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Re: the big .308 Question
the bc is better.and would rather shoot a 175g bullet for any reason.papper/hunt'n.the more weight you sling out there the better they fall.
the bc is better.and would rather shoot a 175g bullet for any reason.papper/hunt'n.the more weight you sling out there the better they fall.
Re: the big .308 Question
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: esromvre</div><div class="ubbcode-body">My twist rate </div></div>
+1 and I would suspect the 175s give a longer barrel life...per:
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: esromvre</div><div class="ubbcode-body">My twist rate </div></div>
+1 and I would suspect the 175s give a longer barrel life...per:
Re: the big .308 Question
According to my software, the 155 has a little less drop, but the 175 has less drift.
According to my software, the 155 has a little less drop, but the 175 has less drift.
Re: the big .308 Question
175... Zzz.... a thing of the past. The Gucci 155's will always prevail.
the days of launching cannon balls (178s, 175s, etc.) at depressingly slow MV's are long gone. But then again, what the hell do I know? I just lost $40 in video poker. That's a box of Scenars.
175... Zzz.... a thing of the past. The Gucci 155's will always prevail.
the days of launching cannon balls (178s, 175s, etc.) at depressingly slow MV's are long gone. But then again, what the hell do I know? I just lost $40 in video poker. That's a box of Scenars.
Re: the big .308 Question
I happen to be using 155 scenars right now. I chosose this because A: they shoot in my gun, B: at my MVs I can get out to 1300 yards by the time the bullet drops to Mach, And C: I can get to 1000 yards at 30 MoA on the scope, and D: I still have 900 left from my last big purchase.
The 175s are still excellent bullets, its just the 155s are not able to deliver the punch out farther and at lower drops.
I happen to be using 155 scenars right now. I chosose this because A: they shoot in my gun, B: at my MVs I can get out to 1300 yards by the time the bullet drops to Mach, And C: I can get to 1000 yards at 30 MoA on the scope, and D: I still have 900 left from my last big purchase.
The 175s are still excellent bullets, its just the 155s are not able to deliver the punch out farther and at lower drops.
Re: the big .308 Question
175's are OK, but put you at a disadvantage against the 6.5's and 7mm's beyond 500 yards. 155 Scenars transform a .308 with no appreciable loss of barrel life. That said, I prefer 175 VLD's to both.
175's are OK, but put you at a disadvantage against the 6.5's and 7mm's beyond 500 yards. 155 Scenars transform a .308 with no appreciable loss of barrel life. That said, I prefer 175 VLD's to both.
Re: the big .308 Question
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 918v</div><div class="ubbcode-body">or effective range or accuracy or barrel life... </div></div>
The 155 has the same BC as the 175. The bullets are essentially the same size and shape, so I can't imagine why one would be more accurate than the other. Barrel life in .308 is a non issue for the overwhelming majority, 2700 vs. 2900 fps makes little difference.
The 175 is obsolete.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 918v</div><div class="ubbcode-body">or effective range or accuracy or barrel life... </div></div>
The 155 has the same BC as the 175. The bullets are essentially the same size and shape, so I can't imagine why one would be more accurate than the other. Barrel life in .308 is a non issue for the overwhelming majority, 2700 vs. 2900 fps makes little difference.
The 175 is obsolete.
Re: the big .308 Question
Help me understand this a little better. Here's the data from Sierra's Website:
<span style="font-weight: bold"><span style="text-decoration: underline">.308 dia. 175 gr. HPBT MatchKing</span> </span>
.505 @ 2800 fps and above
.496 between 2800 and 1800 fps
.485 @ 1800 fps and below
<span style="text-decoration: underline"><span style="font-weight: bold">308 dia. 155 gr. HPBT Palma MatchKing</span></span> (2156)
.504 @ 2700 fps and above
.470 between 1800 and 2700 fps
.430 between 1500 and 1800 fps
.380 @ 1500 fps and below
So... The 175 is going to spend almost none of it's time >= 2800, so really the BC is .496, but this lasts down to about 1800 fps. The 155 might have a short run @ .504 (>=2700), but then drops off to .470. The BC's are significantly lower than the 175's after that.
