Barrel Conditioning

[dlpowell]

This is good info that should be posted somewhere on the forum so all can easily find.

 

[longcruise]

Marmotslayer - you presented an informative and helpful post and covered all the bases well. I just thought a "polite contrary" might keep the guys who should never disassemble a lawnmower engine or have never found the original hammer spring to their 1911 that went sailing across the dining room table from buggering up a bore.

And, it was well said by yourself. Some people just don't have an affinity for tools or mechanical things. Hopefully they know who they are :haha:

It used to be a flogging offense in the British Army for a soldier to remove the lock from a Bess. Only sergeants were allowed to have screwdrivers.

That seems to be a common theme in military armory practices. I collect and shoot Swiss military rifles and have the translated manuals for several models. Who can do what to what and who is authorized to dissassemble to various levels is clearly spelled out. And, much like the brit view on lock removal, if a swiss soldier allowed his barrel to become damaged due to poor care, the manual explained that the soldier would be charged for a new one. Then, the next page has a photocopy of some poor soldiers invoice for barrel replacement. :haha:

 

[Ken Rummer]

I am planning to firelap the bore on my .50 because the lands are covered with tooling chattermarks. I found the stuff I need at beartoothbullets.com.

Firelapping Muzzleloaders for Accuracy is at http://www.beartoothbullets.com/tech_notes/archive_tech_notes.htm/48

BTB will sell lapping bullets and lapping compound. I just order both yesterday.

I did not notice in the above discussion that the hardness of the lapping bullet is important. This issue is explained in the article. In my view bullets of the proper hardness (BHN of 11 to 12) are the most difficult item to aquire because few people make them.


Another source of firelapping information is at graybeardoutdoors.com. Scroll down to Veral Smith's posts.

 

[paulvallandigham]

The kind of testing reported in the article is biased due to whatever ability the shooter had to shoot open sights. I could not help but note the "alibi" about one of the guns having a heavy, wide front sight. Ability to hold a front sight on target becomes an issue for all testing when its done beyond 50 yards.

I would have preferred the author had put a temporary scope on these guns to eliminate that human factor from the group sizes.

I have no doubt that lapping barrels helps most of them. And, it helps in the ways noted in the article. You do get a smoother bore, less residue in the barrel, and easier reloading. If you cast your own bullets, just use wheel weights to get hard enough bullets for this work.

I note that the article does not tell hom much powder he puts behind the bullets when firelapping. I don't think it was meant to be a secret, but I do think people need to know that you use reduced charge- 30-40 grains, instead of 70 or 120!

He has the information on how Black powder and Smokeless powder backwards. The reason the skirts open so quickly with BP loads is the SKIRT, not the burn rate. The problem with using Smokeless powder behind those hollow based bullets is that the burn pressures are so high so fast, they crack and then break off the skirts as the bullets leave the muzzle of the gun.

You have to have a very heavy, thick skirt to use in front of smokeless powder. Compare a minie ball, for instance, to the hollow based, .38 cal. 148 grain wadcutter. The shape of the hollow, the length compared to the diameter of the bullet, and the relative thickness of the skirts are different, and comparatively much heavier for the Wadcutter, than the minie. The Wadcutter is designed to hold up when shot in front of fast burning, high pressure, pistol powders, like Bullseye, or Unique, or H110. The minie is designed to work well with a comparatively light charge of 60 grains of BP. (FFg)

My only caveat would be for shooters to NOT overdue the lapping. This is not a case where more is necessarily better. Lapping does wear down the lands and that opens the bore diameter, changing the choice of diameter of ball or bullet, and the patch thickness needed to get good accuracy. Frequent measuring with inside calipers is called for during any lapping process. And, you should be expecting to see changes measured in 10,000ths of an inch, not 1,000ths of an inch. If you see a change as great as 1,000th of an inch, you need to stop the lapping. Something is wrong. :hmm:

 

[longcruise]

I am planning to firelap the bore on my .50 because the lands are covered with tooling chattermarks. I found the stuff I need at beartoothbullets.com.

Let us know how that goes.

I did not notice in the above discussion that the hardness of the lapping bullet is important. This issue is explained in the article. In my view bullets of the proper hardness (BHN of 11 to 12) are the most difficult item to aquire because few people make them.

Here are some additional thoughts on the BTB write up. You can take them FWIW.

The use of BHN 11 to 12 bullets is also suggested by Veral Smith at LBT. Veral has an excellent book available on shooting cast bullets, but it is entirely devoted to suppository guns. The reason for the harder bullets as suggested by BTB and LBT is because they are focused on removing restrictions in the bore. The harder bullets will not constrict so readily in the tighter portions of the bore and will eventually open the constrictions up to match the rest of the bore.

