pressures

[ron ward]

i've shot centerfire all my life, reload for them and have several wildcat cartriges.
obviously i know what to watch for as far as pressures go with them, but what do you guys look for in BP guns as you increase the charge looking for that magic load? i assume there must be point where too much charge will make for an extremely lousy day at the range. i see plenty of charts that list load weight with velocities and energies, but they seem to be generally suggestive rather than technically based. is there anywhere that states what is too much powder for a given caliber/projectile,etc. such as a loading manual typical for center fire cartriges?.
i certainly do't plan on shooting my gun at the limit, knowing that hot loads are usually not the most accurate. i don't think i ever shot any one of my centerfire guns at max load, no need to and accuracy is usually found well below max.

 

[nkbj]

Well, I'm like you, wildcattin' as a hobby when Jimmy went back to Georgia. 'Preciate what you're asking.
For muzzleloaders there's Lyman's black powder loading Manual. It's just about the best in print.
Muzzleloader manufacturers recommended loads are most always mild (now there's a safely relative term).
Myself I don't think you'll blow up modern production muzzleloaders if you're just shooting patched round ball. The accuracy will fall off and become the limiting factor. The percussion drum sticking out of the side of a barrel might eventually break off. The nipple might blow out because the threads got boogered up and worn out. I don't think people are managing to burst barrels if they seat a patched round ball on the powder.

But I still turn into a nervous nellie with heavy charges in my .69 rifle. Don't do that very much though because it tears up my steel gong.

 

[Trench]

Like you said it's general, but just stay within the limits stated by the barrel manufacturer. For the larger calibers, best accuracy is usually obtained using 70gr-100gr and most manufacturers give a 120gr max load for round balls.

 

[J.D.]

As a general rule of thumb, begin working up a load of one grain of powder for every caliber. Begin at 50 gr for a 50 cal, for example.

Work up until accuracy falls off, and/or fowling increases dramatically, and report and recoil increase noticeably.

Once you have reached this point of diminishing returns, back off until the best accuracy is obtained.

That said, just work up an good accurate load and stay with that. These ML guns aren't magnumizable by dramatically increasing the powder charge, so anything to far above the best accuracy load is a waste of powder and ball.

God bless

 

[PreglerD]

In Germany all max. charges for ML and smokeless are ruled by law and proofed by the authorities. For ML we have max. pressure of 1400 bar/20.000 PSI.

Regards

Kirrmeister

 

[necchi]

GoodCheer summed it up really well, but this part was key,,

The accuracy will fall off and become the limiting factor.

Of course the pressure limits are made for guns in good condition. I have seen guy's blow nipples! They come back in your face. The guy was next to me, 200grns 2f in a T/C Hawkin (I didn't know it!) He got lucky and only got his face peppered with powder burns, It was his brothers "deer huntin load"!

The olde standby test was too double charge, then double ball a gun, tie it down in a tire and pull the trigger from a distant hiding place with a string! (truth!) If it survived intact, it was deemed safe to shoot with half of what you put init. I think that method is still in the back pages of the Dixie catalog.

Bout' once a year or so there's a photo e-mail going around with someones blown barrel. There was one where a feller FILLED a barrel with Pyrodex and touched it off, it peeled the barrel back like a banana.
When they say,"Here hold my beer, an watch this",,
Take the beer and run!

 

[longcruise]

merlinron, your post is riddled with obvious attempts to apply thinking to ml as parralells to modern stuff.

Not poking at you here, it's just what I see.

These parralells for the most part do not exist. Your best avenue is the one already stated above, use the manufacturers max recommended charges as your guide. Most of these recommendations are as high as or in excess of practical every-day loads.

I too load for an array of center fires and find that you must not just wear a different cap when you change from one to the other, you need to put on a whole different head. :haha:

Your ml gun is not going to show you any consistent signs of pressure. If you shoot percussion and find your hammer blowing back to half or full cock with a fairly new nipple, you may be endangering your new ml "head".

The charts you see for various ml loads, etc. are not that good a guideline as to what to expect from your rifle. It's not very traditional, but a chrono will show you some very interesting things as your experimenting progresses.

