Why powder coating my .45-70 cast bullets might not ever make precise long distance ammunition

[Mitty38]

If I may interject something.
I know the PO is trying not to pound cast or cast the chamber.
Now what Ian said is very important. Enveloping what has been discovered to be our holy Grail.
Now mind you, I never went for the kind of velocity or accuracy you are reaching for. I am just a hobbie, and hunting shooter.

However I have been able to accomplish an accurate load for my 450BM starting with a bullet that cast .002 over bore size.
I was able to size down to bore size. Powder Coat, then size down again. Accomplishing bore size bullet. Built the best load I could. 2moa.
Then tried .001 over bore. Got me to 1.25 moa.
By enlarging the sizer then buying a second one, which I enlarged also. I was able to go up in size .001 at a time . Repeating this over and over.
Finally at .003 over, I got under 1moa. Enlarged the sizer .001 more to .004 over,(with the help of Powder Coat) accuracy went way down.
So bought a .003 over, sizer since I had ruined my other one, hollering it out to .004 over. Backed my size down to .003 over. Got a Good consistent load. 1 moa.
Now It would have been a lot easier to figure out if I had casted. But I still got it.

Now if I was going for better then 1MOA.
I would pound cast it and have these fellows help me figure out the right Metplate and bullet design.

Don't know if this helps but thought I might interject.

 

[Ian]

I know the PO is trying not to pound cast or cast the chamber.

Yep, and it's one of many reasons why:

Why powder coating my .45-70 cast bullets might not ever make precise long distance ammunition​

 

[JimGnitecki]

I could contribute a lot more here but it's not feasible to help someone whose mind is already made up incorrectly about so many things and doesn't know what he doesn't know.

I'll reiterate some high points.

Make a good bullet. If you powder coat, avoid flat-base bullet designs and don't make them hard or too big on the bands. Fit the bullet to the throat, not the bore or groove. Let the bullet jump a little to the ball seat. Case neck tension uniformity is critical to external ballistic consistency. Everything you do at the loading bench that affects the bullet's travel in the first half inch out of the case will make or break what happens when the bullet leaves the muzzle. Every one of these statements has a very involved "how" and "why", and you need to understand both for each correctly in your mind before you can pull it off at the loading or casting bench.

Thank-you, Ian. I'm sorry I did not reply earlier, but our son has been visiting us this Christmas and so I have spent most of my time with him, and not spent any time on the forums. I realize I am a newbie at casting bullets and optimizing for them versus jacketed bullets. But I do well with jacketed: 0.25 MOA with my modern 6.5 Creedmoor rifle, so it's not like I am unskilled. But after months of work with cast bullets, I admit to being somewhat discouraged, and I do question whether powder coating can ever produce the accuracy I want.

To check and make sure that the issues are NOT the rifle or me, I have bought some 350g copper plated production bullets with a Spitzer ogive and good BC, which will give me more distance before they drop below supersonic speed. That will allow me to test them at ranges perhaps as high as 400 or more yards before their speed drops too low to be detected by my new just-arrived Shotmarker electronic target system (The system needs a bullet to be supersonic in order to detect it).

If those plate production bullets shoot well, I'll know it's not the rifle or me, it's the cast bullets. If they shoot no better than my cast bullets, then I'll know it's my handloading skills that need more refinement.

Jim G

 

[JimGnitecki]

If I may interject something.
I know the PO is trying not to pound cast or cast the chamber.
Now what Ian said is very important. Enveloping what has been discovered to be our holy Grail.
Now mind you, I never went for the kind of velocity or accuracy you are reaching for. I am just a hobbie, and hunting shooter.

However I have been able to accomplish an accurate load for my 450BM starting with a bullet that cast .002 over bore size.
I was able to size down to bore size. Powder Coat, then size down again. Accomplishing bore size bullet. Built the best load I could. 2moa.
Then tried .001 over bore. Got me to 1.25 moa.
By enlarging the sizer then buying a second one, which I enlarged also. I was able to go up in size .001 at a time . Repeating this over and over.
Finally at .003 over, I got under 1moa. Enlarged the sizer .001 more to .004 over,(with the help of Powder Coat) accuracy went way down.
So bought a .003 over, sizer since I had ruined my other one, hollering it out to .004 over. Backed my size down to .003 over. Got a Good consistent load. 1 moa.
Now It would have been a lot easier to figure out if I had casted. But I still got it.

Now if I was going for better then 1MOA.
I would pound cast it and have these fellows help me figure out the right Metplate and bullet design.

Don't know if this helps but thought I might interject.

Yes, it DOES help! Your bullet diameter testing echoes what I have done. Same basic result: .058" too small in my rifle, .059" a bit betetr than .060" but very close. But even a small powder coat thickness variance wreaks havoc on BTO, so yeah, fitting to the throat becomes a difficult, maybe impossible, mission with powder coating.

