Taper of coned muzzle

[Clear Spring Armory]

All the debates on what it does to accuracy and the fact I can buy a tool aside, what is the recommended taper in degrees for a coned muzzle? My friend has a machine shop and we're going to try a few things. I guess while we're at it, what's the recommended taper for the short coning that I've read about some doing on this site? Looked like almost 45 degrees. Btw, I searched the site pretty thoroughly and couldn't find any numbers. I also realize there may be alot of leeway there.

[Daryl]

 It's really not a 45degree angle and most definitely not a cone, but a smoothly rounded entrance.
What this type of crown does, is allow the flow of patch and lead to happen at the muzzle as the patched ball
is seated into the bore. Once inside, with a wet patch it is an easy push down to the powder, which cleans the
fouling of the last shot.  We load with ball compression in the bottom of the grooves, usually .005" sometimes
up to .010" compression of patch and ball in each and every groove.
A slow taper does not work as well, as the long taper increases friction & actually makes loading more difficult. We
have proven this on LB's .40 rifle. He was not able to load a combination in his long-coned rifle that loaded easily in
my gun. I tried it in his, and by jingy, it was hard loading in the long cone, not so in the short radiused and smooth crown.

This is a crown DaveC of this site, cut with his crowning tool (which he makes and sells)



Here are a few we've done by hand as below, or on the lathe. Most of mine are done by hand, with emery or wet/dry 320 paper.

[45-110]

Years back when Don Getz did some instructing at Conner Prairie he made a cone.....a definite cone with bore guide to funnel the muzzles with abrasive paper. I made a copy and use it frequently, but don't know the angle. There are pictures on this site that show similar tools and how to proceed.
kw

[Clear Spring Armory]

Yes, I've searched the site thorougly, I've seen all the pictures. But I've never seen any angles put forth. And the only debate I've seen is between the fast taper (radius) shown above, and a slow taper. Was just curious if there is a recommended taper (expressed in degrees) and maybe why.

[Scota4570]

Unless you have very low accuracy expectations do not cone the muzzle. 

A smooth regular crown as described  in the previous post, will make loading easy.  Once the patched ball is past the crown it will not matter.  Using a short starter takes care if it. 

IF you want to avoid the short starter and load a loose combo, return to my first sentence. 

[wattlebuster]

So I guess all us dummy's that have coned barrels have very low accuracy expectations. Momma told me there was something wrong with me. This confirms it

[Mike Brooks]

I never noticed any difference in accuracy coned or not. I probably have low expectations though.

[hanshi]

  Wait a minute!  "Coned", and not "corned"!???  Man did I screw up; no wonder it didn't work for me!  I "Corned" it rather than "coned"!  Accuracy is now "shot to h___"; but the smoke sure smells good.

[mark brier]

I wanted to answer this quickly before I leave and will leave the trig to you for exact angle. The universal one I made before does 30 to 69 caliber. The brass portion is the important part and it is 3 1/4” long. Front is .280” and other end is .700”
Should be all the measurements you need for finding angle.
Mark Brier

[Scota4570]

I would encourage the OP to do a search right here and read the other threads on this subject. 

"Accuracy" is a relative thing.  If one likes to get obsessive and try to make the smallest possible groups off the bench that is one expectation. Say 1" goal at 50 yards?  I am one of those.   I recently tossed a barrel that would not do better 2" at 50 yards consistently. 

IF one casually shoots at trail walks and measures groups "off hand"  then that is a much different standard.  A rifle capable of a 6" benchrest group at 50 yards may satisfy that shooter. 

Neither shooter is right or wrong, they are different games.  There are lots of kinds of shooters.  Heck some never even shoot a ball or bullet, just blanks.  There is plenty of room for everyone. 

On average coning will hurt accuracy to some degree.  I have never heard of it helping accuracy.  That is my opinion, an opinion was asked for.   

Added later:  Why do a cone?   If easy loading is the goal choked barrel is very nice.  A choke can be lapped into the bore.  Yes, it is a lot of work to do.  If the short starter gets the ball past the choke ramming the ball is super easy.  I found accuracy to be excellent. 

[davec2]

This is a repeat of one of my old posts.....and  minor correction to Daryl's post, I don't sell these....I just made them for myself.

