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How Smooth Is Smooth Enough?

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musketman

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There are several post in the building section about lapping the barrel of various muzzleloading rifles, For reasons of patches being cut to polishing the lands and grooves a bit for better loading and shooting capabilities...

Has anyone (besides myself) ever lapped the bore of a smoothbore?

I was able to see slight "chattering" of the bit when my musket was made, so I polished it out...

This brings me to a point, how smooth is smooth enough?

Glass smooth?
Honed smooth? (like the piston wall of an engine)
Does it really matter?

Rough barrels can hold fouling in it's imperfections, thus making loading and shooting harder, I think lapping a smoothbore is a good idea...

What do you think?
 
Polished bright like a chromed lined barrel = perfect, for a smoothbore. Rifles on the other hand, seem to shoot beter if not quite chrome-bright smooth. My ML barels and varmint rifle's barrels are diffiult to look through at a 60 watt bulb, and the moderns ones aren't picking up any copper fouling, but I would say they aren't as smooth as I would like a smoothbore's barrel. I understand that rifle barels can't be chromed-smooth or use too slick a lube for bullets but I've never had a barrel so smooth & slick that it didn't shoot well with some bullet/lube combo.
 
You know its right when you pop the short starter and the patched ball slides down to the breechplug without using the ramrod.
 
I swabbed mine with 0000 steel wool. 100 straight down, 100 straight back with valve lapping compound on the wool and then again the same 100 down and back with the wool alone. Didn't take the ramrod out of the barrel until after the 100 down and 100 back strokes. The barrel was out of the stock with the breech plug out. It took all the "rings" out of the barrel left from the reaming.

I was told this by a damn good smoothbore shooter, so I did it.

Don't know if'n it helped, but it sure prettied it up on the inside. Flintshooter
 
Smoothbores will load, shoot and clean the best when perfectly polished, that's for certain. If possible, and it can be done with polishing compounds, a slight taper from breech to muzzle, or a slight tightening at the muzzle will shoot better. I have lapped-in this type of choke, only a couple thou at most, into two ML rifle barrels & one modern one with excellent results in increased accuracy with slugs. The first was a 24" twist .50 McGowen barrel and the second was a .50 cal Bauska 38" twist. The modern barrel was my .223 dia. Hornet and it's only .005" tighter at the muzzle, but man, does it shoot- always less than 3/8" for 5 shots at 100meters. It wears a 6.5 to 20X scope.
: The .50 Bauska barel liked Maxiballs for 1 1/2 MOA at 100yds., and the McGowen barrel shot 550gr. slugs into 1 1/2MOA at 100meters, but held those 1 1/2" groups to 200yds. which is actually 1/2 MOA.- Metallic sights, both.
 
Oh great. I just read these threads to that pesky mooksetmans question. Now I gotta find the time to polish my G.M. barrel chrome smooth! :curse: :curse:
 
Not really, but it might shoot better.
: As well, if you polish from the breech end, stopping the jag or lead plug-lapp 1", then 2", then 3", then 4" back from the muzzle, 50 to 100 strokes each place with 600 grit & cutting oil, you will lapp in a slight choke that will shoot shot tighter and ball slighty better.
: An expandable lead plug-lapp would, of course, be the best method.
 
But Colonel Peter Hawker says the best makers put in a very slight reverse choke to shoot tight shot patterns.

Hard to argue with the man whose books raised Joe Manton to the top of his profession.

I like to think Hawker might have misunderstood what he was being told and Joe had the secret of chokes decades before Pape got his patent.

Hawker's Manton is still with us, wonder if anyone has ever measured it ::
 
Also, at about the mid 1800's it was felt that to shoot tightly with shot, the choke had to be in the middle of the barrel.
; There were many wierd ideas, but the very best chokes of all time are presently on the 12 bore US military High pressure shotguns for the tungsten loads. It is difficult to imagine a 6 foot pattern at 150 meters. Most modern tight chokes spread that much, totally, counting all strays, at 60 yds or closer.
; Ely's ctgs. for shotguns were a very good idea that worked at long range - too bad we can't get anthing like them today.
: Turned out to be W.W. Greener who developed choking to it's present sporting proportions & design. His guns were seldom equaled in the Field Trials and never by the wierd reverse or middle chokes, which usually shot worse than cylinder bores in actual paper patterning. I do think there was a misunderstanding or perhaps an annomoly when testing, like when a gun accidently shoots a tiny group, never to be equalled again except by another such accident.
 