As far as magic loads go, there is a parralell with the modern stuff. Your buddies perfect load in his '06 might not be much good in yours. Similarly, your magic .50 cal deer load might be miserable in someone elses gun.

My suggestion to finding a load for an ml is kinda backward. What I do is start out by firelapping the barrel and conditioning the crown. Then, with several different ball sizes and three or five prospective patch materials I start shooting all the possible combos at the highest recommeded charge with five shots of each and recover and examine the patchs from each combo. The best surviving patch wins!!

From there I start with that combo and go down in 10 grain increments till a trend shows. No three shot groups here! You need at least ten shot groups to see what is going on. When you find a trend, start testing around that ten grain increment to see if you can find a best load.

Another false parralell is the idea that powder variations from one lot to the next are going to be near identical. We see this in smokeless because it is critical to safe reloading and consistent load data. Not so with bp! :shocked2: The difference between one lot of a given black powder and the next from the same maker can be significant.

Unlike the smokeless powders, this does not pose a risk or danger. But, it can completely throw off your previous load development.

I have no proof of this following opinion, but it might bear some thought; In the event that there is a significant difference from lot to lot of, say, goex ff, then use your chronograph to match the velocity of your previous favorite load.

 

[ron ward]

marmotslayer,
believe me, i am fully aware that what i know of smokeless powder is in no way what-so-ever, applicable blackpowder. my inferences were only to try and get my point across! having never had a BP gun, sometimes i will use a parralell of sorts for the lack of a better way to communicate my question. my "ML head" may be empty right now, but it does know the difference and it can think in more than one direction.... it won't stay empty for long! :thumbsup.
to my mind, your method of finding a load doesn't sound backwards at all. you're just finding the best bias between accuracy and velocity from actually, a more distinct direction. there may be several charges that show good accuracy when working up and you might stop at one that, although accurate, isn't getting all it can in velocity. starting from the top the first stop at good grouping is also the highest velocity at good groups right off the bat.

 

[longcruise]

believe me, i am fully aware that what i know of smokeless powder is in no way what-so-ever, applicable blackpowder. my inferences were only to try and get my point across! having never had a BP gun, sometimes i will use a parralell of sorts for the lack of a better way to communicate my question.

I understand that. Did not mean to sound like I was talking down to you. Mainly I wanted to address the problem that I see with many new ml shooters, and not just for your benefit but for any who might be reading here. You are obviously an intelligent person who will have no problem growing a new head.

to my mind, your method of finding a load doesn't sound backwards at all. you're just finding the best bias between accuracy and velocity from actually, a more distinct direction. there may be several charges that show good accuracy when working up and you might stop at one that, although accurate, isn't getting all it can in velocity. starting from the top the first stop at good grouping is also the highest velocity at good groups right off the bat.

Yes, that is a sure benefit of starting at the top and working down. A good example of ml head vs smokeless head. As any smokeless reloader will tell you, starting at the top and working down would be insanity.

If you wander by some of the "modern" ml sites you will find many their have firmly applied their smokeless heads to their "modern" :barf: ml pursuit and actually think us "traditional" guys are the goof balls. Of course, in a way, we are goof balls. Just the kind of goof balls I like!

Just for clarification, my back wards load devel method is not so much to establish high end combo of accuracy/velocity as it is to sweep away another very important variable in the shooting of the prb. That is the ability of your patch/ball/charge to shoot without destroying the patch. When patches are wrecked, accuracy will dissapear regardless of the charge size.

The bore is conditioned with firelapping and the crown shaped so as not to damage the patch at loading and to allow ease of loading a thicker patch/ball combo. Then, the initial firing is to find the patch/ball combo with surviving patch.

This is particularly important with the less expensive spanish and italian made barrels. They are not bad barrels, they are just not finished very well. It's an economy measure. There is a reason why you can buy a brand new barrel from the Lyman (InvestArms) people for your GPR at only $117 when the same barrel from GM, Rice or any other maker would run you over $200.

