I'm not a big fan of Sweets or CR-10, however, I've used both on occasion. If you use any aggressive ammonia based cleaner I would not exceed the maximum soak time indicated on the bottle.
For overnight cleaning I prefer "Wipe Out" which appears to be both barrel friendly and effective. For heavy copper deposits I would suggest using Wipe Out Accelerator before appling the bore foam. No bronze brushes are necessary, which is preffered by many shooters.
For routine bore leaning I use Butch's Bore Shine and have no complaints. Periodically, I will do a more thorough cleaning with JB compound or Barnes CR-10. If I just feel like letting the guns clean themselves, I'll blast them with Wipe Out.
I must say I was skeptical of the bore foams, but I had two rifles that I had been shooting regularly, .22-250 and a 300 RSAUM. The .22-250 had about 40 or so rounds down the barrel, and the 300 had close to 30. I cleaned both the way I normally would, at that time, and then put Wipeout down each barrel and let it sit overnight, about 30 hr total. The .22-250 barrel had deep navy blue liquid come out the muzzle when I patched it out. The 300 had just the slightest baby blue on the patch.
With that, I modified my cleaning routine. I used to rely on CR-10 to get all the copper out, but obviously with three cycles of following their printed directions and getting clean patches, there was still LOTS of copper in the barrel. I also used to use JB, but I switched over to IOSSO bore paste. It is more like a bore cream, but it is nonabrasive unlike the JB. It does a very good job every couple hundred rounds to remove some of the crust that may have built up so GMTEC can get under it and with some Kroils get it out. Then I'll Wipeout foam it again over night, and get a little more fouling out.
The accelerator is a great investment too if you don't have the luxury of time to wait. In one hour with the accelerator in the bore first, Wipeout will get most of the fouling out. I have found that it does not change the impact point of any of the rifles I have used it in. I look at the accelerator as more of a good thing. Its a great product that I would highly reccomend.
I used the Outer's foam in a pinch a time or two, but after that was patched out clean, Wipeout allowed to sit over night behind it came out blue.
I was finally able to get som Montana 50-BMG to compare against the Wipeout in my barrels. It may have been a curse because since I got it I have not been able to pull a trigger once. ARGH! I am just trying to find the most streamlined methods to clean my rifles for the situations I face and different time-lines. An example would be, you are deerhunting and your sweet thang 'accidently' knocks over your rifle and plugs the bore with dirt. What would you do to clean it out and not worry about changes in impact out to say 500 yards? I know what has worked for me in that situation, and I was lucky that my wisdom to have not cleaned out the back of my Tahoe and gun cleaning supplies from my last range session allowed me to whisk out the dirt, clean it up and keep on hunting with no fear of the hunt being screwed up.
I just recently did a little house cleaning on my cleaning stuff. Ive got a can of wipeout with just a little juice left in it if you want it. Ill send some accelerator too. I think wipeout is great stuff. Ill let is set in the bore overnight, and the nastiest blus sludge youve ever seen comes rolling out of the muzzle when you run that first dry patch. Ive used cr-10 as well, and it works, but is more labor intensive than the wipeout. Definately not the stuff to leave in the bore overnight, and you can't plug it because it has to have air to work. Ive just started using montane extreme50bmg, and its great too. faster than anyhting ive found for sure. My typical cleaning process goes....
soak the bore with GM TEC, run a brush a few times, let it set for 5 min, repeat, set for 5, repeat... all with no patches. patch out, then do one more brush cycle, by this time, the patches will have a lotta blue on them, and all the powder/carbon fouling is gone. If im in a hurry, ill run a nylon brush saturated with 50bmg, and let it set for 10min or so, then pathc it out. usually takes 3 rounds of the 50bmg and its clean. if im gonna let is set overnight, ill accelerator it, then foam it, and path it out in the morning. I used to run a patch of CR-10 after the wipeout to verify all copper was gone, but not anymore.
al of the above is in referance to my worst fouling barrel... a factory 300WM savage.
My suggestion: get you a can of GM top engine cleaner for carbon and powder. then some 50bmg, and a can of wipeout for copper and pic whatever copper solvent youve got time for. Email me and ill get you a sample or two.