Worn nipples and flintlock accuracy

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Yes, I really meant to say that. The general consensus seems to be that a nipple worn to an oversize hole causes poor accuracy in a percussion rifle. BUT, a flintlock flash hole is recommended to be at least 1/16 which would be mighty large for a nipple. Lots of people recommend drilling the flash hole even larger. So, can anyone explain to me why a flintlock can shoot so very well with that big hole in the breech? I have had hammers blow back to half cock on occasion in my younger years so I kind of understand the worn nipple problem, but what about that big jet of flame from the touch hole? Maybe the touch hole vent is consistent and the worn nipple isn't??? Someone probably knows the answer but I hope it is simple so I can understand.
 
Good question and I have no answer.
Just going to guess. Consistently is the key to shooting. Ignition is consistent in flint, while a worn hole in the nipple might be inconsistent.
 
Good question and I have no answer.
Just going to guess. Consistently is the key to shooting. Ignition is consistent in flint, while a worn hole in the nipple might be inconsistent.
My friends who shoot flint lock chunk guns use white lightning liners with their stock hole size. A bit smaller than 1/16 inch dia. And change them out when it erodes x amount. I dont remember what diameter pin guage they use, but it’s only a few thousandths bigger than the stock hole dia. BJH
PS these guys are really fussy about one hole accuracy.
 
Another guess here... you probably will lose accuracy with a worn vent, however if you enlarge the touch hole then regulate the sights I wouldn't think you wouldn't notice until it became too large after several hundred shots....

Less pressure driving the ball the larger the touch hole gets, I would think that would cause the gun too be less accurate.
 
Good question. Often wondered the same myself.
Personally I don't think it makes any difference except a loss of the sweet spot in pressure terms over time.
Combined with a fascination of using to course a powder and a reluctance to put enough in to make a rifle sing some blame a nipple or what ever. Some even guage a recocked hammer as a sign of excessive pressure and proceed to strangle the charge weight!
 
Might be something to do with the hammer not always providing a consistent seal, or reduction of vent gasses when a cone gets too worn. There is no obstruction of the flash hole in a flint lock, so maybe that is the difference. No doubt there is an optimum vent hole size for a flintlock for best accuracy. I do know that cones burn out and my groups blow out, then go back to normal when I put a new cone in.
 
Yes, I really meant to say that. The general consensus seems to be that a nipple worn to an oversize hole causes poor accuracy in a percussion rifle. BUT, a flintlock flash hole is recommended to be at least 1/16 which would be mighty large for a nipple. Lots of people recommend drilling the flash hole even larger. So, can anyone explain to me why a flintlock can shoot so very well with that big hole in the breech? I have had hammers blow back to half cock on occasion in my younger years so I kind of understand the worn nipple problem, but what about that big jet of flame from the touch hole? Maybe the touch hole vent is consistent and the worn nipple isn't??? Someone probably knows the answer but I hope it is simple so I can understand.
Since others of greater knowledge than I are guessing, and since my seven year old grandson, home for the holidays has already exposed the depth of my lack of general knowledge with non stop questions for the past week..........here goes another guess. Could it be the mechanical movement of the hammer being blown back changing dynamics during recoil? I would think that the blow back would have to occur before the ball has left the muzzle.
 
It is my belief that it all has to do with the pressure. As a nipple hole gets enlarged, pressure is lost and groups can suffer. Same goes for a flint lock touch hole. When the hole gets eroded to be larger than what it started out as, pressure drops, and thus velocity causing groups to open up.
 
Perhaps the original premise, ( " The general consensus seems to be that a nipple worn to an oversize hole causes poor accuracy in a percussion rifle." ) is not valid?
I suggest performing an accuracy comparison using the worn nipple and a new replacement.
 
Perhaps the original premise, ( " The general consensus seems to be that a nipple worn to an oversize hole causes poor accuracy in a percussion rifle." ) is not valid?
I suggest performing an accuracy comparison using the worn nipple and a new replacement.
Great idea, i need to shoot a lot more to wear one out! Or drill one out to speed the process up? Or a bevel brothers question in muzzle blast and let them experiment? So many questions!
 
It's not an "apples to apples " comparison.

I would say the bulk of flintlocks are smooth bores compared to percussion guns.

I also think it affects conical shooters more than round ball shooters.

If all else is equal, then it probably has to do with consistency. When a nipple burns out the pressure and load changes, so does accuracy. The load for a flintlock is developed for the gas leakage.
All else aside, I think percussion guns are inherently more accurate than a flintlock because of the lower pressure loss, but the average shooter may never be able to tell the difference.

It's all one big rabbit hole.
 
If you compare the scores shot at the national shoots, there isn't a lot of difference between the two. Smaller vent holes in the flintlocks make more consistent pressure which equals a more consistent POI. Percussion heavy bench guns use a sealed breech. No leakage at all. Speed of ignition in a 50lb. bench rifle isn't all that critical(it won't wobble much), but consistent pressure is. The smaller hole helps that. On the other hand ignition speed is critical for offhand shooting. So a larger hole helps.
 
The OP guessed right. As the vent in a flinter enlarges the accuracy suffers, but in a different way than with a caplock.
As more of the flintlock vent opens, more gas pressure is lost through it. So over time, MV is reduced. Now out to 50 yards, the shooter might not see this for very many years, but out at 100 yards...the lower MV will cause the point of impact to drop. So the shooter may get a good group but "the sights are off". So the flintlocker might adjust his front sight post, making it shorter, and not knowing that what really is needed is to replace the vent liner with one with a smaller hole.

