buildup from coated bullets (xdm)

[motosapiens]

I've shot tens of thousands of coated bullets in the last few years, never experienced this issue before. brand new xdm, rounds plunk at 1.08 oal (blue 115 gr), but after 50-60 rounds they start sticking in the beginning of the rifling. If i pull the barrel out, they no longer plunk, and i can look in there with a flashlight and see some blue at the beginning of the rifling. After thorough cleaning with a copper brush, rounds plunk again. Anyone ever experienced anything like this?

[kcin]

are you shaving the coating off in the reloading process by not putting enough flare in the case mouth?

Edited January 10, 2020 by kcin

[Out of Ammo]

1.08 sounds short enough for the XDM. Did you put black dry erase on the ojive during the plunk test to see if it might be rubbing?

[motosapiens]

18 minutes ago, kcin said:

are you shaving the coating off in the reloading process by not putting enough flare in the case mouth?

 

definitely not. like I said, i've been loading these bullets for a long time.

[kcin]

Just now, motosapiens said:

 

definitely not. like I said, i've been loading these bullets for a long time.

 

It might be a bad batch of bullets.  Call the manufacture ask them if anyone else has been having the same issue.

[motosapiens]

2 minutes ago, Out of Ammo said:

1.08 sounds short enough for the XDM. Did you put black dry erase on the ojive during the plunk test to see if it might be rubbing?

 

the blue's are pretty chubby, with a fairly short profile. they definitely need to be shorter than other shaped bullets, but with the clean barrel, they plunk and easily spin at 1.08.  at 1.10-ish they are often touching the rifling. 

[motosapiens]

7 minutes ago, kcin said:

 

It might be a bad batch of bullets.  Call the manufacture ask them if anyone else has been having the same issue.

 

a reasonable thought, but i've been running them without issue in my cz and in a couple different 1911's.

 

I have a different brand of 124's tho, that plunk at a slightly longer length. Perhaps I'll take 100 of those out to the range next time I go.

 

I'm kinda wondering if i didn't just get a little coating to stick to a new dry barrel at the start of the lands, and then more coating sticks to the old coating until it gets thick enough to interfere. perhaps a thorough cleaning  followed by some polishing (or just some more use) will help. I might also get a box of plated bullets to practice with and then try again after 500 or so rounds down the pipe to smooth off any roughness.

 

fwiw, the gun is brand new, and I didn't clean or oil the barrels or anything before I shot it the first time. Both barrels exhibited the same behavior (4.5" standard barrel and 5.25" threaded barrel). At first I thought one of them might have a shorter chamber, so I switched barrels out at the range, and the other started sticking after a couple magazines.

 

Thanks for the suggestions, btw....

Edited January 10, 2020 by motosapiens

[kcin]

4 minutes ago, motosapiens said:

 

 

I have a different brand of 124's tho, that plunk at a slightly longer length. Perhaps I'll take 100 of those out to the range next time I go.

 

.

That's what I would do.  I have ran into couple of bad batches of projectiles over the years and from my experience it will drive you bat s#!t crazy trying to figure problem.

[kcin]

No problem man,  I had a batch of .40's that was out of spec.  I had been shooting those bullets for years with no problem.  But switched to a new gun about the same time I received a new batch and I was blaming the new chamber and throat for being to too tight... I even went as far as to have the throat reamed.  I was pretty chapped once I figured out what was actually going on. 

[K-Texas]

We say plunk test, but sometimes plunk & spin is more appropriate. When you drop those loads into the chamber and hear a plunk, you should also be able to rotate the round freely. Also remember that different bullet profiles require different OACLs.

[John Boy]

1.08 sounds short enough for the XDM. Did you put black dry erase on the ojive during the plunk test to see if it might be rubbing?

That’s .002 longer than I load them. These are ACME 124 coated RN.


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[motosapiens]

12 hours ago, John Boy said:

That’s .002 longer than I load them. These are ACME 124 coated RN.


