Home Forums Hunting & Shooting Ask The Gunwriters Rifle barrels with button chatter marks + Dyna-Bore Question

I have several rifles from 223 to 338 Lapua with floating bolt heads (hint) that have barrels that look terrible - with a borescope, the first 12 or so inches of the barrel looks like screw threads. All shoot very well - but getting all the blue out is durn near impossible and takes a lot of scrubbing. I use both a foam and a scrubbing type of bore solvent - 10 or so applications is not unusual.

I would like to do a Dyna-Bore treatment but do not know if those copper gathering voids - if finally clean - will allow the Dyna-bore to work well.

I have the stuff on hand - and yes, I know that Doug Burch is the person to ask and he will probably see this post. And I will, but I know from lurking that there is a lot of experience here by shooters here that may have had the same experience that I am having. I can J-B the barrel but in the past that has done nothing to reduce future fouling.

For reference, I have rifles with custom barrels that foul so little that I do not scrub them with a bronze brush - just use a patch with Pro-Shot Copper Solvent IV or foam - and a borescope says they are clean in 3 or 4 patches. I have not had the nerve to go more than 100 roiunds before cleaning but often there is no blue - none, with these barrels after 50 or so rounds.

Any experience along these lines will be gratefully received.

Thanks

How do they shoot with the blue in?

I've used DBC on the chatter-marked bores of a number of rifles with floating bolt heads and it works great. In fact if I get one of those rifles in to test for an article the first thing I do after mounting a scope is apply DBC, because I don't have time to clean a bore every few shots when testing.

I've now applied 3 coats of UBC to a gun with a HORRIBLE-fouling bbl. It is not working enough to notice. I've now fire-lapped it, and the treatment to remove the copper from 10 lapping rounds was several dozen patches with Boretech products over the course of hours, followed by roughly 3 hours and 1 solution change on the Foul-Out. It's finally clean. I may or may not UBC it again; I can't decide what to do with it at this point.

The muzzle end of the bbl looks very poor (with a flashlight and magnifying glass) in terms of 'chatter marks' or failure to ream, but I don't have a bore scope so I don't know what the rest of the bbl looks like inside.

MZ5,

Find someone with a borescope and see what's going on.

DF

Savage barrels are dogcrap, not sure how any snakeoil could fix that. My solution was to call a custom barrel maker and get a real tube.

Lapping would be the best way to address this. Hand lapping, that is. GD

If I have a chance to put a 'scope through it, I'll take it.
If it looks bad enough, I _might_ send it back to the manufacturer. The issue is that it shoots well, at least until the copper gets too thick. My concern is that the manuf. will 'target' the gun from a clean bbl, say it shoots well, and so send it back to me on my nickel.
For my part, if I'd wanted a cheapie action to put a custom bbl on, that's what I'd have bought. I didn't want that.
Hindsight:
I shoulda bought the Ruger...

Fire-lap is the perfect solution for this type of barrel from many personal experiences.

It WILL NOT make a poor shooting barrel magically precise. It will significantly decrease fouling induced precision loss on barrels that are proven to group well but foul and loose accuracy quickly. It will remove the radial marks you see that are a usually a result of the reaming operation on the gun-drilled hole prior to buttoning. I monitor the progress every five shots with a Hawkeye and I can tell you that the finished product is often indistinguishable from a hand lapped barrel. And yes it will move your throat forward, around .011" on the last one I did. My philosophy is I would rather have a rifle that shoots consistently better, right now with longer cleaning intervals than a problematic heavy fouler that has a theoretical barrel life of a couple hundred more rounds.

It is a cheap option to try before rebarelling if your rifle has a propensity to shoot well when clean.

MZ5,

Don't know why DBC didn't work on your rifle, but the folks at Dyna-Coatings do admit it doesn't work on every barrel ever made.

I do know personally that it's worked on three of the barrels from the particular floating bolt-head company mentioned in the original post, and I know quite a few other people who've had success with it in a wide variety of barrels.

Mule Deer, UBC has worked for me on troublesome barrels before. I'm not sure whether OP is referring to Savage or Marlin, since they're both floating-bolt-head rifles. I've seen some things from Savage that, honestly, there's no way UBC could cover for. I don't know whether that's the issue here, but I've put a note to a local fellow I deal with. Perhaps he has or knows someone who has a bore scope.

I've seen one Savage 308 barrel so bad that if you wanted to shoot a deer with a 150, you better load a 180 in anticipation of the loss to fouling.

MZ5,

Yeah, I've seen some barrels that just wouldn't be cured by DBC, lapping or whatever.

The worst I ever saw was a barrel with a complete gap in the rifling about 2" behind the muzzle. I took two inches off the muzzle and had the rest hand-lapped. It shot just the way it had before--terrible!

Thanks for your observations.

