Clean bore vs. "Copper equilibrium"

[Kbbond]

I am relatively new to the realm of shooting MOA. I decided that I finally wanted to drop some coin on a "sub-MOA guaranteed rifle" and a suitable scope... $3,000 dollars later I have a Nosler M48 Liberty in 7mm RM and a Leupold VX-5HD scope.

I have shot both factory and hand loads (I would consider myself a novice handloader, but a very anal retentive handloader who will make sure I have the same weight of powder per charge by adding or subtracting as little as one individual granule of powder at a time), and believe I should be out of the "break-in period" for the rifle. I followed Nosler's prescribed break-in procedure and started watching my groups after that and here is what I've seen.

Factory loads: I've shot HSM ammunition In 140 and 168 gr VLD with mixed results. The 168's shot fairly well with two bullets going though the same hole on many occasions but left a 3rd shot flyer about 1 inch or better out.
I've shot federal premium for break-in ammo and got roughly a 2-3" group at 100yds (granted I wasn't trying very hard with those outside of getting on paper and shooting cleaning rounds.
Finally, I've shot Nosler Custom 150gr partitions rated at 3100 fps with varying results. Some were all over the place and some were within an inch.

Hand loads: obviously there are so many variables with hand loads that I wont go super into detail so here are my observations. I had erratic rounds of H4350 pushing a 160gr accubond and a 175gr. ELD-X. The other day I found that 70gr. Retumbo pushing a 160gr. Accubond, seated at 3.35" COAL was giving me a 0.6" group and that got me excited.

Here's the kicker...

I cleaned my rifle after ever 40-60 rounds depending on what I had available on that day. Cleaning meaning clean until the copper fouling is gone and scrub the hell out of the barrel with a nylon brush until polished.
I went back out to the range with a new batch of hand loads loaded with the exact same recipe and everything and shot a 2" group...what the f***!? After shooting several more rounds (semi irritated) I finally settled in and shot a 0.9" group at 100yards.

So here is my question...

I've noticed the more I shoot, the better my groups are. But after i clean my rifle, accuracy goes to hell (2" groups at 100yds...so not terrible i guess but i want 0.5" especially out of a sub-MOA rated gun). I've been told about copper equilibrium and am wondering if there is any truth, based on my situation, to leaving copper in the barrel for increased accuracy? What I dont get is why all the long range forums insist on clean bore with no copper an achieve 0.5 moa out of rifles when i am seeing poor accuracy after cleaning

 

[Fire_9]

If you gun is shooting well, why are you cleaning it? Let your rifle tell you when it needs to be cleaned. The only time I clean mine is if it’s going to sit in the safe for a few months without being shot or my groups open up.

 

[Kbbond]

If you gun is shooting well, why are you cleaning it? Let your rifle tell you when it needs to be cleaned. The only time I clean mine is if it’s going to sit in the safe for a few months without being shot or my groups open up.

Makes sense, I've just got the impression over the last several weeks that it's all about the clean, cold-bore shot so after every range session I was cleaning. Makes sense now that my groups were going to hell, probably because I was cleaning too much.

Another reason, I watched Gunwerks' YouTube video on cold-bore mapping and saw that a clean, cold-bore shot was In the middle of the following group, so that's what I've been trying to achieve and why I've been cleaning so often.

I think I will just shoot now until accuracy deteriorates before I clean. Seems like the gun likes a high pressure round with some fouling. Thanks!

 

[WapitiBob]

Nosler has an accuracy guarantee on that rifle, I'd ask them what to do before you send it back.

 

[ZBB]

Sounds like you have it figured out. For what it’s worth I don’t strip copper until accuracy deteriorates but I do run a bore snake with a little dab of clp on it after I shoot. I think that copper solvent can be pretty tough on barrels which is one of the reasons why I don’t like using it. When I zero and when I am trying to shoot groups I like to use one of the black pasties that cover up a group on the targets you have. I think there’s one in the second picture. Anyway, I just put 6 or so of those on the paper then I shoot at the corner so I can line the vertical and horizontal of the crosshairs right on the 90 degree corner. It works slick for me anyway.
Zach

 

[cowboy]

If you gun is shooting well, why are you cleaning it? Let your rifle tell you when it needs to be cleaned. The only time I clean mine is if it’s going to sit in the safe for a few months without being shot or my groups open up.