Jim G

 

[Bret4207]

I hjave fired these bullets at .458", .459", and .460" in a barrel whose groove diameter is .4563". That means I have covered .0017" to .0037" of bullet to groove interference. That is plenty of range to have tried don't you think? No way would I wnat to try more than .0037" of interference fit!

And although I TRAGETED getting BHN = 21 with one alloy batch, depsite careful verified calculation and actual preparation, that batch never got anywhere near BHN = 21. It got to BHN = 16 very quickly (within hours), but STAYED there, even as recently as 3 weeks after being cast. I have been checking the hardness with my Lee Hardness Tool regularly, and it has not changed from BHN = 16. 16 should not be too hard for a 28,000 psi load.

Jim G

Sorry I've been gone, dog ate my power cord. Any time you size a bullet you distorting it. the more you size, the more distortion, AND chance of getting the bullet off center among other things. As far as BHN, it's not so much a matter of being "too hard for a 28,000 psi load." It's more a matter of you not being able to separate Bhn/pressure from your thinking on this issue. Bhn is basically irrelevant in your case. Pure lead would likely work fine IF you get the whole fit process working for you. Sounds to me like you have your mind made up, no doubt due in part to Lees "formula". It doesn't work, forget it. And to answer for Ian, a gas check makes things exponentially easier because it strengthens the base and provides a more uniform surface. I'd bet $ it would work in your case too. But you can do this with PB, just gotta get the pieces of FIT
figured out.

ETA- Ref your post #43- A copper plated commercially cast bullet? If so, and putting a rather fine point on it, why do you think commercially cast is going to provide a benchmark when commercially cast is known for not shooting for crap? If you need a benchmark, use jacketed.

 

[Ian]

Bevel base or gas check base without checks, powder coated, are far better than flat base bullets in my experience. Recovered bullets show gas cutting and irregular trailing edge failure on the rear band if there isn't some place for the displaced lead from the land engraves to go. Gas checks solve all those problems.

 

[Rick]

ETA- Ref your post #43- A copper plated commercially cast bullet? If so, and putting a rather fine point on it, why do you think commercially cast is going to provide a benchmark when commercially cast is known for not shooting for crap? If you need a benchmark, use jacketed.

Agree, if I couldn't do any better than commercial cast, plated or not I would quit casting.

 

[Finster101]

Were I going for precision bullets I would not be using "shake and bake" to powder coat. I believe you would get a much thinner and even coat if you invested in an ES gun and sprayed the bullets. I use both methods depending on bullet use.

 

[Ian]

Were I going for precision bullets I would not be using "shake and bake" to powder coat. I believe you would get a much thinner and even coat if you invested in an ES gun and sprayed the bullets. I use both methods depending on bullet use.

Shook and baked, .308 at full jacketed velocity :


Swedish Mauser at 2400 fps:


I could go on.

 

[fiver]

you gotta be not beating up the bullets when you shake them.
if your getting unevenness in your coating,,,, that's on you,, like i said you are your own customer.
try measuring out the powder, the number of bullets, and your beads.
the beads ain't just there so you got something to look at while your sorting stuff out.

 

[Bret4207]

Jim, I'm not trying to beat up on you guy, but I got thinking about this last night. Would I be wrong is thinking that, with your engineering background, you are used to dealing with absolutes? With formulas that provide the right answers every time? If so, that might be part of the problem. As I mentioned before, Lees "formula" for "required Bhn" at a given pressure is crap! Just as thinking Bhn is the big determining factor in successful cast shooting is crap. It simply doesn't work that way. You start with static fit, eg- getting the case centered in the chamber and bullet centered in the case, using an appropriate alloy NO MATTER WHAT THE Bhn IS! The alloy is more important than Bhn, if that makes any sense, but it's not a top 5 major part of fit. Then you have dynamic fit, eg- everything that happens once the firing pin hits the primer. It might help to think of this in thousandths of a second, or less!, as the bullet starts responding to pressure. The base is changing before the bullet is even moving. As the pressure builds it changes more and more until it's into the rifling proper and even then, depending on where your peak pressure comes in, it can still be changing. You'll note the name of this board is The ART and Science of Bullet Casting. I wish it was just a science!!! It's that ART part that can drive you nuts! IME it almost always takes a little outside the box thinking to get a really good load. And then if you change one part of that load, say the primer or brass, you may well find yourself back at square one. It's just the way it is. We've seen hundreds of guys fretting over Bhn, I was one of them! Eventually they either figured out Bhn isn't the answer, or they accepeted 4" groups instead of 1.25" groups or they gave up on cast.

