Smoothbore PRB lube

[flintlock54]

Need to tap into the forum expertise. 16 gauge jug choked barrel. I am loading a .635 ball with .015 pillow ticking that can be started with stiff thumb pressure. No wads or cards. Logic tells me that I should be using a greaser type lube to create a better seal. I am using a lightly oiled patch now and am thinking that I might get better accuracy if the seal was better.

 

By all means try a grease if you want. I think you will find that it makes no difference in accuracy though. The bore seal with a PRB comes when the ball flattens at the rear from pressure of the expanding gas. As it flattens it expands in diameter and compresses the patch thereby sealing the bore. If the patch/ball combo is too loose there will be gas blow-by. Any grease, exposed to the flame and pressure, will blow-by as well in that situation. Also consider this, pressure in a barrel builds because the projectile resists being pushed up the barrel. The more resistance, the greater the pressure will build and the more the ball will flatten to seal the bore. The more slippery we make the patch/ball the easier it will go zipping up the bore before pressure fully builds and the less it will flatten. If grease doesn't improve things try a drier patch. You might be surprised.

JOhn

 

[Britsmoothy]

I swear by a mix of bees wax and olive oil or beef fat and olive oil, helps keep the fouling soft too.

The patch is not a gasket arrangment and will never seal 100% but don't worry about it :hatsoff:

Brits.

 

[roundball]

Logic tells me that I should be using a greaser type lube to create a better seal.

IMO, the accuracy you're getting, followed by reading your patches should give pretty strong indications of any next steps.
If the patches are torn/shredded/darkened(burned) you can look at more lube, but odds are a thicker patch would usually be required to eliminate that(which also has more lube by the way).
Personally I've never found that even well lubed .015" patches held up consistently under large powder charges for hunting loads. I've used .015" at the range for plinking with light 40-50grn powder charges...but .018" pillow ticking quickly became my minimum patch thickness for big game hunting loads, with most of them being .020" / .022" thick.

And I'll add a comment, not to challenge any individual, only to state observations from my own personal experiences that offer a different point of view...others mileage may vary.
In about 20 years of shooting many thousands of PRBs now, and recovering many from water jug penetration tests, as well as game animals, I’ve never witnessed anything that suggests a lead ball routinely flattens at ignition time.
In addition, I have never recovered a ball that even shows any 'patch weave marks'...yet I use nothing but tight fitting PRB combos which always require a firm smack on a short starter to get them started.

For example:
In my .62cal smoothbore Virginia I use .600" balls and .022" precut Oxyoke patches prelubed with natural Lube 1000.
.015" patches shredded/burned, poor accuracy;
.018" patches showed an occasional hole and gave so-so accuracy;
.022" patches come out so clean and still retaining lube that they could be reused again;
Couple inch group at 50yds sitting, shooting from semi-offhand leaning against a post.

 

[tg]

Quite often a very accurate smoothbore laod can be had using no patch and a variety of ball sizes with cards or wads over powder and ball a real tight load may offer a bit of accuracy improvenment but I suspect not much would be agained by just adding more and more grease, I do not know if the jug choke has any part to play in the accuracy of a smoothbore or not, I have never used one rather choosing to stick with the tradaitioal barrel types. I would have to agree with Roundball that the obturation (SP) factor generally has little to do with the accuracy of a PRB it certainly will not squeeze out and fill the rifleing grooves, and many find no difference in accuracy twixt soft lead and very hard lead balls, this is another sign that the "squeezing" of the ball is not a biggy, IMHO anyway, good luck finding the magic combo that gives you what you want.Roundballl has probably one of the larger amounts of various data on this forum collected over the last few decades and has a pretty good handle on the basics that occur when working up loads in rifles or smoothies, there will always be exceptions but his stuff is pretty much on the mark from what I have seen/read.

 

[flintlock54]

Thanks for the info. My recovered patches have small shred marks and some minor burn with 80 grains of ffg. There is resistance with a .015 patch but I can start it with my thumb. I may have to order some wonder lubed .018 and .020 patches. Sounds like I might have enough room with the .020 with a short start.

 

Try this:

http://www.lasc.us/FryxellCBAlloyObturation.htm

I've been trying to find an old BP book that had high-speed x-rays of a PRB just after ignition. The photos clearly showed the flattening of the rear of the ball. Like a lot of other things around here, it seems to have walked off.

John

 

[roundball]

This is how debates get started which sometimes turn into arguments and I won't play.

The link you posted is all about flat based 'bullets'...not 'round balls' which also have gas pressure equally distributed all up around the sides of the bottom half of their shape, and its not relevant to my comments.

In any event the statements I made in my post stand as I stated them.

:thumbsup:

 

No offense intended and no arguement desired. Just figured the gentleman who started this thread should have access to as much information as possible. I believe that the greatest value of a forum is to provide as broad an information base as possible, not just the opinions of a few. I suggested he try something that has worked for me. I still suggest he try it and draw his own conclusions.

John

 

[oldfart1956]

This is how debates get started which sometimes turn into arguments and I won't play.

The link you posted is all about flat based 'bullets'...not 'round balls' which also have gas pressure equally distributed all up around the sides of the bottom half of their shape, and its not relevant to my comments.