How much of a difference does .026 make? Does it make up for 200-300 (+?) fps at the muzzle?
I hope I'm not coming off as a prick -- that's not my intent. Trying to "pick a bullet" myself (purpose=paper punching), and don't really see enough difference here to call the 175 obsolete...
-Slice
Help me understand this a little better. Here's the data from Sierra's Website:
<span style="font-weight: bold"><span style="text-decoration: underline">.308 dia. 175 gr. HPBT MatchKing</span> </span>
.505 @ 2800 fps and above
.496 between 2800 and 1800 fps
.485 @ 1800 fps and below
<span style="text-decoration: underline"><span style="font-weight: bold">308 dia. 155 gr. HPBT Palma MatchKing</span></span> (2156)
.504 @ 2700 fps and above
.470 between 1800 and 2700 fps
.430 between 1500 and 1800 fps
.380 @ 1500 fps and below
So... The 175 is going to spend almost none of it's time >= 2800, so really the BC is .496, but this lasts down to about 1800 fps. The 155 might have a short run @ .504 (>=2700), but then drops off to .470. The BC's are significantly lower than the 175's after that.
How much of a difference does .026 make? Does it make up for 200-300 (+?) fps at the muzzle?
I hope I'm not coming off as a prick -- that's not my intent. Trying to "pick a bullet" myself (purpose=paper punching), and don't really see enough difference here to call the 175 obsolete...
-Slice
Re: the big .308 Question
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HomeSlice</div><div class="ubbcode-body">Help me understand this a little better. Here's the data from Sierra's Website:
<span style="font-weight: bold"><span style="text-decoration: underline">.308 dia. 175 gr. HPBT MatchKing</span> </span>
.505 @ 2800 fps and above
.496 between 2800 and 1800 fps
.485 @ 1800 fps and below
<span style="text-decoration: underline"><span style="font-weight: bold">308 dia. 155 gr. HPBT Palma MatchKing</span></span> (2156)
.504 @ 2700 fps and above
.470 between 1800 and 2700 fps
.430 between 1500 and 1800 fps
.380 @ 1500 fps and below
So... The 175 is going to spend almost none of it's time >= 2800, so really the BC is .496, but this lasts down to about 1800 fps. The 155 might have a short run @ .504 (>=2700), but then drops off to .470. The BC's are significantly lower than the 175's after that.
How much of a difference does .026 make? Does it make up for 200-300 (+?) fps at the muzzle?
I hope I'm not coming off as a prick -- that's not my intent. Trying to "pick a bullet" myself (purpose=paper punching), and don't really see enough difference here to call the 175 obsolete...
-Slice
</div></div>
Im biased but here is another way to look at it, brought to you via Byran Litz's great read "Applied Ballistics for Long Range Shooting"
155smk (2156) adv G1 .449 and G7 .229
175smk adv G1 .475 and G7 .243
The 155's saving grace is that its starts out in the mid to low 2900 fps when the 175 starts around 2700.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HomeSlice</div><div class="ubbcode-body">Help me understand this a little better. Here's the data from Sierra's Website:
<span style="font-weight: bold"><span style="text-decoration: underline">.308 dia. 175 gr. HPBT MatchKing</span> </span>
.505 @ 2800 fps and above
.496 between 2800 and 1800 fps
.485 @ 1800 fps and below
<span style="text-decoration: underline"><span style="font-weight: bold">308 dia. 155 gr. HPBT Palma MatchKing</span></span> (2156)
.504 @ 2700 fps and above
.470 between 1800 and 2700 fps
.430 between 1500 and 1800 fps
.380 @ 1500 fps and below
So... The 175 is going to spend almost none of it's time >= 2800, so really the BC is .496, but this lasts down to about 1800 fps. The 155 might have a short run @ .504 (>=2700), but then drops off to .470. The BC's are significantly lower than the 175's after that.