The guy who takes his brand new CVA, Lyman or Traditions rifle to the range and embarks on the standard system of "working up" a load usually encounters a point where accuracy dissapears. Most of those guys don't realize that it is actually the point at which their barrel is slicing and dicing their patch. :shocked2: All of the guns, both kits and factory built, that I have done this with (1 traditions, 1 CVA, and 3 GPRs) have improved in accuracy, loadability and ease of cleaning. My own .54 GPR was more than hunting accuracy adequate from 50 grains up to 120 grains as long as the patch was tight and tough.

 

[ron ward]

modern muzzleloader.... now there's a contradiction if terms! i could not see myself hunting with an in-line. heck, my center fire bolt-guns are from the turn of the century.
marmot, i didn't se it as being talked down to at all. i am aware that allot of people drift in and out of "smokeless land" when they get started. i just wanted you to know i am aware of the fact they they are two different worlds. i see and hear the "working up" a load with thier BP guns allot from guys i know that shot both sides of the fence and it is as you state, they make 1 and 2 grain increases in their charges and expect to see big changes in something(?). my questions about pressure and it signs in BP stem from the fact that i know it is not anyway near as critical to load density as smokeless, yet at the same time, there has to be a point where you can put too much in a barrel and ruin your day. BP load ranges 50-60 gr. is common where is the point it has to end, in any given caliber?...
as to the signs, you di give me one, i didn't realize the hammer would blow back on a percussion, but it certainly makes sence that it will....the gas isn't going to wait till the big hole isn't blocked.

 

[Dphar]

The classic sign for a percussion rifle is blowing the hammer back sometimes as far as 1/2 or even full cock. This is caused by two things. Excessive pressure and/or a weak mainspring.
High enough pressure will cause excess gas escape from any nipple. The current accuracy load in my 40 caliber rifle using a picket bullet is 80 grains of FF Swiss. This resulted in an immediate and noticable increase in gas escape over 70 grains. Note that cloth patched pickets are noted for needing heavy charges of powder to shoot well sometimes almost 70% or greater increase over the RB.

Blackpowder is limited to about 30000 psi in firearms and this in cartridge guns and bulleted MLs shooting heavy bullets. But a ML shooting high pressure loads has to be properly designed and built.
Round balls will not produce these pressures.
The various "conicals" will produce high enough pressure if moved at velocities close to the round ball, fast enough for a good trajectory to 120-130 yards, will produce pressures high enough to produce rapid erosion of the nipple, hammers blown to 1/2 cock etc.
The Minie ball as used in the Military rifles of the mid 19th century did not shoot heavy charges of powder and MV was only about 1000 fps in most cases. This was one reason they were not practical hunting arms for Civilians.

Heavy loads with FF or FFF blackpowder and the round ball will not generally erode nipples rapidly if the lock is properly made. Bulleted MLs (in this case an underhammer rifle I build some years ago) shooting high pressure loads like a 45 caliber 500 grain bullet and 70 grains of powder will erode a common nipple to the point of producing accuracy problems in 10-20 shots.
The technology is not meant for pressures of this level. High pressure loads need a platinum lined nipple and a lock that produces high pressure on the nipple or sealed ignition. Most MLs used in America have neither.

*Generally speaking* loads over 1/2 ball weight of FFF powder are a waste of time with a round ball. With conicals loads much over 1.5 grains per caliber will produce pressures too high for the typical percussion system. Though many will chime in with opinions to the contrary.
Hotter powder like Swiss will produce increased fouling at heavy charges. I shoot 75-90 and 100 in 50-54 and 58 respectively. The 58 in particular will foul heavily over 90-100 grains of powder. Goex is less susceptible to this but does not produce the velocity and it takes 100+ grains to produce the velocity in a 54.

Conicals are greatly over rated in MLs for general use.
Dan

 

[Zonie]

merlinron

I would suggest that if you are interested in technical studies of the pressures found in black powder muzzleloaders you should buy yourself a copy of Lymans BLACK POWDER HANDBOOK & LOADING MANUAL Published by Lyman Publications, Middletown, Ct.

In this you will find loading data and the pressures they determined thru the use of strain gages mounted on test barrels.

They present both roundball and bullet pressures in a number of calibers.

Although they limited many of their tests to 120 grain powder loads this is not always the case.