Fire_9 is right on the money- and I've proven it over many many rifles. There are more barrels wore out from cleaning brushes then there are from shooting. I have a .308 I use for practice that I literally shoot hundreds of rounds through before the rifle tells me it's time for a cleaning. This particular rifle then takes 5-8 rounds to regain its accuracy.

The only exception to this rule that I follow is I always clean if I switch types or brands of reloading components - I never shoot nosler bullets over Berger or type 1 powder over type 2 - you get the idea. Each component has it's own fowling characteristics so I never confuse the rifle (or me)

 

[antelopedundee]

Makes sense, I've just got the impression over the last several weeks that it's all about the clean, cold-bore shot so after every range session I was cleaning. Makes sense now that my groups were going to hell, probably because I was cleaning too much.

Another reason, I watched Gunwerks' YouTube video on cold-bore mapping and saw that a clean, cold-bore shot was In the middle of the following group, so that's what I've been trying to achieve and why I've been cleaning so often.

I think I will just shoot now until accuracy deteriorates before I clean. Seems like the gun likes a high pressure round with some fouling. Thanks!

Thus they call them fouling shots. Also it makes little sense to spend hours cleaning out copper only to have it go right back in after a few shots. Each barrel is a a critter unto itself. I wonder if Nosler has some sort of standard load that shoots reasonably well in their rifles.

 

[cahunter805]

Like stated above more rifles are damaged by over cleaning and improper cleaning than to many rounds fired.
Don’t clean your rifle until accuracy starts to open your groups substantially. I have rifles with over 300 rounds and still shooting 1/2MOA.
Some powders and cartridges are dirtier than others and may require some carbon to be cleaned out periodically but copper shouldn’t be much of an issue especially with a good quality barrel.
Also most long range forums I’m on don’t talk about a clean bore. It’s more about cold bore shots and their relationship to groups.

 

[ImBillT]

A) “.5 MOA” and “sub MOA” are two very different things.

B) Factory ammo and VLDs don’t really go together. VLDs tends to be a little finicky with regard to seating depth, but shoot lights out once you get that tuned. Some shooters claim that VLDs do not shoot well at velocities much in excess of 3000fps. A 7mag erodes a throat fast enough that keeping VLDs in tune might prove problematic. I would recommend one of the hybrid ogive bullets of you want to shoot Bergers.

The 6.5 creedmore and 6.5-284 Norma were both designed with throats and leads that are optimal for heavy VLD type bullets and factory ammo using VLDs may shoot well in most or all guns chambered for those cartridges.

C) A 7mag isn’t going to hold onto it’s absolute best accuracy for very many rounds, so I wouldn’t spend too much time tuning it.

D) Benchrest shooters shooting tiny cartridges through handlapped custom barrels tend to get their best groups on perfectly cleaned barrels, but shooting sports requiring more than 5-10 shots require the shooter to shoot on a dirty barrel, and the transition between a clean barrel and a dirty barrel is not a place that you want to be when you need the best accuracy out of a gun. Larger cartridges foul faster and lesser barrels foul faster. Your barrel is not going to be that clean for more than a few shots. After that, you’ll go through a period of POI shifts from shot to shot until the fouling in the barrel stops building up any further. That could be 5-30 shots depending on the gun. I liked to have at least twenty through my gun since I last used a brush and copper solvent before I shot an F-class match. I eventually abandoned the brush altogether and would shoot 200-300 shots between running wet patches with Hoppes 9. Outside of benchrest, most if not all shooting sports are set up such that shot strings are too long to shoot a whole string on a clean barrel, and you usually would not have the opportunity to clean a barrel between rounds. Plenty of competitive shooters are shooting under .5 MOA on dirty barrels and they would all tell you not to start shooting a match on a clean one.

 

[JLS]

Clean bores are one of the most overrated things in the shooting world. Your rifle told you what it likes, quit trying to make it like what it doesn’t.

 

[Ajax2744]

Im with the rest that say cleaning a barrel too much will wear the barrel way faster than shooting would. I run a boresnake through the barrel after each shooting but don't clean the copper until groups start opening. Ive read that the copper will fill in little voids in the barrel for the first few shots in a new or freshly cleaned barrel and that once the deposits are filled in you will get the most accuracy out of factory guns. Take it with a grain of salt but that could be what's happening with your gun. I'd also email nosler and ask what ammo they use for their .5 moa guarantee and that might help lead you in the right direction. And last I would just make sure everything is as consistent as possible when shooting. It sounds simple but it amazes me how many guys form/trigger pull will vary shot to shot and keep messing with the scope to "dial it in". Just food for thought

 

[Kbbond]

Thank you all for the information, I definitely had a lot of misconceptions when it came to precision rifle shooting.