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Hmm. Maybe i'm just cutting it too close and just need to load shorter to leave some freebore. I loaded up a hundred a little shorter to try, maybe i can get out to the range today between football games. 

[K-Texas]

The method is easier when you load .355" jacketed bullets. With oversized cast or plated you'll need to use your press. Get your OACL down to the point where with the round in the chamber, the case rim is flush with the barrel hood and then shorten in smaller increments like .005" or less. .005" is enough freebore provided your press can provide tight OACL variations. Not always easy to do with a progressive press. .010" of freebore is not so much to deter accuracy.

 

Most pistol makers are using short chambers for 9 x 19mm these days. The XDm is certainly one of them. They allow for the use of 124 gr. 9mm NATO because of the "universal" long and slender bullet profile. Other bullet profiles like JHPs and truncated cone shapes with short ogives will require a shorter OACL.

 

Something that might help are some cast or poly-coated bullets that the maker calls Round Nose that are something like a SWC in that the bullet diameter above the shoulder is smaller in diameter. Small enough to pass through the barrels throat without making contact with it. Here's a link to one example and I'm not sure you'll find one over 125 grains.

https://www.snscasting.com/9mm-125-grain-round-nose-red-coated-1000ct/

Edited January 11, 2020 by K-Texas

[motosapiens]

update. at 1.075-ish, i was able to get over 100 rounds through the gun without issues. I took it apart at 50-ish and the rounds were just barely sticking in the rifling, but not enough to cause problems. another 70 rounds caused no real change in that. So i'm going to shorten them up to 1.06 and run with that for a while. The only bad part is I have like 3-4k rounds loaded at 1.09-ish, but my 1911's and pcc will eat them up eventually.

 

note to self: in the future, do plunk tests with a dirty barrel, not a sparkling clean brand new one.

 

thanks to all for the helpful suggestions.

[K-Texas]

If the bullet is touching the lands upon ignition, it does raise pressure. How much will depend on the burn-rate of the powder with the faster burners having the higher increase.

[zzt]

On 1/10/2020 at 4:53 PM, motosapiens said:

I might also get a box of plated bullets to practice with and then try again after 500 or so rounds down the pipe to smooth off any roughness.

 

That's exactly what I do with all new barrels, especially Barsto.  Jacketed works even better.

[twb]

I recently ran into a similar problem with my Blue Bullets (9mm 125 gr RN).  I had been loading at a COL of 1.12" for thousands of bullets with no issue.  Then I started having problems with the bullet striking the rifling and not plunking only on my XDM and XDS.  The 1911s and Berettas were ok.  It turned out two of the boxes of 1200 had a different profile (pictures attached).    The XDM and XDS have a shorter throat and that different profile would cause the bullet to hit the lands.  The bullet on the right is the bullet that has caused the problems.  In addition to the profile being different, the length of the bullet changed from .6" to .588" which gave me a change in the insertion depth.  I recently received a new case of bullets and the profile is similar to the original that had no issues.  I contacted blue bullets and they said that they change the molds every 12 months and that the profile with the new molds may be different.  I haven't decided if I am going to change suppliers.  Up until now, I have been very pleased with blue bullets.

It is possible you ran into the same problem that I did.

[jcc7x7]

Moto

I had a Glock 10mm Gen2 I think that loaded up at the beginning of the rifling .

I carried a bore snake and went to pulling it threw breach to muzzle every 50 rounds 

Yeah PITA, but it worked and kept the gun locked up correctly working well.

After a while changed to jacketed and that was that.

 

Just an idea to get you threw the rounds you have loaded!

[igolfat8]

Some powders, with a high nitro content, will soften and attack the paint. Bullseye, TiteGroup, WSF, WST, PowerPistol all have high nitro content. What powder are you suing?

