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questions regarding too much F'n powder

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  • questions regarding too much F'n powder

    So this is my first post b/c i got a couple questions about some powder and bullets i recently acquired. Just a couple days ago i got a hold of about 100lbs of wc680 powder pulled down from surplus 7.62x39. At the same time i also got roughly 6000 rnds of 7.62 bullets, half being 123 grain, and the other half being 125 grain SP. I dont really want to reload all this back into 7.62x39 because 1: i dont have anything that can fire that and 2: you can get it so cheap right now its not worth me reloading it. So i've been poking around and have seen people use this powder to make 300blk. so i guess my question is 2 fold, 1: can i really use this powder and bullet to make 300blk? and 2: if i can, is it possible to use this powder and bullet to make subsonic cartridges? I have plenty of 223 brass that i could cut down and resize. Just curious on all yalls thoughts. Heres some pics too. (Also i know it says 150 lbs net on the front but some of it was used, i dont have much of a way to measure it, but just guesstimating it looks like about 2/3rd is still left, hence why i say roughly 100lbs)

  • #2
    My understanding (to be clear, I have not tried it) is 680 has a similar burn rate to Accurate 1680, which can be used for subsonic 300blk.

    The concern I would have is the condition of that powder. If it is really from 1972 you should open a lid and find out what it smells like.
    Friends don't let friends shoot factory ammo.

    Continuous effort - not strength or intelligence - is the key to unlocking our potential.
    -Winston Churchill


    • #3
      thats what ive seen about it being similar to 1680, just not sure if the bullets themselves are too light, seems like most subsonic ammo is closer to 200gr bullets. And yea i know its still perfectly fine, my fathers had it for most of that time and he's kept it sealed and indoors. I've opened it up once and it looks great, i've added hydrosorbent packs to it to keep it dry plus the entire crate is lined with copper.


      • #4
        It is easy enough to go subsonic with that light of a bullet in .300 BO. The hard part is to get it to make enough gas to reliably operate an AR action.

        7.62x39's come in various sizes from .310-.312. 300BO's are .308.
        Endeavor to persevere.

        Call sign: Limp Wrist


        • #5
          All DD and GL have said.

          wC680 being very close to AA1680 is fair enough, realize that it MIGHT be really close, or not so really close.
          Canister powders for sale to you and I have to be very much like the last batch of canister powder sold to you and I. We have very limited "testing ability".

          Commercial ammo manufacturers however, have full gunpowder testing labs (at lest most do, small guys will contract that out), and so if the "new" batch of WC680 isn't quite exactly like the last 10 ton batch, they can alter the load/charge parameters easily.

          It is much easier to load heavy bullets for a cartridge subsonic, because you can maintain operating pressures, which MAY allow you to keep a self-loading gun self loading.
          147gr in a 9mmP, 200gr in a 300BO, many more.
          To load a light bullet that slow, you have to drop pressures, A LOT, which will usually shut down self-loading gun functions.

          Sticking a .310-.312" bullet in .300BO MAY (or may not) cause chambering and high pressure shooting problems, it all depends on that .300's particular chamber neck area diameter.
          IMO that is the bigger issue than Power-Swaging a .3105" Russian bullet down to .3080"


          • #6
            First off thanks for all the clarification. In response to the gun most likely not maintaining operating pressures, would using a low mass BCG, low mass buffer and different weight springs possibly alleviate that problem?


            • #7

              I actually have better luck getting 7.62x39 AR's to run subsonic than my 300BO's especially with lighter bullets. I run 150 grain .308's in my '39's and believe the lower pressure of the smaller diameter bullets helps them run better? Probably not what you want to hear but 180's are the lightest I've been able to get the 300BO to run subsonic. If you care to run those 123's supersonic you won't have any problems.

              You are going to need ten times as many bullets to use up all that powder. Using my AA1680 load data I interpolated what you have into 62,500 rounds.
              Endeavor to persevere.

              Call sign: Limp Wrist


              • #8
                i know i was guesstimating around 55k, im honestly not even sure what to do with it all (wish there were more options to load 1680 with, if i could do 223 id b set). I guess i could use these 6k boolits to make supersonic rnds and mold 200gr boys to make subsonic rnds.


                • #9
                  Best to use the bullets in a barrel they were intended.
                  I was raised in the 50\'s on jackrabbits and gunpowder.salt and pepper wooda made\'em taste better


                  • #10
                    I just ran a 123 grain steel core Wolf bullet through a Lee push through .309 sizer. The bullet was just over .311 to start and I was able to squeeze it down to just over .310.

                    I'll check it out tomorrow to see if it pops back. Perhaps stepping down from .309 then .308 sizers you can get something you can use?
                    Endeavor to persevere.

                    Call sign: Limp Wrist


                    • #11
                      Originally posted by angryjulian View Post
                      First off thanks for all the clarification. In response to the gun most likely not maintaining operating pressures, would using a low mass BCG, low mass buffer and different weight springs possibly alleviate that problem?
                      As DD said,,, "Maybe".

