Carbon Build Up in TSO 40 S&W Bore

[tdogg]

So I deliberated on where to put this question but since this group is so helpful and it is semi reloading related I chose to put it in the Ammo and Handloading section.  If it needs to be moved by all means move it.

I have a dilemma I've run into with my TSO.  The bore is incredibly hard to clean!  Even after a single match, I will have hard carbon in the grooves that does not come out with any brush (copper, nylon, or Stainless) or solvent soaked patch.  At first I thought my bore was pitted and that was just how it was going to be until I replaced it.  But then I ran a small pick down the edge of the rifling/bore and I was able to scratch it off!  I have tried numerous carbon specific bore cleaners and some others (KG, TM, Hoppes, MP Pro7, Gunslick, and Piston clean) and none seem to touch it.  I have tried soaking and scrubbing and scrubbing and scrubbing but the only real solution is to use Iosso bore paste to manually scrub it off.  Even using the bore paste it takes several patches to come clean.  I normally only reserve the bore paste for rifles that are really dirty and have never had a pistol barrel with this type of caked on carbon. 

I don't have any copper buildup and the rifling/bore looks very shiny when clean.  I don't notice any imperfections that would lead me to think the bore is damaged.  The carbon build up is heaviest near the chamber and travels about half way down the barrel getting lighter near the middle.  I seem to recall it is heavier on one side of the barrel (around the bore circumference) than the other but I am not certain this is so.

At first I thought that it was due to my undersized bullets but I have since switched to a different plated and FMJ and it still does the same thing.  I've run 165gr RNFP plated (undersized) with CSB-5 and Sport Pistol, 180gr RNFP plated with CSB-5 and Sport Pistol, and now some 165gr FMJ with Sport Pistol with the same results.  I nominally target about 170 PF and with these two powders I'm safely in the upper end of the load window.

The gun seems to still shoot very well.  I mostly (only) use this in USPSA matches and am still able to make the long shots with ease.  My last load development with the 165gr FMJ had groups from .6 to 1.3 inches center to center at 10yds (shot from rest). 

I have not slugged the bore yet but it is on my list of things to check.  If the slug/bore is out of spec, then I'll be a little disappointed since this gun only has ~3000 downrange.  It's the only thing I can think of as the problem similar to when you shoot undersized lead and get leading due to hot gasses escaping past the bullet.  Except this is just hot gas getting pressed/ironed into the groove by the plated/FMJ bullet?

Is there anything else I should look into?  Am I just being OCD/neurotic?  Should I just clean it until the patch comes out clean?  Has anyone else ran into this type of issue?  If so, how did you solve it?  As always, I appreciate any thoughts!

Cheers,
Toby

[Matt101]

This seems a bit odd and I can only assume that it is load related.

I can?t remember the last time I really needed to scrub the barrel of either my Shadow 2 or TSO (in either .357 Sig or .40).

I mostly shoot player bullets with some coated lead in the TSO.

The most I every did was soak the barrel in Boretech Eliminator and then use a Lewis Lead remover. These days the S2 is lucky if it gets a dry bore brush through it occasionally.

I?d look to switch powders and/or use correctly sized bullets.


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[tdogg]

Alright, I just slugged the barrel and with my incredibly cheap but surprisingly accurate calipers my groove diameter is measuring about .402-.403!  That is way too big (especially for a factory fitted/tuned comp gun) and think I'm going to contact CZUSA and discuss.  I will take this slug to work and confirm the diameter using my calibrated micrometer but I'm positive my calibers are not that off.

This is a bummer if especially if I have to send it in for work.

Cheers,
Toby

[IDescribe]

1--What did you slug the barrel with?  Alloyed lead  an have a hair of springback.

2-- Cut back on your variables.  Run a confirmed load with one bullet - - preferably a JHP - - and one powder - - Sport Pistol - - and see if it's the same.

[tdogg]

ID,

I used old stick on wheel weights I have had for ever.  I'm pretty sure they are just lead.

Not really experimenting but just what I've loaded over the last year.   The most recent load development with the fmj was just me getting ready when my current stock runs out.

I didn't pay to much attention to the bore at first but ever since I detail cleaned it and noticed the crud in the bore (about 6-8 months ago) I've been diligent in my cleaning and inspection.

Cheers,
Toby

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[Matt101]

I doubt there?s anything wrong with the barrel.

Clean it. Then run a few hundred rounds of WIN USA 180gn JHP?s through it. Then inspect. Keep an eye on the accuracy too.


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[tdogg]

Another thing I should mention is that I've experienced keyholing and random fliers when I was shooting the undersized 165gr plated RNFP bullets.  It wasn't frequent but happened enough to notice during a match (maybe once per).  If my barrel is really 0.402 inches then that most likely explains why I was having issues with the 0.399 165gr plated bullets (all gone now).  That was really undersized!

I can't say that I've seen that in a while but will keep an eye out for it.

Cheers,
Toby

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[Wobbly]

The issue sounds like a chemical reaction issue rather than one based on a coating rubbing off from the bullets. ??

Alright, I just slugged the barrel and with my incredibly cheap but surprisingly accurate calipers my groove diameter is measuring about .402-.403! 

