Ramshot TAC and Suppressed AR's - A Cautionary Tale

[wordsmith]

I realize this is a cast boolit forum and I'm posting a j-word issue, but I thought it might help some of us that live with a foot in both worlds...

I recently acquired a new Rainer 20in Match barrel for my AR-10 308 Frankengun and loaded some 110gr Barnes TTSX rounds running about 3175 fps for maximum effect on coons / hogs. They work emphatically, and are super accurate, so all is well. Or so I thought.

In my Quickload search for a suitable powder, Ramshot TAC looked like a winner for burning rate and fill ratio. Upon testing, it worked as Quickload predicted and I'm off to the races. However, I go to hunt with them and end up on two occasions with brass that is effectively welded to the inside of the chamber when left chambered overnight. Upon removal with a cleaning rod, the brass looks like this (with the rim ripped off by the extractor):

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Notice the blue/green patina in various areas, just like dissolved copper. My borescope indicates similar chamber discoloration and requires Iosso Paste and copper cleaner to shine up again. My untested theory is that the decoppering agent in the TAC is being blown back into the chamber from the suppressor and is attacking the brass when left exposed for hours in close contact with the chamber wall. I've shot hundreds of suppressed rounds using H4895 under the same conditions and have had zero issues. As a side note, I will say that the decoppering agent works as advertised, as borescope examination reveals no detectable copper deposits in the barrel.

As always, your mileage may vary, but I'm switching back to H4895 and will report back if that eliminates the issue. I'd be curious if anyone out there has a similar experience?

[wordsmith]

Here's what the 3 remaining rounds sitting in the magazine look like after sitting overnight. Definitely looks like something attacking the copper.
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[Artful]

Very interesting
Don't use Ramshot TAC myself
- mind if I share the info on a couple of other forums?

[xacex]

Good info. Thanks for sharing.

[dragon813gt]

If TAC is doing this any of the other powders that have copper removers in them should do the same thing, conceivably. I use TAC but don't lead the firearms loaded when done. I'm wondering if a powder like CFE223 will do the same thing.

[leadman]

You don't say what your powder charge is which would help understand what is happening. You state this is a new to you match grade barrel. Could the bore and chamber be tight enough to cause pressure problems? When you worked up the load how did the brass look with smaller amounts of powder?

How does the brass look if you shoot with the suppressor removed?

[Tackleberry41]

Doesn't sound like a pressure issue, but a chemical issue. If its fine w 4895, older powder, no decoppering agents (didn't even know they put that in powders). Yet corrodes like that w TAC overnight, its a chemical issue. Cans blow more junk back inside actions, ARs would be more so with their DI systems.

[wordsmith]

Very interesting
Don't use Ramshot TAC myself
- mind if I share the info on a couple of other forums?

Feel free.

[wordsmith]

If TAC is doing this any of the other powders that have copper removers in them should do the same thing, conceivably. I use TAC but don't lead the firearms loaded when done. I'm wondering if a powder like CFE223 will do the same thing.

I was thinking the same thing, since I was planning to load a bunch of 223 varmint rounds with CFE223 for a prairie dog trip where I planned to use a suppressor.

[wordsmith]

You don't say what your powder charge is which would help understand what is happening.
48.3 gr TAC in mixed Milsurp brass, 59015 psi Quickload prediction, 3161 average measured velocity from Magnetospeed chrono. No signs of excessive pressure.


You state this is a new to you match grade barrel. Could the bore and chamber be tight enough to cause pressure problems? When you worked up the load how did the brass look with smaller amounts of powder?
Go/no-go passed fine, measurements with Hornady Headspace Comparator are similar, if not more generous, than my other 2 308's. Water volume is within the expected range (55.0 gr H2O +/-).


How does the brass look if you shoot with the suppressor removed?
Normal.

[wordsmith]

Doesn't sound like a pressure issue, but a chemical issue. If its fine w 4895, older powder, no decoppering agents (didn't even know they put that in powders). Yet corrodes like that w TAC overnight, its a chemical issue. Cans blow more junk back inside actions, ARs would be more so with their DI systems.

That's what I was thinking. I use an adjustable gas block and use just enough pressure to cycle reliably and lock the bolt back on an empty mag. Interestingly, that's about 40% open based on looking at it through the borescope.

[leadman]

You may want to call Western Powders and ask them about this problem. I shoot Tac in my Contender 223 Rem but no suppressor so I have not seem anything like this.
Must be the can causing it to blow back into the chamber area if brass is normal without it.
Seems like all the new powders like the Enduron powders from IMR have a decoppering agent in them.

[Maximumbob54]

I've seen TAC on the shelf and have some CFE223 and never would have thought about this issue. It would be nice to know what all powders now have this additive in it just as an FYI.