In any event the statements I made in my post stand as I stated them.

:thumbsup:

Aye Roundball, I've argued this point before and agree wholeheartedly with ye. No mere mortal man has ever pulled the trigger on enough powder to flatten a roundballs rear. Conicals...yes. And I have found balls with patchmarks on them. I'll wager it's the tight fit that produced it and durn little to do with obturation. And that was rifled gun balls, not smoothbore. Audie..the Oldfart..

 

[CoyoteJoe]

Try this:

http://www.lasc.us/FryxellCBAlloyObturation.htm

I've been trying to find an old BP book that had high-speed x-rays of a PRB just after ignition. The photos clearly showed the flattening of the rear of the ball. Like a lot of other things around here, it seems to have walked off.John

You may be thinking of the first edition of the Lyman BP Handbook. That shows a photo of a double ball load with both balls flattened at the contact point but the backside of the rear ball was still apparently round.
Friction of the ball in the bore plays almost no part in building gas pressure. Inertia, the ball's resistance to acceleration, is by far the greatest factor in that regard. If obturation of a round ball is to occur at all it would be most noticeable in large calibers with heavy powder charges. But it still would not take the form of a noticeably flattened rear but just a shortening of the front to rear dimension and a swelling of the side to side dimension.
I have always found distinct rifling marks on any recovered ball fired from a rifle, quite apparent even on balls badly flattened by impact. Obturation may or may not be a factor there since I have always favored very tight patch & ball combos I think the same marks would be seen if I just pushed a patched ball through an unbreeched barrel. Come to think of it I have some scrap pieces of cut off barrels, I'll try just pushing a patched ball through some and see what they look like, photos later today. :haha:

 

Thank you, Joe. You are absolutely correct. I incorrectly used the term "flattened" when what I meant was "shortened". Physics dictates that pressure in a confined space will be exerted evenly over the area exposed. The rear of the ball will remain rounded.

As for friction not playing a part, I seem to remember that Dutch Schoultz recommends using the least lube possible so that the PRB resists movement allowing pressure to build. This was the concept I was trying to pass along and suggest that the OP try.

Another thing crossed my mind last night. Since his barrel is jug choked, will the patch have the chance to slip off or partially off the ball when the bore opens up and then closes down again? It would be interesting to know.

John

 

[CoyoteJoe]

Another thing crossed my mind last night. Since his barrel is jug choked, will the patch have the chance to slip off or partially off the ball when the bore opens up and then closes down again? It would be interesting to know.

John

I don't know about that but I suspect there is still enough gas pressure to keep the patch tightly wrapped around the ball even if some gas slips past. Pure speculation here but it seems reasonable to me. :idunno:

 

[George]

You may be thinking of the first edition of the Lyman BP Handbook. That shows a photo of a double ball load with both balls flattened at the contact point but the backside of the rear ball was still apparently round.

Spence

 

[CoyoteJoe]

I've posted the promised photos on the "Flintlock Rifle" section since it is in fact a rifle issue.

Oops, now I see it's gotten moved to "General Muzzleloading".

 

[tg]

The accuracy statements about the double ball load is interesting I know a guy who used two .45 balls occasionaly for deer and they hit within an inch or a bit more at 75 yds. but he used what would be a moderate .45 load as I recall. I played with duoblr ball loads in a .40 and would have been comfortable out to 50 yds with it, but that is about my outside comfort zone with a .40 anyway.

 

[Britsmoothy]

Thanks for the info. My recovered patches have small shred marks and some minor burn with 80 grains of ffg. There is resistance with a .015 patch but I can start it with my thumb. I may have to order some wonder lubed .018 and .020 patches. Sounds like I might have enough room with the .020 with a short start.

yeah I get that too with some linen I have. I get around it by putting a greased patch down first, using a short starter it forms the backing patch into a cup and then I load another patch+the ball on top of it. Send the lot down together. No more burnt ball patches :thumbsup:

brits.

 

[CoyoteJoe]

The accuracy statements about the double ball load is interesting I know a guy who used two .45 balls occasionaly for deer and they hit within an inch or a bit more at 75 yds. but he used what would be a moderate .45 load as I recall. I played with duoblr ball loads in a .40 and would have been comfortable out to 50 yds with it, but that is about my outside comfort zone with a .40 anyway.

Yes, I also thought that statement a bit strange. I tried one double ball load from a .50 cal rifle and the two balls hit a paper target within two inches of center at 75 yards, I'm not sure I could have done better if I'd fired two separate shots. I never followed up with further testing but I'd not discount double balls for hunting.

 

[roundball]

I've experimented with double ball loads at the range, haven't tried it hunting.

T/Cs early load data charts actually lists double ball loads for the .45 and .50cal...tried them both at 50 yard targets, and they both printed 1.0-1.5" side by side...surprisingly accurate.

Also experimented with 3-.490s in a paper sleeve in a .62cal smoothbore and got 5 inch clusters at 50 yards...also pretty respectable

But trying 4-.440s in a paper sleeve, due to their smaller size their left/right stagger-stacking created so much off-set from one ball to the next that they went off in 4 random directions after muzzle exit making about a 2 foot pattern at 50yds.