Groove depth: what do you consider practical?

[piwo]

My .54 Colerain mid-weight barrel has land to land diameter of .542" consistently on all lands. Groove depth measurement between .575" and .5775" This means I have to find a patch .033" - .0355" above bore diameter to seal "properly" In all honesty I don't see sealing issues on the few patches I've been able to recover, but will need look harder and make sure. This is a LOT of patch material required in my opine, a lot of material that must bite the lead at the lands regardless of what size ball one uses. Colerain web site says they cut their grooves to .012 per side, but mine is .0165 and one that is .0175 deep.

Any of your muzzleloaders have such "generous" grooves? Just curious...........

[451 Pete]

Piwo,
The patch in a round ball rifle is not really a gasket to seal the bore. It is more of something to protect the round ball during it's journey down the barrel, impart spin to the round ball and provide lubrication to the bore. The deep rifling is there to make loading between shots easyier. I would say if the rifle is shooting well and you are seeing no sign of patch's being cut or burning out you should be in good shape. Colerain has a reputation for makeing a pretty good barrel and is known for a good product.

Pete

[Good Cheer]

Here's a for instance, by example, visual aid. While it may not look like it, this recycled barrel (photo before lapping) has some deep rifling when you go from those narrow little lands to bottom of the curved grooves. Sealing the bottoms of the grooves isn't necessary for accuracy.

[405]

Actually, I think you need to halve your patch thickness number to use as a starting point. My experience tells me no two RB guns are alike in preference for either best ball diameter or best patch thickness. So, if those numbers are right I'd probably start with pillow ticking (.015-6"), shoot some .530 and .535 balls, compare the results, then go from there. It's always been hard for me to predict results from guessing ball and patch thickness even when I know exact bore and groove diameter when first testing a RB gun- shoot and experiment seem to work best.

[JeffinNZ]

Let's say you are loading a .535 ball you will be looking for patching of .020 to being with I would suggest.

.020 + .020 + .535 = .575

I am baby sitting a .54 GPR and with a .530 ball is likes .024 denim patching.

[piwo]

Let's say you are loading a .535 ball you will be looking for patching of .020 to being with I would suggest.

.020 + .020 + .535 = .575

I am baby sitting a .54 GPR and with a .530 ball is likes .024 denim patching.

Well Pete, this is the math I've done and attempted. With as deep as the rifling is I cannot match it exactly as stated because even with a bore dripping in lubricant, you tear the patches or deform the ball terribly. With the requirement of a patch that is a tenth of an inch larger than would be required if the barrel was cut to the dimensions the manufacturer states I think could be significant.

I'm not new to shooting RB's but look for opinions from many sources. there is one school that says you certainly should fill the grooves, one that says it's not required, one that says you should fill the grooves with the "crush factor" of the patching material (making things even tighter). I guess my point is that I believe .035 deep is a bit deep, and am curious if anyone else has slugged their barrel to determine the depth of theirs compared to the bore diameter. I do not have a .535 roundball mould to cast with at this time and need to get one. At the going price of a Lyman mould it will be a while. I have some Lee moulds but my larger roundball all have "fins" on them and I'm not a fan. My .630 casts roundball that look like the planet Saturn with it's rings!

[excess650]

I would suggest that you go with a THICK patch. The heavier weight pillow ticking that I have is about .020" after washing twice. I have cotton duck cloth that is closer to .025" and some denim that goes to at least .030".

My Colerain .62 seems to be liking the .020" pillow ticking and .025" cotton duck with .605" RBs. I have a .615" and can't load them with even a .015" patch, so I had to go smaller with the ball and thicker on the patch.

The pillow ticking was showing evidence of cutting on some patches, but no sign of it at all on the cotton duck.

Patch lube can and will make a difference. I'm currently using Track Of The Wolf's mink oil. Unlike water based lubes, it won't freeze or contaminate the powder charge in a hunting situation.

In your case I would suggest a .530" or .525" ball and thick patch. Too, you may need to polish the muzzle and bore if its a new barrel. Scotchbrite on a jag may help in the bore, but if you're cutting at the muzzle, you'll need to round the edge thats doing the cutting.

BTW, I just checked the info at TOW and then Colerain's website. TOW specs .012"-.016" groove depth. Colerain specifies .012" on .40cal and less and .016" on larger than .40cal.

Rice lists .016" depth on radius groove rifling. IIRC, Getz is in the .016"-.018" depth on the radius groove rifling.

[piwo]

I would suggest that you go with a THICK patch. The heavier weight pillow ticking that I have is about .020" after washing twice. I have cotton duck cloth that is closer to .025" and some denim that goes to at least .030".

