10mm alloy suggestions that won't cause leading?

[Tripplebeards]

I only mixed up 8 pounds in my lee 4/20 pot and poured it into ignots. It’s very easy for me just to melt it back down and add more pewter. So optimum hardness 12, 13, 14BH…or a little harder?

Thanks for the help.

[Tripplebeards]

The I added 6oz more of pewter and got it to 11BH today. Casted up about 7 pounds worth till my Mold pins started sticking and wouldn’t close shut. I PCd them and will have to size and load a few tomorrow.







I traded off all the 7.5 BH HPs to a member for some 243 J words. Kept me from having to smelt all the pretty boolits back down .


I ll have to retest my COWW boolits in a few more days. They are WAY harder than I expected. The softer one…lol…is 17.9BH and the other is 14BH. Apparently the softer one got REALLY hard for some reason when adding 2% pewter. They are both air cooled as well. Wouldn’t think a HP at that alloy would open at 10mm velocities? If so maybe blow the HP pedals off?

Those COWW alloys both came out of brand new COWW boxes. Different brands. I acquired a bunch of each from Sears when the auto center shut down. They were from the late 70’s or early 80’s. The COWW that tested 14 was pretty close to that hardness to begin with. The other that tested 17.9 was only 12.3 or 12.7 if I remember when I tested it five years ago. I will retest in a few days to see if they change.

[Tripplebeards]

Tested both coww alloys today. The softer one is 12.5BH (the one that tested at 17.9 twice yesterday) and the harder one is 15.4BH( the one that tested 14BH yesterday). I will check again in a week.

[Tripplebeards]

I loaded up 15 each in all three alloys to try. Figured I'd still wait a few days for the coww alloys to fully harden. My guess is they are probably 99% done hardening. I seated a test boolit of thr softest alloy which was 11bh 16:1. I then pulled a measured. It was still at the original size of .402. I also did the same test after applying a crimp. I adjusted my hornady crimp die down even out the flare on the bell and to let my case fall in and out of my glock 20 barrel. The outside of the crimp measured .423 to .424 in spots.

Dummy round tested to see if my boolit sized down. I used my Hornady crimp die instead of the lee. As stated above they might get sized down with the carbide ring in the lee so I used the hornday just in case...and from now on when I crimp these.




Pulled and measured after seating and crimping...



All loaded up with 7 grains of unique. I loaded them a hair longer to 1.270" since I had more room in magazine. Figured it would cut down on the pressure and velocities a little but imo being closer to the lands increases accuracy. I so weighed each group of alloyed boolits and they are all within 1 grain of each other.

Feeling pretty confident that bone of these will lead my barrel. Guess I'll find out soon.
The blue boolits are 11BH, orange are 12.5BH, and purple are 15.4 BH as tested for alloy hardness yesterday.

[Tripplebeards]

Just got back from the range. I tried 12.5 BH coww alloy first. I don't know if I would call what I saw leading? Almost looked like a light grey color in the rifling. A few strokes of my chore boy wrapped brush and the barrel looked clean. Then I tried the 15.4 coww alloy. Looks like I had a little leading. I used my chore boy brush again and cleaned what looked like leading out in about a minute of scrubbing. Definitely saw lead streaking. I then shot the 11BH. I had a light wash of leading. Took a couple minutes of cleaning and all was removed. All the leading I observed was towards the end of the barrel. I did notice some lead spotting in the crown area with the 12.5 BH. So imo they all showed signs of leading. The ACME 180 grain. 401 did not a few weeks back using 5.8 grains and 6 grains of green dot. I'm wondering if I'm pushing these to hard with 7 grains of unique? The velocity should have been around 1150 fps. Would assume to much pressure? Before I give up on this project I'm debating on trying all the same alloys again with 5.8 grains and 6 grains of green dot. Also wondering if I need to order a wolf barrel? They are only around a $107 shipped and have regular type rifling in them. Also wondering if I need a GC mold for 10mm if I want to run HP boolits at soft enough BH so I get expansion. Kinda scratching my head on this project. I've loaded for my 77/44, 450BM, 336, 45 colt Ruger new vaquero, 329NG, and ruger 9mm all with zero leading. This 10mm glock is really kicking my butt.

