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7mm RM Cleaning and Breakin Options

Okay, you're familiar with math and physics, so let's talk specifics. First, let me correct myself. I am keeping loads for a few different calibers in my head and the 100 gr. bullet was for a different caliber that I am reloading. There is a 115 gr. load of a faster burning powder (Varget) for the 7mm RM. The starting load is 53 gr. There is a 115 gr. load of Varget for the 7mm-08. The starting load is 43 gr. That's 23% more powder for the starting load of a faster powder, for the exact same bullet (Speer HP) for the 7mm RM. There is a CFE 223 load for the 7mm-08 for the exact same bullet. The starting load is 45.4 gr. Please explain what physics would come into play that would make a maximum 23% increase (55.8 gr.) in the slower burning CFE 223 for the exact same bullet in the 7mm RM unsafe. I'm not trying to work up a load for maximum accuracy or velocity. I'm only trying to melt some copper so that it will get wiped out with one pull of a dry boresnake. I'm aware that too little powder might result in a bullet not leaving the barrel, but that will be detected by the boresnake and it seems highly unlikely. So it really seems extremely unlikely that I would be risking rifle or life if I started with 46 - 55 gr. of CFE 223 and then looked for signs of over/under pressure.

And regarding the dueling experts, can you really call someone an expert at something they haven't tried? I understand that there are people here who have a lot of experience at working with custom barrels that they breakin properly and keep fairly clean, but none so far have said that they tried to do what others have said that they have successfully done. If you were showing me the results of borescoping or some other means of detecting efficacy of copper removal, I would be foolish not to listen, but I'm not seeing that. So is there nobody on this site who has tried this?
The short answer is that the relationships are not linear. One can orient very different functions in Cartesian space in such a way as to have them intersect at a given point or have them appear to have a proportional relationship over some sequence of dependent values. If one were to look at a handful of these points and nothing else, one might conclude that a proportional relationship exists. They would be wrong. Very wrong.

Internal ballistics are three-dimensional problems. Thinking about them in a two-dimensional way can ruin your rifle and/or initiate your entry into the health care system. One does not need first hand experience to know that something will either work or it won't. Newtonian physics and extensions thereof do a pretty good job of explaining almost all of the observed behaviors in physical systems. One need not independently derive gravitational constants every time one drops a coffee mug in the kitchen to KNOW that the mug will end up in a hundred pieces all over the kitchen floor.

And as JRS said, you are not going to melt copper and remove it by continuing to shoot. If you want to listen to internet jockeys that claim they can shoot a bore clean, go ahead. On the other hand, you may want to consider the collective advice of folks that have been 'at this a while'. The notion that one can shoot a bore clean is preposterous. It has never been done. If you figure out how to do it, you will be rich beyond the dreams of avarice.
 
Going to cut to the chase here:

Just a few suggestions before you kill or maim yourself because that's where you are headed with your home brew loads.

Buy a reloading manual and read about powder burn rates as they apply to DIFFERENT CALIBERS.
Buy or borrow a borescope so you can determine if you have copper and if it is being removed. Lyman makes a cheap one that will provide you with a good look at what your cleaning regimen is doing.
If you have copper, buy one of the PROVEN copper removers like Sweets or similar, and use Iosso or JB Bore paste.
Considering you are new to the site, use the search function at the top of the page for more information. There are literally THOUSANDS of years of experience posted on this site. Utilize the ones posted by barrel makers, world record holders, consistent match winners, gunsmiths, high volume shooters and others that post here. You won't find that quality of advice or knowledge anywhere else on the web.

Please read the part below WARNING! WARNING! WARNING! WARNING!

http://www.frfrogspad.com/burnrate.htm

Having said all that, consider rebarreling. Even though you only shot 200 rounds, your barrel may still be toast.
 
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From the top of the burn rate chart from Western Powders: http://www.frfrogspad.com/burnrate.htm

Comparative Powder "Burning Rates"
The chart below lists powders currently and commonly available in the US.
They are listed in order from the fastest burning to the slowest burning.

