost looks honed.

Link to view bore images after 200 shots...https://photos.app.goo.gl/zFvkL37McxW95tBF6

 

[justin amateur]

How do you know if there's an abrasive in the residue?
Any way to find out?

Probably

Okay....easy enough.

Pull apart some cartridges,
primer in one foil tray, powder in another

Liberate my inner pyromaniac and ignite the primer, then the powder
and by chance, or luck, there was no flare up, just a puff of smoke in each foil tray.

Piece of marine stainless from my store of boat parts,
marked into 3 zones. One for bullet rub only,
one for bullet coated with primer residue,
one for bullet coated with powder residue.

Rubbed each bullet in it's sector for 25 passes back and forth.
Not much pressure applied using two finger tips to hold the bullets.

Top sector, bullet only, some lead and bullet lube deposited, but no scratches.
Middle sector, primer residue coated bullet shows visible scratch patterns.
Bottom sector, bullet with powder residue shows a few scratches.

Looks like the primer residue is responsible for the majority of the polishing.

Good thing I'm easily entertained.
Kept me busy for 30 minutes in the garage.
Wife came out and asked: Is something burning? I can smell it in the kitchen.

 

[68hoyt]

Keep it up ,,,, this was kind of a topic of discussion the past couple of weeks with family , thanks

 

[Drew M]

Great topic,
watching with interest

 

[Matagorda308]

Following.
With great interest.
Thank you for your efforts and great documentation. I’ve been hoping the new Teslong borescopes would allow more experiments like this one.

 

[Matagorda308]

How do you know if there's an abrasive in the residue?
Any way to find out?

Probably

Okay....easy enough.

Pull apart some cartridges,
primer in one foil tray, powder in another

Liberate my inner pyromaniac and ignite the primer, then the powder
and by chance, or luck, there was no flare up, just a puff of smoke in each foil tray.

Piece of marine stainless from my store of boat parts,
marked into 3 zones. One for bullet rub only,
one for bullet coated with primer residue,
one for bullet coated with powder residue.

Rubbed each bullet in it's sector for 25 passes back and forth.
Not much pressure applied using two finger tips to hold the bullets.

Top sector, bullet only, some lead and bullet lube deposited, but no scratches.
Middle sector, primer residue coated bullet shows visible scratch patterns.
Bottom sector, bullet with powder residue shows a few scratches.

Looks like the primer residue is responsible for the majority of the polishing.

Good thing I'm easily entertained.
Kept me busy for 30 minutes in the garage.
Wife came out and asked: Is something burning? I can smell it in the kitchen.

Which ammo did you pull apart for this test?

 

[justin amateur]

Some cheap Aguila Super Extra, 3 cartridges
Dumped the powder, then used a paper clip to scrape loose the primer....gently....very gently.

Most of the rimfire I've read about uses lead styphanate as a primer.
Contains silica/glass powder as the igniting agent.
The silica can be up to 20% of the primer by volume.
That's a hefty bit of abrasive.

 

[oldfatguy]

With the high round count 22lr barrels are good for is the abrasive a problem?

OFG

 

[justin amateur]

Abrasive problem?

Read an article that Eley changed their primer mix due to excess wear just forward of the leade.
That was a while back, no further information available.

 

[68hoyt]

I read eley changed in 2008 , what have you found out ?

 

[justin amateur]

Still reading Hoyt.

Module 05 :: Primer Manufacture

projects.nfstc.org

Priming Compounds and Primers Introduction - Ballistics

A priming compound is a highly sensitive explosive chemical which, when struck by the firing pin or hammer of a weapon, will explode with great violence,

www.bevfitchett.us

Priming Compositions - Chemical Analysis Of Firearms

Priming compositions for firearms ammunition are mixtures which, when subjected to percussion, provide a sudden burst of flame that serves to ignite the

www.bevfitchett.us

US4689185A - Priming method for rimfire cartridge - Google Patents

A priming method for rimfire cartridges is disclosed in which a propellant solution is disposed adjacent a centrifugally located primer material in a rimfire cartridge. The solvent is then evaporated to leave a propellant film near the primer material in order to provide slower, more uniform...

patents.google.com

 

[68hoyt]

Thanks for sharing

 

[1badDart]

With the high round count 22lr barrels are good for is the abrasive a problem?

OFG

I have a 52D Winchester and a Remington 40XB that came from the CMP, both show signs of plenty of use yet both shoot very well. I'd be willing to bet that 98% of rimfire owners will never shoot enough to have a problem.