[Laguna Freak]

I’m shooting a 2-2-96 160 HP sized bore + .001” in .40 S&W 4” bbl. Load test 6.2 to 6.8 gr Silhouette left virtually zero leading after 30 rounds. 20 rounds 6.8 to 7 gr left a little leading. 7 gr shot best groups ~ 1.5” at 21 yards. I may decide to live with a little leading.


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[shooting on a shoestring]

I suggest your focus should be on the other end of the boolit flight, the stopping end. Tune your alloy (and add a trace of copper) to get the best performance with the best velocity to stop your boolits in the 4th water jug in a row. As long as the barrel leading is small enough not to cause degradation in accuracy over a magazine or two, you’re golden.

Then move to a easy to cast boolit of the same weight so POI is same as hp boolit. Spend your time, money and primers to get that practice round to shoot clean as you want. You’ll shoot lots of those and very few hp’s.

Let me further suggest that Unique is a poor choice in 10mm unless you’re seeking to down load to 40 ballistics. You might get your hp to shoot clean with a minimum charge but I think you should give up trying to shoot Unique at 7 grains while looking for no leading. Blue Dot, AA7 and AA9 will stand a better chance of getting you to no leading.

Also, my experience with my OEM G20 barrel is it has a very poorly cut chamber. The back half is over SAMMI specs. This does help it to feed and gives clearance for dirt. But, the cartridge sits at an angle to the bore axis. I moved to a KKM barrel and found it gave me a wider window of loading to get both accuracy and no leading.

I was also frustrated with the velocity spreads I was seeing until I boosted the recoil spring weight to 22 pounds.

But…..
Instead of using hp’s I went to Accurate 40-172F and shoot them around 1300 - 1350fps. They mushroom nicely and stop in the 4th jug. And they’re easy to cast. That’s my definition of success in 10mm.

[Tripplebeards]

Thanks for the reply. I haven’t had a chance to shoot the pistol since archery season has using up my time. I did powder coat over my .402 Boolits which took them to .404. I plan on loading some up with Greendot and testing them. I’m gonna leave the unique alone from now on with 10 mm and Cast. If the .404 still lead i’ll look at either polishing the inside of my barrel or just buying a replacement wolf barrel for 100 bucks. Once I get a chance to shoot them at the .404 diameter I’ll post if I had any leading or not.

[jonp]

I agree with shooting on a shoestring. Unique works but isn't the best choice for the 10mm at least in my Poly 80 Glock clone. Haven't tried Smokes powder yet but I have some sitting on the table waiting.
Please do post on that .404 size as it sounds a little large to me. With that IDK if I would size the boolit a little smaller then powder coat. Maybe size to .401? That's what I am going to try with my new 10mm. Probably start at 12bhn. Looking for target loads not top end stuff. I've never used Green Dot but some swear by it especially in the 45acp for target.

[Tripplebeards]

I’ve already tried them at .402 diameter with leading. The largest spot in my barrel was .401. I honed out a lee .401 die to .402 for sizing. After the .402 powder coated boolits leaded in 4 different alloys ranging from 7.5 to 15.3 BH. i powder coated a second layer over the .402 powder coated and then sized to .402 boolits. They are consistently measuring .404 now. I’m guessing I have a ruff bore and or the unique powder could be the issue with a fast burn. According to load data some members have helped me with for 10mm and 160 grain boolits (my HP cast average 158/159 grains) it says I’m still a grain and a half or so under max loadings. So I want to eliminate the idea of “an undersized” boolit before I move on to a barrel issue. I will be trying out green dot powder for future loads since I have close to 8 pounds of it and basically nothing else for pistol powders. I didn’t have a leading issue with 180 grain, .401, ACME boolits with leading using a mid weight change of green dot. Think I was around 5.8 grains and then re tested with 6 grains if I remember. I will have to look at my reloading notes. But I’m using a 20 grain lighter cast boolit this time around. I would assume the greendot pushed the ACME boolits with a lot less pressure than the 7 grains of unique load and 20 grains less in boolit weight. I have a craftsman scope I will have to see if I can try and fit down my barrel to see if the bore is ruff.

