Post by Bullshop on May 27, 2021 8:50:48 GMT -7
Question
Hello Daniel hope you are well,
I picked up some 38-56 brass from you a few months back. Formed from Starline 45-70.
I shoot a lead bullet sized to 0.3805 with a gas check.
Chambers fine when loaded in Bertram cases.
Neck bulges a tad more in the reformed Starline brass compared to the Bertram and the CTG it will not chamber.
Is this an instance where I could look into outside neck turning and if so do you have any recommendations on equipment and specfications?
Also, I am shooting 29.3 grs of IMR4895 in my antique 1886 38-56 and getting 1450 FPS.
The bore is bright with strong lands but there is blackpowder pitting.
I have read Williamson, Waters, Scoville, Venturino, Sharpe and my load and velocity seem to fall in line on the low end just above blackpowder velocities.
I cannot find any pressure data on the 38-56 CTG. Any thoughts would be appreciated.
I understand if you are too busy to address these questions.
answer
There is no one right or simple answer to your questions but I will attempt to at least try to help.
First off for a simple answer I think yes that neck turning may well solve the problem you are having but I must add that it is not the only option to solve the problem and would not be my first choice if this was my problem to solve.
My effort would be to first address bullet diameter. A very simple way to gain understanding of the situation will be to mic the neck diameter of loaded cartridges loaded in each type of brass with the same diameter bullet.
By then reducing the bullet diameter to an equal amount of the difference in neck diameter between the two types should likely also solve the problem
There is a common but incorrect understanding today that for accuracy with cast bullets bullet diameter must be equal to or greater than the barrel groove diameter that they will be fired in. To try and explain this common misunderstanding let us first clarify the nomenclature so communication is crystal clear,
#1 bore diameter, is the diameter of the hole drilled into the barrel before it is rifled.
#2 groove diameter , is the total diameter of bore added to the rifling depth times two . Times two because it is measured from both sides.
Depth of rifling is usually around .004” so measured from both sides adds about .008” to the total of the groove diameter of a barrel. For instance if your 38-56 have a barrel groove diameter of .380” then your bore diameter will be something close to .372” .
Consider this for a moment if you will that all modern muzzle loading rifles are shooting bullets that are equal to or less than bore (not groove) diameter and the modern breed of ML rifles are extremely accurate.
Also consider that I have an original vintage Winchester mold that is marked 38-56 wcf and it drops bullets between .376” to .377” diameter. This was a common practice in the day of BP cartridges to utilize bullets that were between bore and groove diameter so as to eliminate chambering problems that could arise due to BP fouling. Your problem is very common when vintage Winchester rifles are loaded with bullets of barrel groove diameter.
The key here for accuracy is to match the bullet alloy hardness to a powder burn rate that will positively obturate the bullet in the barrel to make a positive gas seal. When black powder is uses you have a very fast powder burn rate but fairly low chamber pressure. This combined with a fairly soft bullet alloy allows a positive obturation of the bullet in the barrel for that important gas seal as the bullet enters the barrel
Too slow a powder burn rate and or too hard an alloy may result in not enough obturation to make the positive gas seal as the bullet enters the barrel which can result in poor accuracy and possibly leading of the barrel.
With the trend of modern thinking on this line most people facing such a condition would guess that they need a harder bullet alloy when the right solution is exactly the opposite .
In my experience ruling out the use of black powder to achieve good accuracy with bullet diameters of less than barrel groove diameter that two conditions must be observed. Those conditions are that bullet alloy hardness should not exceed about BHN-10 and that powder burn rate should not be slower than that of Alliant (formerly Hercules) # 2400. Slightly slower powder burn can be used (SLIGHTLY ) but should be matched with a softer alloy.
So to cut this short and keep it simple if faced with your situation I would try reducing the bullet diameter to the point where cartridges chamber freely coupled with a bullet alloy of about BHN-9 or less in conjunction with a powder burn rate not slower than one of the 4227 powders on the burn rate chart.
I suspect the results will be acceptable and no less accurate that your loads with the larger diameter bullets in the thinner neck wall cases. Good Luck !
