Powder coating tough enough to slow expansion of hunting alloys?

[Silvercreek Farmer]

Anyone test PCed expansion next to traditional lube for the same alloy?

[KVO]

I tested it awhile back with pistol bullets. Far left bullet in each group had the HP cavity intentionally filled to the top with PC powder before baking and completely plugged the HP. All 20:1, shot into Clear Ballistics gel with a double layer of a pink polo shirt that was donated by the wife. Hence the pink fibers in the HP cavities. Makes for good contrast. Black is NOE .40 200gr WFN (180gr as HP) shot from M&P40c, blue NOE 358-135, and green MP 360-640 HP shot from a ~3.8" 9mm bbl. All impact velocities chronographed between 920-1085 fps or thereabouts for all of them (without digging through my notes for the gory details). Some plugging effect, nor does it turn them into ballistic tips. Bottom line PC has negligible effect on expansion as prepped for normal use via BBDT. If you're shooting at rifle velocities I expect no measurable difference beyond your base alloy's ductiliity/malleability.

[Silvercreek Farmer]

Good work, thank you!

I tested it awhile back with pistol bullets. Far left bullet in each group had the HP cavity intentionally filled to the top with PC powder before baking and completely plugged the HP. All 20:1, shot into Clear Ballistics gel with a double layer of a pink polo shirt that was donated by the wife. Hence the pink fibers in the HP cavities. Makes for good contrast. Black is NOE .40 200gr WFN (180gr as HP) shot from M&P40c, blue NOE 358-135, and green MP 360-640 HP shot from a ~3.8" 9mm bbl. All impact velocities chronographed between 920-1085 fps or thereabouts for all of them (without digging through my notes for the gory details). Some plugging effect, nor does it turn them into ballistic tips. Bottom line PC has negligible effect on expansion as prepped for normal use via BBDT. If you're shooting at rifle velocities I expect no measurable difference beyond your base alloy's ductiliity/malleability.

[Outer Rondacker]

Look how beautiful those bullets look after opening up. I could look at that all day. Good test too.

[Rapier]

Trying to make sure I understand the 20:1 notation. Is that lead to tin?

[Edward]

Trying to make sure I understand the 20:1 notation. Is that lead to tin?

YUP/Ed

[KVO]

Yes lead:tin. You can get by with very low amounts of antimony with proportionately high tin content but unless you are going to test it out assume ANY antimony will cause fragmenting. Run the velocity up and you don't need a HP unless impact velocity will be lower due to extended range. Unless you want a grenade as penetration will suffer.

[KVO]

At the risk of hijacking (sorry OP).

357 mag. The left solid bullet is coated w/ clear PC BTW not naked. Cup pts on the left also lost 10-15gr, too much velocity for even the modest HP. Side note I think a short tapered cone like the NOE cup points is more forgiving than the MP radiused cup points. I've since reshaped the MP pins for that mold along those lines.


40 S&W



9mm
20:1 left / low tin range scrap right


As has been said in other threads barrel length matters. Several others (Curious Shooter, OS OK, Forrester to name a few, credit is due) worked quite a bit on impact velocity vs muzzle velocity. Can be hard to tune IV to performance which honestly makes the tried and true FN or WFN solid a safe bet if you don't plan on experimenting.

[mehavey]

ALCON: Tin does very little to harden a lead-tin (binary) alloy.
20:1 in that regard doesn't even make BN 8.
(Consider tin to be a "flowing" agent for mould fill-out rather than hardening.)

But in fact soft is good for expansion.
Use the PC for leading protection.