Using the harder bullets in ML guns may or may not be useful. First off, you need to identify actual constrictions in your ML bore that you feel are a problem and you may also need to lap with heavier bullet charges in order to upset the harder bullets into the bore. If they don't upset and obturate the bore, they can't do their work.

This is not a problem with suppository guns because generally the slug starts out larger than the bore. Shooting with mild charges will not be a detriment in that situation.

I don't know what it would take to make the harder bullets work in an ml as far as powder charge goes. There is no doubt in my mind that the harder bullets will do their work just fine if they upset and obturate the bore. Softer pure lead bullets will do the same thing but it will take more bullets to do the job. The job refered to in that statement being to remove bore constrictions.

While the fellow at BTB seemed to find constrictions rampant in his ml guns, that has not been my experience. Maybe he uses a more sophisticated method of measureing than I do. If I can't feel a constriction in an ml barrel, then as far as I'm concerned, for all practical purposes, it's not there. The emphasis on practical.

I once thought I had constrictions in two places on my TC .50 cal Hawken barrel. This was my first ever ml gun from back in the mid '70's. For quite a few years I shot nothing but concals in that gun. Usually with 100 grain loads. :shocked2: When I noticed the constrictions I assumed it was a barrel defect. By that time I had for the most part left conicals behind and did not think much about the constrictions and just enjoyed shooting prb loads. One day while cleaning after a shooting session the constrictions came to my attention again and a light bulb went off; Maybe those constrictions were persistant lead deposits. Well, after a serious session with modern solvents, copper kitchen scrubbing pads and finally, some steel wool, I had indeed pulled some lead out. Thereafter I never noticed the constrictions again.

That's just one persons experience and does not mean that lead is the cause of all ml barrel constrictions. It is however worth some consideration, IMO.

If you do want to try the harder bullets, acquiring them is no more expensive than the acqusition of a Lee conical mold. Cast your conicals out of wheel weights. Air cool them and let them age for at least two weeks at room temperature and the BHN will be right in the 10 to 12 neighborhood.

I think the whole idea of the harder bullets in an ml could be a way to improve firelapping in ml guns. I avoided them because I wanted to use minimal velocities (recommended by Veral Smith) and I was not attacking constrictions. My sole purpose was to smooth out patch cutting edges in the bore.

OTOH, if there are any constrictions there that are not felt with a patched jag, how could it do any harm to remove them?

You could determine what charge it takes to upset the harder bullets by firing them into a sand berm with ever increasing charges until you notice that the recovered slugs have expanded into the grooves completely.

I'm very curious to read about your results. Hope you will start a thread on the topic.

 

[longcruise]

I note that the article does not tell hom much powder he puts behind the bullets when firelapping. I don't think it was meant to be a secret, but I do think people need to know that you use reduced charge- 30-40 grains, instead of 70 or 120!

Actually, if you re-read the article, you will find his powder charges.

I suggested to KV that he determine what it takes to upset the harder bullet by doing his own tests just because the guy who wrote the BTB article did not provide any such info and apparently left it to chance. The charge needed to upset the bullets will be dependent on the weight of the bullets, the caliber of the gun and the powder granulation or brand of powder used, IMO.

I differ with you on your thoughts on the diff between modern and bp powder pressure characteristics. While modern powder reaches much higher pressures eventually, the BP is an instantaneous igniter and while it's pressure spike does not go as high, it is immediate. Some suppository modern powder lead bullet loads when shot with under size bullets do not upset the bullet enough to obturate the bore. That same load with a max of bp and a softer bullet would do the job immediately even though the end velocities might be much lower.

My only caveat would be for shooters to NOT overdue the lapping.

I don't know how much overdoing it would take to overly enlarge the bore of a rifle, but it has never happened to me. There's a lot to be said for using the correct tools (compounds manufactured strictly for the purpose of firelapping) and reading as well as actually following the instructions. :haha: Anybody who has ever assembled a kids Christmas bicycle at around midnight Christmas eve already knows that.

 

[paulvallandigham]

I will try to dig out some references on powder burning rates for Black and smokeless powder for you. We will continue to disagree on this point.

I don't know why you pull one sentence out of a paragraph and then attempt to attack me about it. If you read the rest of my statements, my reason for caution is well stated.

"Lapping does wear down the lands and that opens the bore diameter, changing the choice of diameter of ball or bullet, and the patch thickness needed to get good accuracy. Frequent measuring with inside calipers is called for during any lapping process. And, you should be expecting to see changes measured in 10,000ths of an inch, not 1,000ths of an inch. If you see a change as great as 1,000th of an inch, you need to stop the lapping. Something is wrong. "

I would add to this that a DIGITAL caliper is probably the right choice of instruments to do this kind of measurement, as the vernier, and dial calipers do not go to the 10,000th of an inch measurements, usually. Micrometers with clutch adjustments will also measure to 10,000ths of an inch, but they are more expensive Micrometers, than others you may have, or find to buy. If you choose to use a micrometer, you have to slug the barrel, and measure the lands and grooves on the slug.

