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Forum Index > Rifles general discussion > Inquiry re: Copper Fouling with the SST

Inquiry re: Copper Fouling with the SST

27 Jun 2020
@ 02:23 pm (GMT)

David Lenzi

Bear with me, this is a long story that ends in a question: has anyone noticed SST fouling their bore with Copper beyond what they would consider "normal?"

I recently acquired a Tikka T3x Lite in 7mm RM. After my first range trip I thought to myself "Huh, hardly seems fouled at all, despite the 40 or so rounds that just went down the tube." That trip was Barnes and Federal factory ammo loaded with the LRX, Accubond and Ballistic Tip. The LRX intrigues, but the other two were mostly to see how the rifle would do.

My second trip to the range was 154 and 162 SST, factory loaded Superformance Ammunition. The result was vivid, oddly pretty, copper steaks. I eventually tired of cleaning before they were removed. I went out a third time with a couple of ladders of 162 SST (H4831sc and RL23). I fired my cold bore shot with the factory SST SF...good news being the rifle was spot on. I put down another with a hot barrel between 10 shot groups, still spot on. Retired after 22 rounds total to find the same bright, thick copper steaks.

I confess that I didn't fully clean the bore this time, either. That's not to say I didn't patch, scrub, Scotchbrite, JB, etc. I did and the copper was reduced to about what I would consider normal fouling in one of my other rifles.

I headed out again today to shoot a ladder with 168 Matrix VLD that I've had for years and, frankly, need to burn. I might have found a node for velocity, albeit lower than I'd like (but that's H4831s for you), but what really surprised me was that when I went to clean the bore I could swear that it ended the session cleaner than it started.

After 20 rounds of the Matrix, there was no vivid copper streaks to be seen. Even after I patched with Ballistol (going for powder/carbon) and took another look, there still seemed to be LESS copper in the bore than when I started the session.

Now, the rifle managed some quite nice shooting with the SSTs...but...Lord, the fouling...any idea what that might be down to? I cannot say I've noticed it before in any other rifle, either.


28 Jun 2020
@ 08:42 am (GMT)

Nathan Foster

Re: Inquiry re: Copper Fouling with the SST
Hi David, just a couple of important points to go over first.

Never shoot 10 shot groups with this rifle, that is to say, do not let this barrel get hot. If you want to put 10 shots on a target, try to keep the rifle at ambient temps all the way through (up to an hour or more). If you want to test to see how the rifle holds its zero under pressure (for follow up shots on game), perform this session once, after developing your optimum load.

Do not use scotchbrite on this particular chamber. This form of lapping should only be used to clean up very rough chambers (generally other rifle brands) during the break in. Following this, you should avoid any harsh lapping until the throat is showing wear (although with 10 shot groups, there will be significant fire cracking at around 200 rounds). But generally, it is best to avoid doing much at all with the Tikka unless you have to (e.g fitting bullshit attachments to the rifle - bipod, muffler, bubble level, Fitbit, phone holder, cup holder, a framed photo of you and your mum with identical tatoos and tactical beards at Disney Land).

There are some rough Sako and Tikka rifle chambers, but these are very rare for modern rifles. You will know if you have one of these because the rifle will produce both heavy copper fouling and groups of around 3 to 6" at 100 yards. But as a reminder, any form of lapping should only be utilized after all copper has been removed. never use lapping materials or compounds to remove copper. The bore needs to be stripped to bare metal before one considers lapping.

One of the main problems with this rifle is heat. As the barrel heats up, it swells. As the barrel swells, dimensions are reduced. As this happens, we will see more copper fouling. Along with this, if the barrel is either fluted or threaded, the barrel will eventually swell in these areas, eventually losing accuracy.

The SST bullet is not a wide bullet. It comes in at .284", around .0005" less than some of the newer bullets. The jacket alloy is thick but soft, helping to ensure reliable expansion. Fouling will be most evident with the SF loads as these are much faster (friction) than other factory loads.

The LRX alloy is harder, therefore it produces less fouling. But this should also be an indicator of its downrange performance. If I collected some stones from our creek, packed them into a box and labelled them LRS, you would not be fooled into thinking that these are suitable for long range. The same applies here.

The Tikka chamber design often works well in conjunction with the Hornady ammo, both the ogive shape and the COAL. Its a fluke. In some instances, the 154gr will shoot a bit better than the 162gr. But quite often, both will shoot well. Hand loads can take accuracy a step further. But it does take some discipline on the part of the shooter to make the Tikka Magnums perform.

All I would suggest is that you obtain a harsher solvent (e.g Sweets or Wipe-out etc), then take more time with your cleaning. Let the solvent soak in, come back every half hour or perhaps once an hour and scrub it with a bronze brush, then leave it alone again. If it takes a half day to clean, so be it.

If however, the rifle shoots terribly with a clean bore, then you may wish to experiment with only partial copper removal (swabs, no bronze brushes). Common sense will guide you in this matter, you already know what heavy copper fouling looks like compared to mild fouling.

So basically, all I am suggesting is that you leave the rifle alone at various stages. Leave solvents to soak. leave the rifle to cool more between groups.

