Question re DV Formula

[gjn]

I've ran your DV formula for several calibers and LBT bullet designs and found it quite interesting.One item your formula does not take into account is bullet weight and I was wondering if you felt that was not a significant factor assuming a weight within normal parameters for that caliber? I would assume bullet weight would be relevent to accuracy (ie. longer bearing surface,twist rate,etc) and overall penetration (the heavier the bullet the greater the penetration assuming all else is equal) but was wondering what you thought and whether weight had any other significance to you. For instance would a deer hit with a .410 210 WFN react any different than one hit with a .410 275 WFN as they have the same DV value at the same velocity? Thank you.

[Veral]

  I'm glad you asked.
  If you'll notice, I don't sell many lightweight handgun bullets, but lean toward heavy ones.  So very light bullets haven't been considered much in my formula.  Yet, the efficiency of large flat noses is so high that bullet weight has little influence on the DV formula if large bones aren't hit.  For deer sized game and smaller, which is all most US hunters will ever be able to afford to hunt, the lower end bullet weights which I offer in magnum revolver calibers will hold their wound size all the way through in most cases. 
  For example the 41 cal weights you name.  At the same impact velocity you would not be able to see a trace of difference in the wounds on broad side and quartering shots.  On a very large deer hit stem to stern, the wound would be slightly smaller at exit with the lighter than with the heavier, but the deer would go down in it's tracks with either.  In fact we can take the weight for 41 down to 180 gr before the performance difference gets real noticable.  So, I've kept the formula simple, because that's good enough.

  You are definately right that heavier bullets are most accurate, so long as weight doesn't get so extreme that stability from inadaquate velocity/rifling spin, becomes a problem.

  Your next and un asked question, Would the WFN penetrate far less than the LFN?  Very little.  Ross Seyfried told me he shot both nose styles, in either 44 or 45 caliber, I forgot which, at the same speed with the same bullet weights, into wet newspapers.  The LFN penetrated 2 inches less, both going something over 50 inches, as I recall, and both holes dead straight right up to where the bullets stopped.  Yet the WFN wounds nearly twice as large as the LFN in 44 caliber!  We are talking about efficiency that I don't understand, nor does anyone else, methinks.

[gjn]

Thank you for your time and insight. I am a big fan of your WFN designs at the heavier end of the scale in each caliber. I find around 850-900 fps they are pleasant to shoot in any caliber,very accurate and will do most anything. At 1100-1250 fps they hit like a freight train, penetrate thru everything and anchor anything they hit.

[Veral]

  Wonderful!  You figured out why I designed them that way!

[docmagnum357]

I had wondered the same thing, given i will probably never hunt anything bigger than white tail deer myself.  I read somewhere that the original hollow points, the " Express" bullets were more for accuracy than terminal effect at the very first.  they had a longer bearing surface, were weight to the rear, and were somehow thought to be better overall.  Then there was the advantage of the hollow point's expansion, which proved to bwe a sometimes thing then just as it is now. 

I have always found longer bullets to shoot better in my revolvers.  I have understood the advantages of a wide flat point since i cut the noses flat on 22 lr ammo as a child.  What i have come to wonder as an adult is weather the hollow base idea has any merit for a game bullet, with the nose size and shape being to veral's design.  The one real drawback i see id the weight forward attitude of the bullet.  Everything else would tend to enhance accuracy and performance. 

THe hollow base would allow a longer bearing surface for going from cylinder to barrel.  It would allow for the differences in chamber throat, forcing cone and barrel better than a gas check.  It would seal the bore, and virtually eleminat ethe need for a gas chec on any revolver that had anything like a close fit between throat, forcing cone, and barrel.  If it was designed for the pressure range found in the loads we most often shoot it would be fantastic. It shouldn't need much lube, because the lube would'nt be shot down the barre l ahead ooof the bullet .   

[docmagnum357]

I have shot the base off  hollow based wadcutters trying for too much velocity.  But if the alloy and the size/ shape/ strength of the hollow base were right for the pressure......
Anyhow, just a thought on how we could get the advantages of a 300 grain plus bullet as far as shape of metplat, bearing surface length, and the tightness of seal, bullet to bore of a lapped barrel throat(s) combo, and still keep the weight and pressurte down, and conceiveably powder capacity up. I would be game to try one, if Veral would design the " skirt" so it wouldn't blast off , and had the weight down to around 200 grains, and the length up near a 310-320- grain Wide flat nose. 

I guess the trick would be the skirt- strong enough not to blow off, weak enough to expand and seal the bore.  That and designing a cavity that would reduce the bullet's weight by 100 grains and still be fairly concentric.  Something to thionk about, and as I say, something i would buy, if the price wasn't much more than a regular mold.  Should hit like Thor's hammer, as 15-1600fps are possible in a 44 mag without too much pressure, and a 200 grain bullet.

[Veral]

  You guys have some wrong concepts about hollow base bullets.  They increase friction against the barrel DRAMATICALLY, and friction is the problem with cast bullets at magnum handgun pressure and greater.

  Lube does NOT blow down the barrel ahead of the bullet if the bullet is properly fitted, and I spell out how to properly fit cast over and over in my book and in this forum.  One can get the best performance possible from lead without gas checks by keeping the base flat, and higher performance than possible with plainbase when gas checks are used.  The highest performance possible in either case will be with LBT bullet lubricants.  If you are getting leading with some other bullet lubricant, and believe you have bullets fitted properly, try some of our LBT Blue Soft lube and your eyes will be opened!

  As for hollow points.  If used with lead that contains even very small amounts of antimony, the expanded metal will fracture and break off the shank before the mushroom  reaches full expansion.  They work well for tin lead or pure lead alloys only, and at the moderate to low velocities these alloys are capable of, do give a dramatic difference in performance on medium size critters like coyotes and smaller.  For good stout loads, nothing will kill faster than a wide meplat bullet (i.e. the LBT WFN and WLN) driven at a speed that produces a DV (displacement velocity) of 100 to 135.  A higher DV and kill speed goes down on big game.  An HP will produce an extremely high DV, which is why they kill erractically.

[docmagnum357]

I never thought of the incresed friction.... And please understand, i am sold on the wfn nose profile.  I also understand how to fit bullets, just thinking everybody might not want to go to all the trouble.  i usually start lapping as soon as i trade for a revolver, never buy one new( they all need tuning, lapping anyway) and enjoy the process.  Some people don't.  I am glad to know that friction goes way up with hollow bases, or i would have eventually wasted a good deal of time and possibly money barking up that tree, if nothing else, just to get the length without the weight. 

[docmagnum357]

I admit i have never used Veral's lube, i make my own, and it seems to do a fine job, as does Lee liquid Alox.  I always keep my loads down two or three grains from Max, and As I said above, i usually lapp the throats and barrel as soon as i get a revolver.  Just don't have trouble with leading unless i haven't " cleaned up" the bore. If I were going for top loads, I would probably swear by Veral's lube and nothing else.

Just thinking aloud, as it were...........

[Veral]

  I barked up 'that hollow base tree' for several months some time before I got into making molds.  Had an automatic swaging machine, which I built, with intentions of selling swaged bullets, both hollow and solid base.  Learned too much with it though, and dropped the notion before setting it up completely automatic, and gave the machine away, with dies for the most popular handgun calibers, when we left Cornville Arizona.