WARNING! WARNING! WARNING! WARNING! WARNING!
The actual burning rate and position on this chart can be drastically altered by many factors including case size, bullet weight, expansion ratio, operating pressures, lot to lot variation, manufacture date, etc. Industry tests have shown that a powder's location on this list can shift by 5 - 6 positions or more depending on conditions.


This data was typical under the test conditions it was developed under but may not be true under your circumstances.

Do not attempt to make powder changes or determine a load based upon this data.
 
The short answer is that the relationships are not linear. One can orient very different functions in Cartesian space in such a way as to have them intersect at a given point or have them appear to have a proportional relationship over some sequence of dependent values. If one were to look at a handful of these points and nothing else, one might conclude that a proportional relationship exists. They would be wrong. Very wrong.

Internal ballistics are three-dimensional problems. Thinking about them in a two-dimensional way can ruin your rifle and/or initiate your entry into the health care system. One does not need first hand experience to know that something will either work or it won't. Newtonian physics and extensions thereof do a pretty good job of explaining almost all of the observed behaviors in physical systems. One need not independently derive gravitational constants every time one drops a coffee mug in the kitchen to KNOW that the mug will end up in a hundred pieces all over the kitchen floor.

And as JRS said, you are not going to melt copper and remove it by continuing to shoot. If you want to listen to internet jockeys that claim they can shoot a bore clean, go ahead. On the other hand, you may want to consider the collective advice of folks that have been 'at this a while'. The notion that one can shoot a bore clean is preposterous. It has never been done. If you figure out how to do it, you will be rich beyond the dreams of avarice.

I asked for "what physics would come into play that would make a maximum 23% increase (55.8 gr.) in the slower burning CFE 223 for the exact same bullet in the 7mm RM unsafe" and I got non-specific handwaving about what can happen. If we were talking about dropping coffee mugs, your statements might make sense, but we are talking about burning powder and creating pressure. How routinely have you seen extrapolated powder quantities react in a drastically non-proportional manner to powders of similar burn rate at the published starting load level when otherwise varying only the case capacity?

And again we get down to which "Internet jockeys" (your term) to believe, the ones who claim they "know" what will happen based on zero similar attempts or the ones who claim success on at least one attempt. Can you honestly think of a better reason to run the experiment yourself? A fairly cold bullet starts a journey down a cold barrel, smearing bits of its copper jacket into nooks and crannies as it gets hotter while a superheated gas creeps along its side and pushes it and also strips those copper bits off. Somehow this gas only strips off the fresh copper and leaves the old copper alone? Seems unlikely, but that's exactly what the experiment is for.

JRS, do you always believe everything that a manufacturer tells you and never deviate from their recommendations? Your Hodgdon quote is contradicting the claims made by people who have run the experiment and at least so far, I've not heard of anyone who has run the experiment who claims it did not work, only people who have not run the experiment who claim it will not work and people who have run the experiment who claim it did. Isn't that suspicious? As I said, some borescope data to support your belief would make it more credible. Otoh, I've seen no borescope data proving their claims either, thus the experiment.

6MMsteve, I don't have a borescope, so if I run the experiment and reach a point where I think the bore might be pretty clean, I hope to be able to tell whether that's the case by employing the old fashioned method, by looking at patches. But whether a borescope is required has no bearing on the experiment. The proof will be in the decrease of copper (or lack thereof) and the increase in accuracy (or lack thereof) after a re-breakin.

hogpatrol, for some reason you think that I do not have and have not read a reloading manual. You are wrong on both counts and I can't imagine why you would assume otherwise. Eventually, rebarreling might be required, but that has no bearing on whether the experiment will show copper stripping or not.

seymour fish, you have not established credibility as an expert in reloading, bore cleaning, BASE jumping, or risk assessment, so...
 
