Superformance Powder and SOOTY Brass?!

G

GF271

Inactive
Howdy!

I am a long time shooter, first time handloader. I'm starting with working up loads for my most basic rifle using the following components:

Make/Model: Remington 700 SPS Tactical AAC
Caliber: .308 Winchester
Barrel: 20", 1:10" twist

Brass: Federal, once fired
Bullets: SMK 168gn
Primer: Federal 210, Large Rifle
Powder: Varget

While waiting for Varget on backorder, I have Hodgdon Superformance I would like to experiment with. I am aware this may not be and ideal powder. However, I can find little info on it and I would like to carefully work up a load to understand it's viability. I loaded and chronographed (3) 3-shot groups:

41gn @ 1975fps
42gn @ 2020fps
43gn @ 2100fps

I expected the fps may be low as I was starting at that point for safety. integrity of all the spent cases was good. However, they were quite sooty on the outside and my barrel was filthy.

1) Why are the cases so sooty?

2) Is it a condition of too little powder?

3) Would a magnum rifle primer help this by encouraging a complete burn?

3) COAL is 2.935" as I am trying to make up for a ton of free bore in the factory barrel (The round is touching the lands at a COAL of 2.64"). Is shallow bullet seating a cause of the soot?

Thanks for any input!
 
Superformance is way too slow a powder for a 308 Win. You are getting soot from low pressure and incomplete burn. Superformance is meant for more "overbore" applications than the 308 Win. If you want to use a powder that slow, you'll need a much heavier bullet to push in order to get complete burn.

What other powders do you have on hand?

Jimro
 
Are those loads from a reputable loading manual? Those velocities seem far too low to be produced by published loads with such a slow powder. Agree with "Jimro"-get a more suitable powder.
 
Low chamber pressure.
You aren't getting a chamber seal.
...Which makes matters worse (further lowering chamber pressure) and makes the charge burn even dirtier.


It's just the wrong powder.


CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

QuickLoad (using a tweaked version of W780 for an approximation) doesn't think you can get enough powder in the case to even reach 35,000 psi, let alone anything near normal operating pressure.

I haven't used Superformance, but I have used several similar powders. My experience is the same as the QL prediction - it's just the wrong powder.
 
You must log in or register to reply here.
Back
Top