It sounds like you came to the conclusions I have seen, if the barrel is about ready to be replaced, try fire lapping and see if it saves delays you a $300 + new tube. I would be interested in how far down the barrel material is removed before the grit stops "washing away" the barrel, as I am sure the process makes a choke of the throat and quite possibly drops the pressure pulse similar to a long throat ala Weatherby and the 204 ruger factory chamberings.


I did the initial firings on 3 17 caliber DBC barrels but have not had a chance to inspect and start the initial cleaning/ borescoping to see how well it did. I need to set up a camera so I can record my inspections for later review, thinking I may get one of the ebay cheap pencil cameras that you load onto your computer for it's larger storage capacity and larger screen.


If memory serves, some of the "bullet lapping kits" are as course as 600 grit? That is pretty agressive and I suspect would leave deep scratches that 1200 grit wouldn't remove without many firings..??


Allen

Steelhead - my 204 and 223 will often put 3 well-developed handloads in less than 1/4". My 30-06 with its favorite factory ammo (I usually do not develop a handload for my game rifles) has been around 1/2" sometimes - but usually well under an inch. My 110BA has not shot as well as the one John (Mule Deer) has reported but I have yet to work on a load for it - I have been mining brass and have now found the lowest cost factory ammo with 338 Lapua brand brass.

Thanks all for your experiences. I am still getting blue from this particular 223 but am far enough along with Copper Solvent IV scrub and patches to now check for blue using only Wipe Out and a plastic jag.

I have not heard yet from Doug Burch but have sent him the link to this thread. For me in this instance the real question for barrels like these is just how clean should they be before a Dyna-Bore Coat application will be effective.

Especially, John, thank you for your frank comment about your experience with the barrels on rifles with a floating bolt head. That these rifles usually shoot nice groups out of the box is great; my desire here is to lengthen time between cleanings when shooting prairie dogs and ground squirrels and quicker cleaning.

Exactly how such ugly looking barrels can shoot as well as mine do remains a mystery to me other than I am now nearly convinced that the first few inches are much less important (even if rough) than the last several inches of the barrel where group size is the performance issue. My one experience with fire lapping was that there was little or no change in fouling; perhaps I did not do enough lapping, and that was before I had access to a bore 'scope.

Thanks, all.

[quote=hemiallen

If memory serves, some of the "bullet lapping kits" are as course as 600 grit? That is pretty agressive and I suspect would leave deep scratches that 1200 grit wouldn't remove without many firings..??


Allen [/quote]

600 grit is actually very fine when working on steel and will produce a polished surface finish. The NECO kits include grits down to 220 to start if required. I have primarily used the Tubb pre embedded bullets or loaded ammo. The very first, course compound produces approximately the same surface finish as custom, single point cut, hand lapped barrels when I view them side by side. Tubb does not publish what the actual grits are, only compound number 1,2,3 and so on. There are scratches in any lapped bore, hand or "fire" lapped, but the key is they run longitudinal to the bore. I do know that a bore surface that is polished too shiny will actually copper foul worse. That particular surface profile cut-off may vary with with your specific bullet and jacket alloy, but something around a 320 grit is pretty nice looking.

And you are correct there is probably some choking effect towards the muzzle. I have never slugged or pin gaged a post firelapped barrel to confirm, but it is obvious during the shoot, clean, boresope process that the imperfections at the throat are the first to disappear and the ones near the muzzle are the very last.

I have used NECO and Tubb's, for whatever reason the Tubb's seems to work much better. either is a better choice than DBC

Question- how much experience do you have with DBC, and do you understand how it works?

Thank you Tennessee.


I use 1200 to polish surfaces like Bolt lugs and other sliding items to polish the high spots ( vs remove material in great quantity), 600 seems gritty enough to be more than I expected to work, but I honestly haven't opened the jar in awhile. Time to open it and compare.

Allen

hemiallen,

I believe the coarsest grit in the NECO kit is 220, but would have to check to be sure.

I've done a lot of experimentation with fire-lapping over the years, and last year did a bunch more in several rifles with worn throats. I used the coarsest NECO grit to eliminate the "gator skin" area just in front of the throat, which was accomplished in 10-15 shots. The lapping area didn't go very far down the bore (which has been my experience with fire-lapping) since the grit wears off the bullet in the first few inches.

Instead of following up shooting some of the finer grits, causing more wear, I DBC'd the bores. All of them shot better than they had for a while, though not as well a when new, and copper fouling was reduced enormously. The barrels should also last considerably longer now, since the cracked area of a throat tends to cause hot powder gas to circulate there, instead of heading on the down the bore. (I published an article about all this in VARMINT HUNTER, and some Campfire members saw it, though evidently not all, probably because they believe any worthwhile information only appears on the Internet.)

There's no reason to use just one method for treating a fouling bore, but in my experiments I have had better luck overall with DBC over straight fire-lapping.