Lead lapp cast in the barrel, on the rod, with a screw in one end to expand the lapp as it wears. Another way, especially with smoothbores, is to machine the lapp to fit a threaded pushing rod, and have it bored for a long, slightly increasing dia. screw for the other end to expand the lapp. This way a new lapp doesn't have to be re-cast as they wear down. As the lengthwise hole is tapered to 1/16" in the middle of the lapp, the lapp expands in the middle more than at the ends, so it contacts over a longer length than jsut at the end. This helps the lapp cut faster.
 
The Russkies were shooting what I would call a jug choke during the 70's in clay bird competition (smokeless). The barrel was left cylinder bore but was bored about .100 larger (.050 per side), six inches back from the muzzle, with the last inch left cylinder bore. It was like an interior Cutts Compensator - the thought being that the shot column would expand a bit in the overbore and then choke back at the end. However, everything I have read about patterning stresses reducing or eliminating shot deformation and too much choke just lengthens the shot string. I think Daryl's method would give a mild choke without damaging too much shot.
 
Choke story. Now as a firearms instructor for the police department for several years I got to shoot and test a LOT of buckshot loads in every configuration you can get in factory 12 ga. ammo.
Just very breifly for those of you interested in buckshot for rural self defense (accidently taking out a couple neighbors unlikely) 00 3"mag. Fed. Premium in a mod choke works very, very well, patterning out of some mod. chokes with all 15 pellets inside a 10" circle at 40 yards. Rem, next, then Win. if all in the BEST loads. Buffered, copper, plated, 3" mag.
Now while in southern Va. I had an opportunity to be a guest at a gun club, Beagle club in fact. he dog of choice for running the little deer in the swamps that abound in that region.
Those guys had guns that would kill deer at 100 yards with BUCKSHOT!!!!
A short barrel was 32", some 38" BOTH jug or reverse choked WITH choke tubes!
All loads were handloads. They bought hard copper plated 00 buck, buffering compound, and loaded those suckers to the gills. All abrrels were backbored and ported. They would really hold a pattern and were set up for deer only, buckshot only.
I've loaded my own buffered shot loads and home brewed buffered loads are better than factory buffered because you can much more evenly distribute the buffering compound though out the shot. The buffering kind of buffering compound really makes a difference also.
I'm trying to figure out how to do this for my .62. Perhaps a paper ctg. of some sort?
I know a whole bunch about making buck perform.
I proved many times with an 870 police riot gun (no choke)that with the old soft 00 buck pellet 9 count 2 3/4" load you could miss a man sized target COMPLETELY at 25 yards!
 
There was an article in the Minneapolis paper this summer about the pros hired to thin deer herds in urban areas, silently, and with no danger to neighbors. They would drop deer in parks with folks all around unaware of what was happening. They used an 8 ft. barrel. They shot some kind of projectile that was a wad of shot, which would not expand much, if at all.
 
That WAS quite an stricle, wasn't it. The barrel extensions and extensions most were but not all, in some cases, were ported full length, many of them, gave very little noise and very tight patterns. They also used special low velocity loads to keep under the speed of sound. The already low pressure was bled off by the time the shot column got to the muzzle, and therefore there was no muzzle blast to disturb the shot. It was delivered very gently.
 
I've never shot PRB's from a smoothie but have put a lot of shot downrange and there are more snake oil recipe's for patterning than there are enough guns to use them on.

Bird shot and rifles both like the smoothest bore you can get and highly polished chrome lined bores are one way to get it. I've lapped many a rifle bore both CF and ML to get rid of roughness, get rid of sharp edges on rifling, remove rust/fouling, ect. I don't really favor any one lap over another, my choice depends on what needs doing to what. I use leather, cotton, scotch pad, lead and rubber the most. Lead laps are limited to rifle/pistol bores, smooth bores I use a flexible rotary lap turning at least 650 rpm for heavy work and no less than 2200 for polishing. Combinations of lap materials can prove very effective as well, leather on each end, scotch pad to the inside and a double thick leather or single rubber in the center. The scotch pad will hold a lot of abrasive compound and as you move up and down the bore it will dispense evenly to the rubber and leather laps.

