Rifle Accuracy/PC/Hardness

[Ian]

I can't drink (allergy plus meds). Did bring plenty of peanuts though.

 

[462]

Wow, over a page of posts and not one of them showed any amount of arrogance or condescension, and nobody was offended neither. Tell me this isn't a place full of friendly friends.

 

[Ian]

LRoss's mess of beautiful panfish made me hungry. We never let a thread go to waste around here, do we?

 

[Mitty38]

Emmett and others who subscribe to the theory of loading so that peak pressure is just below the alloys ultimate compressive strength so that it doesn't distort, let me ask you this: What happens to your .311" bullet that is fired into a .300 x .308" barrel?

Bullet distorted, didn't it?

How much pressure did it take to do that?

What else went wrong with your bullet in the first half inch of movement, long before peak chamber pressure was even reached?

Do not take a whole lot of stock in the"if low enough pressure it going to spring back to shape when it leaves the barrel" theory.
But....
My goal is to try not to mash it too much before it gets into the throat. Just enough to insure a good seal to start.Let the distortion be mostly controlled by the throat and barrel where it is more consistent.
I believe by going that route I can better achieve this, especially since I am less experienced with different powders the you fellows. I believe testing hardness and trying to match or slightly go over the alloys comprehensive strength, helps me get there easier.
I think the powder coat prevents some malleability. Thus I push a little harder with it. Course I am learning and can be wrong. Respectfully listening.

Beer and catfish sound better. However I will not waist a good size pan fish.

I can only have a maximum 32 OZ of beer in one day, about once a week or it messes with my meds.

 

[Ian]

Just throwing things out there to make the grey matter stir a little. I ran the Lee tests with Lee moulds and had excellent results, FWIW but I think the actual pressure versus alloy strength had little to do with the success, but if you adhere to those guidelines it works nonetheless. When you look at what velocities are achieved by Lee's method you'll see that they tend to be in the "easy" accuracy zone anyway.

 

[Mitty38]

Just throwing things out there to make the grey matter stir a little. I ran the Lee tests with Lee moulds and had excellent results, FWIW but I think the actual pressure versus alloy strength had little to do with the success, but if you adhere to those guidelines it works nonetheless. When you look at what velocities are achieved by Lee's method you'll see that they tend to be in the "easy" accuracy zone anyway.

Can not learn without input. Can gain input if do not listen. Can not listen if no one speaks.
Input is always appreciated.
Thanks

One thing that does stun me with the pistol 50 yard loads. In .357 range. Which is all I have done with this so far.
Now mind you I've not been able to complete delving into this. But so far it seams add powder coat to the same bullet, size it the same size, and it seams to need a faster kick in the butt to obtain the same accuracy as the traditional lubes.

 

[fiver]

that might just be because the bullet is further along in the when time because of the slippery, and all you did with the faster powder was put it back where it was without the coating.......... [there ya go if you want to think about things]

 

[462]

I don't powder coat (yet, anyway) so please excuse my ignorance, but does that mean with handguns as Emmett has been experiementing, powder coating doesn't have any real advantage over traditional/conventional lube?

 

[fiver]

well advantage or not it's a different system and needs to be treated as such.
from what I make of it the better advantages of it are.
the bullets are clean.
the coat is temp insensitive.
it allows you greater latitude in alloy selection [usually a softer rather than harder alloy is an advantage]
the only real CORE issues to deal with is powder fouling so old barrel first shots are generally in the group.


a neither here nor there thing is it generally likes to be sized closer to jacketed than cast [unless your dealing with some ridiculously oversized mil-surp throat]
but in say a newer 308 rifle I'd be inclined to size to 309 rather than 310 like I would with cast.

 

[Brad]

To me it has the big advantage of being far cleaner. No greasy residue all over everything. Bullets never stick together. No lube in dies or on fired cases.

 

[462]

Thanks, gents.

 

[Mitty38]

I don't powder coat (yet, anyway) so please excuse my ignorance, but does that mean with handguns as Emmett has been experiementing, powder coating doesn't have any real advantage over traditional/conventional lube?

Well it did bring a small casting 30 caliber,bore rider bullet. From a mould that was gave up on,to a size big enough in my 06 that I could size it to the throat and the nose fit better. Turned it into a tack driver. I would say that is a pretty good advantage.

 

[462]

My question pertained to handguns, or that was the way it was intended.