I asked for "what physics would come into play that would make a maximum 23% increase (55.8 gr.) in the slower burning CFE 223 for the exact same bullet in the 7mm RM unsafe" and I got non-specific handwaving about what can happen. If we were talking about dropping coffee mugs, your statements might make sense, but we are talking about burning powder and creating pressure. How routinely have you seen extrapolated powder quantities react in a drastically non-proportional manner to powders of similar burn rate at the published starting load level when otherwise varying only the case capacity?

And again we get down to which "Internet jockeys" (your term) to believe, the ones who claim they "know" what will happen based on zero similar attempts or the ones who claim success on at least one attempt. Can you honestly think of a better reason to run the experiment yourself? A fairly cold bullet starts a journey down a cold barrel, smearing bits of its copper jacket into nooks and crannies as it gets hotter while a superheated gas creeps along its side and pushes it and also strips those copper bits off. Somehow this gas only strips off the fresh copper and leaves the old copper alone? Seems unlikely, but that's exactly what the experiment is for.

JRS, do you always believe everything that a manufacturer tells you and never deviate from their recommendations? Your Hodgdon quote is contradicting the claims made by people who have run the experiment and at least so far, I've not heard of anyone who has run the experiment who claims it did not work, only people who have not run the experiment who claim it will not work and people who have run the experiment who claim it did. Isn't that suspicious? As I said, some borescope data to support your belief would make it more credible. Otoh, I've seen no borescope data proving their claims either, thus the experiment.

6MMsteve, I don't have a borescope, so if I run the experiment and reach a point where I think the bore might be pretty clean, I hope to be able to tell whether that's the case by employing the old fashioned method, by looking at patches. But whether a borescope is required has no bearing on the experiment. The proof will be in the decrease of copper (or lack thereof) and the increase in accuracy (or lack thereof) after a re-breakin.

hogpatrol, for some reason you think that I do not have and have not read a reloading manual. You are wrong on both counts and I can't imagine why you would assume otherwise. Eventually, rebarreling might be required, but that has no bearing on whether the experiment will show copper stripping or not.

seymour fish, you have not established credibility as an expert in reloading, bore cleaning, BASE jumping, or risk assessment, so...

What physics? Fundamentally, this ---> P∝1/V

I assume that you are able to apply Boyle's Law in a dynamic (differential) form and adapt it to changing volume and temperature over time. Want me to wave my hands some more? A little tougher than calculating percentages, but I'm sure you can do it!

Why exactly are you wedded to the notion that one should be able to shoot a bore clean with CFE 223? Do you really think that the entire shooting sports community has been wandering around aimlessly since the invention of gunpowder, waiting for you and your desire to experiment? I bristle at your implication that this community is collectively nothing more than a troglodyte squatting at the mouth of a cave, grunting at the sun. Your thoughts are hardly original and you may want to do a little more research - the knowledge base is vast and deep.

If I were you, I'd mind my manners and listen to people that have a lifetime of experience in the general field - that includes many with credentials and experience in the physical sciences. Without this humility, your attitude will do nothing but get you a spot on the list of finalists for the Darwin Awards. You are 'experimenting' with something that produces ~60K psi peak pressure eight inches away from your face. If you don't respect it, it'll kill or hurt you.

Final word - Trying to shoot a bore clean with some magical powder formulation is a fool's errand. Choose the wrong magic powder for your experiment and you might hurt yourself.

I'm out.
 
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What physics? Fundamentally, this ---> P∝1/V

I assume that you are able to apply Boyle's Law in a dynamic (differential) form and adapt it to changing volume and temperature over time. Want me to wave my hands some more? A little tougher than calculating percentages, but I'm sure you can do it!

Why exactly are you wedded to the notion that one should be able to shoot a bore clean with CFE 223? Do you really think that the entire shooting sports community has been wandering around aimlessly since the invention of gunpowder, waiting for you and your desire to experiment? I bristle at your implication that this community is collectively nothing more than a troglodyte squatting at the mouth of a cave, grunting at the sun. Your thoughts are hardly original and you may want to do a little more research - the knowledge base is vast and deep.