 

Take a few tablespoons of your powder and put it into a zip lock baggie along with a couple bullets, then seal it up. Leave it there for 3 days and then remove the bullets. See if the powder is sticking to the bullets or if the gloss on the paint has turned dull. If so, then take your thumbnail and test the paints hardness to see if it’s softened. If so, then that is likely your problem. Ignition will blow Some of the softened paint off the bullets base and allow it to build up just after the chamber.

If you choose to continue to use high nitro powder, it’s best to shoot to ammo within a day or two after loading. The longer it sets loaded and is exposed to nitro, the more ill effect it has on the paint.

 

Try Sport Pistol powder and see if your problem goes away. It’s specifically engineered to NOT attack the paint.

[BJB]

9 hours ago, igolfat8 said:

Some powders, with a high nitro content, will soften and attack the paint. Bullseye, TiteGroup, WSF, WST, PowerPistol all have high nitro content. What powder are you suing?

 

Take a few tablespoons of your powder and put it into a zip lock baggie along with a couple bullets, then seal it up. Leave it there for 3 days and then remove the bullets. See if the powder is sticking to the bullets or if the gloss on the paint has turned dull. If so, then take your thumbnail and test the paints hardness to see if it’s softened. If so, then that is likely your problem. Ignition will blow Some of the softened paint off the bullets base and allow it to build up just after the chamber.

If you choose to continue to use high nitro powder, it’s best to shoot to ammo within a day or two after loading. The longer it sets loaded and is exposed to nitro, the more ill effect it has on the paint.

 

I've heard this claim repeated over time but for polymer coated bullets it's not true......at least with TiteGroup.  It might be true with the do-it-yourself powder coated bullets that are just paint, but with a good Hi-Tek polymer coated bullet like Acme, Blue Bullets, or Ibejiheads it isn't true.  I saw this claim repeated so many times on forums that I decided to test it.  Over two years ago I put a handful of Acme, Blue Bullets, and Ibejiheads in a zip-lok bag with a cup of Titegroup.  In over two years the coating on these bullets appears to have not changed in any noticeable fashion.  They look brand new.  The coating isn't soft or dull or flaky.  I've taken one of each brand out and smashed them with a hammer and the coating is still bonded to the lead 100%.  

 

This zip-lok baggie full of bullets & TiteGroup still sits on my loading bench, and I even put the smashed bluets back in.

 

I plan to take a few out & load them up & shoot into water jugs to recover the bullet to see if there is any noticeable change identified there.  As a matter of fact I have some Acme & Blue Bullets that I loaded a couple years ago with TiteGroup during load development and then stored away.  I can also shoot & recover some of these.

[pcschwenke]

This past year I ran a few thousand Hi-TeK coated bullets in my XDm, revolvers, and 1911s.   Near the end of the year my pin gun was having accuracy issues and it was due to lead build up in the barrel & comp.  In all the years shooting hard cast lead, I never had build up this bad.  I discovered it at a match...   A friend using the same bullets had exactly the same issue.   At a large Pin Shoot, I witness two of the bullets splitting in half after hitting a bowling pin...   True hard cast lead will not split.  After doing some research, I realized that high temperatures are used to cure the Hi-Tek which most likely is softening the outside of the bullets.   If you scratch off the Hi-Tek, the lead beneath is pretty soft.   The coating may reduce fouling in the barrel, but I wonder if it burns off the base while being fired and leads porting.   The bullets I have been using are 145gr 9mm and are by far the most accurate in my XDm.  

[igolfat8]

Hi-Tek coating is cured and baked at 400*F which is not what I would consider high temperature . Keep in mind that lead bullets are cast at 700*-750*.  I too have shot a lot of HT coated bullets in open pistols and you are correct that it will foul some barrels and most comps. Powder coated / polymer coatings won’t leave as much fouling, if any. I’ve recovered powder coated bullets from berms and the rifling will not cut through the coating but the HT bullets I’ve recovered always show bare lead exposed in the groove and land marks.