Harder is more accurate?

[adam_mac84]

http://castboolits.gunloads.com/showthread.php?116741-If-you-think-so-try-this

Was reading this while trying to work through a 9mm issue...

I am sizing down my boolit in the 9mm case. WCWW all the way to ACRange Scrap.
I have a few methods i use based on the alloy (different expanders to save boolit as best as possible)

Basically, my .356 WCWW gets sized to .355, and the .358 ACRS was getting sized to .353 (keyholing), and now .355 (new expander).

The WCWW shot considerably better (same loads 1020fps, within 20FPS, 3.9 grains HP38) than ACRS which are starting as larger diameter
(both squeezing down to the same diameter in the end)

Both PC with Smoke's.

Curious if there would be a reason for better accuracy in the harder boolit. All other factors are the same, minus the expander used.

i ask because I would like to be able to use RS as a primary alloy due to availability to me at this point in time

forgot to add... barrel slugs .355/.3555

I was thinking the RS would obturate better than the WCWW

[Rcmaveric]

I use straight range scraps from the the Lee .356 mold. I had leading the last inch of the muzzle though. Played with lubes till it stopped.

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[sutherpride59]

Well depending on what powder you use and how much will determine just how hard your alloy needs to be. I helped my buddy figure out his alloy by step ladder loads. Load to the min load and move up in .2-3 grain increments to the max load, shoot a couple 5 round groups at 25 yards and see what groups best. If best groups are had closest to min load then your alloy needs to be harder or you need to use a powder that creates less pressure. If your groups are best close to max then a softer alloynor less powder is needed.

[sutherpride59]

Also with the range scrap if you do need it harder then you can buy some super hard alloy from roto metals and use that to further harden your lead.

[Lloyd Smale]

I allways seem to have better accuracy with harder alloys. Especially in semi auto guns. Most of them tend to have shallow rifling and my guess is the harder alloy gets a better grip on the rifling. That and the fact that you get less deforming from the bullet feeding out of the mag. I see it in 1911s and especially in glocks and M&Ps. there seems to be a point of diminishing returns at around 18bhn though. Revolvers seem to do a bit better with softer alloys but do improve with hardness too and don't seem to reach the point of diminishing returns and a good revolver just seems to to better the harder you go period. Most guns that do better with softer alloys do it because tolarances are bad and things like "bumping up" tend to help but those guns don't stick around here very long.

[adam_mac84]

Load to the min load and move up in .2-3 grain increments to the max load, shoot a couple 5 round groups at 25 yards and see what groups best.

If best groups are had closest to min load then your alloy needs to be harder or you need to use a powder that creates less pressure. If your groups are best close to max then a softer alloy or less powder is needed.


I am chewing this one over in my head.

It is a great insight. I am loading for close to minor PF. So, this makes sense... not a hot load, so the harder boolit seemed to be better in this instance. So possibly if I increased charge, the softer boolit may be better?

To an above question. Mold is Lee 356-124 2R.

[runfiverun]

it may do better at a higher pressure.
it would do better at a larger diameter.

[adam_mac84]

it would do better at a larger diameter.

I agree, that is the kicker. Needs short OAL (MAX 1.070) to clear rifling, even in expanded case, that is pretty deep, and it squeezes down the base to the dreaded .355. Is improved with new expanders (for 38). The quest continues. At least the leading issues are improving :).

casting is still way more fun

[runfiverun]

the oal of that bullet is it's biggest problem.
but a die that opens the internal diameter of the case would help.

[sutherpride59]

I am chewing this one over in my head.

It is a great insight. I am loading for close to minor PF. So, this makes sense... not a hot load, so the harder boolit seemed to be better in this instance. So possibly if I increased charge, the softer boolit may be better?

To an above question. Mold is Lee 356-124 2R.