If I were you, I'd mind my manners and listen to people that have a lifetime of experience in the general field - that includes many with credentials and experience in the physical sciences. Without this humility, your attitude will do nothing but get you a spot on the list of finalists for the Darwin Awards. You are 'experimenting' with something that produces ~60K psi peak pressure eight inches away from your face. If you don't respect it, it'll kill or hurt you.

Final word - Trying to shoot a bore clean with some magical powder formulation is a fool's errand. Choose the wrong magic powder for your experiment and you might hurt yourself.

I'm out.

I've repeatedly asked for something other than "Because I know what I'm talking about" in support of arguments. I've seen everything from "calculate it yourself" to "because the manufacturer says bad things might happen" presented as evidence, but nothing anything like credible evidence. The owner's manual of a new rifle says that all breakins should only be attempted with factory ammo and some even say that handloads void the warranty. Does that stop anyone here from using handloads for a breakin? I'm not particularly wedded to the notion that one should be able to shoot a bore clean. I asked for pros and cons of methods and heard only cons from people who have never tried it. Am I wrong about that?
 
Hawkeye and Lyman bore scopes

I suggest that you clean your gun with good bronze bristle brushes, start off with Montana Extreme Copper cream or Jb, follow by Montana Extreme copper killer, follow with a patch of lighter fluid.

I have had several Browning A bolts

This load has shot very, very accurately, after I had a Williams or Gentry muzzle break put on them:

140g Nosler ballistic tip or accubond
Rem brass
Rem 9 1/2
65-66g of IMR 4350
Touch the lands with the bullet
Amazing accuracy.
Most guns like either 65.5 or 66g

I re spring my own A bolts

Best wishes and Happy New Year!
 
Hawkeye and Lyman bore scopes

I suggest that you clean your gun with good bronze bristle brushes, start off with Montana Extreme Copper cream or Jb, follow by Montana Extreme copper killer, follow with a patch of lighter fluid.

I have had several Browning A bolts

This load has shot very, very accurately, after I had a Williams or Gentry muzzle break put on them:

140g Nosler ballistic tip or accubond
Rem brass
Rem 9 1/2
65-66g of IMR 4350
Touch the lands with the bullet
Amazing accuracy.
Most guns like either 65.5 or 66g

I re spring my own A bolts

Best wishes and Happy New Year!

Thank you for the recommendations. I will try this load when I think I've done what I can to re-condition the bore. What do you do to prevent the Montana Extreme products from damaging the bronze brushes?
 
I throw the brushes away after 100 strokes, they are wore down to a smaller dia.

Montana Extreme products are oil based.

Re-condition the bore = clean it down to bare metal...Montana Extreme copper cream and a good brush will do this in a hurry, so will JB, but the Copper cream is easier to clean up.
 
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Re-condition the bore = clean it down to bare metal.

I intend to get it down to bare metal, but then I plan a sequence of shooting and cleaning 20-40 rounds in the hopes that it will improve the accuracy. That may not be necessary or fruitful, but I want to check off that box in the list of variables before I decide whether the barrel is just not accurate enough. Borescopes won't tell me whether I've improved the accuracy.
 
The 7 Mag's accuracy is enhanced by the addition of a muzzle break, as the shooter is not getting their brains kicked out and can relax.

Bore scopes tell you if you have cleaned your rifle well, which gives you a fighting chance on load development. 7 mags need cleaning often and I fear that if you fired yours 200 times without cleaning that you will certainly need Montana Extreme copper cream or JB to get down to bare metal.

What is your cleaning regiment?

After cleaning your rifle, take a small flashlight and look down the muzzle end of the bore. If copper is present, you see it look like gold.

While working up loads, three shots will do it. Five shot groups copper foul the barrel very quickly.

It would be a good idea to check the screws on your stock and make sure they have not worked loose from vibration.

Are you shooting factory loads or handloads?
 
The 7 Mag's accuracy is enhanced by the addition of a muzzle break, as the shooter is not getting their brains kicked out and can relax.