In the small .32 and .36 caliber they limited the powder load to 70 grains as the breech pressures were very high, in some cases exceeding 21,000 PSI.

Although this doesn't sound like a high pressure to someone who shoots modern cartridge guns one must take into account that the materials used to construct the typical muzzleloader are far from high tech.

While cartridge guns often use alloys heat treated to tensile strengths in excess of 190,000 PSI the typical muzzleloader is made from low carbon steel often with a tensile strength of less than 64,000 PSI.

(A note to those unfamiliar with Tensile Strengths:

Tensile Strength is a measurement of total failure of the material.

It is used in conjunction with the crossectional area of the material. This can be thought of as the wall thickness in a gun barrel.

By itself, the Tensile Strength value does not signify the pressures that the barrel can withstand.
Given a small crossectional area, a material with a 64,000 PSI tensile strength can and will fail with a chamber pressure of only a few thousand pounds per square inch.)

 

[Dphar]

i've shot centerfire all my life, reload for them and have several wildcat cartriges.
obviously i know what to watch for as far as pressures go with them, but what do you guys look for in BP guns as you increase the charge looking for that magic load? i assume there must be point where too much charge will make for an extremely lousy day at the range. i see plenty of charts that list load weight with velocities and energies, but they seem to be generally suggestive rather than technically based. is there anywhere that states what is too much powder for a given caliber/projectile,etc. such as a loading manual typical for center fire cartriges?.
i certainly do't plan on shooting my gun at the limit, knowing that hot loads are usually not the most accurate. i don't think i ever shot any one of my centerfire guns at max load, no need to and accuracy is usually found well below max.

Black powder and smokeless are apples and oranges. Blackpowder is a low energy propellant. Smokeless is a modified high explosive that is capable of considerable mayhem if used wrong.


The prime problem with pressure in MLs comes from shooting bullets rather than balls and attempting to get the velocity as high as a RB. Even though some pressure gun data may show little difference in pressure between a conical and a rb in the same barrel with similar loads practical experience shows the conicals show much higher pressure signs. If the peak pressure is similar as some pressure data indicate then the conicals must maintain a higher pressure much longer.

The other problem is the materials and the design on many MLs in use. Many use steel with very poor characteristics when subjected to internal pressure. I.E. There are barrel makers who use steels that the steel maker specifically states should not be used for barrels. Most of these are in the custom barrel market.
The breech design used for many MLs both foreign, domestic, custom or factory are not really suitable for the pressures encountered with conicals and heavy loads. But people use them for this anyway.
The bottom line is that the patched round ball and black powder are the best combination for ML arms except those used as target arms, slug guns, picket rifles etc and these are really only practical for use on the rifle range anyway.

The shooter must inform himself and considering the wealth of misinformation concerning MLs and especially propellants and projectiles, it can be very difficult to obtain accurate information.
But again if round balls and BP are used its much harder to get into any trouble.

Dan

 

[ron ward]

dan and zonie,
wow!, great info, that's the stuff i'm looking for! :bow: you guys can quit telling me that BP and smokeless are apples and oranges... i was aware of many, many years ago ago!! :grin: :grin: :thumbsup:
i'll have to look for that lyman book. our librarry doesn't have anything when it comes to BP, or any guns for that matter. i think it's run by a gun-hater, about 10 yrs ago, i noticed that all of a sudden any books that had to do with the shooting sports or hunting suddenly disappeared from the shelves shortly after she got the job as head librarrian.

 

[dyemaker]

I wondered about this for example... The Pedersoli Jager rifle is available with a fast twist and has a flintlock. I wonder how much pressure lost out the venthole factors into things. Of course more powder could be used but such a rifle is just not meant for bullets.

I looked at one years ago when they first came out and decided against buying it. I'm glad I did.

Just a random thought.

 

[nkbj]

dan and zonie,
wow!, great info, that's the stuff i'm looking for! :bow: you guys can quit telling me that BP and smokeless are apples and oranges... i was aware of many, many years ago ago!! :grin: :grin: :thumbsup:
i'll have to look for that lyman book. our librarry doesn't have anything when it comes to BP, or any guns for that matter. i think it's run by a gun-hater, about 10 yrs ago, i noticed that all of a sudden any books that had to do with the shooting sports or hunting suddenly disappeared from the shelves shortly after she got the job as head librarrian.