 

[hockeyref]

........ If you choose to use a micrometer, you have to slug the barrel, and measure the lands and grooves on the slug.

Paul,
How would you go about slugging the ML barrel? I suggested using cerrosafe in another thread... When I've done CF bolt guns, I was able to push the slug straight through and "feel" anytight spots.... Since we only have access from one end it complicates matters...

 

[paulvallandigham]

If you are not going to remove the breechplug, then you don't have much choice but to use cerrosafe. You build a rod, with a plug on the end and put it down the barrel as long as you want the cast to be. Then pour the cerrosafe in and around it. If the bore is large enough,you may be able to get away with sliding a heavy piece of brass rod down the barrel, to use to tap out the cast. If that can work for you, then all you need it to some kind of plug in the barrel to stop the cerrosafe. Cleaning patches, paper towels, dampened, etc. will all work. Mind the directions on the product on how long you have to measure the dimensions before the cast expands more, after removing it from the barrel.

I am not quite as afraid or concerned about removing breechplugs from rifles as many members here seem to be. If whatever is not working in a barrel is not something that would be covered by a factory warranty, take the plug off and fix it, or take the gun to a gunsmith who can take the plug out and fix the problem. I recall my friend Don ordering a T/C Spanner( wrench) to take off the plugs on T/C guns back in the late 70s. He still had to use a 2 1/2" pipe as a handle extension on the device to get the plug to turn. AND, he had me down below the bench vise, with a pipe wrench clamped to the barrel, with slabs of plywood to protect the flats of the barrel, Pulling Against his turn, before we were able to back the plug out. But he got the plug out, fixed the problem- I don't recall what it was, now--- and put the plug back in with some anticease. You would never know the plug had been pulled from the gun. He later made his own plug wrench, with a long steel handle to give him the needed leverage. I know of just one time that he had to add that pipe extension to get a plug off. I wasn't available, but he called me to tell me about it, and to thank me for teaching him how to increase the leverage using a piece of pipe. In turn, I called my father, who had taught, and showed, me how to do that many times as a kid, and told him how I had passed on his training. We all had a good laugh. It seems like such a minor matter now, and such an obvious solution to the problem.

With the plug out, of course, you can make a proper lap and lap the barrel from the back end. If you plan ahead, you can put a bit of "choke " in the bore of a rifle, which contributes the accuracy of any rifle. I am talking a few 10,000ths of an inch from breech to muzzle.

There are target shooters today who lap their barrels every night during a multi-day shooting event. I don't see the need, but they claim they get better groups with a sharp clean edge that is " new" each day. They are willing to go through a $1,000 barrel every year, and some will do more than that. I think they are trying to buy accuracy, rather than earn it with better shooting skills. But, its their time, and money. :thumbsup:

 

[longcruise]

I will try to dig out some references on powder burning rates for Black and smokeless powder for you. We will continue to disagree on this point.

Comparing smokeless burn rates and bp burn rates is pretty much an apples to oranges kind of thing. The burn rate of smokeless is progressive under pressure. Pour some out on the ground and light it and it will burn lazily. Do the same with BP and you might get burned. It goes poof pretty much instantly. It burns the same way in your barrel but a bit faster under pressure.

I've satisfied myself on this score with the results of my BPC loads. For example, I can load a 385 grain 1/20 tin/lead bullet that measures .456 over 5744 for a velocity of about 1350 fps and get poor accuracy and leading out of a rifle that measures .458 because the 5744 does not bump the bullet up upon ignition. A BP load under the same bullet with slight compression shoots accurately and without leading because the near immediate rise in pressure bumps the bullet up before gasses have a chance to blow around it on the way down the bore.

Anyway, most forum members are probably a bit bored with this talk about modern stuff.

I don't know why you pull one sentence out of a paragraph and then attempt to attack me about it. If you read the rest of my statements, my reason for caution is well stated.

I wasn't attacking you at all. We differ on many scores and sometimes my responses to you may come across as attacks but they are not. . . . Usually

I'm just trying to keep the discussion on this topic as factual as possible. Your alarm over barrel damage might cause readers here to feel that firelapping their guns is treading on iffy ground. Just not so if people simply heed the instructions of the component manufacturers.

Since 1992 I have firelapped 6 modern handguns, 9 modern rifles, and 9 muzzleloading rifles. There was never a glitch with any of them. I do have the quality of micrometers that you speak of and they easily measure to 10,000ths. None of these projects grew the caliber to extents that required any changes in ammunition or patch material. If a bore "grows" from .50 to .5005, I assure you there will be no noticeable effects on the load with the exception of easier loading and usually lower velocity.