[Ramjet-SS]

Rough bore might be the issue to bad you didn’t have an after market barrel to try

PM me I have one you can try for fellow cheesehead 🤣

[Tripplebeards]

Yeah I sure would like to try an aftermarket barrel. I don’t have any buddies around that own a on a Glock 10 mil with an aftermarket barrel or I borrow it to try.

[gwpercle]

Tripplebeards I would say it will work.

I run 50/50 COWW/pure lead , PC'ed out of my Glock 20, at 1200 fps with 180 gr. cast boolit....no leading.

In fact, I have been using 50/50 and Smoke's Powdercoat for all my loadings for handguns with great results.

Like !

I've had the same results with 50/50 COWW & soft lead ... boolits air cooled and lubed with Lithi-Bee lube . 9mm to 1200 fps , 30-30 win. to 1600 and Handguns in 38 , 357 , 41 mag , 41 special and 45 acp .
About 7 years ago my free unlimited COWW source retired from the tire business ...
I had all this lead sheathing scrap from the construction business , read about 50-50 in hunting section and started using it to stretch my COWW supply.
I like it better than straight COWW and like Hickok ... no leading !
Gary

[Ramjet-SS]

Yeah I sure would like to try an aftermarket barrel. I don’t have any buddies around that own a on a Glock 10 mil with an aftermarket barrel or I borrow it to try.

DM me

[Tripplebeards]

So I’m finally getting back on this project! Bow season and rifle deer season is over here. Muzzle loader hunting with my unused buck tag is open till Thursday. Then anterless only Thursday through Sunday. So after a week I’m going to test again. I couldn’t hunt today with relatives in town so I loaded up a dozen of 16:1, 11 BH and some 12.5BH in 50/50 COWW alloy today. I had a little leading with both alloys sized at .402”. I powder coated both boolits again and didn’t size. They measured .404”. When I do the plunk test without any crimp applied some dropped right in and some stopped about 3/4’s of the way into the chamber. I did not apply any crimp what so ever but ran them up completely into my lee crimp die with the crimp adjustment plug screwed all the way up to the top. Just from running them into my crimp die without crimping was enough to push the case neck flare in and just enough that my loaded ammo drop in and out easily. I measured a couple of the necks after running them through the crimp die without crimping. They measured .423”. The boolits seemed to hold in place without any crimp applied so I will test this time without any crimp applied. I still need to pull one and make sure they are still at .404”. I’ll try and pull one later today and report back. I also loaded them long at 1.272” along with a slower power and lighter charge. I tried 7 grain of unique last time. This time around 5.8 grain of green dot. I didn’t have any leading with .401 ACME boolits but did with my own cast HP’s sized ar .402 for some reason. I did try a hotter powder and higher charge which could have been the issue. The other issue I was worried about was maybe having a ruff bore. I swabbed the barrel today with some mothers chrome polish a good 50 to 60 times. Never got the black colored oxidation I get when polishing metal. So I tried again for about a minute and a half. The polish never turned black but was more of a darker brown. Hopefully if there were any burrs or ruff jagged cuts in my rifling they smoothed out. I’ll test the week after this coming to see if I get any leading. I didn’t pull a boolit to see if it got down sized after seating and knocking down the fair. I did load an extra so maybe I’ll pull and measure one before I hit the range.




Now that I’ve had time to think about my leading issue. I’m wondering if the 7 grains of unique was just to hot and torched the base of my boolits? Guess I ll find out when I go shoot next week. I figured between trying to polish the inside of the barrel, load with a lesser charge with another powder, and jumping up .002” in boolit diameter should hopefully keep me from leading on my next test. Fingers crossed!

If it still leads I might have to take members up on borrowing an aftermarket barrel.

[Tripplebeards]

I pulled one each color since one was in brass and the other in a nickel plated case. Both down sized to .400". I would assume it was from running them through the lee crimp die. I'll have to pull them all and start over using my hornady die's crimp.

[AlaskaMike]

7 grains of Unique should be just fine. I used that with my 175 grain Lee truncated cone bullets and it worked well. My alloy is just COWW + 2% tin.

[megasupermagnum]

I think you are on the right track on sizing. It might be worthwhile to try some bullets with regular wax lube too just to eliminate coating issues as a problem.