I'm not going to try anything now, I'm just trying to understand this. So please spare me the hysterical cries about safety, and reloading manuals.

Here is the deal. I 'm loading for a .458 win mag. I'm loading to practice and hunt local deer next season. I have a few loads, but not really what I want.
All of my previous experience with my competition stuff, loads have given me what I want in short order. So I have had no interest in look at anything else.
But with the .458 I want a 350gr in the 2200fps range. All of the load manuals get a velocity of 2500 or 2600 fps. I have to assume these powders pretty much fill the case and get good accuracy. But I want a bit less velocity. I like the option of going hotter if I want to later, but not now. Now I want to ease into it. I also don't want a velocity of 1400fps which is what most of the reduced loads end up at. That is ridiculously slow, and not useful to me.
So one choice would be a small amount of a faster powder. But a pinch of a fast powder rolling around a big case would probably give hang fires and poor consistency. This seems like a bad and dangerous way to go.

??? The other way is to use a slower powder which would not have the opportunity to build pressure. I am guessing it would get the case full, without ever building the slow high pressure a slow powder is capable of. A slow powder in a case like the 300win mag will build and push a smaller bullet fast. No so in a straight wall cartridge.

Is this about right, or am I just completely missing something.
Also, is there a computer program or something already available which gives an idea what to expect with new loads. Or a website or something.
It really does seem it should be a fairly straight forward thing to just go to a slower powder to reduce velocity a bit and still keep the case full.

Basically correct, though a pinch of fast powder (a pistol powder like Unique is what is typically used) can be more consistent than what you think.
Using a full case of a too slow powder can actually cause more mis-fires and hang-fires than a fast powder if the powder doesn't produce enough pressure to burn properly. Something like US869 (a 50 BMG powder) in the 458 Win Mag may not work at all.
You can also simply use a reduced load of the faster rifle powders used for normal loads in the loading manuals. For the 458 Win Mag that would be 4198 or Reloader7. You don't need to go much below the standard starting loads (2400 fps) to get 2200 fps; and may get the most consistent, accurate load of any of the methods.

QuickLoad is one computer program that tries to predict pressures and velocities of given loads. There were several others, but AccuLoad's website seems to have been taken down, and the Powley Computer isn't designed for reduced loads.

The burning rate charts show Power Pistol [bullseye 84] as faster than AA#5.

But when I experiment with overloading a 9mm pistol, looking for pressure sign, I find that AA#5 is much faster at high pressure.

So the burning rate must be a function of more than one test variable.

I see I had a lot of this backwards. It's probably good for me to ask questions. I would have been concerned that reducing loads like RE7 down below what is listed on the manual would cause problems. I guess I was thinking there would be a volume issue, and therefore a consistency problem. I don't know where I got that idea.
And the idea of very slow powders having the hang fires is something I never knew about. Once again my limited experience showing itself. Thank for the input.

quote:

Originally posted by CMcDermott:
Basically correct, though a pinch of fast powder (a pistol powder like Unique is what is typically used) can be more consistent than what you think.
Using a full case of a too slow powder can actually cause more mis-fires and hang-fires than a fast powder if the powder doesn't produce enough pressure to burn properly. Something like US869 (a 50 BMG powder) in the 458 Win Mag may not work at all.
You can also simply use a reduced load of the faster rifle powders used for normal loads in the loading manuals. For the 458 Win Mag that would be 4198 or Reloader7. You don't need to go much below the standard starting loads (2400 fps) to get 2200 fps; and may get the most consistent, accurate load of any of the methods.

QuickLoad is one computer program that tries to predict pressures and velocities of given loads. There were several others, but AccuLoad's website seems to have been taken down, and the Powley Computer isn't designed for reduced loads.

Frank, just curious why you want to slow it down from 2500/2600 to 2200

quote:

Originally posted by frank4570:

But with the .458 I want a 350gr in the 2200fps range. All of the load manuals get a velocity of 2500 or 2600 fps. I have to assume...

No they don't. Metallic Cartridge Reloading 3rd Edition lists a max charge, 74.0gr Varget yields 2233fps for 350gr jacketed bullet. You could reduce that charge by 10% if you wish and go even slower. Also, Accurate Arms XMP5744 is a good powder for reduced loads. 50gr might get you in the ballpark.