Bore scopes tell you if you have cleaned your rifle well, which gives you a fighting chance on load development. 7 mags need cleaning often and I fear that if you fired yours 200 times without cleaning that you will certainly need Montana Extreme copper cream or JB to get down to bare metal.

What is your cleaning regiment?

After cleaning your rifle, take a small flashlight and look down the muzzle end of the bore. If copper is present, you see it look like gold.

While working up loads, three shots will do it. Five shot groups copper foul the barrel very quickly.

It would be a good idea to check the screws on your stock and make sure they have not worked loose from vibration.

Are you shooting factory loads or handloads?

Copper is definitely present.

The gun was exclusively a short to medium range deer hunting gun for the first 7-8 boxes of factory ammo. Then I fed it handloads for longer range shots at coyotes and deer. It is the model that came to be known as the A-Bolt I after the A-Bolt II came out with the BOSS muzzle break, so any added muzzle break would be an expense I have no need to expend. I tame the recoil with a shoulder pad or with the Lead Sled.

I did not fire 200 times with no attempts at cleaning. I did at least partial cleaning with Hoppes #9 several times, but in a hunting situation, you never want to shoot at game with a clean bore (too many flyers that way), so cleanings only occurred at the end of the season and the gun wasn't used every season. Three or more fouling shots were typical prior to re-sighting the gun after cleaning. I normally shot three shot groups after sight-in to have a baseline. I normally shot two inch groups with it because I usually didn't have optimal conditions for sight-in. At the beginning of each season, I would check whether the gun was still on target.

In 2016 I started focusing on trying to achieve sub-MOA accuracy with it and shooting it well out to 400 yds. I have done better with a .308 Ruger American Rifle at that distance. I'm in the process I improving a 400 yd range with a stable shooting bench. I haven't achieved sub-MOA yet, but I am eliminating variables that may be impeding that. One of the variables is whether it has ever received a proper breakin. It hasn't, so it will, even if that is a futile attempt.

When I get it satisfactorily clean, I will shoot one shot and then re-clean it for the next 10-20 rounds. Then two shots and then re-clean for the next 10-20 rounds. These will probably be the 160 gr. Nosler Partitions that I have been shooting at deer for about five years, but with a powder change to H-4831. After that I will shoot three to five fouling shots and then work up a load with 145 gr. Barnes LRX bullets and probably H-4831. This is a friend's recommendation. He thinks I will get great accuracy out to 400 yds. After that I will try the load you recommended, with a thorough cleaning and re-fouling first. It will be interesting to see which performs better. If I don't achieve sub-MOA with either, I will attempt to eliminate all other variables to determine whether re-barreling is required.
 
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The load that I gave you shoots 3" groups at 600 yards with a High power scope,Bullets touch at 100 yards, and I have worked with 5 Browning A bolts in 7 mag, seat those 140's to touch the lands. Even two Browning auto's shot the same loads very well with the 140g. Several of the bolt guns shot 1 1/2" at 300 with the 140g and IMR 4350.

Push a patch of lighter fluid down the barrel after cleaning, 1 fouling shot will suffice and it will not be very far off.

Hoppes #9 is not very aggressive in removing copper, and the brush does most of the work. Throw away a brush after 70-100 strokes.(Sinclair, Pro Shot, Hart bronze bristle brushes I think are made by the same company, buy a couple of dozen)

With the few rounds down your bore, I doubt seriously if you need a new barrel.

Your determining the correct OAL to the lands will tell you volumes, you need to master this process before you proceed. Jump the barnes .050, Seat the Noslers to kiss the lands. I would urge you to shoot the 160g Accubond vs the partition since you are interested in small groups at 400.

If you are interested in how to make bronze bristle brushes last longer, wash them off with one of several products:

Carb cleaner
engine starter

If you want to make the Montana Extreme copper killer work faster, then brush with one of their plastic brushes.

The Berger 168g VLD hunting and 168g Classic are great bullets for your browning, max load of Retumbo, fed 215's, seat the bullets .005 off the lands to a slight jam.