Well if you are worried about power factor then I would suggest you find a load that will put you at 130-135 power factor so in the winter time these loads will still be match legal. After you figure out the right charge to get you where you want work on the alloy. For my buddy when we were setting him up in 9mm for USPSA we started with 20 boolits of 50/50, 20 of clip on wheel weight +2% Sn air cooled, 20 COWW water dropped, and 20 COWW ice water mixed with antifreeze dropped. What do you know the ice water dropped didn't group as tight as the water dropped or the air cooled. So that's what he uses for minor power factor now with tightgroup. If he switches to a different powder we will have to revisit the alloy again. That is the best way to do it if you have the time.

When you have a set speed then you have to adjust the alloy to gain accuracy, also I highly suggest you slug your barrel and size your boolits appropriately. If you are using a Lee push through sizer for your PCed boolits then if it is too small you can reame it out a little, there are plenty of articles on here about it. You also may give as cast/as PCed a try.

[runfiverun]

right you have an alloy flow and pressure limit.
in my 9mm loads I basically use a 1/3 alloy sized to 358 on top of 3.2grs of red-dot or bulls-eye and the HM-2 130gr bullet sized to 358.
I have gone up and I have gone down [down isn't always reliable] up is just faster.
I just want holes in paper and 100% function, I get both and I get it in 6 different guns.
I tweaked my accuracy by manipulating my lubes viscosity until it stopped helping then I bumped the load around a touch.
[I'm good with minute of clay pigeon at 25 yds]

[mdi]

Just a thought as the fellers above have better answers than I do regarding accuracy and hardness; You aren't using a Lee FCD on your cast reloads, are you?

[guicksylver]

More than one individual has found that it's not necessarily the bullet style or hardness but in many cases it's an issue with the throat of the barrel...recutting the chamber and giving it more leade can solve a lot of problems..try googling that and see what you come up with...

A lot of people have delved into the issue of the various leades manufacturers use in their pistol barrels...

[adam_mac84]

Just a thought as the fellers above have better answers than I do regarding accuracy and hardness; You aren't using a Lee FCD on your cast reloads, are you?

No. I just run it through without the plug in it to iron out flare. Is not pinching bullet down


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[Shiloh]

At the midrange velocities I run, water dropped range scrap runs as well as harder alloys. When I was doing upper midrange, harder seemed to help a little. My midrange cycle, are accurate, and recoil is moderate. no need to go faster.

Rifle bullets are a harder alloy.

Shiloh

[popper]

You should just taper crimp. Not run the crimp die all the way, it will resize your boolit.

[mdi]

No. I just run it through without the plug in it to iron out flare. Is not pinching bullet down


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So, you're not using the FCD, just running the cartridge through it? If you put a cartridge through an FCD, you are using it and unless you punched out the carbide ring, you can be swaging the cartridge/bullet down...

[adam_mac84]

MDI. *edit*. I am using FCD just to case size, not taper crimp with the additional piece under the plunger. I was mis-understanding how it works, and am now looking into 'de-flaring' during seating to see if i can eliminate use of the FCD in the event that it causes any sizing down (pulling bullets and measuring both to confirm today)

I wanted to follow up on some results.

New expanders have solved any sizing down problems, and I have eliminated leading.

Workup for accuracy (at minimum PF) showed best accuracy at a (low?) charge of 3.5gr HP38. Second best at 3.7
Range Scrap, 1.060 OAL.
Glock 34, ZEV barrel

I will test lower this weekend (ran 3.5, 3.6, 3.7, 3.9 grains) to see if I gain more accuracy or not.

My problem is, lower charge may drop me below my threshold (128 grain boolit) for minor.

Should I look to a slower burning powder, given some of the information above and the fact I was finding more accuracy at the lower charge? I was going to work up some Titegroup, but am starting to think going to a faster powder may not be the answer. I have plenty of TG and HP38, as I have tried to keep things tidy on the bench, but willing to add a 3rd powder to my pistol mix if necessary.

The 3.5 grain HP38 is workable for 3 gunning and range, but was hoping to get a little more out of it (was spread of my spread hand from rest at 25 yards). Meaning, it is just as likely to make me hit an 8" plate as it is to miss one :)