Quite some time ago I read an article by Peter Alexander about coning a bore.  His article included a drawing of a reamer he made.  Having a fair felicity with machine tools, I didn't think that reamer was particularly good, although simple to make.  I had a tool grinder I use make up one of the simple reamers and one of my own design with a left hand twist, right hand cut.  Both have interchangeable pilots that I match machine to the bore diameter.  As expected, the simple reamer works but not nearly as cleanly or as fast as the spiral reamer.  It takes me about three minutes to cone a bore.  Just to check, I put a hand coned barrel back in the lathe and checked the runout of the coned surface with the bore.  Could not detect any runout.  Guns seem to shoot right where I point them, although I have now shifted over to Daryl and Taylor's muzzle "rounding" except I do it with a tool I made up.  Also takes about 3 minutes.

Reamers:



Muzzle tools:

I have always liked the way Daryl puts a nice large radius on his muzzles (as pictured near the end of this series of posts

    http://americanlongrifles.org/forum/index.php?topic=12383.0 )

However, setting up to crown a muzzle like this in the lathe is always a pain.  So I made this hand tool to quickly put a clean, smooth radius on the edge of the muzzle.  Here is a picture of one of the barrels I have with the standard 45 degree chamfer as it comes from the manufacturer



Here is the tool showing the single radius cutter insert.  The nose / pilot of the tool is 0.0005 under bore size





Here is the tool in use



And here is how the crown looks after a few rotations of the tool.  Actually, this picture still looks like a chamfer and does not show how clean the radius is...I need to try to get a better picture...but the radius the tool makes matches the close up picture of the cutter insert and is not quite as large as it looks in the photo.

[davec2]

Oh....and Clear Spring.....to answer you original question, the tapered reamers I had made were 1 to 1.5 degree tapers.

Dave C

[snapper]

I used a tool very similar to the one that Mark B. shows.  Bought it from a member here that makes them.   I need to clean up a muzzle of my double rifle that had slight damage to it.   It worked as promised and it also fixed my accuracy problem.  The POI at 50 yards went from 6 inches left to dead center.

Fleener

[Clear Spring Armory]

Oh....and Clear Spring.....to answer you original question, the tapered reamers I had made were 1 to 1.5 degree tapers.

Thanks, that is what I was looking for. Just something we wanted to play with. Actually, my buddy is going through a hard spot and mostly just want to keep him busy at something that isn't his daily grind. Thanks guys
Dave C

[Tizzy]

Accuracy and consistency are two seperate yet both desirable qualities of a good rifle. To achive maximum consistency with all other variables being the same...propellent gasses must remain consistent in both pressure and blowby velocity surrounding the projectile circumfrance  as it exits the muzzle of the weapon. In short...coning the rifle will not hurt the consistency of a rifle,(accuracy and load development will be up to you) so long as the above stated parameters are met. In the words of the late Don Getz, (the bullet must exit the rifle the same way each time.) That is the most truthful and simplistic  way that I know to put it..... just make sure whatever coning tool you use makes for a consistient crown....you might acctually increase accuracy by reducing bullet distortion due to hard loading.

[Bob Roller]

DaveC's radiusing tool is a great idea.He obviously can make anything he needs or thinks up as do I.
I have one that can true a muzzle in the range if need arises and can be powered by a battery powered
hand drill. I will see about getting a picture sent.It's basically a guided fly cutter and as it is now it can
only be used with a .450 bore but adaptors can be made for other calibers.
Another idea for a tapered or "funneled" muzzle can be had with a standard taper pin reamer that will
be 1/4" per foot taper.To do this right, a lathe is a MUST.

Bob Roller

[westbrook]

I wanted to answer this quickly before I leave and will leave the trig to you for exact angle. The universal one I made before does 30 to 69 caliber. The brass portion is the important part and it is 3 1/4” long. Front is .280” and other end is .700”
Should be all the measurements you need for finding angle.
Mark Brier

I get right about 3.8 deg of taper

Teacher always said to "show your work"

.700-.280 = .420 difference

.420/2 = .210  cuz were only interested from the center line out...not side to side.

.210/3.25 = .064615 per inch

1 degree will raise 1" .017"  so....