The velocity statement in the BTB article states correctly that advantages are better accuracy, easier loading, less fouling and higher velocity.
I would differ with the writer in that every single ml that I have chronographed before and after firelapping has shown a reduction in velocity. I attribute that to a reduction in the inertia of the projectile which gets moving more readily in the smoother bore.

My sole purpose in doing the barrel conditioning tutorial was to provide some help to forum members in getting accuracy with their prb loads. When it is done carefully and correctly, it will often provide stunning improvements in accuracy.

One need only look through the huge number of topics on lube, patching, ball size, etc., etc. to see that many forum members are having problems getting their guns to shoot accurately. You yourself have participated in many of those threads, so I don't have to tell you how frequently these problems show on the forums.

These guns are usually the over the counter finished guns or common affordable kit guns. The barrels on these rifles are sharp inside and poorly crowned. The crowns often cut patching going in, the rifling cuts patches going in and coming out. As charge weights go up, the shooter sees accuracy fall away suddenly. If they know and understand the importance of reading patches, they usually see sliced, diced and burned patches. OTOH, many of them don't realize the importance of reading patches. They end up settling for what their rifle will do and leave it at that. Many times we are able to buy their rifles cheap. Notice that I have not expressed any opinions on the use of over powder wads.... oooops, too late! :haha:

Then there are the endless turd hunts for the perfect patch, ball size, lube, etc. Sometimes these help but usually not. IMO, there is too much empahsis on solutions through changing these components and not enough on the true offender, which is the turd barrel. That turd needs to be polished!

For any new shooter or old shooter with a newly acquired rifle I suggest the following regimen test procedure:

Take the rifle to the range and load it up with the manufacturers suggested maximum powder charge. Use a known quality patch material such as Wally world ticcing or Joannes #40 pocket drill. Use a ball that is not easy to load but does not need to be hammered to get it started. Use about any lube such as spit, crisco, whatever. shoot five shots and then look at the patchs if they are in good condition with no cuts or even the most minor fraying, then you are in pretty good shape. OTOH, if they are cut, blown, or even show minor fraying where they ran on the rifling, then lap the bore and crown the muzzle. It's not neccessary to use the procedures I outlined. That is just one way.

Once the bore is lapped and the muzzle crowned, take it out and repeat the same test. In nearly all cases, the patches will be in fine shape and the rifle is ready for load development, hunting or target shooting.

I call this working down a load. We already know the gun will shoot without wrecking the load components at the max so now we can look downward for an accuracy load if we don't want to shoot max.

One can take this a step further and do the test without any lube at all. The bore needs to be wiped thoroughly between shots to allow the unlubed patch to slide down the barrel. Once again, the patches will have survived. And, no, they won't burn through due to lack of lube. They do not need lube to prevent patch burning. As hot as it gets under the patch, it is over with in milliseconds and there is not time for the patch to burn through. Burned patches are the result of excessive blow by due to the patch ball combo being way too loose or the barrel condition damaging the patch which allows excessive blow by and burning of the patch.

BTW, Paul, I'm not preaching to you on this personally. Just trying to give shooters some new options to consider in their shooting.

OI don't know why you pull one sentence out of a paragraph and then attempt to attack me about it. If you read the rest of my statements, my reason for caution is well stated.

I know this comes across as an opinionated rant, but I assure you I'm wide open to other ideas and solutions to just about any problem.

 

[paulvallandigham]

Just for your consideration, when my brother and I were exploring how to reduce the differences between Goex and Swiss powders, he discovered that using an OP wad with the goex, even in a smooth barrel, increased the velocity while decreasing the SDV. Then, He used a greased cleaning patch to run down the barrel and out again to lube the barrel in front of the PRB. That further decreases his SDV, while increasing the velocity.

I understand that some barrel makers actually rough up the area at the back of the bore, to increase resistance for the PRB, and get higher chamber pressures, and more complete powder burns. And, just recently someone noted that another maker would rough up the last few inches of the bore behind the muzzle, to grab onto wads, out of smoothbores, and separate the wads from the shot as it was released at the muzzle. It would be interesting to run that kind of thing- before and after-- over a chronograph to see what benfit is derived other than what is stated.

 

[Ken Rummer]

Thanks to everyone for the feedback.

This is an Investarms 1:60 barrel. There are no tight spots apparent to me. My objective is to smooth out the visible rough spots on the tops of the lands so the patches won't get chewed up.

I think this will become a new post in a few weeks.

 

[longcruise]

Good luck. I'm very curious about the harder bullets and how they work out.