6.5 G formed from 7.62x39 vs Starline G Brass using ST Auctions surplus WC846 Powder

[bearmn56]

Been away from my CZ 527 Grendel, 24" barrel for a while. Have a bunch of G cases that I formed/fireformed from IMI, Win, and FC 7.62x39 fired brass. Worked up loads using the insert to my Lee Grendel dies. Being a careful loader I started low and worked up. Top pressure loads in the formed cases were below the listed loads in the insert. I set the rifle and load development down for a while. I finally located 100 Starline G cases and have just gotten back into load development. Also, during the down time, I bid on and got, on Gunbroker, 16lbs of WC844 and 16lbs of WC846 form ST Auctions....at a very nice price per pound. This is advertised as pull down powder that was pulled by an arsenal, tested and packaged in 8lb jugs. I did some ladder tests on the WC844 in some different calibers (222, 223, 6.5G) and found that my lot was virtually identical to H335...and perhaps a tad slower. But that is not the purpose of this thread. I started testing the WC846 powder and found that it is SLIGHTLY FASTER than the WC844! Certainly completely usable for all of the appropriate calibers that can use H335. I found in my workup loads that the formed cases, with their large rifle primers, showed pressure much sooner than the load worked up in the small rifle primered Starline G brass. BTW, in the Starline cases I am using CCI450 primers. In the large primered formed cases I am using F210M primers. Curious....I weighed 4 Grendel cases. Before weighing, I FL sized and trimmed all 4. The formed IMIs were the heaviest at 125grains. The FC and Win were in the 120ish range and the Starline case was only 108 grains. This is a whopping 17 grains max difference.....or over 10%. This difference completely explains the max differences between the formed and factory brass. An example is with the 120gr Horn A-max. My top load in the formed cases is 25.5 gr WC846 for 2360fps avg at 15feet. In the Starline G cases, with the same bullet, my max load is 27.0gr of WC846 for 2475fps at 15feet. Starline cases give me a useful, especially in the Grendel, 100+ fps. One thing, for certain, that I learned from this is the reformed cases have MUCH LESS case capacity than the Starline. I have shot some cast bullets in my CZ Grendel with very good results. The formed cases, with their reduced case capacity, will work very well with cast bullets. Smaller case capactity, with the smaller powder charges needed for cast bullets will be perfect. My next task is to find another 100 Starline G cases.....no small task with the shortages that we are experiencing now. One last thing. If you are a somewhat experienced loader, surplus powders, with their very reasonable prices are a very viable option...especially if one shoots a lot. DISCLAIMER: THE LOADS LISTED ABOVE WERE SAFE IN MY RIFLE USING THIS PARTICULAR LOT OF WC846.....OTHER LOTS OF THIS SURPLUS POWDER MAY BURN FASTER OR SLOWER AND SHOULD BE USED WITH REASONABLE CAUTION. Good Shooting. William Smith, Montana Territory

[StoneHendge]

x39 brass (aside from Starline 7.62x39 brass) uses a higher ratio of zinc than most other brass. Probably due to both cost (zinc is cheaper than copper) but presumably also for corrosion resistance. Zinc is less dense than copper, so not only do your cases have less volume due to more metal by weight, they have less volume since the alloy used has more volume for weight.

I have extensively used Starline x39 brass which has the same alloy as their Grendel brass and hence volume. Using the LRP has a significant impact on pressure, especially with faster powders. Having more "spark" igniting a fast burning powder seems to make the pressure peak come faster. It's not something to chase velocity with, but very accurate loads can still be found. I've been using Fed 210s which have the same brisance as the 210Ms

[VASCAR2]

Watch the Starline Brass website. When they permit back order place an order. A lot of times the order will ship within a few days. When I first got into the 6.5 Grendel I used some 7.62x39 brass and all x39 brass is not created equal, some brands work better for fire forming. Once I had enough 6.5 Grendel brass I pretty much quit using FF x39 brass. If I do use x39 brass it is situations where I might not be able to recover my brass.