                      I have 2 1911's, full weight is essentially identical, within a few ounces, over 30 ounces empty.
                      1 is a .45 Automatic, uses a 22-pound recoil spring, stock 19-pound hammer spring, slide is all steel.
                      1 is a .22 Rimfire, No idea how weak that recoil spring is, but it ain't strong, slide is ZINK alloy, not steel, I would be surprised if the mainspring under the hammer strut is much over 10 pounds, because it isn't hard to rack, right from closed.

                      A rather extreme example, but, a gun outfitted for 450-foot-pound energy ammo vs. an almost identical gun outfitted for 120-foot-pound ammo.

                      There are TWO ways that you MIGHT get that to work in a .300BO gun.

                      First,, start with a Carbine Gas System, not a mid or rifle-length system.
                      If you were to want to do this full-time, pistol-length gas system.
                      The longer the gas port is away from the chamber, the less gas pressure the drive system will get, period, so move that gas port closer to increase what you get.

                      Second, yes, lighter buffer spring, light as f**k buffer, and a light carrier.

                      Then pray, because I can't think of anything else to add to it.
                      You can go to reduced power hammer spring, the hammer is the first thing that fights the carrier moving backwards, BUT, you start asking for unreliability from light hits.

                      The pistol length gas system would likely work without super-light reciprocating parts (MAYBE again, maybe not as well).


                      • #12
                        Absolutely awesome replies here, giving me lots to think about.

                        Like the idea of gettin a suppressed, SBR style AR that could use lighter (and cheaper/easier to obtain bullets) that are still subsonic. Guess ill actually have to spend the bucks on the gun first and then play with it from there. Worse case scenario I still have a light SBR that can still easily handle any other 300blk.

                        And to add about bullet sizing being .311 instead of .308 I've been reading that it doesn't much matter with that small of differences. Here's a post talking about it from a while back referring to 7.62 being used in blackout. (

                        Plus just thinkin out loud, would the higher pressure from the larger diameter bullet in a smaller diameter barrel actually help with pressure to operate the AR action? Just a thought.


                        • #13
                          Plus just thinkin out loud, would the higher pressure from the larger diameter bullet in a smaller diameter barrel actually help with pressure to operate the AR action? Just a thought.
                          IMO, not enough to be meaningful.

                          Realize too, that the ONLY time that .311 bullet is .311, is UNTIL it hits the throat and then rifling.
                          Once that .311 bullet is in the bore, it ain't .311 any more, and never will be again. It's a .308" bullet now.
                          Millisecond Power-swaging.

                          You are probably misunderstanding gas pressure drop in a gun barrel.

                          Look at the .223R/5.56 AR As Designed:
                          The cartridge fires at an AVERAGE (important word) pressure of 55,000psi, IN THE CHAMBER.
                          As soon as the bullet starts forward, that pressure drops. By Boyles Gas Law, it drops by 1/2 every time the distance from the bullet base to the breechface doubles.
                          The Rifle Length Gas System, is designed to deliver 20,000 to 25,000psi to the carrier to operate the action.
                          The Carbine Length System (NO other changes) delivers roughly 35,000psi gas pressure to the action's operating systems. This is why Carbines first gave trouble when new outrunning magazines and damaging bolts until weighed down with super-heavy buffers to slow them down, and why they STILL overheat very badly.
                          The Pistol Length System (No other changes) delivers 50,000psi or so of gas.

                          Now,, that is burning 25-ish grains of gunpowder inside a .22-caliber barrel.
                          Pressures drop A LOT FASTER from only burning 15-17 grains of powder AND doing it in a 50% greater volume bore (.30-caliber).

                          I do not know of anywhere that anyone has "charted" the pressure drop curve with .300BO ammo (done repeatedly with .223R/5.56x45mm), but it is very possible to start with 55,000psi in the chamber and NOT have 20,000psi at the carbine system, depends on powders used.
                          If you are only starting with 25,000psi trying to make light-weight subsonic ammo, it is unlikely in the extreme that you get enough pressure to drive the gun 7" later down the barrel.
                          4" down the barrel,,,,, MAYBE.

                          Gas-driven guns are designed to Port Pressure levels.
                          One of the problems the early AR had, when it was "experimental" the IMR powder that it was designed to was very irregular lot-to-lot.
                          As soon as Uncle Sam said "I want 50,000 a week for the next 2 years", cherry-picking powder lots was O.U.T.
                          So then they fed it (among other things) the same BallC that was feeding .308W/7.62x51mm in M14's, M60's and Miniguns, but it caused higher port pressures, increased the cyclic rate (among other fouling issues special to the AR15 design).

                          The Port Pressure rule is why the #1 "solution" to every guy who stops in and says "My start-level reloads won't cycle my rifle (AR or not, no difference if it's a piston gun or DI)." the answer is "put more powder in them, turn them up.


                          • #14
                            FWIW, a lot of fellers use 125 gr bullets in their Garands. I've seen a lot of 125 gr., 30-06 load talk over at the CMP forum...
                            I\'ve learned to stand on my own two knees...