More pressure or softer/harder lead?

[flybyjohn]

I am casting for .45 ACP for pinking steel targets. I have the Lee 452-200 SWC 6 cavity mold and am coating with Hitek bullet coating. I am using VV n310 powder. I test the hardness with a 8.73mm steel ball bearing and 200 lbs (91kg) of force for 30 seconds. I measure the dimple diameter placed by the ball bearing on the base of the bullet that has been filed smooth and flat, and put it into the BHN equation to get my BHN. I have been shooting the cast and coated bullets within a couple days of casting and test the bullet hardness just before or after the shooting session to get an idea of where I am at for hardness.

I am getting leading in the first 1/3 of the barrel within the first 75-100 rounds. The lead looks clean and the lead is being deposited in the grooves. I have researched the hardness vs pressure quite a bit but have also heard many say that they use a BHN of 8 all the time with 45 acp with no leading. I can try a bit more powder but am starting to get outside of the velocity I want to have. My bullet should be plenty soft enough to obturate with the pressure it is at now but it looks like I am getting gas cutting on the side of the bullets. With the following data, what would be the suggestions to take to try to eliminate the leading of the barrel. The leading has occurred in all three of these loads in the lower 1/3 of the barrel.

200 LSWC made of COWW and Stick on WW water dropped and tested at BHN 7.5-8 after cooking Hi-tek coating

all bullets sized to .453"
Barrel slugged at .4515"

3.5gr N310 - 700 fps
3.7gr N310 - 756 fps
3.9gr N310 - 793 fps

I am thinking of trying 4.1 gr of powder before going to a little harder alloy.
Do you think I am getting failure to Obturate or using too soft of a lead alloy?

I will pull a bullet tonight to see what diameter it is after being seated.

[flybyjohn]

I will add that using a harder commercial cast hitek coated bullet that I did not get any leading.

[rancher1913]

use only coww not soww, you will get around a 12 hardness and make sure you slug the bore and size to match. proper sizing with stop most leading problems.

[Springfield]

You're testing the hardness after coating the bullets?

[CASTER OF LEAD]

+1 for what rancher1913 said. Fit is king .

[adam_mac84]

I will say, i had nearly the exact problem you have (in 9mm). Fought it the whole summer with different powders, loads, etc. Long story short, it was my crimping process. Went to 'de-belling' and seating in one step to minimum needed to plunk, and POOF my leading went away. I was not able to get away from swaging the base, and my guess is it was taking the first 1/3 or something to obturate.

Don't know that it will fix your problem, but this was my solution (in a whole different caliber/animal)

[flybyjohn]

Spring field, yes tested after the coating but I clean the bottom of the bullet off to smooth lead before the test.

Rancher, I am using a 50/50 mix of the COWW and SOWW and water drop them. I had heard people saying that for a 45 with plinking loads that it was a good alloy to use. Just wanted it to work so that I can use some of the stickons I have.

Coating in HiTek requires you to cook the bullets several times in an oven at about 400 degrees. So I thought that testing after the cooking process would give a more accurate estimate of the lead hardness that I was going to shoot. Now lead is a funny thing I just found out. I decided to take a batch and water drop them after the last cooking session to see if I could bring back some of the hardness lost during the baking procedure. I tested a sample of these water dropped bullet just after water quenching and I picked up about 1 BHN to a total of 9 BHN. 5 days later, I was sizing that same batch and it was quite a bit harder to push through the sizer. I tested 3 of those same bullets and they all were between 12.5 and 13.5, using the same tester, weight, and time. Maybe water dropping takes a bit of time to build to the full hardness that it delivers.

I am going to try to shoot some of these harder bullets tonight and see if there is any leading issues with this harder bullet.

[Dusty Bannister]

If there is any shrinkage void, it will be in the center of the base of the bullet and that may result in a faulty reading of the hardness. Mic the completed cartridge and advise what the case mouth of the loaded round reads. It might be possible that to get smooth and easy feeding you may be excessively crimping the case mouth, resulting in an undersized bullet.

Quenching a low antimony alloy does take longer to reach final hardness.

[17nut]

How about you seat a bullet in an empty case and then pull it?
See if the cases are sizing the bullets down further thus rendering then to small.
Also a problem for many, loading 9mm.

[marek313]

I powder coat , water quench, size all in the same day if I can. It takes at least a week for boolits to reach max hardness from WQ. See how your having hard time sizing after few days. Thats exactly why you should size right after. As for 45 I only use range scrap + 1-2% Sn but after PC and WQ they still get to about 12bhn so no leading issues here. Another thing as they age and get harder you'll also find that they will grow in size too. I size my 357s to .3575 and after they age for few weeks they are perfect .358 when its time to load.

[ioon44]

You might need to look at the throat / forcing cone of your barrel, this area being to short or sharp can damage the Hi-Tek coating.

I shoot COWW with a little tin added for fill out and get about 11 to 12 BHN and two coats of Hi-Tek, out of a NEI 200 gr SWC mold my bullets weigh 203 gr and I size them to .4525" and use a very light crimp.

MY IDPA load is 4.2 gr of N310 running 820 fps, this load runs really clean out of a Wilson Combat barrel.

I done water dropping years ago and find it easier to alloy to the BHN I need.

[flybyjohn]

Dusty, I measured both sides of the bullet. After checking the base I flipped it over and machined off the nose and checked it there with the same results.

The case mouth after crimp is .4740 to .4745. That is with a federal case and a pmc case. The COAL is 1.241. I slowly adjusted the crimp a 1/16th at a time until the cartridge would just fit into the chamber. I removed the carbide ring from the bottom of my LFCDand use it in the forth stage to crimp after seating in the third.

A pulled bullet from the case reads the same as it did when it went in - .453"

Here's a picture after 60 rounds of the 12 bhn over 4.0 gr of n310.
I pushed about 10 dry patches through before this picture.