Yes, the small town new librarian phenomenon. It makes you want to look around for the trucks loaded with pods or maybe firelit marching circles of glockenspiel players. Now we have shelves filled with tripe and multiple internet terminals.

 

[nkbj]

I wondered about this for example... The Pedersoli Jager rifle is available with a fast twist and has a flintlock. I wonder how much pressure lost out the venthole factors into things. Of course more powder could be used but such a rifle is just not meant for bullets.

I looked at one years ago when they first came out and decided against buying it. I'm glad I did.

Just a random thought.

http://www.shooterschoice.com/pedersoli/pedpics/S246.jpg
Oh wow. I could play with this all week but somebody else would have to pony up for it.
What size was the barrel across the flats? Do you happen to recall?

 

[Stumpkiller]

Somewhere I read that a maximum powder load should be about 3/5 of the weight of the ball in grains (the inverse of the Golden Mean for you DiVinchi Code guys). That's the beauty of muzzleloading and black powder. We don't need chronographs or digital scales.

Set the ball in the palm of your hand and just enough powder to cover the ball will be a good starting load. :wink: Then you up it (if necessary) until it gets a good "crack" instead of a boom.

 

[David W.]

Somewhere I read that a maximum powder load should be about 3/5 of the weight of the ball in grains (the inverse of the Golden Mean for you DiVinchi Code guys). That's the beauty of muzzleloading and black powder. We don't need chronographs or digital scales.

Set the ball in the palm of your hand and just enough powder to cover the ball will be a good starting load. :wink: Then you up it (if necessary) until it gets a good "crack" instead of a boom.

Darn, Stumpkiller, you beat me to it for covering the ball with powder. It was the very first thing I learned and the information came from Dixie Gun Works. Those were my greenhorn days and had to ask a lot of questions. I admit that I was deathly afaid of exceeding a "suggested MAX load" for fear of blowing myself to smitherinies. I would not have, under any circumstances, use FFFg in a caliber larger than .50. Now that's all I use in my .62. I just reduced my chage by 20%. The 20% is because I use Swiss and it's more potent than Goex.

Now, as far a "cracking" goes, I have no trouble with that in a .36 or a .50, but high velocities in my .62 is another matter! I just do not like the heavy recoil.

 

[paulvallandigham]

Wow! Its been a lot of years since anyone dragged out that old Stuff about measuring powder! Yeah, its still in the back of the Dixie GWs catalog. I guess we will always have to put up with it.

About the powder charge, my gun club had an annual meeting of members, and someone brought a powder scale, some balls, and powder. He picked 5 men at random from the club, gave each of them a ball to put in their palms, and then asked them to each cover the ball with powder. Each of the powder charges were then weighed on the scale. The weights for the 5 men varied as much as 50% one way or the other. Hardly any kind of accurate measure!I believe the balls were .45s, the most common caliber being shot in the club at the time, and the powder was FFFg Goex.

As for the " load up to that loud Crack", the crack is simply the burning powder gases leaving the muzzle at a velocity above the speed of sound, which is approx. 1135 fps. It turns out, when you use a Chronograph to find out what velocity you are actually getting, that these gases reach the speed of sound faster than do the PRBs, or bullets. The gases are hotter, and expand much faster than the slower, heavier bullet or lead ball can.

This old Rule worked fine back in the day when they didn't have chronographs, but today, most hunters would feel undergunned if they were firing a load that leaves the barrel at 1135 fps. MV. We routinely discuss PRB velocities in the 1500-1900 fps range, and think nothing of it. All those loads will create that " Crack" when fired, but the crack tells you nothing about the true velocity of the bullet/ball. I hope I don't have to argue the difference between 1135 fps. and 1900 fps. And, no mention of recoil forces has been made, here. What might work well in a .36, or .40 cal. rifle shooting a PRB, would not be the best choice of velocity for someone shooting a .58, or .62, or .75 cal. rifle.