quote:

Originally posted by MJines:
Dan, my question back at you would be why, what's the point? I think far too many people pursue the velocity issue when I am not convinced that at the end of the day it makes much damn difference with heavy bullets. To me a heavy, large bore bullet moving at modest velocity is all you need to ensure excellent penetration. Plus you will shoot more accurately and shoot more often since the rifle does not beat you to death like Hilly's. Read some of what Kevin Robertson wrote in The Perfect Shot in the chapter on terminal bullet performance. The experience with pushing impact velocities is mixed. Sometimes we cannot help but feel that too much of a good thing has got to be better . . . sometimes it is not.

. . . damn you ask a lot of questions. Is it an Aussie thing? Is Hilly putting you up to it?

quote:

Originally posted by 416Tanzan:
I guess that I think a little differently than most. I like to match case capacity to its safe capability. When building a 500 calibre I passed up on the Jeffrey and 500 Mbogo because I didn't want to use a full-capacity load at 8000-8500 ftlbs. So I went with the 500 AccRel for hunting loads at 6500-7000 ftlbs.

For the 416, if I wanted 400 grains at 2400 fps, then I would get a 416 Ruger or 416 Remington. The same calibres would run the 350 grain .416" bullets at 2600 fps. However, if someone has a Rigby in a modern bolt action like the CZ, then loads that are probably in the high 50's and nudging 60,000 psi are very doable. Study the following picture:



These Rigby cases are from this year's buffalo, as is the bullet. The primers are delightfully rounded and are not pushing true max loads or flattened primers. Think of these loads as conservative, restricted loads for a "416 Weatherby-ish capacity."

The load? 101.5 grains Reloder 17, Fed 215 match primers, Hornady brass, and 350 grain TTSX bullets for an adjusted, chronographed muzzle velocity of 2825 fps.

Now why would anyone want such a load? Well, it is more than adequate for buffalo as the bullet testifies. It impacted at 2610 fps, blew the petals, and then the 74% body weight formed a secondary mushroom! An amazing little bullet. More importantly, that bullet has a BC of .444 and flies FLAT, FLAT, FLAT. When sighted in at 2" high at 100 yards, the bullet drops -7" at 300 yards. That makes the bullet a wonderful eland load, too. In fact, you would be hardpressed to find any eland load to rival this. At 400 yards, and that is a very very long way in Africa, the bullet only drops 21" and hits with 3379 ftlbs. Yes, at 400 yards. At 200 yards it hits with 4626 ftlbs. Again, that is about as good as it gets for an eland load. And from 0 to 100 yards, the energies drop from 6200 ftlbs. to 5371 ftlbs., so you have buffalo more than covered, with more energies at 100 yards than the 458 WM or 375H&H at the muzzle.

Anyone shooting these loads should practice and get used to holding the rifle tightly so that a quick followup shot may be taken. My various CZ's have all been comfortable to shoot, but they do take some practice before walking after Mr. Mbogo. Enjoy the build up and practice. Whatever loads and bullet weights you end up with, the 416 will work admirably. Simply limit the range and trajectory to the capabilities of the load.

Those are my two shillingi worth.

quote:

Max loads published for the Rigby specify about 38,000 CUP pressure. The .416 Weatherby runs much more pressure. I think 60-65,000?

quote:

Originally posted by RIP:
JIM,

Why did you say "psi" in relation to "Copper Crusher Units of Pressure" when you should have said "CUP" what?

Piezo = psi
Crusher = CUP

You are not helping people get unconfused over comparing the old CUP units to modern psi units.

CUP is going the way of the dodo, eh?

quote:

Originally posted by 416Tanzan:
In order to use Quickload the powders need to be adjusted to fit the batch lot. It would appear that my current Rel-17 is running 8% slower than the data processing by RIP. For example, 101.5 grains produces 2825fps and rounded primers with the 350 gn. TTSX. Dropping down to 99.5 grains produces 2763fps and rounded primers. At that rate, one would expect 96.5 grains to produce around 2675 fps.

Velocities have been checked with three different chronographs (2 Pro Chrono and 1 Chrony), though not at the same time and with enough variation that I would only want to give the velocities a rating within +/- 30fps accuracy. To add to the variation, I've used three different batches of R-17 over the last four years. It means that everything is a 'ballpark' figure. Even the 300 yard tests three weeks ago are 'ballpark' because only two 416 rounds were sent downrange at 300 yards in order to conserve ammunition. (Ammunition is a pain to get over to Africa, with airline 11-lb. limits and needing to find a situation for continuous travel all the way to TZ.) The drop was as expected, 6 in., but with only two shots under less than optimum conditions and sight picture, the drop must be deemed 'hunting worthy' out to 400 yards, but no where precise enough for regulating powder burn rates.

quote:

Originally posted by Gerard:
I approached the problem from a different angle by pressing bullets into a barrel on a hydraulic press and by measuring the pressure required to fully engrave the bearing surface. This yielded a set of numbers that only told me one style is less or more than another. Then we shot a variety of makes in a ballistics lab and determined how far down the barrel the maximum pressure we chose was achieved. This yielded a further set of confusing numbers where it could only be seen that one was further than the other. Only when I calculated the total displaced material volume and tempered it with the hardness, material yield, ductility and Poisson's ratio, did the numbers start making sense.

I learned some things from this protracted exercise:

And I learned some things from just the above brief description of the quest for knowledge.

1. Some bullets generate a starting pressure of more than 9,000 psi.
Would that be steel-cored-jacketed AP bullets, or steel-jacketed-lead-cored bullets used as solids?

2. The average cup and core bullet generates between 3,500 psi and 5,000 psi.
I'll buy that.

3. Less than 1,100 psi is measurable but has no effect on anything measured.
I'll buy that too, and apply it as a comfort in assigning my plastic sabot load a start pressure of 1000 psi for QuickLOAD.
Whatever it is, it must be pretty low, and however low, is not going to make much difference in the calculated pressure or velocity.

Coating has little effect on pressure at low levels of engraving force and I abandoned that direction once the fact was established.
Oops! I did not mean to imply that the proprietary coating on the GSC bullets was moly. Excuse please!

quote:

Originally posted by gohip2000:
yes, the Rigby is underloaded (If you want to say that) so you should be completely safe starting a 400gn bullet at 2400fps with the listed powders.

I was the one that had the 350gn TTSX tips break off in the magazine under recoil. the rifle was a CZ 550 416 rigby loaded at about 2500 fps.
The tip that boke off was always the top cartridge in the magazine because the tip would hit the feed ramp at an angle under recoil and pry the tip off. Loosing the tip didn't bother me accept that the tip got lodged in the action and jammed it up.

Not sure if this is happening to other people, but it did happen to me at the range.