watching other threads on bullets leads me to try to define for myself what I am looking for in an optimum Buffalo Bullet in .510".

Broading speaking, of course, one wants accuracy, bullet integrity, and terminal performance.

On the accuracy side, a true .510" diameter would intuitively be better than bullets that are designed to be .509" or even .5085".

In addition, the ability of a bullet to easily pressure fit into a particular barrel would be a plus. Both lead core bullets and driving band bullets have an advantage in this criterion, especially the driving band types.

Lower pressure with a particular load is also an advantage as it gives more versatility. the driving band designs of GSC and NorthFork come to mind here, particularly GSC.

A flatter trajectory, meaning potentially lighter bullets and higher BCs, is a plus, as well, since this would allow backup use as an eland bullet. The lightness must be balanced, of course, with guaranteed penetration.

Bullet integrity refers to its ability to plough through bones and retain substantial bullet weight and momentum. The monometals are inherently more reliable. Lead-cores can work, but they have a history of sometimes overexpanding.

On terminal results, one wants guaranteed penetration coupled with a maximum wound channel. The CEB "inverted, radial umbrella" terminal picture may be contrasted with the "inverted, fat club" picture of a wound channel.

When all of these are put together, one might propose the GSC 450grain HV as a composite model to measure other bullets by. It is light for calibre but with enough weight to be good for buffalo and it has a high enough BC (.330) to be used at any reasonable eland or hartebeest range. I think I've mentioned before that the 450gnHV is a well-designed bullet.

The Barnes .509 inch, 570 grain TSX, launched at a MV of 2,500 fps, and placed properly, in the boiler room, inside 50 yards, will knock a Cape buffalo off its feet. It's a sight to see. More than that I do not need.

But I would experiment with a bit lighter and faster, just for comparison purposes.

What happened to the Guffalo?

quote:

Originally posted by Michael Robinson:
The Barnes .509 inch, 570 grain TSX, launched at a MV of 2,500 fps, and placed properly, in the boiler room, inside 50 yards, will knock a Cape buffalo off its feet. It's a sight to see. More than that I do not need.

But I would experiment with a bit lighter and faster, just for comparison purposes.

Mike I loaded about 18 rounds of 570g TSX's in my 500 Jeffery all using IMR 4350. The last three in front of 126g of IMR 4350 were all over 2500 fps. That will clear your sinuses! I'm sticking with my wimpy load of 103g H4895 pushing the 570g TSX at 2300 fps. I do believe you that your load will knock a buffalo off of it's feet

Well, I only have a wimpy 500AccRelNyati. I'm not sure that it should do 2500fps with a 570grain bullet. 2350fps puts the muzzle energy at about 7000ftlbs (6990). And after cracking two stocks I need to wait until the next one is double-bedded before I try again.

Back to bullets, there is a tradeoff between velocity and momentum. Heavier allows very slightly higher momentum, but one pays for this in velocity and steeper trajectory. For buffalo only this is OK, but I like options of opportunity, too. So at what point does one call the intersection of momentum and velocity?

If I want 2600fps, then I probably want to limit weight to 450grains (=1170 relative momentum units). If I wanted or would be satisfied with 2450fps, then I could go with 510 grains and stay under 7000ftlbs (1250 relative momentum units [mass-in-grains/10 x vel fps/100]).

You definitely got that right! .510/450gr HV is best all-arounder: One bullet, one dead buffalo, 450-grains at 2650 fps, impact at 80 yards:

quote:

Originally posted by RIP:
You definitely got that right! .510/450gr HV is best all-arounder: One bullet, one dead buffalo, 450-grains at 2650 fps, impact at 80 yards:

I still love that picture. It makes things look like a 270 on an oribi.

quote:

Originally posted by chuck375:

quote:

Originally posted by Michael Robinson:
The Barnes .509 inch, 570 grain TSX, launched at a MV of 2,500 fps, and placed properly, in the boiler room, inside 50 yards, will knock a Cape buffalo off its feet. It's a sight to see. More than that I do not need.

But I would experiment with a bit lighter and faster, just for comparison purposes.

Mike I loaded about 18 rounds of 570g TSX's in my 500 Jeffery all using IMR 4350. The last three in front of 126g of IMR 4350 were all over 2500 fps. That will clear your sinuses! I'm sticking with my wimpy load of 103g H4895 pushing the 570g TSX at 2300 fps. I do believe you that your load will knock a buffalo off of it's feet

570 grains at 2,500 fps has done it every time for me. The buff generally do get back up, but on wobbly legs and not for long. The .500 knocks all the fight right out of them.

The recoil is not fun at the range, but with a well made rifle, it's manageable.

Of course, in the field, the recoil is never felt. All that's felt is the almost superhuman power of being able to wield and deliver .510 caliber, 2,500 fps lightning bolts. It's a quantitative difference, but it's a qualitative difference, too.

Well, 2500fps and a 570 bullet produce 7900ftlbs, around 8000 if the velocity creeps over 2500 a few fps.

My Nyati can't do that, so I guess I would be limited to 2350fps. Even that tends to rock me on the bench and knock me off my rests. Yes, it feels powerful.

The principle of reducing recoil is to use a lighter bullet and to use a faster burning powder. If this can be done without giving up terminal performance, that is first prize. Lower recoil makes for a better shooter.

Foremost one must have accuracy because that increases the most important job: Shot placement.

Secondly one must have consistency: The bullet must always work in the same manner, that is the only way on which it can be relied to do a job consistently.

Thirdly, the bullet must be reliable: If it is a solid, it must not break and, when it deforms, the deformation must add to the qualities that will allow deep, linear penetration. If it is an expanding bullet, it must give linear penetration, it must expand from as low a speed as possible and, when impacting hard, it must not turn to dust.

If we do not have accuracy, consistency and reliability, we have an also ran.

After these qualities, one can then consider ease of loading, care of the barrel and availability.

Gerard,
Thank you for your input. The explanations on the other thread on maximum velocity and bullet stability were especially eye opening.

As for recoil and fast powder, I've already switched to H322 because I couldn't get enough H4895 into the almost straight-walled case to reach 2600-2650fps with a 450grain GSC-HV.

I haven't decided what muzzle velocity to end up with. 2600fps would allow me to hunt almost identically to my wife with her 375 loaded down to 4000ftlbs. A GSC 265gn .375" HV at 2600fps does just under 4000ftlbs. The same velocity with a .510" 450 gn HV does 6750ftlbs. That would be fine for hunting since recoil is not noticed and barely remembered when shooting an animal, as Michael mentioned above. Alternatively, I could drop down to more traditional DG levels and aim for 2450fps and just under 6000ftlbs (5999 ). We'll see what works out in the lightweight little rifle (22" barrel, 9.5lbs scoped) But first I need to get back to the US and put a new stock on the Nyati.