 

[justin amateur]

Be aware, that particular priming methodology is pretty old school and not largely practiced with higher end ammo,
which is a big reason it’s higher end, ELEY in particular. ELEY eps ammo, for instance, is for ELEY priming system.
the older method with liquid mixture being spun was found to yield fairly uneven primer distribution.
Now they take a wet matrix in pellet form, drop it in and press it to swage it evenly throughout rim.
A few years back Shooting Times did a comprehensive writeup all about ELEY and still should be available online....pretty good read.

I'll find it and read it Tim, thanks for the heads up.

The Best of The Best Gets Better

You don't have to be an Olympic shooter to appreciate Eley's excellent rimfire ammunition.

www.shootingtimes.com

From the linked article...

the goal of the TenEx improvement project was to increase the percentage of reference groups (less than 15mm diameter at 50 meters) from 8 to 10 percent to 30 percent. Current Eley TenEx Ultimate EPS ammo averages 50 percent.

So only half of the Tenex Ultimate is capable of sub 15 mm groups at 50 meters.
The rest exceeded that grouping, and that's the best of that label.

15 mm is about 0.59 inches measured outside of hole to outside of hole at widest point.
Subtract 0.21 inch and you get a ten shot group of 0.38 inches center to center.
That's better than I can do for 10 shots at 50 yards.

 

[45cal4life]

Holy crap!!! Thank you for not only doing this research, but also putting it out there for all to see

 

[justin amateur]

Thank Tim.
He was the one that pointed out I was basing my opinion on unsupported information.
No documentation of barrel wear during break-in to substantiate my thoughts.
I like hard data. Difficult to argue with images taken of the same spot at 100 shot intervals.

 

[~JM~]

Very interesting. Appreciate the effort.

Have you ever experimented with JB Bore paste or Flitz polish? Recall reading those two products & Kroil are popular with the Bench Rest crowd.

 

[justin amateur]

Checking for improvement, early morning before the wind picks up.
SK Biathlon Sport at 50 yards.

CZ 455 Varmint, heavy bags, new barrel

Still not producing consistent results.
Group average size is dropping but aggregate almost the same.

How much and where does the burn residue end up in the bore?
Good question. Before cleaning, after this mornings session,
pulled the barrel, grabbed a camera and played with focal length and lighting.
managed to get a few images that best illustrates the answer.

And the answer is, a lot of residue and everywhere from the leade to the muzzle, top, bottom and sides.
That explains the wear patterns showing up all through the bore.
Heavier clumps in different spots, biggest on the bottom of the barrel.

Time for a comparison

Shots 1 through 50 with SKBS.

Then shots 200 through 250

Second box shows better results than the first.
Each target shows improvement with progressively smaller groups sizes.
Still slinging strays, but significant improvement with increased number of rounds sent.
0.45 inch best group on the first target, 0.3 inch on the second.
Hopefully that rate of improvement holds up.

The leade as received from the factory

and after 300 rounds, the lands still appear rough
but the grooves show polishing has occured.

Link to borescope images after 300 rounds https://photos.app.goo.gl/LVPSsHLJSs64pfaS9

 

[justin amateur]

@JM... I've read about Flitz and JB being used to polish the bore on a rifle,
but never tried it. I'd rather purchase a custom barrel that is
already as good as it is going to be, as opposed to attempting
to improve a hammer forged factory barrel to obtain better results.

 

[*rim-star*]

Great write up Justin, I have looked at many a CZ factory bore with a bore scope, the ones that have the tool marks in the leade and first few inches of the barrel always threw strays for me, the ones that had very few or no tool marks didnt throw as many strays.

 

[huntnh]

Very interesting keep up the good work

 

[goneballistic]

Great write up Justin, I have looked at many a CZ factory bore with a bore scope, the ones that have the tool marks in the leade and first few inches of the barrel always threw strays for me, the ones that had very few or no tool marks didnt throw as many strays.

That seems to be the theory behind the tubb barrel conditioning bullets. They have abrasive on them and are designed to smooth the bore out as you work through them.

 

[justin amateur]

Some days all you can do is laugh.
Bulk 22lr at 50 yards in a 6 to 10 mph swinging tailwind is one of 'em.

Federal 36 grain CPHP

Shifting wind direction and speed with poor quality cartridges threw some amazing strays.

The next 50 sent were Remington Thunderbolts

And the Thunderbolts were better quality than the Federals.
Even with the ridiculous wind conditions.

Doesn't matter, just an excuse to put another hundred through the barrel.

Above after 400

Below as shipped

Now, even the tool marks in the leade are showing smoothing.

 

[~JM~]

Looking better. Are you able to tell if the copper plated has more "finishing" properties than the lead?

