PC and Chamber Pressure

[GregLaROCHE]

Has anyone seen any information on how PC effects chamber pressures? Higher, lower or not at all?
Thanks

[bstone5]

Have not seen any change in pressure with powder coated bullets. I load at low range of powder charges on the hand guns. Have never loaded at the upper range of powder charges.

[Smoke4320]

very few people here have actual chamber pressure measuring equipment
I think Larry Gibson may be the only one
you might ask him via PM if he has tested this..
I would be interested in the results as well

[Lloyd Smale]

Velocity runs a bit less with pc then the same bullet and load conventionaly lubed so id have to guess pressures are slightly higher due to friction. My pc loads run about the same speed as jackted bullets the same weight so id say although it might increase slightly loading data in the reloading manuals is safe.

[evoevil]

I would like to see more on this also

[Bama]

Velocity runs a bit less with pc then the same bullet and load conventionaly lubed so id have to guess pressures are slightly higher due to friction. My pc loads run about the same speed as jackted bullets the same weight so id say although it might increase slightly loading data in the reloading manuals is safe.

My experience has been a little different. When compared to Lyman manual for gas guns, paced bullets run from 150 to 350 FPS faster than listed velocities when checked with an inexpensive chronicle chronograph. Velocities pretty well match when using Jacked bullets. From an engineering point of view the grind of the powder and its color componits could have an impact but from performance impact is very little.

[Forrest r]

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For me the pc'd bullets have always been faster. Same bullet cast from the same alloy/same time.
PC VS Traditional lube ='s pc is faster with fast burning pistol powders and rifle powders

[fredj338]

At pistol pressures, I don't think there is much variation. My PC bullets will run about 20fps faster than lubed lead. Well within std deviation with most powders.

[Smoke4320]

Generally PC'ed bullets should run about 4% faster.. Less friction not more.
One of the reasons you have to start over . you cant just take a lubed load and sub a pc bullet and expect the same group
Barrel harmonics will be different

[Lloyd Smale]

I guess im wrong. I was just going by what I was told on here back when I started using pc. that and my 9mm testing showed velocitys about identical to my jacketed loads which run a bit slower then convetionaly lubed cast bullets. I never did chrono the same bullet and load conventionaly lubed and pc'd. I guess I need to break out the chrono and try it. I do know that comparing the same load with pc and coventionaly lubed versions of the same bullet does effect groups. Sometimes by quite a bit.

[Dragonheart]

The only significant testing I have done is with handgun loads. My chronographed loads indicate about a 5% increase in velocity, so Smoke is right as far a percentage of increase in PC velocity.

Federal has the means and has done a lot more testing on Polymer Jacketed bullets. Federal says PC is a superior lubricant creating less friction; this can be substantiated by cooler barrel measurements.

As long as one is observing safe loading practices I wouldn't lose any sleep worrying about overpressure PC loads.