I don't own a 458, but I fire 365gr homecast lead bullets in my 416 Rem mag for practice and deer hunting. You could too.

I would suggest that you find a load using SR4759.
same as my handle. The powder is about the same burning rate as IMR 4227 but the granules are very large and bulky and take up a lot of room in the case. It should be nearly a case full for the combo and spped you are interested in.
I use this powder with 1/2 case full loads of about 23 to 25 grains in the 40-65 and 45-70 BPCR rifles with heavy 400 & 500 grain bullets. I get groups right at the limit of my vision with iron sights of about 1.0" to 1.5" on a good day.

66.5gr-XMR2015, 66gr-H4198, 70gr-Accurate2230, 51gr-XMP5744, 64gr-RL7, 45.5gr-SR4759. .The SR4759 may be a little on the low side. there should room to work up.Hope this helps! Be cautious! roger

That kind of speed is not useful to me right now. I haven't been shooting in a while so I need to work up. Also the greater speed will only tear up meat on a deer, nothing else.

quote:

Originally posted by GSP7:
Frank, just curious why you want to slow it down from 2500/2600 to 2200

Oops, my mistake. I'm mixing up 300gr bullets and 350 gr bullets.
I want the vel of the 350s in the range of about 2000 to 2100. After I am comfortable with the recoil I will look at bullet drop over distance and impact results. But I think 2100fps with the 350s will work well.

quote:

Originally posted by onefunzr2:

quote:

Originally posted by frank4570:

But with the .458 I want a 350gr in the 2200fps range. All of the load manuals get a velocity of 2500 or 2600 fps. I have to assume...

No they don't. Metallic Cartridge Reloading 3rd Edition lists a max charge, 74.0gr Varget yields 2233fps for 350gr jacketed bullet. You could reduce that charge by 10% if you wish and go even slower. Also, Accurate Arms XMP5744 is a good powder for reduced loads. 50gr might get you in the ballpark.

I don't own a 458, but I fire 365gr homecast lead bullets in my 416 Rem mag for practice and deer hunting. You could too.

quote:

The powder is about the same burning rate as IMR 4227 but the granules are very large and bulky and take up a lot of room in the case.

I did not know about SR4759 bulkiness. It has been suggested to me for my purpose too. Shooting a rifle at reduced speeds can make it real sweet to shoot! (I had to do that when I first started out with my 44mag revolver).

4759

My manual does not list a load for the 350gr bullet. But in the 400gr bullet top speed is 1445fps. That's awfully slow.They are very comfortable to shoot, but very slow.
I don't think I will get anywhere near 2000fps with a 350gr bullet.

Ok. So is there any reason to believe a lighter charge of RE7 would be dangerous? I have heard good things about RE7 and I have some. My manual lists 69gr as a starting point at 2186fps. I'm thinking 60gr, and work up to dial in accuracy.
I could use it for groundhogs if I can get the accuracy.
I have no idea what the velocity will be. I don't really care at this point. I want accuracy and comfortable recoil.
Oh, I weighed my rifle. It's 9 pounds, not 10 pounds. Nice to carry though.

Manual loads for SR4759 are typically set up as reduced pressure and velocity loads.
However if you look at IMR data for the powder it lists 44.5 grains as a max for a 500 grain bullet at 1645 FPS. A 350 grn bullet would be a good bit faster with the same load.

SR4759 is not often listed for full velocity full pressure loads because it runs out of SPACE first.
Top velocity loads for the same burning rate are usually given for 4227 because it is the same burning rate and is much more dense.

quote:

with the .458 I want a 350gr in the 2200fps range.

Direct from Hodgdon's website.....
71 grains of "Benchmark" will get a 350 grain bullet moving 2250 FPS

Frank,

You should contact the powder manufacturer and ask their advice. Accurate Powders has a place on their site to ask a question, as I remember. Very helpful, no guess work.

Give it a try, I dont' think you will be disappointed.

You could start with a max. .45/70/350 load of IMR 3031 for the .45/70 Ruger No. 1 pressure level, and add however much more is needed for 2200 FPS in the .458 case. I'd suspect somewhere around 63-65 grains of 3031 would do the trick.

I found that 60 grains of RE7 in my Ruger No.1 45/70 gave 2270 FPS with the 400-grain Barnes original semispitzer. This load is close to 50KPSI, and gives 58 foot-pounds of free recoil. It was a safe load.