The initial testing for my 720 grain LFNGC 458 bullet is complete. A forum member volunteered to develop load data and test accuracy and penetration. The following report is not recommended load data and may not be safe in your firearm. The accuracy and penetration tests will be complete in a few weeks.

Here is the report.

Today I fired three each of the three loads I wanted to try. Below, I report the raw data, the averages, and the extrapolated muzzle velocities. Speeds were recorded at 15 feet. The MV estimates were done with the Sierra Bullets “Infinity†ballistics program using the Hornady 500 gr RN bullet as a surrogate. The recorded speeds are remarkably consistent.

IMR-3031 51.0 gr
Shot 1 1676
Shot 2 1657
Shot 3 1661
Avg 1665
MV 1680

H4198
Shot 1 1754 51.0 gr
Shot 2 1741
Shot 3 1759
Avg 1751
MV 1765

IMR-4895 51.0 gr
Shot 1 1566
Shot 2 1558
Shot 3 1572
Avg 1565
MV 1580

I have attached a photograph of the heads of the fired cases. They are orientated in rows, top to bottom. As you can see, the primers in the top row (3031) are somewhat flattened, the middle row (4198) are flattened and slightly cratered, and the bottom row (4895) are nicely rounded. Based on this very limited test, I consider 1650 fps MV to be maximum for this bullet in my gun. On my next trial I will decrease the charge of IMR-3031 to 50.0 gr, reduce the charge of H4198 to 48.0 gr, and increase the charge of IMR-4895 to 52.0 gr. I will continue to use Federal Magnum Large Rifle primers. I’ll make a similar report then. It may be a week or two, but I’ll get to it as soon as possible.

Greetings,
very interesting.. but your picture isn't what you described, as there are no primer pictures.

I am interested in seeing your results

jeffe

Dang, that is a long bullet!! Is there any case left?

Sorry! Here are the cases.

Will these stabalize in a 1:14 twist? If they do at 100yards I will buy some.

thats .490 sd

put it next to a 45-70 case... it is almost the same length...

You stand a good chance of tumbling a bullet with a bullet that long, if it hits a Buffalos rib, longer bullets have been tried in the past with poor results on big tough animals. I think you can go to far in either direction.

The other thing is the .458 has sufferec historically from a lack of powder space and this one should about kill it off.

Just my opine and I don't even know what you intend to use such a bullet for, it may have a place in other diciplines, I don't know.

I like the nose profile and that it is gas checked. However, if it lost 2 of the 5 grease grooves and weighed 550gr max. Then I would consider getting a bullet mold, as I do my own casting.


As it is, 720gr, I see no usfull purpose for it.

If you want to shoot 700+gr bullets, .50cal is the min. bore size, .550 - .577 cal is even better.

Keith

quote:

Originally posted by ptaylor:
Will these stabalize in a 1:14 twist? If they do at 100yards I will buy some.

I will have the accuracy test results in a week or so. It should be stable at 100 yards. I've shot many 600 grain Barnes Originals with good accuracy and they are almost as long as the 720 cast.

Still interested in testing some for the 458 SOCOM. Need to be .459-.460 though, my barrel is a little on the loose side.

I bet it makes a great deer flattener.

quote:

Originally posted by 500grains:
I bet it makes a great deer flattener.

even if it hits sideways...

lemme think a minute...the 45-120 is 3.25" long, and in a single shot the throat could be cut to allow length of maybe 4" to 4.25" OAL. That would leave enough room for a LOT of powder. Personally, I would think 458 bullets max out at about 600gr for usefulness.

JMHO

Rich
DRSS

quote:

Personally, I would think 458 bullets max out at about 600gr for usefulness.

indeed but like many things here it is for fun and preference...it would be fun to touch a few off

We see the primers but what do the cases look like just forward of the rim? Can we get a shot of that please?

Here are the preliminary accuracy test results. These were test development loads and not accuracy loads, so they should get a little tighter. 1.33" at 50 yards. Not bad for test loads.

Those look quite close to the ones I throw out of a mould for a 460W, I leave them un gas checked and use a soft mix for my 45-120, they come out at 715 grains and with a 112 grains of FFG ounches clean thru pigs and black bears, bet these would work great also.

I think I see the perfect cast projectile for my 2008 project, the 458 Gibbs. When Dave Manson made me the reamers for my 550 Gibbs, we envisioned a family of four super magnums, 550/510/475/458. Now I know where to shop for bullets.

Rich
DRSS