My Colerain .62 seems to be liking the .020" pillow ticking and .025" cotton duck with .605" RBs. I have a .615" and can't load them with even a .015" patch, so I had to go smaller with the ball and thicker on the patch.

The pillow ticking was showing evidence of cutting on some patches, but no sign of it at all on the cotton duck.

Patch lube can and will make a difference. I'm currently using Track Of The Wolf's mink oil. Unlike water based lubes, it won't freeze or contaminate the powder charge in a hunting situation.

In your case I would suggest a .530" or .525" ball and thick patch. Too, you may need to polish the muzzle and bore if its a new barrel. Scotchbrite on a jag may help in the bore, but if you're cutting at the muzzle, you'll need to round the edge thats doing the cutting.

BTW, I just checked the info at TOW and then Colerain's website. TOW specs .012"-.016" groove depth. Colerain specifies .012" on .40cal and less and .016" on larger than .40cal.

Rice lists .016" depth on radius groove rifling. IIRC, Getz is in the .016"-.018" depth on the radius groove rifling.

I was looking at the website but everything sort of ran together and it was difficult to read: don't know if it was the browser or the site and I missed the "deeper" depths discussion. Well, I have the .530 RB's, and twice washed denim from the fabric store that mikes to .020 and .022 "crush" measurement. Neither will load without deforming the roundball. I picked up some ticking that crushes to .016, .017 and .018 and am giving them a try. Still need to try a different size roundball: anyone have any "rent a moulds" availalbe??

[405]

With really deep grooves the bore/groove/patch thickness/ball diameter math gets a little fuzzy simply because ulimately and past a certain point the bore diameter is going to limit what can be loaded without a mallet and short starter.

At first I thought the groove diameter listed was a typo, but if it's indeed .576 then WHEW! Might just get some thick ticking or light denim, wash it a couple of times, and try the patched RB with a 1/8" felt overpowder wad.

[mooman76]

I have a 535 but it's a Lee.

[piwo]

With really deep grooves the bore/groove/patch thickness/ball diameter math gets a little fuzzy simply because ulimately and past a certain point the bore diameter is going to limit what can be loaded without a mallet and short starter.

At first I thought the groove diameter listed was a typo, but if it's indeed .576 then WHEW! Might just get some thick ticking or light denim, wash it a couple of times, and try the patched RB with a 1/8" felt overpowder wad.

It is indeed .576, but excess650 finds that all the bigger bores are .016 or so, and so I guess it's NOT out of line. Big surprise here since I've always been under the impression you need to fill up the grooves. As the good folks here are telling me, that ain't gonna happen. So be it. I'll work up the tightest patch that doesn't deform the ball or tear. Work my way down and see which shoots best and call it a day.....

Moonman, does your lee cast well? Hell I'd shuck out the money for one if I thought I could get one to cast well. I guess I've just lost confidence in them.

Anyone have any luck getting a stubborn one to cast well?

Thanks for the input guys. This is good...........

[Mk42gunner]

I've got a .530 Lee that casts well, if I pay attention when casting.

Robert

[missionary5155]

Good morning
Do not forget the pure lead ball will obturate at ignition with BP tightning up everything you have within that bore. Like above-- experiment. You will find for different needs there may have to be some variance. If I want to shoot my favorite caliber.58 more than 3 shots without swabbing I use a thin linen patch after the 3rd shot. Accuracy does not change much at all and loading through 10 shots is accomplished. Experementation and lots of time with your rifle will help you understand what it likes the best and in turn will give you the best performance. Merry Christmas !
Mike in Peru

[piwo]

I've got a .530 Lee that casts well, if I pay attention when casting.

Robert

As far as getting the mould up to heat, lead temperature and keeping appropriate places of the mould lubed, I'm not sure what other things are in my control that cause balls that have a near 360 degree "halo" of lead around them. I don't find any burrs that would obviously keep the faces from making good contact and there is significant gap when closed: though I have other moulds that you can see daylight through when closed and they don't give that result. the channel for the guide bars at the bottom are very "rough' cut, but that's not the problem unless they're simply not deep enough.

What might I might not be "paying attention" too?? Certainly open to suggestions.

missionary5155
A very Merry Christmas to you and yours as well!! Your point is a good one, though I've never been able to recover a shot roundball so I really don't know to what degree that obturation occurs. Accuracy is OK with my rifle, but not great. I seek to optimize the patch ball combination to remove that variable, and also to have a good Midwestern US "winter" patch lube combination which I fear might be causing some "first shot" inconsistencies with the rest of the groups. That’s where the re-visit of patch thickness arose and that’s why the groove depth discussion. I honestly haven’t shot my muzzle loaders all year nor have I cast for them all year. I was bad this year: spent all my time at the range playing with a Mini-14 trying to get it set for coyote hunting. But my love is BP and I’m back in mode, now just trying to remember everything I forgot!

