Copper queen
 

Hey folks just curious what your experience with benchmark barrels has been. I recently had a rem 700 chambered in 257 Roy with a 26” benchmark barrel. This thing is giving me fits with copper fouling. I’m shoot 100 grain partitions out of it . I can shoot five 3 shot strings before it opens up and is fouled . I clean it with wipe out until the blue stops . I’m hoping it breaks in soon but I’m 50 rounds in now with no change. What had your experience been with benchmark barrels and copper ? Thanks. BT1

I've got 2 custom rifles with Benchmark barrels. I did do the barrel break-in procedure on their page. Cleaning was done alternating with Wipeout and KG copper remover in the process.
It took about 100 rounds in each barrel for velocities to stabilize.
Minimal copper fouling in either barrel at any time.

I only have one Benchmark pipe. My experience is quite the opposite of yours. Mine is chambered in 300RUM. Velocity difference would be substantial. Honestly, I’ve yet to shoot this barrel until it actually requires a cleaning. I’m the first to admit, I clean to much. I believe the longest interval has been about 80 rounds between cleanings and accuracy still wasn’t falling off. Cleaning has been super easy. First round after cleaning is hardly off or out of it’s fouled zero. That’s crappy you’re having issues. Are you cleaning for carbon as well? In my 257, it carbons up much faster than it coppers. I love Wipeout for copper removal but I’ve found it does very little for carbon and in the spicier cartridges, carbon has given me more grief than copper has.

Sounds like your barrel never got lapped properly.
I had a barrel like that come from shilen. Had to send it back.

I haven’t used carbon cleaner on barrel yet no. If I clean so that I have zero blue on patch and shoot one round you can visibly see a streak of copper on lands at muzzle.

Take the gun back to the smith that put the barrel on. What you are seeing is not normal for a Benchmark barrel, or any other good custom barrel, broke in or not. It needs to be replaced, or at least sent back to Benchmark to be fixed but that is probably more expensive than just spinning on a new barrel.

Call Gary eakin and talk to him
Tell him what your doing and what your seeing
He will help you out

Ya I’ll call Gary . I actually bought this barrel from him.

I’m shooting three now. I broke the last one in with 9 shots. It quit fouling at all after 9 shots anyway. That was verified by a bore scope.

Is this a buttoned or cut rifled barrel?

You know I’m not sure I just requested a 25 cal barrel 1-9 twist and they had a benchmark in stock so I bought it.

Have you tried any other bullets?
Quick little google search and other have had issues with partitions causing excessive fouling. Might be be the jackets??

Ok good to know I’ll look into that.I was really hoping to use partitions at that speed I thought they would be the ticket.

Might just need more rounds through it
But doesn’t hurt to try something else too
A frames are a bonded partition. Handle the speed even better

Ok I’ll give them a try can’t hurt. I thought of shipping gun to smith again seems like no fun at all. Thank you for the info .

I would like to know how you determine this by one post in a forum ??
So your saying the barrel is junk ??

See what Gary thinks
He will have the answers I’m just making suggestions and options lol

The original post said after 5 3 shot groups the gun won’t hold a group anymore.

The worst factory barrel should hold 15 shots if cooling between groups.

Benchmark has a superb reputation

Those phone bore scopes are awesome for the price. There was a thread on them. I would inspect the bore to start and look at the buildup as you shoot and see what happens and how quickly.

Smith should easily be able to let you know if they do some quick testing and Gary is the Canadian benchmark dealer so a few plans to attack this problem

That is exactly what I am saying. How, pretty simple, NO custom barrel, no matter what bullet or speed, should copper up so bad in 15 shots that the groups open up. Even a factory barrel that does that is defective. You pay good money for a top end barrel I won't screw around trying to fix or deal with something the maker didn't do right. It doesn't take much ammo and travel costs to the range to equal the original cost of the barrel. I find too many guys spend way to much time futzing with stuff rather than just going back to the maker who should deal with the problem. Be interested to hear what the OP comes up with in the end.

Whats "opening up" mean? 1" group, 3" group 10" group? What time frame are you shooting in? 1min between shots, 10secs, 3min? Jamming another round in quickly because the last on diddnt go in the right hole seldom works out for the good. I have quite a few benchmark barrels, all of them shoot fairly well. Usually clean them after most range days which typically is 50-80 shots, same with bartlein or rock creek or McGowan. Use wipe out as my primary cleaner, most will have copper streaks visible in them, rarely will see it affecting my results and striving for 0.5-0.75 MOA to 880yards.

I know when I lose confidence in a rifle on how it shoots or how it feels in my hand, I let it sit in the safe and pick up something else to play with. If my shooting with that one sucks too I go fishing for a week to clear my head.

You only have 50 rounds down it, so maybe 3 or 4 range sessions, is the load holding up? I hate to say it because Im only a half believer in the numbers from a chronograph, but are these changing between shots.

Contact Gary, he is a good source of help

so I shoot my three shot string over the course of say five minutes taking my time . After that string is done I’m letting barrel cool down to warm as it does see temp come up fairly quickly in 257 as you probably know. When I say it “ opens up “ I go from .75 moa to 2 inch groups and it only gets worse.

What happens if you let the barrel cool down to atmospheric temperature, instead of just to warm?

I assume this barrel is stainless?

That is strange. I don't have experience with that caliber. But do remember my former Sako 300winmag with a thin profile. Would get the 4shots in a MOA group then would get warm and start spraying everywhere. Was more of a caliber issue with the thin barrel and heat compared to the barrel being bad. If you did super slow strings or used in a hunting type situation of 2 shots max of aiming it was great, but in a bench situation was horrible. Would have to let it drop back to almost a cold bore situation before it smartened up again

Maybe yours is acting like that? Just my suggestion from spending lots of money on powder and bullets to find out that one doesn't act like how my heavier barreled stuff works. Trade off between happy carry and happy bench

That is exactly why I asked what happens if he let's the barrel cool fully, instead of just letting it cool to warm. He needs to rule out barrel heat as a factor.

Indeed it is stainless 3 contour

So Gary spoke to benchmark and they recommended running another 50 rounds through my barrel. I have been assured they have my back on this . Can’t ask for better service than that. I’m pleased . Will update as I go here.

How simple, yup I guess when you can diagnose with out looking at something you are way above the rest of us.
Before a person jumps to conclusions and blames anyone or anything on a barrel. Most of us would use a bore scope, and slug the barrel.
Not hard to do and at least you have facts.

I am not a benchmark barrel fan to start with and think the are mediocre at best .

After talking to Garry he asked about speeds and mentioned I’m way over . Took chrono and gun out again yesterday at 69 grn of r22 it’s going 3640fps and getting extractor marks on brass. Looking at my results I’m getting nosler max load speeds at min published load .... I’m going to try this over again and start below minimum published data and see what happens.. head scratcher for sure. I was thinking the r22 was hot but even my 4831 loads were well above published speeds . What would cause this ??

The only thing that causes high speed is high pressure. For your pressures to be so much over published loads means either you have a REALLY tight chamber, too tight a neck which doesn't allow good bullet release or a very short freebore. It could also be a combination of all of those things. A quite remote though possible other explanation that accounts for heavy Coppering and way over speed loads is if the Bore isn't actually .257. If the bore is tighter/smaller than spec it can cause this same issue. Personally I would not be shooting this gun any more until I had checked it 12 ways to Sunday or had a really good smith go over it in detail.