Effectiveness of Flat base vs Boattail on game animals - Page 2

MeekAndMild · July 29, 2007, 10:15 PM

Nate, what kind of bullets are you using? Are using a flat bottomed brand x with 40% weight retention and trying to compare it to a boat tailed brand y with 65% weight retention? (I shouldn't use brand as a variable here as within brands there are often styles with a wide variety of expansion rate and weight retention. But it illustrates the question.)

nate45 · July 29, 2007, 10:41 PM

Quote:

Nate, what kind of bullets are you using?

I put this in post # 9 it's the most I have on one brand and I have know idea what their respective weight retaining properties are.

Quote:

Here's a good actually example: my Dad's favorite rifle cartridge is .25-06 he for years he used the 117gr Serria SBT Gameking he shot 100+ deer with it all ran an average of 40 to 50 yds before falling.

When I told him about my switch to the flat base after hearing of their increased effect and noting it myself.

He switched to a 117gr Serria spitzer Prohunter since then he has shot 30+ deer with that combo all have either dropped or ran less than 25yds.

I myself have noticed the most difference in effect with two different brands the .308 150gr Nosler Ballistic tip and the 150gr Speer spizer flat base.

Like I've said before there's nothing scientific about this it just seems to me and some others I've spoken with that the FB has a greater effect.

Perhaps it does come from increased fragmentation and certain brands of FB expand and fragment more violently than some BT and thus make a more severe wound.

I have no idea if this is true of FB and BT hunting bullets in general.

Scorch · July 30, 2007, 12:12 AM

I'm with Art on this one. There is no difference you or I will ever see. I have hunted and killed animals all over the West over the past 30 years. I have participated in shooting matches for a number of years. I have never noticed a difference between the terminal effects of BT or FB bullets of the same design and weight. You poke a hole in an animal and they react differently depending on what they are doing at the time. You poke a hole in paper and the only thing that establishes group size is where the barrel was pointed when the round went off. Looking for an answer anywhere else is looking for exceptions and anecdotes to prove a claim.

Art Eatman · July 30, 2007, 09:54 AM

This holds only--repeat, only--for Sierra .30 bullets:

I had a 150-grain SPBT blow up in a mule deer's neck. No exit. It was at about 30 yards. 26" on the '06, loaded max. My estimated muzzle velocity, based on my experiences with holdover and Sierra's external ballistic tables for trajectory, was around 3,100 ft/sec.

A Sierra fellow got into the discussion here at TFL. He stated that I had driven the bullet too fast for the range at which I hit the deer. The jacket on the boat-tail is a tad thinner than on the flat-base. Had the velocity at impact been down around 2,700, it probably would not have blown apart. He further stated that a 150-grain flat-base would probably have held together.

Velocity at time of impact is thus a factor.

All other kills, at longer ranges, have had the boat-tail to be very effective; generally with exit wounds.

In the mule deer incident, the blowup didn't matter. A neck shot is a neck shot, and the deer didn't go anywhere from where he was lying as I walked up on him.

Art

FirstFreedom · July 30, 2007, 09:01 PM

I was gonna say, that's exactly what you WANT with a neck shot - a blow up. Good reason to drive them fast and try for neck shots. But then you limit yourself if only a vitals shot makes its appearance (say, at a range too long to try for a neck shot).

HiBC · July 30, 2007, 09:51 PM

Always,these issues are more complex.
Ross Seifred has far mor experience than I.His contention was that the cylindrical portion of the jacket contributed greatly to jacket-core integrity.
He said boattails were far more prone to separate (fail)
He also said at reasonable (300 yd or less) hunting ranges,the effects of the better BC on velocity/trajectory are not significant.

All good info.

I use my rifle for fun (not just big game hunting) at long ranges and I dial in one load,sightin and scope .I use HiBC heavy boat tails.
I have been using Accu-Bonds when I think they are a good idea(200 gr in a 30-338).It works.While I would not shoot Game at 700 yds,at my 5000 ft altitude 2900 fps at the muzzle is still breaking 2000 at 700 yds,kind of like a 30-40 Krag at 100 yds.Those work

davlandrum · July 31, 2007, 10:21 AM

Quote:

Here's a good actually example: my Dad's favorite rifle cartridge is .25-06 he for years he used the 117gr Serria SBT Gameking he shot 100+ deer with it all ran an average of 40 to 50 yds before falling.

When I told him about my switch to the flat base after hearing of their increased effect and noting it myself.

He switched to a 117gr Serria spitzer Prohunter since then he has shot 30+ deer with that combo all have either dropped or ran less than 25yds.

Are we discussing an "average drop dead distance" difference of 15 to 25 yards? Not enough difference, even if 100% accurate, to make me change anything I am doing...