The caplock does not have the powder as close to the outside air, as does the flinter. Remember there is an air gap between the cap, through the nipple and the drum, or through the "snail" breech, and the main powder charge. As guessed, the hammer holds down the cap, and the breech explosion compresses the tiny bit of air in that gap, but it's consistent. When the blast starts to lift the hammer, it then gets inconsistent. Consistency is one of the very first rules of accuracy. AND like the flinter, the caplocker might not notice the problem at 50 yards, especially if the caps are damaged but the hammer only moves off the nipple for a fraction of an inch and returns to rest upon the nipple. At longer ranges, however, the inconsistent MV will amplify the group changes on the target, and it will be readily seen. Might take years for a hunter to see it, but a target shooter will likely spot such a change much sooner.

What's old is new.... modern ammo hand-loaders will get a pressure loss and voila, a flier hits the target outside of the desired grouping when a primer is pierced. I won't go further as this is not a modern rifle forum nor website.

LD
 
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I just asked this on another forum last night about the nipples flash hole...

"
Okay So right now I have 4 original rifles dating back from the 1840s & 50s. Some seem to have the original nipples in them as they are rusted in solid with more than likely, no chance of removal. My shotgun for example, the bore and nipple are both in great shape and original from the 1840s-50s flintlock to percussion conversion. This nipple uses a very obsolete #9? nipple and guess what? It uses a 1/16" flash hole that's drilled straight though. No funneling down into a tiny .028-.030" flash hole as we see on today's nipples. I go back to my other 12ga shotgun, another 1840-50s percussion, again... 1/16" flash hole through and through. 1850's J&D Little .38cal half stock.. 1/16" through and through again... There is no possible way, all 4 guns were drilled out at some time! I've never once read about the nipple flash hole size in any book, concerning original guns say from the 1830s-1860s.

Even with that 1/16" flash hole, I get no blow back into my face with my 10ga shotgun. All of the rifles/shotguns that have this large flash hole, do however, have heavy main springs in the locks.

So do we have anything written down in a book somewhere that mentions the flash hole size on nipples from the era stated above? I've been reading through the Muzzle Loading Cap Lock book by Ned Roberts and I haven't even stumbled across flash hole size or even replacing a "worn out" nipple, in this book. I did however come across a page where they mentioned switching over to a Berdan primer for better ignition."
 
I did however come across a page where they mentioned switching over to a Berdan primer for better ignition."
You may want to take note of but be a bit wary of The Muzzle-Loading Cap Lock Rifle, as it's really about shooting 40 rods (220yards) with a patched, conical bullet. That's a pretty specific application. Unless you too are into that part of muzzleloading.

Roberts writes that he considers normal hunting distances for round ball to normally be 110 to 165 yards...:confused:
"Nearly all round ball hunting rifles were cut with a slow twist of rifling and quite deep grooves to use a heavy charge of powder in proportion to the weight of the ball and are 'express rifles', as they were called years ago, thus they gave a low trajectory over ordinary hunting ranges -20 to 30 rods- which is so desirable when shooting at unknown ranges, with high velocity for those times, and consequently good killing power.
Yet..., we know from The Sporting Rifle and Its Projectiles, penned about 60 years prior, that although the British author James Forsyth always ordered his round ball rifles to be able to reach out to 200 yards, he rarely went beyond 100 yards when shooting game, even dangerous game...and he used massive powder charges and very large caliber rifles. His minimum for deer was a 14 bore rifle. Forsyth supposed the same hunting distances were true for hunters in other wooded areas around the world.

Roberts also mentions putting a little smokeless powder down the barrel first at the breech, then loading the black powder on top of it. He refers to this as a "duplex" load of about 5 grains of "smokeless shotgun powder" followed by the black powder charge. This gives the shooter a much cleaner burn of the black powder according to Roberts. Roberts also mentions a champion shooter using a duplex load and a modern primer (instead of a cap).

LD
 
ok but that doesnt even have anything to do with the nipples flash hole diameter. He has quite a bit of info for patched round ball shooting too.
 
Yes, I really meant to say that. The general consensus seems to be that a nipple worn to an oversize hole causes poor accuracy in a percussion rifle. BUT, a flintlock flash hole is recommended to be at least 1/16 which would be mighty large for a nipple. Lots of people recommend drilling the flash hole even larger. So, can anyone explain to me why a flintlock can shoot so very well with that big hole in the breech? I have had hammers blow back to half cock on occasion in my younger years so I kind of understand the worn nipple problem, but what about that big jet of flame from the touch hole? Maybe the touch hole vent is consistent and the worn nipple isn't??? Someone probably knows the answer but I hope it is simple so I can understand.
I'm pretty sure the gun will be just as accurate; just not as high up on the target. Day-to-day, I doubt that most people would notice, because they would be adapting their aim gradually over a long period.
 
Ned Roberts mentions chaps using a little modification that screwed onto the cone drum that held inside a modern primer, so this set up had no gas leakage at all. Used on the 40 rod long range slug rifles. I am guessing the gas leakage from a cone is likely always some issue, and as I said earlier it gets worse when the cone gas cuts and the groups start to blow out.
 

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