Powder Coated Bullets are keyholing

[243winxb]

The mold drops right at .356 and I powder coated them and sized them to .3560"

Tap a oversize .360" bullet into the barrels throat. Measure. Size to .0005" smaller.

Looks like a different mold is needed that will produce a LARGER as cast diameter. Pure linotype can add as much as .002" to as cast diameters.

Fit is KING. (after adding some linotype.)

[Thomas918]

Since you are getting a heavier bullet out of a mold made for 130gr is telling me you have a very high lead content. Probably close to pure. For example my 147gr mold out out 150gr bullets when using an almost pure lead mix but when using a hardball mix it puts out 145gr. Hardness is a larger factor in 9mm than alot of people say because 9mm is a fairly high pressure round. I had pretty bad keyholing before hardening my lead. Soft lead also leads to being sized down by the case when seated

[Thomas918]

I'm also using a Canik Rival.

[GregLaROCHE]

PCing shouldn’t be the problem. As mentioned, the hardness of the alloy or the boolit not large enough diameter, is most likely reason.

[hermans]

I have the same problem now with my 9mm keyholing after I started with a new powder for powder coating my 138gr MP bullets.
So I am sizing to .357 as I always have done. I am using COWW with a little lead added for stretch my alloy somewhat, the BHN measures 15 with my Cabine Tree Hardness Tester.
I have pulled a bullet and it still measures .357 exactly, measured with a micrometer, yet it keyholes when shot on a target at 10 meters.....
The only difference I could see is that with the new powder, the coating looks much thicker that with the old powder.....could too thick a coating cause this keyholing? When I switch back to my old coated bullets, I shoot a very tight group at the same distance.
I am looking forward to hearing your expert opinions, since I am at a dead end now with this problem.

[wv109323]

I did try a 124 Lee TC boolit. I powder coated and sized to .3570 and dropped the charge to 3.6g. of Titegroup. I only shot 10 rounds but no keyholes.

[243winxb]

9 mm 135gr LRN from Summit City with bad coating. Leaded the barrel on another forum. https://www.thehighroad.org/index.ph...ullets.920929/