sabotless- boattail vs flat based

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jims

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If one were shooting sabotless would a boattail bullet have any of the disadvantages that it has in a saboted load? Pros and cons versus the flat based bullets in sabotless are wanted. Thanks
 
jims,
the way I see it there is basically two types: flat base and boat tail.Of the two, the boat tail has the most potential for accuracy in that the base can be more precisely made. Also, the boat tail will produce less aerodynamic drag than will an otherwise identical bullet with a flat base. This means the boat tail design will shoot flatter at extended range than will a flat base ; all other variables being equal.

Where I feel the problem comes in is having to load this type of bullet down the barrel from the muzzle end and not from the breech end. A boat tail bullet typically has less bearing surface than a flat base bullet of equal size.

The problem with shooting sabotless is getting a bullet that will fit down the bore that will stay seated on the powder charge and will stilll shoot accurately.

Generally a bullet that matches the groove dia of the bore or slightly larger by appx .001 will shoot the best. Loading from the muzzle end you probably wont get anything down the barrel much over .002" past land dia.

The potential for getting a long bullet like a boat tail with a short bearing surfaced misaligned in the bore would be high. I would think the flat base with a long bearing surface would be the way to go for best accuracy in a flat nose or round nose design.

Loading from the muzzle end sabotless I would stick to the bullets with the longest bearing surface that most closely fits the land dia of the bore.

Shooting cast boat tail bullets might help some as the softer lead would tend to expand more than jacketed bullets filling the grooves but at reduced velocities and still the possibility of misalignment.

Loading from the breech end I would go boat tail, from the muzzle end sabotless ,I would go loooooongest bearing surface bullets with the point of your choice.

Pocampo
 
If CH ever provides me the correct dies we will know. I have plent of the .451 TMZs I'd like to resize to .450 and shoot in my 45.

When it happens I'll post it here first.
 
Pocampo said:
Generally a bullet that matches the groove dia of the bore or slightly larger by appx .001 will shoot the best. Loading from the muzzle end you probably wont get anything down the barrel much over .002" past land dia.


Loading from the muzzle end sabotless I would stick to the bullets with the longest bearing surface that most closely fits the land dia of the bore.


Pocampo
From what I've seen you can't get a jacketed bullet that's larger than .0005" the boore down the barrel unless you're stronger than I am.

One good thing we have is the TMZ boat tail has a very long bearing surface because it is copper and long indeed for a 290 grain bullet. I have high hopes but only time will tell.
 
Pocampo said:
Generally a bullet that matches the groove dia of the bore or slightly larger by appx .001 will shoot the best. Loading from the muzzle end you probably wont get anything down the barrel much over .002" past land dia.


Loading from the muzzle end sabotless I would stick to the bullets with the longest bearing surface that most closely fits the land dia of the bore.


Pocampo
From what I've seen you can't get a jacketed bullet that's larger than .0005" the bore down the barrel unless you're stronger than I am.

One good thing we have is the TMZ boat tail has a very long bearing surface because it is copper and long indeed for a 290 grain bullet. I have high hopes but only time will tell.
 
I tend to think a flat based bullet would be better for smokeless, sabotless shooting for two reasons: 1) it seems to me that obturation of the bullet into the lands would be quicker, more consistently and easier with the flat base, and 2) the most accurate short and medium range bullets are all flat based as far as I know. example: all 6PPC (243) and 22PPC benchrest bullets are flat based, the 52 and 53g 224 match bullets are flat based - there must be some good reason for this. Additionally the 30 cal , for score, benchrest bullets are also flatbased. I realize the longer range bullets are boat-tailed where it must be that the increased BC of the BT helps more than any minor acccuracy degradation due to the BT vs FB. I have a Fred Moreo 22-250AK IMP done as a heavy varmint rifle which is capable of consistent 0.28" 5 shot gps @ 100ydswith 80g Starke bullets but just over 0.3" with 80 Sierras and 75 A-Maxs. This accuracy advantage holds to over 300yds. At 500yds and greater the accuracy is about the same and the BC of the two latter 2 bullets becomes an advantage. At 300yds with a smokeless MLer I see no significant ballistic advantage of a BT bullet.
 
SW said:
I tend to think a flat based bullet would be better for smokeless, sabotless shooting for two reasons: 1) it seems to me that obturation of the bullet into the lands would be quicker, more consistently and easier with the flat base, and 2) the most accurate short and medium range bullets are all flat based as far as I know. example: all 6PPC (243) and 22PPC benchrest bullets are flat based, the 52 and 53g 224 match bullets are flat based - there must be some good reason for this. Additionally the 30 cal , for score, benchrest bullets are also flatbased. I realize the longer range bullets are boat-tailed where it must be that the increased BC of the BT helps more than any minor acccuracy degradation due to the BT vs FB. I have a Fred Moreo 22-250AK IMP done as a heavy varmint rifle which is capable of consistent 0.28" 5 shot gps @ 100ydswith 80g Starke bullets but just over 0.3" with 80 Sierras and 75 A-Maxs. This accuracy advantage holds to over 300yds. At 500yds and greater the accuracy is about the same and the BC of the two latter 2 bullets becomes an advantage. At 300yds with a smokeless MLer I see no significant ballistic advantage of a BT bullet.

Good info Steve. Back in the early and mid 80's I new a gunsmith that was converting Ruger Number Ones to muzzleloaders. He was shooting smokeless and sabotless. He found that boattail bullets were difficult in the accuracy department. He had the same theory for poor acuracy.......sealing the bore at the base of the bullet is all but impossible on a boattail.

Incidentally, a good friend in Clarksville Arkansas bought a White Muzzleloader in 41 caliber back in the late 80's. The only bullets available for the gun were extremely long, heavy and expensive. We tried 41 caliber jacketed hand gun bullets.......210 grains I believe.....they shot great, were much cheaper and were deadly on whitetails when pushed by 80 or so grains of FFF blackpowder.

Your observations on any trajectory/retained energy advantage are right on. Inside 300 yards a boattail will offer no usable advantage to a hunter.
 
SW you are preety much in the X ring on that one. To get utmost accuracy and maximum velocity, you have to have instantanious obturation of the bullet. Only a flatbase or a concaved base is going to give that. A boattail bullet is going to give slow and erratic obturation, at best IMO.

Regardless of sabotless caliber, we are still talking about muzzleloaders here. As such, we are not going 30-378 Wea. type trajectories. Realistically, about all we can hope for is about 250-300yd MPBR, and as such a boatail would basically have no advantage over a flatbase bullet.
 

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