[mooman76]

If the mould doesn't close all the way either from tiny lead particals or because it has trouble lining up proper and needs a little help to close even(setting on a flat surface). All my Lee RB moulds cast good. They get a very small seam on them but not a halo like you describe. Mine is an old single cavity I bought on ebay by mistake.

[piwo]

If the mould doesn't close all the way either from tiny lead particals or because it has trouble lining up proper and needs a little help to close even(setting on a flat surface). All my Lee RB moulds cast good. They get a very small seam on them but not a halo like you describe. Mine is an old single cavity I bought on ebay by mistake.

heating up the lead in a few minutes and am going to cast a few. We'll have pictures. I read where folks will scrawl out the vent lines to deepen them so maybe I'll try that before I start,

[piwo]

Well, I did a casting session and the problem seems to be temporarily resolved, but in an odd way. If you examine the picture you'll see the mould and three balls with Fins, then one without. Looking at the mould you'll see at the 6 O’clock position lead build-up. It's super thin, but it's there. ONLY after that lead built up did the nice ball on the far right get cast, and on subsequent RB's as well. Lead buildup on the face of a mould is considered a problem and not a solution, but in this case it was the solution. My interpretation is that the mould has an alignment problem but the thin band of lead straightens it out.

Not sure if it's repeatable after the mould cools down and the process is restarted, but I'll be doing that as well to test. Not optimum, but I got a few dozen that are usable.

[451 Pete]

Piwo,
You definitely have something going on with that mold. I would almost say it has to be not closing properly or something is wrong either with a pin or maybe stuck behind a pin kor maybe its respective groove to cause the problem. I have had pins come loose in Lee molds before ... basically just put them back in when they cool and go back to casting. I'm curious what you find.

Pete

[piwo]

And now that I've measured them, They're out of round....... vary between .695 and .700

[Mk42gunner]

As far as getting the mould up to heat, lead temperature and keeping appropriate places of the mould lubed, I'm not sure what other things are in my control that cause balls that have a near 360 degree "halo" of lead around them. I don't find any burrs that would obviously keep the faces from making good contact and there is significant gap when closed: though I have other moulds that you can see daylight through when closed and they don't give that result. the channel for the guide bars at the bottom are very "rough' cut, but that's not the problem unless they're simply not deep enough.

What might I might not be "paying attention" too?? Certainly open to suggestions.

Mainly with my Lee blackpowder molds; it is being careful when I close the mold, along with consistant grip on the handles. I have one of the .54 cal REAL molds that is a real PITA to use, I have to close it on a flat surface or it casts a visibly misaligned boolit. Since I had it prior to getting the .530 RB I have always been very careful with it.

My 312-185 doesn't seem to care, I can close it any old way and it turns out good boolits.

Well, I did a casting session and the problem seems to be temporarily resolved, but in an odd way. If you examine the picture you'll see the mould and three balls with Fins, then one without. Looking at the mould you'll see at the 6 O’clock position lead build-up. It's super thin, but it's there. ONLY after that lead built up did the nice ball on the far right get cast, and on subsequent RB's as well. Lead buildup on the face of a mould is considered a problem and not a solution, but in this case it was the solution. My interpretation is that the mould has an alignment problem but the thin band of lead straightens it out.

Not sure if it's repeatable after the mould cools down and the process is restarted, but I'll be doing that as well to test. Not optimum, but I got a few dozen that are usable.

I can't get your picture to show up, I hate trying to get a new computers settings right.

From your description, I had somewhat the same problem with a 6 cavity Group buy mold. one time I would get good round boolits, the very next cast they would measure .312x.322. I even have a finned set of five boolits that I saved for some odd reason.

I was to the point that I introduced it to the old horseshoe rasp, but the occassional round boolit held me back.

I finally found that the alignment pins had caused the aluminum to swell when they were pressed in and if they werenn't in perfect alignment the mold wouldn't close. I found it by heavily smoking the entire mating surfaces of both sides and vigorously closing the mold several times. When I saw the soot getting thin, I trimmed the aluminum with my pocket knife; no more problems. I could have done a better job of trimming it, but it works now.

I realize there is a difference between a 6 cavity alignment system and your mold, but maybe this wil give you an idea.

Good Luck,

Robert