Schamankungulo · August 6, 2007, 06:23 PM

The boattail , as noted is pretty much on par with the flat base inside 300 yards or so .. It maintains downrange velocity better due to less drag ..
It is pretty well noted that a flat base is more accurate ( tinier groups ) , my WAG on this is the flat base is bore diameter , and there fore has less chance of being off kilter leaving the muzzle ..
Accurate means different things to different people .. Even tho a long range shooter has the skills to put a flat or boattail , probably anywhere they want it , a long range shooter wants all the advantages he can get , therefore , the boattail , with less drag = more downrange velocity and less drop ..
In 99.5 % of hunting situations , I think it is a moot point as to which is better ..
Also remember that BC is directly affected by MV .. Your .540 BC bullet maybe .540 with a MV of say 3000 fps , go over or under and the BC changes up or down ..
I dont hunt beyond 250 yards or so , and I prefer the other BC bullets , ballistically challenged .. Gimme a round nose or a flat point any day ..

July 30, 2007, 12:12 AM	#28
Scorch Senior Member Join Date: February 13, 2006 Location: Washington state Posts: 15,248	I'm with Art on this one. There is no difference you or I will ever see. I have hunted and killed animals all over the West over the past 30 years. I have participated in shooting matches for a number of years. I have never noticed a difference between the terminal effects of BT or FB bullets of the same design and weight. You poke a hole in an animal and they react differently depending on what they are doing at the time. You poke a hole in paper and the only thing that establishes group size is where the barrel was pointed when the round went off. Looking for an answer anywhere else is looking for exceptions and anecdotes to prove a claim. __________________ Never try to educate someone who resists knowledge at all costs. But what do I know? Summit Arms Services

July 30, 2007, 09:51 PM	#31
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,288	Bonded matters Always,these issues are more complex. Ross Seifred has far mor experience than I.His contention was that the cylindrical portion of the jacket contributed greatly to jacket-core integrity. He said boattails were far more prone to separate (fail) He also said at reasonable (300 yd or less) hunting ranges,the effects of the better BC on velocity/trajectory are not significant. All good info. I use my rifle for fun (not just big game hunting) at long ranges and I dial in one load,sightin and scope .I use HiBC heavy boat tails. I have been using Accu-Bonds when I think they are a good idea(200 gr in a 30-338).It works.While I would not shoot Game at 700 yds,at my 5000 ft altitude 2900 fps at the muzzle is still breaking 2000 at 700 yds,kind of like a 30-40 Krag at 100 yds.Those work

July 29, 2007, 10:15 PM	#26
MeekAndMild Senior Member Join Date: August 2, 2001 Posts: 4,988	Nate, what kind of bullets are you using? Are using a flat bottomed brand x with 40% weight retention and trying to compare it to a boat tailed brand y with 65% weight retention? (I shouldn't use brand as a variable here as within brands there are often styles with a wide variety of expansion rate and weight retention. But it illustrates the question.)

July 30, 2007, 09:54 AM	#29
Art Eatman Staff in Memoriam Join Date: November 13, 1998 Location: Terlingua, TX; Thomasville, GA Posts: 24,798	This holds only--repeat, only--for Sierra .30 bullets: I had a 150-grain SPBT blow up in a mule deer's neck. No exit. It was at about 30 yards. 26" on the '06, loaded max. My estimated muzzle velocity, based on my experiences with holdover and Sierra's external ballistic tables for trajectory, was around 3,100 ft/sec. A Sierra fellow got into the discussion here at TFL. He stated that I had driven the bullet too fast for the range at which I hit the deer. The jacket on the boat-tail is a tad thinner than on the flat-base. Had the velocity at impact been down around 2,700, it probably would not have blown apart. He further stated that a 150-grain flat-base would probably have held together. Velocity at time of impact is thus a factor. All other kills, at longer ranges, have had the boat-tail to be very effective; generally with exit wounds. In the mule deer incident, the blowup didn't matter. A neck shot is a neck shot, and the deer didn't go anywhere from where he was lying as I walked up on him. Art

July 30, 2007, 09:01 PM	#30
FirstFreedom Junior member Join Date: May 31, 2004 Location: The Toll Road State, U.S.A. Posts: 12,451	I was gonna say, that's exactly what you WANT with a neck shot - a blow up. Good reason to drive them fast and try for neck shots. But then you limit yourself if only a vitals shot makes its appearance (say, at a range too long to try for a neck shot).

August 6, 2007, 06:23 PM	#33
Schamankungulo Junior Member Join Date: August 5, 2007 Location: Bama Posts: 14	The boattail , as noted is pretty much on par with the flat base inside 300 yards or so .. It maintains downrange velocity better due to less drag .. It is pretty well noted that a flat base is more accurate ( tinier groups ) , my WAG on this is the flat base is bore diameter , and there fore has less chance of being off kilter leaving the muzzle .. Accurate means different things to different people .. Even tho a long range shooter has the skills to put a flat or boattail , probably anywhere they want it , a long range shooter wants all the advantages he can get , therefore , the boattail , with less drag = more downrange velocity and less drop .. In 99.5 % of hunting situations , I think it is a moot point as to which is better .. Also remember that BC is directly affected by MV .. Your .540 BC bullet maybe .540 with a MV of say 3000 fps , go over or under and the BC changes up or down .. I dont hunt beyond 250 yards or so , and I prefer the other BC bullets , ballistically challenged .. Gimme a round nose or a flat point any day ..