I think you will be OK. I doubt any harm has occured - especially if the rifle is still producing some copper fouling. In any case, your question will most likely help others in the same boat.
28 Jun 2020
@ 02:32 pm (GMT)

David Lenzi

Re: Inquiry re: Copper Fouling with the SST

Point well taken on the Scotchbrite. After the first 40 rounds, I was sort of blown away by how little fouling there was. No hint of roughness. The T3x cleaned fairly normally today, but not SST either.

I'm working on ways to cool the barrel more quickly...haven't come up on anything good. The 10 shots...perhaps "string" is better than "group." I'm recording chrono data, trying to zero in on a load. Not much to show for it so far.

Though my T3x has been on a weight gain plan and is now up to ~8.75 lbs, that's down to stabilizer, bedding, scope and sling. It's actually my lightest rifle in "ready to go" configuration.

The fouling with the SST is a bit of a bummer if it proves difficult to deal with because the projectiles shows so much promise. I think I have some KG-12 around somewhere that'll be a step up from the Bore Tech. I binned my Sweets a while back.

As to the Barnes...the LRX is what it always should have been. Granted, the bullet is long for the weight, but it now at least features a not entirely abysmal BC comparable to others of similar weight and respectable velocity. I think it will prove versatile for close range use, and that is my interest.

Hopefully I haven't stuffed it shows tremendous potential. I got it as a project rifle, figured to part it out and build something on the action. It's been so good in its stock trim that I've tabled that to work with as is. Oddly, the T3x stock with vertical grip added appeal to me quite a bit...comb could be 1 cm higher, but otherwise...

Why must it come down to patience?! Curses! I suppose I can take another rifle along to run hard while it cools. I appreciate the insight.

29 Jun 2020
@ 08:56 am (GMT)

Nathan Foster

Re: Inquiry re: Copper Fouling with the SST
Yes, a thermos flask, a book or perhaps an audio book, and so the hours pass.

As per the vids, your fingers should be bruised and battered at the end of the day, sore the next day. If you have sore hands / fingers the next day, then you know that you did your part.

If you need to, take some factory SST ammo or hand loads and experiment with torque settings (write everything down as you test!). Disassemble the rifle between each of these tests and re-assamble it, whether torquing up or down.

The Sweet spot for the 154gr SST is normally around 3020 to 3050fps in this rifle. The 162gr likes to go around 2960 to 3000fps. Don't worry about powder so much just for now. Just stick with one of the powders you mentioned.

The three areas to focus on are ammo concentricity, torque settings and technique. If nothing pops, change to the 180gr ELD-M and drop 4 grains below your previous lower node, then work up again (aim for 2800fps). If this does not work, move on to hand relieving the bedding - at the range, with your previously most accurate load. Be very subtle about this, gentle, almost imperceptible, going by feel of fit. If this does not work, pull the barrel and start over. Tikka do make duds once in a while, they are not supernatural gods and not all of this is on you.
29 Jun 2020
@ 09:16 am (GMT)

Nathan Foster

Re: Inquiry re: Copper Fouling with the SST
One more thing. Perhaps refrain from ladder testing this rifle. I know its all the craze these days, lots of waffle from sponsored golf tees and baseball caps on this topic.

By now you are aware of the rifle's basic velocity range. Stick with three shot groups, half grain increments in and around the sweet spot areas I suggested above or where you have seen some promise. This will drop you down to around 12 rounds plus a fouler per range session. About how it should be for a T3.

The .5 grain jumps are meaningful (harmonically) and over three shots you can focus on technique. Most of these assholes pushing ladder tests couldn't shoot the T3 lite to save themselves and much of the data would therefore be moot. When shooting a rifle of this ilk, you need to have zero variables over the course of a few shots so that you can also focus on the major problem - human error.

Probably seems like nothing but it may just help a bit more.

Once you have an idea of loads, you can come back in with .2 grain increments around established or suspected sweet spots.
29 Jun 2020
@ 02:16 pm (GMT)

David Lenzi

Re: Inquiry re: Copper Fouling with the SST
I'm regretting my MSv3 a bit at the moment. I cannot seem to get it sorted on my T3x in a way that doesn't impede my ability to shoot it. Part of that is that it moves under recoil, I'm sure. I'd heard, of course, that Tikka have slow barrels. That hasn't been my finding.

What I've seen thus far:
154 SST SF and 162 SST SF - like it says on the box.
Barnes VOR-TX - 3225, a bit over spec.
Federal Nosler 150 AB - perhaps a shade under the spec 3025.

I have been hoping to find some velocity stability which was why I undertook the ladder. I have seen that with H4831sc @ ~ 2900 fps w/ 168 Matrix right at book max (Sierra). I haven't hit the right combo, at least with the chrono on, shooting the Hornady stuff. I was close to the velocities you cite with the RL23. I get the sense your recommendation is more a variation on OCW testing - I've got a bunch of empty cases to load, so I'll give it a shot, thanks.

Once I get dialed in, and fine tuned, it'll be nice to focus on the shooting without the nagging question about whether or not the ammo is up to it in the back of my head.

My error with this rifle as a shooter tends to manifest horizontally...or rather, it is pronounced enough with this rifle to be easily discernible. I'll have two shots touching one another...and a third off to the side. I'm working on fundamentals and sling use. You certainly can't free recoil an 8.5 lb 7mm RM on a bipod, that's for sure (nor would I try).


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