Hello Daniel hope you are well,
I picked up some 38-56 brass from you a few months back. Formed from Starline 45-70.
I shoot a lead bullet sized to 0.3805 with a gas check.
Chambers fine when loaded in Bertram cases.
Neck bulges a tad more in the reformed Starline brass compared to the Bertram and the CTG it will not chamber.
Is this an instance where I could look into outside neck turning and if so do you have any recommendations on equipment and specfications?
Also, I am shooting 29.3 grs of IMR4895 in my antique 1886 38-56 and getting 1450 FPS.
The bore is bright with strong lands but there is blackpowder pitting.
I have read Williamson, Waters, Scoville, Venturino, Sharpe and my load and velocity seem to fall in line on the low end just above blackpowder velocities.
I cannot find any pressure data on the 38-56 CTG. Any thoughts would be appreciated.
I understand if you are too busy to address these questions.
answer
There is no one right or simple answer to your questions but I will attempt to at least try to help.
First off for a simple answer I think yes that neck turning may well solve the problem you are having but I must add that it is not the only option to solve the problem and would not be my first choice if this was my problem to solve.
My effort would be to first address bullet diameter. A very simple way to gain understanding of the situation will be to mic the neck diameter of loaded cartridges loaded in each type of brass with the same diameter bullet.
By then reducing the bullet diameter to an equal amount of the difference in neck diameter between the two types should likely also solve the problem
There is a common but incorrect understanding today that for accuracy with cast bullets bullet diameter must be equal to or greater than the barrel groove diameter that they will be fired in. To try and explain this common misunderstanding let us first clarify the nomenclature so communication is crystal clear,
#1 bore diameter, is the diameter of the hole drilled into the barrel before it is rifled.
#2 groove diameter , is the total diameter of bore added to the rifling depth times two . Times two because it is measured from both sides.
Depth of rifling is usually around .004” so measured from both sides adds about .008” to the total of the groove diameter of a barrel. For instance if your 38-56 have a barrel groove diameter of .380” then your bore diameter will be something close to .372” .
Consider this for a moment if you will that all modern muzzle loading rifles are shooting bullets that are equal to or less than bore (not groove) diameter and the modern breed of ML rifles are extremely accurate.
Also consider that I have an original vintage Winchester mold that is marked 38-56 wcf and it drops bullets between .376” to .377” diameter. This was a common practice in the day of BP cartridges to utilize bullets that were between bore and groove diameter so as to eliminate chambering problems that could arise due to BP fouling. Your problem is very common when vintage Winchester rifles are loaded with bullets of barrel groove diameter.
The key here for accuracy is to match the bullet alloy hardness to a powder burn rate that will positively obturate the bullet in the barrel to make a positive gas seal. When black powder is uses you have a very fast powder burn rate but fairly low chamber pressure. This combined with a fairly soft bullet alloy allows a positive obturation of the bullet in the barrel for that important gas seal as the bullet enters the barrel
Too slow a powder burn rate and or too hard an alloy may result in not enough obturation to make the positive gas seal as the bullet enters the barrel which can result in poor accuracy and possibly leading of the barrel.
With the trend of modern thinking on this line most people facing such a condition would guess that they need a harder bullet alloy when the right solution is exactly the opposite .
In my experience ruling out the use of black powder to achieve good accuracy with bullet diameters of less than barrel groove diameter that two conditions must be observed. Those conditions are that bullet alloy hardness should not exceed about BHN-10 and that powder burn rate should not be slower than that of Alliant (formerly Hercules) # 2400. Slightly slower powder burn can be used (SLIGHTLY ) but should be matched with a softer alloy.
So to cut this short and keep it simple if faced with your situation I would try reducing the bullet diameter to the point where cartridges chamber freely coupled with a bullet alloy of about BHN-9 or less in conjunction with a powder burn rate not slower than one of the 4227 powders on the burn rate chart.
I suspect the results will be acceptable and no less accurate that your loads with the larger diameter bullets in the thinner neck wall cases. Good Luck !