Were these digital calipers ? If so, they can't be trusted at that level becasue software is used in the caliper to keep the readout from flickering. So when you are between 2 numbers (which is all the time) the software decides what will appear on the screen. This is not a problem for a thimble micrometer, which is not afraid to show you that the reading is between 2 numbers.

 

[tdogg]

The issue sounds like a chemical reaction issue rather than one based on a coating rubbing off from the bullets. ??

Alright, I just slugged the barrel and with my incredibly cheap but surprisingly accurate calipers my groove diameter is measuring about .402-.403! 

Were these digital calipers ?

 

Not sure what you mean by chemical reaction? If it was what would be reacting?

I'm definitely not seeing any copper fouling or any plating or jacket material.   If it's there it comes off with the initial patches.

No I use an old set of no name dial calipers that I've had for 20 years.  Unfortunately last year i dropped them and chipped one of the id measurement points.  I've been looking at replacements but haven't pulled the trigger yet.

So I brought home my micrometer set and the average slug diameter is 0.4018 inch.

That is well above spec.   I'll slug it a couple more times just because but I think this is my problem?

Cheers,
Toby

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[tdogg]

Slugged twice more with a groove diameter of 0.4020 inch both times.  This time I made the slug a little larger in diameter before pushing it through so that it cut off the extra upon entering the bore.

I reviewed my data and when I slugged my 40p it was 0.3998 using the same materials and method.

I'm going to contact cz and see what they say.

Cheers,
Toby

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[tdogg]

So I contacted CZ and they did send me a RMA.  I decided that before I send this gun in for inspection, I'd do a comparison between my SP01 and the TSO shooting the same quantity and mix of bullets through each on freshly cleaned barrels.

I shot 80 rounds through each, with a mix of 3n37 Gold Dots (+P), 165gr plated over Power Pistol, and 180gr plated over Sport Pistol.  I compared the bores after shooting each and the results were very similar.  The bores both had some fouling but it wasn't apparent that the TSO was any worse.  I ran one patch of Hoppes #9 through each and then one dry patch and inspected.  They both had some fouling still but it was very minor.  The test didn't confirm my suspicion that my TSO barrel is more prone to fouling.

Part of my concern of sending this particular gun into CZUSA is that it came with a factory fitted barrel from CZUB.  If I sent it in and CZUSA replaces it, then I most likely would loose the factory fitted barrel along with the matching serial number.  Now this isn't a safe queen and I would be crazy to sell this gun (ever) but loosing the factory barrel just seems wrong.

So I think I'd rather keep the factory fitted barrel and actually purchase another barrel and fit it myself and keep the factory barrel as a backup.  I think I'm going to contact CZUSA back and let them know I'm not sending it in.  I'll pursue the spare parts and save myself the hassle of waiting for the warranty service too.

Cheers,
Toby

[M1A4ME]

I've fit two barrels now (Pre B CZ85 and a Tactical Sport .40 S&W).  There's a thread (maybe more than one) here about fitting barrels.  Just go slow, wipe the crud off, check fit - often, during the metal removal process.  I used a stone for this vs. a file.  It's slower, but that's because it takes off less metal for the amount of effort you expend.  Harder/longer but not easy to take off too much metal - and it's smooth when you get done.

The only comparison info I can make about the barrel cleaning is that I've noticed my P07 and P09 barrels clean up faster/easier than the CZ75/85 pistols.  The P07 especially (I shoot it more) seems to be very shiny in the barrel with very little effort, even after shooting lead bullets.

A couple of my CZ75 Compacts are a pain to clean vs. the others.  I think, sometimes, the metal on some parts is just a little rougher than on other guns.  The tools they use to cut/shape the metal parts wear out and need to be replaced.  There is a difference between when the tool is installed vs. when it's removed - or they wouldn't be replacing it.  As it wears the parts made/machined with it vary in qualities from when the tool is new to when it is replaced.

[IDescribe]

I don't remember the details, but the metal/finish of the P-07/P-09 barrels is different than other CZs.  I know it's at least harder metal, as people who ream their CZs have a tougher time with P-07/P-09.

[tdogg]

Yeah I've read a couple of threads on fitting barrels along with watched a couple YouTube videos.  I've never done it but look forward to the challenge.  I may wait and try a KKM precision match barrel hopefully available this fall.

I couldn't tell you why this last round of testing resulted in similar minimal amounts of fouling?   Maybe shooting the hot gold dot loads helped clean out the bore?  The power pistol load were also on the warm side at about 185pf.

Maybe I'm just not pushing my competition loads fast enough? With sport pistol they are near the top of the load window and they seem to shoot fairly clean. 

I think for now I'm just going to up my cleaning routine and keep an eye on it more frequently.

Cheers,
Toby



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[M1A4ME]

I can't sit here and say it works, but I can repeat what I've heard.

At the end of a shooting session when you've been shooting dirty ammo (lead, dirty powder) shoot a few good jacketed hollow points loaded with a cleaner powder through the barrel and it will remove some of the fouling form the dirty loads.  Like I said, I can't testify that it works, but some people claim it does.