I like my compound on the thin side and prefer mixing my own starting with a base of commercial compound and modifying it to my likes. I use clover brand simply because it's what I have on hand and can get easily. I'll thin the compound with Rigid brand dark cutting oil until it gets almost runny but not quite, just about to pancake batter consistency. I wipe the bore with cutting oil prior to starting and add more oil as necessary during the lapping to keep things flowing nicely. Generally, if you're not making a mess, you're asking for problems. Gummed up laps can do way more harm than good and thus is why you need to keep the laps free of build-up to ensure even cutting at all points. Less of a concern when using a rotary lap but the practice is good to keep. When doing a rifled bore, it is critical to rotate the lap one rifling groove at least every 10 strokes to ensure even cutting. If using a non-formed lap like scotch pad or steel wool, rotate 10 degrees every 10 strokes. Lapping is not difficult but can take a good barrel that needs only a little TLC and turn it into scrap iron quickly if done wrong. Biggest thing is getting the bore clean after lapping. I prefer to shove at least one end into a bucket of #1 or #2 oil (kerosene/diesel) and scrubbing it out letting the oil wash out all the compound then follow with a de-greasing solvent (I use non-chlorinated brake clean) till you get nothing but a clean patch then just give a light coat of oil. Mineral spirits will work in a pinch too.

Jug chokes have been around for a long time and were just re-born with new names in the late 1970's or early 80's. Browning and others trying to corner the market with "super chokes" and "special trap chokes" and so on. Nothing more than what was being done 150 or more years prior to this, just given a new name and lots of advertizing. No one choke will pattern well for all shot sizes either. A rather minimal jug of .002" over bore diameter may work great for shot sizes 8&9 while a .004" will work best with 7.5 and 6. From what I've seen in practice, the more you go over the bore diameter with the jug, the better the patterns will get with larger shot out to around .009" for BB size shot. There is a lot of debate on the length the expanded section should be but most agree on 1.5 to 2 times the length of the shot charge within the bore.

I think that most pattern problems can be cured much easier by adjusting powder/shot charges and the wad column. Plastic shot cups and "pushin' cushion" wads may be easy loading and save the bore from steel shot but beyond that I think they're useless. I'll bet you dollars to dog cookies that you can take any gun with any plastic wad you want and I'll show you a better pattern with card and fiber wads. Slower loading but if you really want to dial a pattern in, it's the only way to go.

Buffer agents can also be used to provide pattern control. The buffer does two jobs, one in helping prevent pellets from deforming by squashing each other on firing and two to help keep pellets riding against the bore from imparting a spin. Commercial buffer agents (normally virgin PVC powder) can not only cost you on average 90% more than buying the same stuff from an industrial supply but usually make a considerable mess. Static electricity will have it sticking to everything except the shot pellets. While it's a little more crude and old, the flour/cornmean mixture has been proven to work and be very cheap and easy to deal with. 1 cup all purpose flour to 3 cups powdered corn meal. For the ML I pre-load film containers with shot charge and pre-measured amount of buffer, quick shake to ensure even mixture before dumping down the bore. Cartridges are somewhat easier, drop the shot as normal and then spoon some buffer on top and touch the casing to the lyman turbo cleaner to vibrate the buffer into the shot. Unless you get exceptionally tight crimps on casings, it's best to use a .025" OS card under the crimp to keep from getting pockets full buffer.

Cu and Ni plated shot will usually pattern better simply because they are harder and resist damage better. The rounder and harder the shot, the better the patterns will be. I prefer using Cu or Ni for turkeys and other tough game but regular "magnum/chilled" shot works good for everything else. Interesting fact is that using the same exact load for plated and unplated hard shot of the same size will result in no noticable pattern difference. Field experience does indicate better penetration with plated shot.

My personal feeling is that for shooting shot or bullets, you can't get a bore slick enough.
 
Mark,

A very well written and informative post...I have a few years of shotgun experience but only shooting gobs of dove and quail - nothing in the competitive arena. Thanks, Anvil
 
Scotch-brite green spun on a drill and long metal rod sloted for the Scotch-brite like a patch tip. In and out,up and down ,like a mirror. A little light oil won,t hurt.
 
Scotch-brite green spun on a drill and long metal rod sloted for the Scotch-brite like a patch tip. In and out,up and down ,like a mirror.

Just like honing a cylinder in a motor, only with a smaller bore and a longer throw...

I would suggest a brass or aluminum rod though, just in case you hit the side of the barrel during the stroke...
 
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