200grn Shockwaves and Lehigh BC'S.

Grouse45 · 04-12-2009, 08:16 AM

I went to the range yesterday to really start testing the 200grn Lehighs with Polymer tips on them. Right away i realized the bullet was to long to stabilize in a 1/30 twist barrel. I was shooting my 45caliber Disc Elite. The accuracy was horrible. After talking with Dave we will need to shorten the bullet for the guy's that want the extra BC. That will probably mean lighter as well.

So when all failed i decided to run some BC'S for the T/C Shockwave and the 200grn Lehigh Hollow point. Here are the numbers i got.

Lehigh 200grn
Actual BC 0.157 (The website lists it at 0.158 so your actuals validate this)
Drop - 0"(100yd), -8.7"(200), -34.3"(300)

T/C ShockWave 200grn
Actual BC 0.195
Drop - 0"(100), -7.7"(200), -29.2"(300)

The more i look at this, the bullets are with in 1" at 200yds. Wow, i wont be needing a tip that's for sure. But those that need them, Davewill be working on them very soon.

All shots were with 130grns of BH209 and Federal 209A Primers. Avg MV was 2350

sabotloader · 04-12-2009, 09:07 AM

Grouse45

Quote:

After talking with Dave we will need to shorten the bullet for the guy's that want the extra BC. That will probably mean lighter as well.

Probably why Barnes had to drop to 195 grains with the Copper Bullet and yet explains why the 200 XTP and SST/SW being shorter do stabilize from so many guns..

Grouse45 · 04-12-2009, 09:24 AM

I was actually thinking that as well. That's probably why they use a 175 and a 195grn bullet.

sabotloader · 04-12-2009, 09:52 AM

Grouse45

I hope eveyone understands that BC is a function of velocity over a given distance, because when you look at the Hornady Web Site it lists the 200 SST with a BC of .265 as compared to your .195. Hornady knows the actual optimum velocity to use to compute BC for that bullet and hence the BC computes to or near .265. Your BC's are calculated on the actual velocity from your gun with that specific powder charge and sabot. So those are your ACTUAL BC's - which probabably more reflective of what the average guy might shoot.

Here is an example from Sierra which I think presents a more acurate BC number for their projectiles than most any other manufacturer..

These are the numbers for a Sierra bullet of near the same size... but also rember these numbers are computed on Pistol velocites. Sierra has not been bitten by the ML bug.

.400 dia. (10mm) 180 gr. JHP
.400 Diameter
180 Weight
.161 Sectiona Density

BC for given velocity

.140 @ 1150 fps and above
.160 between 1150 and 1000 fps
.170 between 1000 and 850 fps
.120 @ 850 fps and below

Since Grouses shoot, I ran a ballistic chart using my Triumph or Omega's as the example gun. Because my two examples are 50 cal I will not get the velocity that he gets in a 45. I use a velocity of 2200 fps as the base as I can shoot 200 grain XTP's at that velocity.

spaniel · 04-12-2009, 08:09 PM

Grouse's numbers for the 200SW match up rather nicely with what I calculate based on real-life shooting. My working number is slightly lower but I shoot slightly lower velocity, so that makes sense.

Actually, I don't think velocity has anything to do with Hornaday's published number of .265. That is so high compared to what you get when you actually shoot the bullet, I don't think you could generate that BC on the range at any velocity where the bullet would hold together. IMHO it's just plain wrong. Perhaps someone who has shot them really fast from a Savage would know for sure. Either way, the ML market is the primary purpose for this bullet, 1800-2200fps, and .265 is WAY off from what it shoots in that velocity range so they shouldn't even publish that number.

Too often, I think companies just run the calculation on a computer and publish it without ever shooting to verify. An extreme example is Precision Rifle, which claims to calculate both on computer and shooting but then goes with whichever is higher!!! Some of theirs are high by about 40%.

The only number that matters is the one calculated from real shooting...

sabotloader · 04-12-2009, 08:17 PM

spaniel

Thanks for your observations. I really have wondered about the published numbers myself - they have always seemed high to me also. I do wish I really knew how they were derived.

I have always had a little better feeling for the way Sierra publishes their BC but I do not how accurate they are either.

spaniel · 04-12-2009, 08:24 PM

Quote:

ORIGINAL: sabotloader

spaniel

Thanks for your observations. I really have wondered about the published numbers myself - they have always seemed high to me also. I do wish I really knew how they were derived.

I have always had a little better feeling for the way Sierra publishes their BC but I do not how accurate they are either.

For some reason, manufacturers of ML bullets seem to do a much worse job in the BC department than for centerfire bullets. For example I can take the MV for my 300WM, then enter the exact BC, and the drop will be spot on. I shot to 860 yards last year and was within 2 inches on drop.

Grouse45 · 04-14-2009, 04:36 AM

Spaniel, How do you like your Winchester short mag?

spaniel · 04-15-2009, 11:10 AM

Quote:

ORIGINAL: Grouse45

Spaniel, How do you like your Winchester short mag?

It's actually a regular Winchester Magnum, not a WSM (Remington Sendero). I wanted to shoot heavy bullets (200gr) and in a factory WSM you have to eat into your case capacity to feed them from the magazine. The WSM is a great round if you either build a custom on a long action, or if you put an after-market extra-long mag box into a stock short action gun then re-barrel with the throat cut appropriately to seat the bullets out. Lacking the cash to do either of the latter options at the time of purchase, I went with the regular WinMag and have had no regrets (though my bull elk at 683 yds may beg to differ).