There you go, anyway!

 

[Joshua]

Well it did bring a small casting 30 caliber,bore rider bullet. From a mould that was gave up on,to a size big enough in my 06 that I could size it to the throat and the nose fit better. Turned it into a tack driver. I would say that is a pretty good advantage.

I’m the guy that gave up on that mold.

That episode convinced me to try powder coating. I can blame Mitty. I copied what he did with another mold that was casting undersized, I increased the bullet size with PC.

For pistol bullets I believe I will continue to tumble lube for my low pressure cartridges. Also low node plain base rifle. It is just so easy to coat a large amount of bullets quickly.

My oven is small. My high pressure problem child the 40 Smith & Wesson Shield gets PC’d bullets. PC works best in that application.

I’m also using PC on bullets that I want to go fast out of my rifles.

For pistol bullets it boils down to what is best for the application and convenience. I can’t see a difference in accuracy between the two.

I can deal with sticky bullets for now.

Someday if I get a bigger oven, and install a ventilation system, I might powder coat everything, maybe.

Josh

 

[Ian]

PC doesn't melt out of the grooves of bullets in the magazine of the pistol in the map pocket of my truck at 165⁰ in July.

Good conversation BTW.

 

[Mitty38]

Don't tell no one but I cast way too hot and was erratic, when I first started casting.
I frosted and rounded the lube groves on about 200 bullets.
I dropped the plans to pan lube.
Powder coated a few of them kinda thick and sized. I actually got some fairly good shooters out of them, I would say as good as box fmj ammo. So PC'd and loaded up the rest.
Saved me from remelting and starting over again.

 

[Joshua]

Oh my gosh! This party has gone downhill! Now we are talking about the weather!!!

We hit 101 degrees Fahrenheit in 1981!

We average 80 degree days in August. Our hottest month.

We rarely have snow stick for more than a few days below 500 feet.

Not really defending lube. Just saying temperature isn’t as big an issue in my neck of the woods. The vast majority of my shooting weather is going to range between 40 and 80 degrees Fahrenheit.

And, my hunting bullets will be powder coated.

 

[Mitty38]

Minerva Ohio
w showers

32
°F | °C
Precipitation: 100%
Humidity: 92%
Wind: 10 mph
Temperature
Precipitation
Wind


But don't those little powder coat jackets keep your bullets from catching a winter chill?
Oh and if your hunting you no longer have to worry about the animal getting lead poisoning when you miss your mark and wing it, then it limps away! LOL

 

[Bret4207]

There is so much to this game that I find it mind boggling. Just take the bullet, PC or traditionally lubed, sitting in the chamber and smack the primer. Just a discussion on the theories, and they are pretty much theories, on what happens in the first 1/2-1" of movement could take up a dozen pages and we'd still miss things. That's what I love/hate about this game- it never gets down to an absolute science, no "this is the only way in every gun" type of thing. Change one thing, bullet, alloy, seating depth, etc, and everything can change for good or bad or not at all. I've put myself to sleep many nights running the variables through my head, and I;m not even looking to push anything out the barrel past 21-2200 fps! It's both maddening and fascinating.

 

[popper]

Reading an army doc from the 90's about rifle bullet performance. Analysis of a lead slug (30 cal) with 500# force on the base, which generated 300# force radially on the bbl. Measured data with strain gauges. Another analysis, slug is composed of disks. Front disks don't move (mass) and back ones have the pressure applied to cause radial growth and pressure. Process moves to the front until the slug is moving. Harder alloys give greater radial pressure/friction! Once the slug starts moving, radial pressure drops to 50# range, about the same as my calculations for rifling force.
Ok, first is like swaging. Hopefully pressure expands the case and base. Then it expands to fill the throat and then sized down by the bore. That really work softens the alloy. The softer blob (hopefully little distortion) goes down the barrel. Ian's 'fit'!
I first started casting 40SW & #2, LLA then went to PC and much softer alloy. PB + LLA/BLL tumble lubed tends to blow off with hot loads, better with GC. Next was RD 170 (GC & PB) for 30/30. Pretty much same results but COWW (~50/50 HT) type alloy. Then 308W PC and 4% Sb + Cu HT PC alloy that works great. My 'formula' is soft as your desired accuracy will allow. Cu and As really do help. I can alternate PC/BLL in BO/GCd and see no accuracy difference, same exact load.