How much of a difference does .026 make? Does it make up for 200-300 (+?) fps at the muzzle?
I hope I'm not coming off as a prick -- that's not my intent. Trying to "pick a bullet" myself (purpose=paper punching), and don't really see enough difference here to call the 175 obsolete...
-Slice
</div></div>
Im biased but here is another way to look at it, brought to you via Byran Litz's great read "Applied Ballistics for Long Range Shooting"
155smk (2156) adv G1 .449 and G7 .229
175smk adv G1 .475 and G7 .243
The 155's saving grace is that its starts out in the mid to low 2900 fps when the 175 starts around 2700.
Re: the big .308 Question
Now that I reread what you asked, I guess I just stated the same thing... LOL
After running the numbers through jbm, the 155 takes the cake... Slightly better in the wind, a couple tenths of a inch@1k, and 30 to 40 inches less drop all depending on how you run the numbers.
Now that I reread what you asked, I guess I just stated the same thing... LOL
After running the numbers through jbm, the 155 takes the cake... Slightly better in the wind, a couple tenths of a inch@1k, and 30 to 40 inches less drop all depending on how you run the numbers.
Re: the big .308 Question
Niles, what is your recipe for the 155's? ive been thinking of trying them but havent yet, i throw 175's and 168's right now in a 26" sps 1-12
Niles, what is your recipe for the 155's? ive been thinking of trying them but havent yet, i throw 175's and 168's right now in a 26" sps 1-12
Re: the big .308 Question
Momentum, by definition, is the product of an object's mass and velocity. Newton's First Law applies. The affect of drag (bc) on the bullet has to be addressed in relation to the mass also. Bullets with similar drag coefficients but one weighing 13% more than the other will show different affects as they slow down, which is shown by Sierra's multiple bc's for different velocities. Since the 155 starts out only 7% faster than a 175 (a 13% heavier projectile), the effects of drag are more pronounced as it slows. Can you imagine the bc of a depleted Uranium projectile, whose mass is 15% higher than lead??? Of course, you would have lower initial velocities due to higher chamber pressures for the heavier projectile. Palma shooters only recently (1992?) went from using 190gr bullets to 155s. The higher mass bullets will always have a place on the range. Mass has a direct effect on momentum, while drag is an acceleration, and thus is on the first derivative (lower order of magnitude) for effect on the bullet's flight.
Momentum, by definition, is the product of an object's mass and velocity. Newton's First Law applies. The affect of drag (bc) on the bullet has to be addressed in relation to the mass also. Bullets with similar drag coefficients but one weighing 13% more than the other will show different affects as they slow down, which is shown by Sierra's multiple bc's for different velocities. Since the 155 starts out only 7% faster than a 175 (a 13% heavier projectile), the effects of drag are more pronounced as it slows. Can you imagine the bc of a depleted Uranium projectile, whose mass is 15% higher than lead??? Of course, you would have lower initial velocities due to higher chamber pressures for the heavier projectile. Palma shooters only recently (1992?) went from using 190gr bullets to 155s. The higher mass bullets will always have a place on the range. Mass has a direct effect on momentum, while drag is an acceleration, and thus is on the first derivative (lower order of magnitude) for effect on the bullet's flight.
Re: the big .308 Question
But out of the 155 and 175 bullets which one is going to give the most pain at the end of the journey. I'm not talking about punching paper. I guess you need to decide what your application is.
But out of the 155 and 175 bullets which one is going to give the most pain at the end of the journey. I'm not talking about punching paper. I guess you need to decide what your application is.
Re: the big .308 Question
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TinKnocker</div><div class="ubbcode-body">But out of the 155 and 175 bullets which one is going to give the most pain at the end of the journey. I'm not talking about punching paper. I guess you need to decide what your application is. </div></div>
The one that arrives on target.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TinKnocker</div><div class="ubbcode-body">But out of the 155 and 175 bullets which one is going to give the most pain at the end of the journey. I'm not talking about punching paper. I guess you need to decide what your application is. </div></div>
The one that arrives on target.