 

[ImBillT]

Another side note. You don’t have to be THAT perfect with your powder charges. At 100yards large velocity spreads will shoot groups that blow your mind. As ranges increase velocity spread become more important, but I’ve had loads shoot single digit SD with .5gr variation in powder charge. Be as accurate as you want to be, but don’t let getting it down the exact kernel take up shooting time. I’ve heard of guys cutting kernels with a razor blade to get the exact powder charge in every case and I can’t think of a bigger waste of time and effort.

Now don’t go haphazardly loading ammo 2-3gr apart in charge weight.

 

[Walkathon]

I'm not a precision rifle shooter, or a hand loader, but after I scrub the copper out of my gun barrels, it usually takes 3-7 rounds before they group well again. My .270 win guns both like Hornady 140 gr Interlock factory ammo and my stainless .270 takes 6 or 7 rounds after cleaning to group 1" again, and my other .270 win with a standard blued steel barrel only takes 2-3 rounds after a cleaning before it shoots well, usually around .750" groups. I usually clean the bores with Bore Tech (standard and copper remover) after the season is over and oil them, then fire a few rounds through them when I start to shoot them again in the spring or summer. Just my experience with cleaning the copper out.

 

[std7mag]

For the copper question.
My Rugers especially like copper in them.
I tried cleaning the copper out once. Took about 40 rounds to get back what i once had.
I clean the carbon with Hoppes#9.
Leave my copper in my barrel.

 

[SD_Prairie_Goat]

I've done a fair amount of testing with this very subject. Long story short, what I have seen is every gun I have had needed a certain amount of copper left in the barrel to keep the grouping tight. For example, my weatherby vanguard needs about 7 rounds after a real thorough cleaning to get the grouping back below 1" at 100yds. After those first 7 rounds it will stay at under 1" for a very long time.

 

[375H&H]

I think part of the problem is following a "break in" procedure. I have never seen one followed on the new rifles I have been around and they all shoot within MOA. Having some copper in your barrel for shooting/hunting purposes is just fine. I don't enjoy cleaning my guns enough to want to clean them while at the range or while hunting.

However for longer term, competition shooters might keep the copper in their barrels, but they also don't have an issue replacing barrels more often than I would prefer. I clean mine once a year after I am done hunting and definitely get the copper out, as copper will eventually cause pitting and not allow the preservative oil to protect the base metal. Excessive copper fouling will also decrease the "grab" that the rifling has on the bullet and affect the stabilization as well as velocity/pressure of the fired round.

I use Butch's bore shine which will not harm the barrel and scrub with a brass brush until all copper is gone. Nylon brush will not remove the copper sufficiently.

Short term copper is fine, long term copper is bad.

 

[antelopedundee]

Any idea how often the bullet makers clean their test barrels?

 

[GlockZ]

Almost all my rifles shoot better with a little fouling in them. I made the mistake once of cleaning my 338WM with copper solvent, and it took me almost 60 rounds for it settle and shoot the way I'm used too. Never again will I use copper solvent. So allI use is Hoppe's #9 and that's it.

 

[Fire_9]

I think part of the problem is following a "break in" procedure. I have never seen one followed on the new rifles I have been around and they all shoot within MOA. Having some copper in your barrel for shooting/hunting purposes is just fine. I don't enjoy cleaning my guns enough to want to clean them while at the range or while hunting.

However for longer term, competition shooters might keep the copper in their barrels, but they also don't have an issue replacing barrels more often than I would prefer. I clean mine once a year after I am done hunting and definitely get the copper out, as copper will eventually cause pitting and not allow the preservative oil to protect the base metal. Excessive copper fouling will also decrease the "grab" that the rifling has on the bullet and affect the stabilization as well as velocity/pressure of the fired round.

I use Butch's bore shine which will not harm the barrel and scrub with a brass brush until all copper is gone. Nylon brush will not remove the copper sufficiently.

Short term copper is fine, long term copper is bad.

Everything I’ve ever read and been told is that the powder residue is what causes the pitting, not the copper