Again, no offense intended, but there aren't a lot of absolutes in this game.

ETA- You also have to accept that not all barrels, even from the same manufactuer, are cast friendly. You seem to have a tight barrel, you dont want to mess with the scope to run a slug through it to see if it's full of tight and loose spots and I'm not sure how many rounds you have through it. Some barrels do far better after several hundred rounds (jaceketed) have been run through them. Were it me, I'd be slugging that barrel so I could get an idea of what the interior feels like. You may have a tight breech end and loose muzzle end!

 

[JimGnitecki]

. ..

ETA- Ref your post #43- A copper plated commercially cast bullet? If so, and putting a rather fine point on it, why do you think commercially cast is going to provide a benchmark when commercially cast is known for not shooting for crap? If you need a benchmark, use jacketed.

I went plated cast versus jacketed because I think it is acombiantion of my casting, and the thickness variance on powdercoating, that is creating much of the problem for me. Ntext step if the plated castd on't shoot is a jacketed test.

Jim G

 

[JimGnitecki]

Bevel base or gas check base without checks, powder coated, are far better than flat base bullets in my experience. Recovered bullets show gas cutting and irregular trailing edge failure on the rear band if there isn't some place for the displaced lead from the land engraves to go. Gas checks solve all those problems.

I have heard conflicting storied about the merits of flat base and bevel base bullets. U suppose a person has to try both in EACH rifle. And, I was hoping to avoid gas check, but maybe I cannot if I stick with the cast bullets, especially since I want moderately high velocities.

Jim G

 

[fiver]

yeah.
i have problems with anything much over 1200 or so with plain base bullets in the longer straight cases.
i don't know why, i can run plain base bullets in my pistol caliber rifles up bout as high as i care to.

the 375 win and 45-70 just don't want to cooperate without a gas check though.
with one i can treat them the same as i do the smaller pistol cases, and run them up even beyond the smaller case size velocities if i want to take the recoil.
the 45-70 with a 425gr. bullet starts getting not fun at about 1600 fps. BTW.

 

[Brad]

If I wanted to shoot accurately at longer ranges with a 45-70 I would not be powder coating.
I would get a few books by Paul Matthews on shooting black powder in cartridges and follow what he says. Talk with the BPCR guys, they do a pretty damned good job with black powder and cast bullets at longer ranges.

 

[JimGnitecki]

Were I going for precision bullets I would not be using "shake and bake" to powder coat. I believe you would get a much thinner and even coat if you invested in an ES gun and sprayed the bullets. I use both methods depending on bullet use.

if you think about it, you'll see that It's impossible to spray powder evenly on bullets unless you do them ONE at a time, with the bullet rotating on a fixed speed platter, for a precisely timed consistent period of time for each bullet. That of course is impractical. When you try to spray an ARRAY of bullets, consistent thickness is impossible. if you need an absolutely consistent thickness, which you DO on a curved bullet ogive, powder coating is not the way to get it in a hobby setting.

Jim G

 

[JimGnitecki]

If I wanted to shoot accurately at longer ranges with a 45-70 I would not be powder coating.
I would get a few books by Paul Matthews on shooting black powder in cartridges and follow what he says. Talk with the BPCR guys, they do a pretty damned good job with black powder and cast bullets at longer ranges.

I have Paul Matthews' book. He shot both black powder and smokeless. However, his focus was on hunting, and at short ranges on top of that. So, to him, penetration, mushrooming, and energy content were the important points, especially when he went after wild pigs. Interrestingly, he and i reached the same bullet weight and velocity conclusions: moderate bullet weight and lots of velocity. And yes, he depended on gas checks and gooey lubricants.

The black pwoder guys all shoot heavy bullets at speeds clustered around the transonic speed range, and thye put up with the rainbow trajectories and transonic effects. I want more velocity and less trajectory.

Jim G

 

[Cadillac Jeff]

What Brad said. + not with a Lee bullet either

 

[JimGnitecki]

I tested those 350g production plated cast bullets today at up to 1750 fps. Very promisiing results for a brief and very limited trial experiment with just 3 different powder loads. After I analyze my rnage data, I'll post about those bullets in a new separate thread.

For now, I am pausing all my bullet casting and powder coating self-flagellation, and will explore what this plated bullet, desgined for a different purpose, might be able to do in the Pedersoli.

Jim G

 

[Brad]

Hate to tell you this but you can’t make a 45-70 shoot flat to 300 yards. Been then, tried that.
Recoil will eat you alive and you still have a rainbow trajectory. Might reduce drop at 300 by 4-5 inches but it still won’t be better than a 30-30.
Learn to shoot well and make good ammo and ignore the trajectory. If you know the range and the ballistics you can adjust the sight. That is why the sights are adjustable.