Boat Tail Bullets?

[people]

The Club I used to belong to has a very strict no muzzle break, no sound suppressor, no loading from a mag even if you drop it from the rifle after you have loaded so there is only one round in the rifle, none of this and none of that stuff.

 

[tunered]

Somewhere here last week it was said that if bullets leave the muzzle stable they will stay stable or even gain stability as vel decreases, now its being said that boattail bullets may not stabilize till 300 yards, WTF. Does anybody who knows what they are talking about care to reflect??. ed

 

[6BRinNZ]

Somewhere here last week it was said that if bullets leave the muzzle stable they will stay stable or even gain stability as vel decreases, now its being said that boattail bullets may not stabilize till 300 yards, WTF. Does anybody who knows what they are talking about care to reflect??. ed

Go have a read of Brian Litzs Book "applied ballistics for long range shooting"...the best advice I can offer when talking about balistics information is talk to a balistician...or read his book...

 

[tunered]

Books and the real world dont always stand true. Anybody? Instead of links to avoid my question. ed

 

[6BRinNZ]

tunered...over to you...have a read on this site about Brian.

I'm out..

 

[tunered]

If this question comes up again Ill be sure to butt in and mention nobody has the answer, go read a book. BS. ed

 

[jo191145]

Mike

Another consideration is the crown. I've noticed some factory barrels these days with "washed out" crowns. Looks like someone hit em with a buffing wheel. Usually not evenly either ;D
Such a crown condition will affect a boatail more than a flatbase.

Martin and perhaps tunered

http://www.appliedballisticsllc.com/index_files/EpicyclicSwerve.htm

That conversation is a lot like barrel break in. Absolutely no need for my uneducated opinions but you can start to formulate your own.

 

[6BRinNZ]

.

If this question comes up again Ill be sure to butt in and mention nobody has the answer, go read a book. BS. ed

I could offer my opinion but that would still leave you here - "Somewhere here last week it was said that if bullets leave the muzzle stable they will stay stable or even gain stability as vel decreases, now its being said that boattail bullets may not stabilize till 300 yards, WTF. Does anybody who knows what they are talking about care to reflect??. ed"

It is my opinion that the book holds answers, or at the very least explanations (specifically for stabilisation issues) outside of "each barrel is unique", for behaviour that we see as a symptom which is why I suggested it.

 

[tunered]

Thanks, I read the article, link above. I do believe that bullets sometimes leaves the barrel unstable and does stablize down range, but what i dont believe is that bullet that went at 1in at 100yrds will somehow find its way back into line of site and shoot 1in at 200. How many shooters here has guns that shoot better at 300 than 100?? ed

 

[K0na_stinky]

Thanks, I read the article, link above. I do believe that bullets sometimes leaves the barrel unstable and does stablize down range, but what i dont believe is that bullet that went at 1in at 100yrds will somehow find its way back into line of site and shoot 1in at 200. How many shooters here has guns that shoot better at 300 than 100?? ed

Exactly what I'm puzzled by.

 

[Johnboy]

well for me I have yet been able to shoot a flat Base bullet out of any of my rifels.and I have two 223's and two 30 cal. rifels.but I can get a BT bullet to make one ragged hole at 100 yards.so I guess the OP and I both need to trade out loading skills so that we can learn off each other.then the problem at hand will no longer be.

but will add that I have been able to get a Flat Base bullet to shoot at a longer distance.even did a test to see what was going on.loaded up the same load with same bullet.shot it at 100 then at 200.and the 200 5 shot group came out smaller than the 100.so I came up with the idea that it took a greater distance for the Flat Base bullet to shoot.so help me out with this.thats if you want too.just seems to me it takes a greater distance for the FB bullet rather than the BT bullet.just seems it takes the FB bullea longer time to form a tail wind rather than the BT does.but hey its just something I put some not alot of thought in.just been able to do better with a abt bullet and my thoughts.and that I am not a BR guy neither.just love to shoot.

 

[CanusLatransSnpr]

Jo, I have often wondered if I should have the barrel on my .22-250 recrowned! It is a factory barrel and sometimes they aren't crowned the greatest. I have almost 500 rounds down the tube on that gun so it couldn't hurt? I may have to make an appointment with Terry to have that done! As far as my .243 goes, the crown on that barrel is good. Its a McGowen Savage drop in tube and Terry checked the crown on it before installation. That one has 106 rounds down the tube on it! I still wonder if it isn't me or something I may be doing wrong though?

Johnboy, I agree. If we could collaborate our reloading skills, we could make some fine shooting ammunition !

Also, I would like to apologize for bringing up this somewhat "controversial" topic and starting yet another pissing match on here! I was just looking for some honest answers to my problem is all. Sorry!

Mike

Mike

 

[mc223]

Another consideration is the crown. I've noticed some factory barrels these days with "washed out" crowns. Looks like someone hit em with a buffing wheel. Usually not evenly either ;D
Such a crown condition will affect a boatail more than a flatbase.

Along with the leade angle and length have the first contact with the bullet and needs to be as straight as posible. The crown needs to be perpendicular to the bore. Crown shape will effect the disturbance of the expanding gasses which can effect the bullet flight. This it seems would be most prevalent in an overbore cartridge like the OP is using.