Re: the big .308 Question
Higher mass projectiles definitely have their place. 190s, 210s, 220s, and 240s all have even better BCs than the 175/155.
With that said, when you compare the differences between the performance of the 155 and 175 in .308, the 155 is the clear winner in my opinion. Bullets heavier than that would not be so clear, if you could get sufficient velocity out of them without high pressures. In a longer cartridge, I'm not sure the 155 would be ideal.
I have some 175s left from my experiments, but I'm switching to the 155s exclusively. They shoot well in my 1 in 12 barrel and even the old Sierra 155s hit hard enough at 600 to be worth it.
Higher mass projectiles definitely have their place. 190s, 210s, 220s, and 240s all have even better BCs than the 175/155.
With that said, when you compare the differences between the performance of the 155 and 175 in .308, the 155 is the clear winner in my opinion. Bullets heavier than that would not be so clear, if you could get sufficient velocity out of them without high pressures. In a longer cartridge, I'm not sure the 155 would be ideal.
I have some 175s left from my experiments, but I'm switching to the 155s exclusively. They shoot well in my 1 in 12 barrel and even the old Sierra 155s hit hard enough at 600 to be worth it.
Re: the big .308 Question
Bear with me...
1/4 mile race between a big block 454 and a turbo charged 4 cylinder... both have been modified to run the quarter in 11.5, a respectable time. One is working "hard" to give you the desired results, while the other is working "VERY hard" to give very similar results..... which motor will need to be rebuilt first? Probably the Blown 4, given the current metal tech. those parts are run harder and will wear faster(read; more powder/throat erosion while giving similar performance)....so its really up to you...fastest 155 or fast 175..
If I didn't own a gas gun.. It would be a close race...
FWIW, I enjoy a big V8(and have a M1A), hence I vote for the 175gr.
Bear with me...
1/4 mile race between a big block 454 and a turbo charged 4 cylinder... both have been modified to run the quarter in 11.5, a respectable time. One is working "hard" to give you the desired results, while the other is working "VERY hard" to give very similar results..... which motor will need to be rebuilt first? Probably the Blown 4, given the current metal tech. those parts are run harder and will wear faster(read; more powder/throat erosion while giving similar performance)....so its really up to you...fastest 155 or fast 175..
If I didn't own a gas gun.. It would be a close race...
FWIW, I enjoy a big V8(and have a M1A), hence I vote for the 175gr.
Re: the big .308 Question
Wow
this has been beat to death like forever
So in quick layman terms
155 scenar/New 155 berger Fullbore
logic
eyeball 175smk and 155scenar side by side the slightly more aerodynamic looking bullet = 155scenar
Facts
175smk and 155scenar have about same BC, if anything scenar is slightly better
2 bullets same BC
one @ 2800fps and one @ 2975fps
which do ya use is pert easy...right
its really that simple
Wow
this has been beat to death like forever
So in quick layman terms
155 scenar/New 155 berger Fullbore
logic
eyeball 175smk and 155scenar side by side the slightly more aerodynamic looking bullet = 155scenar
Facts
175smk and 155scenar have about same BC, if anything scenar is slightly better
2 bullets same BC
one @ 2800fps and one @ 2975fps
which do ya use is pert easy...right
its really that simple
Re: the big .308 Question
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pacomdiver</div><div class="ubbcode-body">Niles, what is your recipe for the 155's? ive been thinking of trying them but havent yet, i throw 175's and 168's right now in a 26" sps 1-12 </div></div>
I've played with the 155 amax a little but not any others in that weight, mostly like you, 168's and heavier with a few 110 v-max for good measure.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pacomdiver</div><div class="ubbcode-body">Niles, what is your recipe for the 155's? ive been thinking of trying them but havent yet, i throw 175's and 168's right now in a 26" sps 1-12 </div></div>
I've played with the 155 amax a little but not any others in that weight, mostly like you, 168's and heavier with a few 110 v-max for good measure.