.064615/.017 = 3.8 degrees

[Justin Urbantas]

I wanted to answer this quickly before I leave and will leave the trig to you for exact angle. The universal one I made before does 30 to 69 caliber. The brass portion is the important part and it is 3 1/4” long. Front is .280” and other end is .700”
Should be all the measurements you need for finding angle.
Mark Brier

I get right about 3.8 deg of taper

Teacher always said to "show your work"

.700-.280 = .420 difference

.420/2 = .210  cuz were only interested from the center line out...not side to side.

.210/3.25 = .064615 per inch

1 degree will raise 1" .017"  so....

.064615/.017 = 3.8 degrees

Makes my head hurt. I'll have to trust your math, cause I sure won't be double checking it!

[RichG]

I've used the tapered tool sold by the member on this forum on 2 rifles. both shoot better than I can see anymore. I think the purpose of coning is for a quick reload when hunting ,not target work. In my 54 Lehigh I use a .525 rb , .020 patch with mink oil and 90grs. O.E. 3f. anything less than 90 grs doesn't shoot. In my 58 trade rifle, I use a .565 rb .025 patch with mink oil and 120 gr 2f O.E. Both combinations thumb start into muzzle and ram down easily with no short starter. Again less powder shoots poorly. The 58 is a green mountain with a 1-72 twist. With a looser ball/patch combination it requires more powder to get the ball/patch to seal. I wouldn't shoot a trail walk with either of these loads.

[Clear Spring Armory]

I've used the tapered tool sold by the member on this forum on 2 rifles. both shoot better than I can see anymore. I think the purpose of coning is for a quick reload when hunting ,not target work. In my 54 Lehigh I use a .525 rb , .020 patch with mink oil and 90grs. O.E. 3f. anything less than 90 grs doesn't shoot. In my 58 trade rifle, I use a .565 rb .025 patch with mink oil and 120 gr 2f O.E. Both combinations thumb start into muzzle and ram down easily with no short starter. Again less powder shoots poorly. The 58 is a green mountain with a 1-72 twist. With a looser ball/patch combination it requires more powder to get the ball/patch to seal. I wouldn't shoot a trail walk with either of these loads.

Ya, actually, this is the reason I want to fool around with coning or putting a radius on my muzzle. I mostly shoot small calibers, .32 and under. Its tough getting a thick patch down in small caliber (for me. I know, I'm useless, someone else probably does it all the time with no radius or cone). The reading I've done here on this site tells me that a thick patch and overall tighter load is the way to go, and I agree with the logic. But I've broke a few ramrods trying it, and I want to try what Daryl suggests now. Just don't want to use my thumb, lol. And would like to have a coning tool incase someone wants one done, on top of the reasons previously given. I asked here under the building section, not the shooting section, because I wanted to see if there is any science or theory behind the angles, etc., or at least start a discussion about it, when making the tools.

[Clear Spring Armory]

Actually settled on a radius tool like what davec2 has. I would like to hear a bit more about that.

[SingleMalt]

I use Joe Wood's coning tool.  I've never had a problem with use or accuracy.

[taco650]

I coned a barrel with a tapered hole alignment tool I used to use when doing auto body repair.  Taper was about the same as that on Mark Brier's tool.  Wrapped it with some 320 sand paper, then 600.  Made loading ball and patch a press fit to get it just past the muzzle.  Accuracy not affected.

[Dphariss]

Before coning a barrel with a deep cone people should read the description of the bore of the rifle that Baird thought could be Francis Parkman's rifle in his "Hawken Rifles: The Mountain Mans choice. If you have a hard time loading a rifle crowned as Daryl has shown your problem is not the crown cold be lube or technique etc etc.
This is similar but is cut on a lathe with two different cutter setups. One photo is of the barrel in the lathe. The other is with the barrel fouled after a proof shot.

Dan

[heinz]

I learned how to crown barrels from Clark Frasier who was a national champion match shooter withe the NMLRA and competitive for over 50 years.
Clark proved all his techniques on heavy bench guns checking what worked best.  He crowned exactly like Daryl.
He also said to lay the ball on the crowned muzzle without a patch: if it went in by itself the ball was too small.  If you could push the ball in easily with your finger, it was about right for use with a pillow ticking patch.  We lapped out molds with valve lapping compound or toothpaste to get the size right.  Always used a short starter.