 

[K0na_stinky]

well for me I have yet been able to shoot a flat Base bullet out of any of my rifels.and I have two 223's and two 30 cal. rifels.but I can get a BT bullet to make one ragged hole at 100 yards.so I guess the OP and I both need to trade out loading skills so that we can learn off each other.then the problem at hand will no longer be.

but will add that I have been able to get a Flat Base bullet to shoot at a longer distance.even did a test to see what was going on.loaded up the same load with same bullet.shot it at 100 then at 200.and the 200 5 shot group came out smaller than the 100.so I came up with the idea that it took a greater distance for the Flat Base bullet to shoot.so help me out with this.thats if you want too.just seems to me it takes a greater distance for the FB bullet rather than the BT bullet.just seems it takes the FB bullea longer time to form a tail wind rather than the BT does.but hey its just something I put some not alot of thought in.just been able to do better with a abt bullet and my thoughts.and that I am not a BR guy neither.just love to shoot.

For my load development I stopped shooting at 100 yards. I find that I can shoot more accurately at 200 yards then I can at 100 yards. I find it easier to line up the reticale on the target at a further distance. Maybe that is what is happening here and people don’t realize it. Or maybe I’m crazy.

 

[minnesota]

What about if you have a factory rifle with to large of a chamber , you full length size, and you don't seat up to the lands of the rifling. Your case would be slightly caulked and your bullet would be at a slight angle to the barrel, it would be harder to stabilize a boat tail bullet than a flat base bullet due to the smaller bearing surface of the boat tail bullet.
I am sure their are a lot of explanations for this occurrence. I know one of my buddies rifles chamber is cut quit larger than mine, because I had to resize after he shot one of my loads.
Their could also be the occurrence of the run out of the bullet and the previous problem combined. Also if you have a shorter neck and you do not get your bullet seated far enough in the cartridge, the bullet would be easier to knock, so the run out would change and be off.

 

[minnesota]

For my load development I stopped shooting at 100 yards. I find that I can shoot more accurately at 200 yards then I can at 100 yards. I find it easier to line up the reticale on the target at a further distance. Maybe that is what is happening here and people don’t realize it. Or maybe I’m crazy.
[/quote]

I have modified the targets that I print off so the X on the targets is orientated the same way as the X is, so you are not lining up the cross in the scope with the cross lines on the target, instead you are orientating the center of the X with the center of the Cross hairs.

 

[CanusLatransSnpr]

mc223, I like where your going with what your saying there. It makes sense to me!

minnesota, I do own a Hornady OAL gauge with modified cases for both chambering I'm shooting. The .22-250 I bump the shoulders .0015" and the .243 I'm shooting virgin brass that the bolt closes on with a bit of a crush fit so I don't think it has anything to do with any of that. However, I don't have the ability to measure runout on loaded rounds. My loaded ammunition has .002" neck tension and there is plenty of bullet seated for neck purchase. I appreciate your thoughts as these factors could cause such an occurence.

Mike

 

[mc223]

Another consideration is that spin stabilization may not be adequate for the bullet length regardless of the bullet shape.

When the spin is close to being right for the bullet's length, the precessing is minimized and the bullet "goes to sleep" If it is too slow the bullet will not be as stable as it should. (That is why Jeff Cooper says it's wrong to shoot groups at 100 yards for accuracy testing and suggests 300 yards. If your twist isn't right for the bullet used your group size will be larger at long ranges than would be expected by extrapolation of 100 yard data due to bullet wobble.)

 

[bozo699]

Jo, I have often wondered if I should have the barrel on my .22-250 recrowned! It is a factory barrel and sometimes they aren't crowned the greatest. I have almost 500 rounds down the tube on that gun so it couldn't hurt? I may have to make an appointment with Terry to have that done! As far as my .243 goes, the crown on that barrel is good. Its a McGowen Savage drop in tube and Terry checked the crown on it before installation. That one has 106 rounds down the tube on it! I still wonder if it isn't me or something I may be doing wrong though?

Johnboy, I agree. If we could collaborate our reloading skills, we could make some fine shooting ammunition !

Also, I would like to apologize for bringing up this somewhat "controversial" topic and starting yet another pissing match on here! I was just looking for some honest answers to my problem is all. Sorry!

Mike

Mike

Mike,
You have nothing to be sorry about, the people using Sniperhide language should be sorry if anything! You ask a legitimate question and members answered the best they could.6brinNZ came up with a very good answer, if you are not getting the answer to your question read a book that a expert on the subject has written. I actually have this book and it is not a easy read it is very technical and written by a genius with a scientific mind and you almost need a scientific mind to understand it, but the answers are in the book if you want to dig for it.

People,
I understand what you are saying. I can shoot a mile or just over at my place but it is rugged country and not easy to get to the targets to re paint them. I do shoot a 1000 quite regular and some 1200, what are you shooting @ a mile and how well are you doing?

Wayne.

 

[minnesota]

mc223, I like where your going with what your saying there. It makes sense to me!

minnesota, I do own a Hornady OAL gauge with modified cases for both chambering I'm shooting. The .22-250 I bump the shoulders .0015" and the .243 I'm shooting virgin brass that the bolt closes on with a bit of a crush fit so I don't think it has anything to do with any of that. However, I don't have the ability to measure runout on loaded rounds. My loaded ammunition has .002" neck tension and there is plenty of bullet seated for neck purchase. I appreciate your thoughts as these factors could cause such an occurence.

Mike

If you have the OAL gauge, I am assuming you have the bullet comparator attachment for your micrometer. If you do take one of your sized cases/debured cases and humer me, put one of your bullets and place on top of unloaded case and measure. Now take one of your loaded rounds and measure. Take the difference and see what you come up with. I am not calling you a rookie by any means, but when I started reloading I was assuming I had a sufficient amount of the bullet in the case. What I found out was that with the flat base bullets had enough and the boat tails did not.

Good luck, see what you come up with.