 

[justin amateur]

@JM.... I rubbed the nose of an unfired wax coated lead 22lr
on a piece of polished steel and showed no abrasion.
Did the same thing with a copper washed 22lr and again, no scratches.
It looks to be that the burn residue is providing the abrasive
and the bullets are doing the work of dragging it through the bore.
The more shots sent, the more smoothing is taking place.
Doesn't matter hi-v or subsonic, only round count.
Results have improved when using the SK Biathlon after 200 shots.
Next test for accuracy will be at 500 shots.

 

[~JM~]

Much like the custom fire lapping bullets/compounds used in revolver barrels.

 

[Doctorwho1138]

This is an interesting thread. Thanks for sharing

 

[sniperstudent]

Thanks for the efforts and info. I will be checking in on the barrel polish progress.

 

[justin amateur]

No assumptions Tim.
As you pointed out, I have no real documentation of barrel break-in or wear during the first 1000 shots.
I'm not using anything but a nylon brush and patches to eliminate any claims that the bronze brush
was responsible for the linear abrasion marks. Will the barrel show wear and/or improved results?
Not my responsibility to draw that conclusion. I can comment on what looks to be happening,
but the final decision will have to be made by those comparing the images for themselves.
I've never seen a long term borescope project like this with rimfire, where all the images are available to view.
I'm doing my best to provide a full record of the bore finish after each 100 shots.
Also providing an image of every target shot during the process.
That's as good as I can do, as I have no access to a test tunnel.
If you'd like, I wouldn't mind a duplication of the process being done by y'erself.
Set it up, use a different cleaning method, indoors from a fixture, and document what occurs.
Two sets of independent data is just good research procedure.

Have I seen changes to the bore during the first 400 shots? Yes.
Has there been improvement in the results on target with the SK? Yes.
Have some of the burrs that were visible in the initial images been removed? Yes.
Is primer residue capable of acting as an abrasive and cutting into a steel surface? Sure looks like it.
If you hand lap the bore on a custom barrel, don't you coat the lead lap with an abrasive to smooth the rifling? I believe so.
So far what I've seen indicates accuracy is improving and the bore in this factory barrel is being smoothed out.
What will happen after 1000 rounds remains to be seen.

 

[gkgeiger]

Justin, please keep up your good work. Most of us appreciate it.

 

[justin amateur]

knock yourself out

Can do Tim....good thing I'm easily entertained.


Tim? What happened?
You offered some useful criticisms, then deleted them? Why?

 

[Hi-Wall]

I fire lapped a Ruger Stainless Single Six by shooting RWS CB Langes with the lube removed and replaced with Clover brand 320 grit valve grinding compound. Ruger Stainless steel is harder than a traffic cop's heart. I stopped after 50 rounds. I did get better accuracy with both cylinders. I realize all I am doing is inducing wear so when I saw an improvement in grouping I quit.

 

[AGrizz]

Not trying to get in the middle however. If they are proven facts then where are these proven facts? What and where is the verifiable documentation? We can all learn something new. Please help us in this process.


Just for clarification: I do not normally update an older message. However my original response was in relation to a posting here by " Tim " that has since been deleted. That information is gone. Most people do not delete there original messages. I hope he returns with a good critique at the end of this testing for Justin.

 

[justin amateur]

@AGrizz...that's my problem, couldn't find any documentation of rimfire barrel wear during the first 1000 shots.
Plenty of opinions as to what is occurring and claims of improved accuracy after 2 bricks of 22lr sent.
However, no actual documentation of change over time. That's what Tim pointed out in a previous thread.
I was basing my comments on unsubstantiated information. A search of the internet showed he was correct.
Opinions and anecdotal evidence aplenty, hard data/images none with rimfire. When ya' can't trust y'er information
ya' have to try it for y'erself. I've been doing that with rimfire for about 9 years .
Determining if those internet rimfire truisms are based on fact or wishful thinking.
Things like free floated barrels, find the brand y'er rifle likes, sub-moa all day long,
precision shooting with 17hmr and 22wmr, consistent accuracy at 200 yards, supersonic transition.
Try 'em, document 'em, figure out what works and what are incorrect conclusions based on minimal data.
Everyone needs a hobby, rimfire keeps me occupied.

I think Tim might be a bit annoyed that I don't agree with his opinions/experiences.

It's possible I might have pissed him off-fa-fa.

I do affect some folks that way.
Likely because I question everything.

 

[sniperstudent]

I would have liked to have seen the proven facts so I could decide for myself what the facts had so say. Keep up the good work justin. Your efforts on this matter and other matters have helped many. What do you torque the barrel grub screws to when installing the barrel on the CZ?

 

[justin amateur]

I torque the barrel screws at 34 inch/lbs.
Produces best results in my A and B model 455 receivers.