I think you have a couple of things you need to master and products you need to buy to help mastering these skills:

Cleaning a rifle

Measuring the Over all length to the lands

The last lead sled that I shot off of wiggled around tremendously. Sand filled bird shot bags on 2x6's would be a much more stable platform to shoot off of, with an addition of a rear "Bunny" bag.

I put a full 25 lb bag of lead shot on the back of my bench, leaned up against the butt of the stock, and a 7 mag kicks like a 17 Remington
recoil%20shotbag%20001.jpg
[/URL]

I dug up the last groups that I shot with my dad's A bolt, same as brothers', scopes were 8-25 leupold long range
7%20mag%20groups%20002.jpg
[/URL]
7%20mag%20groups%20001.jpg
[/URL]
 
The load that I gave you shoots 3" groups at 600 yards with a High power scope,Bullets touch at 100 yards, and I have worked with 5 Browning A bolts in 7 mag, seat those 140's to touch the lands. Even two Browning auto's shot the same loads very well with the 140g. Several of the bolt guns shot 1 1/2" at 300 with the 140g and IMR 4350.

Push a patch of lighter fluid down the barrel after cleaning, 1 fouling shot will suffice and it will not be very far off.

Hoppes #9 is not very aggressive in removing copper, and the brush does most of the work. Throw away a brush after 70-100 strokes.(Sinclair, Pro Shot, Hart bronze bristle brushes I think are made by the same company, buy a couple of dozen)

With the few rounds down your bore, I doubt seriously if you need a new barrel.

Your determining the correct OAL to the lands will tell you volumes, you need to master this process before you proceed. Jump the barnes .050, Seat the Noslers to kiss the lands. I would urge you to shoot the 160g Accubond vs the partition since you are interested in small groups at 400.

If you are interested in how to make bronze bristle brushes last longer, wash them off with one of several products:

Carb cleaner
engine starter

If you want to make the Montana Extreme copper killer work faster, then brush with one of their plastic brushes.

The Berger 168g VLD hunting and 168g Classic are great bullets for your browning, max load of Retumbo, fed 215's, seat the bullets .005 off the lands to a slight jam.

I think you have a couple of things you need to master and products you need to buy to help mastering these skills:

Cleaning a rifle

Measuring the Over all length to the lands

The last lead sled that I shot off of wiggled around tremendously. Sand filled bird shot bags on 2x6's would be a much more stable platform to shoot off of, with an addition of a rear "Bunny" bag.

I put a full 25 lb bag of lead shot on the back of my bench, leaned up against the butt of the stock, and a 7 mag kicks like a 17 Remington
recoil%20shotbag%20001.jpg
[/URL]

I dug up the last groups that I shot with my dad's A bolt, same as brothers', scopes were 8-25 leupold long range
7%20mag%20groups%20002.jpg
[/URL]
7%20mag%20groups%20001.jpg
[/URL]

I switched to Butch's Bore Shine when I determined that the Hoppes wasn't working. A friend recommended Sweets 7.62 and others have recommended other products. I have and use all the proper equipment (bore guide, carbon fiber rod, etc. including the OAL measurement tool), but I'll admit I can work on using it better.

I've read elsewhere that 7mm RM A-Bolts shoot better with bullets in the 140 - 160 gr. range due to their 1:9.5" twist rate. I've heard bad things about the Nosler Accubond for hunting (failed to expand), but that was for a 30-06 so I'm willing to give it a try. 400-500 fps faster should help with expansion.
 
I switched to Butch's Bore Shine when I determined that the Hoppes wasn't working. A friend recommended Sweets 7.62 and others have recommended other products. I have and use all the proper equipment (bore guide, carbon fiber rod, etc. including the OAL measurement tool), but I'll admit I can work on using it better.

I've read elsewhere that 7mm RM A-Bolts shoot better with bullets in the 140 - 160 gr. range due to their 1:9.5" twist rate. I've heard bad things about the Nosler Accubond for hunting (failed to expand), but that was for a 30-06 so I'm willing to give it a try. 400-500 fps faster should help with expansion.
"I've heard":rolleyes:
 

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