2400 in the .458WM

[RangerBob]

I've been lurking here for some time, but this is my first post. I know some of you guys from the old Sixgunner Board, the Gord Board, and the Leverguns Board. Since I do most of my shooting with cast bullets, I thought I'd better settle in here for a while.

I have been testing cast loads in the .458WM for a couple years. I think I'm up to nearly 40 loads.

I got a 400grHB recently, and it's been a troublesome bullet. 50gr of 4895 and 50gr of 3031 where awfull. I could barely keep bullets on a sheet of paper at 50yds. The bullet seemed to want to move slower.

Yesterday I tried 42gr of 3031 and got better results.

But the load that scared me was 27gr of 2400. I have never used a pistol powder in such a large rifle case. You read stories that this may or may not be a safe practice. This is a published Alliant load, but I still had reservations.

Well, the groups where really, really good. 50yd groups were around 1.5", but could get 4 shots touching in less than 7/8". That's about as good as I've been able to do with cast bullets in this rifle.

Can anyone confirm that this is a safe load? Is this type of performance expected? Thanks for any information that might settle my fears and let me enjoy this load.

RangerBob.

[felix]

Bob, you are asking the correct question(s). In general, the odds of an unsafe condition gets higher as the amount of powder in a case falls from full capacity. This creates the condition where the primer ignites more powder than at the beginning of the powder column. If all of the powder is flashed at once, then that's OK too but only when the case volume is miniscule. Anything in between is dangerous. However, some powders, like 2400, seem to behave fairly well with severely reduced loads. Not worth a chance in my opinion. Fill the case up with shotgun plastic called PSB to the point of very slight compression. ... felix

[RangerBob]

Felix,

Do you mean that I can get similar performance, and increased safety, by using a shot buffer between the powder and the bullet?

The reason I ask, is that I've heard that 2400 does not require a filler. I'm a little leary of fillers . . . but I may get over it.

RangerBob

[felix]

Bob, PSB fills the airspace completely and almost melts completely when shot. Therefore, PSB is not a threat of becoming a "secondary" bullet. The airspace should be filled to prevent the formulation of obnoxious wave forms which can pack enough energy to ignite the powder in an instaneous fashion. If you like 27 grains of 2400, try 23 topped off with the PSB for starters, and work up to where the groups appear identical in shape and placement to the 27 grain load. ... felix

[Harry O]

You may want to read this. I have no personal experience with what you are asking and don't know the person writing this, but it sounds very much like what you are talking about.

http://www.reloadammo.com/liteload.htm

[felix]

"SEE" IS A REAL HAPPENING INDEED! Even if they produced it in the labs they are not going to talk about it. Yes, they have produced it, and I have zero doubt about that. ... felix

[buck1]

Years ago, my dad made some light loads for a 458 w/ 2400 W/O a filler. -IF- I recall, it was 22 gr 2400 under a cast bullet that I cant recall.
He had to point the rifle skyward before each shot, then slowly lower it to position the powder by the primer.
As I recall it was a tac driver load.
BUT he stoped when he had strange pressure sighns. I dont recall what they were as this was 20+ years ago but something spooked him away from it all together.
Not much help ,but I thought it may help just a little. ................BUCK

[RangerBob]

Buck1,

I did take the precaution of tipping the rifle muzzle skyward between shots. And like you noticed, the load was very accurate.

I went back and looked at the fired cases. I think I'm seeing some variation in primer condition. Some just look like they took higher pressure than others. This could be a bad sign.

BTW - has anyone tried 5744 for this application? Do you recommend it?

Bob.

[Bass Ackward]

I have a 7X57AI that I won't shoot reduced cast loads in for this reason. I have had SEE events along with their preliminary warning sign, the collapsed case enough times to back off.

I read Norm Johnson response whom I have great respect for, but I disagree with his 38 Special and Bullseye analogy. The flash hole for a primer is in the center of a case. The larger the diameter of a case design (caliber) that you go, the farther that a small charge of any speed powder is away from the venturie effect of the flame. If you ignite the front part of the column and the wave starts expanding back, where does it go? But there have been unexpalined blow up with that caliber too that have just been written off as double charging. Could be? MAybe not too. Who knows?

Case volume in my mind is not the key so much as case design. A straight sided case design with or without a sharp shoulder allows for the most opportunity as I see it, assuming that the charge creates a certain amount of space. The Ackley theory of sharp shoulders is to increase powder burn rates. And based on my experience with his case designs in multiple calibers, this is true.

A tapered case body design (30-06) allows gravity to work for you pulling the powder back towards the flame. So space is filled up with metal narrowing the chance for frontal ignition. So reduced charges of even slow powder would be less of a problem in that case design as compared to a 308 which would allow powder to .... hide from the venturie flame so to speak. Igniteting from the deflection off the shoulder or the base of the bullet from the front of the column. A 30-06 is not immune from the phenom by any stretch, just that it improves your odds. This is why I have always favored the 06 family for cast over 308 designs unless the odds are for fuller case charges like the 358 Win. That is the only caliber you will hear me tout for cast in the 308 line.

[Char-Gar]

Humm.. I was under the impression that PBS didn't melt, but was just blown out the muzzle. I use quite a bit of it, and several times other shooters asked If Iwas using black powder, due to the white cloud when I fired. It is not the quality of stuff in the air, like black, but you can see it. You shure can smell it in the air after you touched off a round.

[felix]

PSB does not entirely melt into liquid, but softens to continually change shape. Much like angled case walls helps to change a wave front configuration. Anything box-like is what waves like to bounce off of to maintain their shape, and that's the problem. Irregular shapes tend to bust up waves from combining into a large one that can cause the powder to go haywire. (Yes, the standard 2.7 BE center-fire load under the flush wadcutter has been know to go south in the Smith model 52; the load was changed to 2.9, at least in the Hartford CT pistol circuit before I left in 76.) ... felix

[waksupi]

The Lyman Cast Bullet book recommends using a tuft of dacron over the 2400.

[RangerBob]

Waksupi,

I have the Lyman Cast Bullet Handbook, Third Edition.

I went back and checked, and the book does recommend dacron filler for 2400 loads in 45-70. But my book doesn't mention using dacron in the .458WM. It may be an oversight. I can't see why dacron would be a good idea in 45-70 but not needed in a similar, but larger case.

Anyone have much experience with 5744 in this kind of application?

[Nazgul]

I have fired many rounds in a 459 WM using 5744. Data is available from Accurate website. They have been accurate and mild shooting using the 405gr Saeco pointed cast bullet. No filler is required with 5744.

I tried IMR4895 at reduced loads using the same bullet, something on the order of 40 gr in a 458. Got very spotty ignition. Used a filler of dacron and the ignition problems went away.