[W.E.G.]

All that nastiness on the brass in the OP is run-of-the-mill suppressor spewback.

I used to own a suppressor.

I used to own an AR15 with one of those stubby barrels that are often found in the company of suppressors.

I got rid of the suppressor and the rifle because it blew so much nastiness back in my face (main reason) and into the trigger mechanism and magazine.

All brass (factory ammo of many flavors - and every stripe of handload) fired in that gun ended up with that sort of fouling on it. If you want to re-use brass that was used in a suppressed AR, you need to collect it, and clean it right away. Otherwise, it will forever look like **** unless you clean it in the sort of solution that you don't want to use for
making brass gaskets that have to contain 62,000 PSI.

That, and the fact that you STILL needed to wear ear protection when firing the suppressed rifle, as the CRACK!!! of the bullet leaving the barrel will make your ears ring if you
don't plug-up.

If you like nasty brass, and you like breathing blowback smoke that belches out of the ejection port on each shot (BTW, "gas buster" charging handles DON'T WORK), the short-barreled, suppressed AR is just for you.

(un-retouched screen-shot capture from random bubba-suppressor video on youtube)
http://i227.photobucket.com/albums/dd7/rkba2da/rifle%20pics/AR-15/suppressorsilencergasface.jpg


Oh yeah, and paying to repair baffle strikes is lots of fun too.

http://i227.photobucket.com/albums/dd7/rkba2da/rifle%20pics/AR-15/HALOcrack2-1.jpg

http://i227.photobucket.com/albums/dd7/rkba2da/rifle%20pics/AR-15/Gemtech/Gemtechrepairinvoice_zps960f5fe5.jpg

[wordsmith]

FINAL UPDATE: So I worked up a new load using WC 844, the milsurp rough equivalent of H335. I was able to quickly dial in on the desired velocity and proceeded to fire about 30 rounds. From there, I allowed the last round to stay chambered about 36 hours to see if it stuck. In fact, it was very easy to remove from the chamber, and had none of the odd discoloration I experienced from TAC. As a reminder, the TAC rounds were welded in place in less than 12 hours. I hope this helps someone if they're getting into the suppressed AR game.

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[funnyjim014]

From what I've read the anti copper fowling agent helps prevent the copper from bonding to the bore and does not "Eat" the copper.

[wordsmith]

From what I've read the anti copper fowling agent helps prevent the copper from bonding to the bore and does not "Eat" the copper.

I'm not 100% sure of the chemical reaction that does the work. All I can conclude with any certainty is that with a simple switch of powder from TAC to WC 844, I was able to restore reliability to my suppressed AR-10. This reliability was also observed shooting H4895 and Varget, neither of which has anti-copper agents (to my knowledge).

[Artful]

Thank you for the update Wordsmith.

[Tackleberry41]

All the blowback is a bit of a semi auto issue. The ones that come out of my mosin, don't even look fired their so clean, not even warm from being fired. Friend has a 300aac with a can, me and his daughter are not fond of shooting it being lefties, for the stuff we get spit back at us. Told him he needs to get one of the gaskets for the charging handle. And being DI only makes it worse.

Im not sure the real use behind decoppering agents. We seemed to have survived a long time without such things. Hopefully other brands wont get on the same wagon and it become the norm.

[wordsmith]

Addendum / Final Final Update...

After some time, I ran into the same issue (though not as severe) with WC 844. While shooting with a buddy in his nearly identical setup, with his loaded ammo, he experienced zero issues. This got me started thinking about what could be happening, or what had changed, since I started having these problems, and had my epiphany.

My brass cleaning routine had changed, specifically the addition of wet cleaning with stainless steel pins in my new FA wet tumbler. This process produces amazingly clean brass, apparently so much so that it leaves brass vulnerable to chemical attack in this particular situation, even though I used Wash and Wax soap and citric acid treatments on the final cleaning.

My validation experiment was simple. I took the same batch of loaded ammo that got stuck and ran it through a 15 minute walnut media tumble cycle with a generous helping of FA brass polish. I took the ammo on a weekend hunting trip and fired several rounds, leaving the ammo chambered overnight as before to see if it would stick. Long story short - it worked great. No unusual discoloration, no failures to extract, no failures of any kind.

In summary - I now put a final tumble lube on all loaded ammo that is wet cleaned with stainless steel pins. In this case, I used FA brass polish, but I'm guessing Nu Finish might work equally well. Hopefully this helps someone out there.

[DerekP Houston]

Oh very interesting thanks for sharing. Who knew you could get the brass *too* clean!

[Screwbolts]

Oh very interesting thanks for sharing. Who knew you could get the brass *too* clean!

I did!