Weight (i.e. grains) & velocity change of Bullets after powder coating, Hi-Tek, etc

I shoot suppressed. Just wondering what's the before & after weight & velocity readings readings of various coatings.

For instance a 147 grain bullet goes to 156 grains after powder coating and 150 after HI-TEK. 140 grain is subsonic before powder coating but speeds up when it's coated. I'm making those number up of course but I'm curious how all this stuff impacts weight and velocity.




random links which were inspiration for this question:
Here's a thread on powder coating which talks about bullets going faster:
http://castboolits.gunloads.com/show...oating-Boolits

Here's a link to HI-TEK
http://www.bayoubullets.net/Coating.html

only a couple grains

popper; do you know if there is a velocity difference in same loading between greasers and coated?

I see about 40 to 50 FPS increase with powder coated boolits in my 300 blk.

Thanks jailer

I don't have a chrono but I have noticed my 9mm load does not work quite as well.
My original load was a Lee 125g rn over 3.0g of AA nitro100nf. It cycled flawlessly and was VERY accurate out of a Glock 19 w/ a Lone Wolf barrel.

Same exact everything, only replaced the tumble lube for powder coat and accuracy was acceptable but nothing to brag about. Worse, it did cycle 100% but failed to lock the slide back. Never happened before. Not even once. The only change was powder coating.

Just checked my chrono data for 38 Super.
Cast with 92,6,2,alloy 15 BHN
Lee 125gr RN conventional lube with Jake's Purple cerasin lube.
Actual weight Ave 125.2gr
Sized .357
Load 4.6gr AP-70
Ave Vel. for 10 rounds 1157fps

Lee 125gr RN 2 coats HI-TEK Red/copper mixed 5-1-7.with Extreme Catalyst
Actual weight Ave 125.5gr
Sized .357
Load 4.6gr AP-70
Ave Vel. for 10 rounds 1154fps

So from this. I'd say virtually no difference.

RD 30-30 179.9/179.2 3 coats of HT green. 0.3145/0.3125.