Any interest in a subsonic Copper projo?

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  • motoxxx_ryder
    Warrior
    • Mar 2015
    • 180

    Any interest in a subsonic Copper projo?

    I have a guy who got his 07ffl and is currently making custom projectiles in 308 458 and various pistol calibers. If there is enough interest in a subsonic projectile i can work with him to get something made. price would be between 1-1.50 a peice more then likely (don't quote me it depends on length of projectile). I have some pictures of the 458 and the 300blk subsonic bullet he produces.

    If there is enough interest ill have him join and work with some of the more senior members on bullet design. The typical design is 3-4 petals that hold together until enough soft material fills the HP then the petals rapidly expand and shear off creating their own would trail and the puck itself tumbles to do its own damage.

    458 socom design



  • motoxxx_ryder
    Warrior
    • Mar 2015
    • 180

    #2
    300blk

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    • Klem
      Chieftain
      • Aug 2013
      • 3506

      #3
      Interesting, What weights are we talking about?

      Comment

      • Variable
        Chieftain
        • Mar 2011
        • 2403

        #4
        Anybody good on the old stability calculators? I know 160 grain Hornady RNs run just fine out of my 10.5" with a 1-7.5" twist. Guys with slower 1-8 twists have had good results as well. I think somebody even got away with it in a 1-9"(?), but don't quote me on it.

        The problem with the copper HP bullets will be that they are longer for their weight. I know that'll factor in a bit. I'd love to get my mitts on some 170 grain pills if they'd stabilize in my 1-7.5" twist. A safer bet to try might be the 160 grain weight though.

        I'd be in for some in the "buck a pop" region.
        Life member NRA, SAF, GOA, WVSRPA (and VFW). Also member WVCDL. Join NOW!!!!!
        We either hang together on this, or we'll certainly HANG separately.....

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        • Variable
          Chieftain
          • Mar 2011
          • 2403

          #5
          Also: I'm in the process of a build that'll use an Al or Ti lightweight bolt carrier with a 12.5" barrel. I got close enough with full gas (suppressed) in my 10.5" and an M16 carrier that I think a lightweight bolt carrier and full gas from a 12.5" barrel might actually cycle with a subsonic load using plain old Trailboss loads.... Hmmmmm. Might be interesting.

          I'd want the heaviest bullet that would stabilize.
          Life member NRA, SAF, GOA, WVSRPA (and VFW). Also member WVCDL. Join NOW!!!!!
          We either hang together on this, or we'll certainly HANG separately.....

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          • Variable
            Chieftain
            • Mar 2011
            • 2403

            #6
            Playing with the JBM calculator it looks like stability won't be the problem. Length will...



            A 1.5" pill loaded into a 1.52" case might be a bridge too far.LOL

            I don't have the length off the top of my head (I'm at work), but here is a pic of my old 160gr. Hornady RN loads. Going from lead to copper will make it harder to get the weight without getting ridiculously long...





            ETA: Here is the stability calculator I was using: http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi
            Last edited by Variable; 03-26-2015, 12:20 AM. Reason: Add link...
            Life member NRA, SAF, GOA, WVSRPA (and VFW). Also member WVCDL. Join NOW!!!!!
            We either hang together on this, or we'll certainly HANG separately.....

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            • motoxxx_ryder
              Warrior
              • Mar 2015
              • 180

              #7
              Length in perspective the 170gr 300blk was about the length of a 220gr.

              I'll reach out and see if he can get a ballpark weight and length. What's the longest projectile you can use and still be a reliable feeder.

              Once again I'm new to the 65 but if we can get a working sub bullet then I have no need for the 300blk

              Is there any issue running it deeper into the case with a list powder similar to how we run the 300?

              Comment

              • JASmith
                Chieftain
                • Sep 2014
                • 1620

                #8
                Make sure your contact understands that the Grendel has a compound throat.

                PM me with your email and I'll send more info that will help get the bullet nose happy in the Grendel.
                shootersnotes.com

                "To those who have fought and almost died for it, freedom has a flavor the protected will never know."
                -- Author Unknown

                "If at first you do succeed, try not to look astonished!" -- Milton Berle

                Comment

                • lead chucker
                  Warrior
                  • Sep 2014
                  • 241

                  #9
                  I would be interested in some if we could get them to run subsonic.

                  Comment

                  • Klem
                    Chieftain
                    • Aug 2013
                    • 3506

                    #10
                    Originally posted by JASmith View Post
                    Make sure your contact understands that the Grendel has a compound throat.

                    PM me with your email and I'll send more info that will help get the bullet nose happy in the Grendel.
                    I'm thinking the Grendel's compound throat will be the least of your worries. Over 100-150metres which is about the realistic range of subsonic rounds you won't even see the difference on an animal, let alone when practicing on paper.

                    What will be of concern is;

                    1. Having enough pressure at the gas port to cycle (5,000lbs min).
                    2. Filling the case to at least 80% to prevent Secondary Explosion Effect(SEE) and Flash-Over.
                    3. Having a shape of tip that reliably feeds up the ramp (RN tips in Blackout are notoriously unreliable. Pointy tips are better).
                    4. Long supersonic barrels of 18+ inches will make more difficult keeping it under 1050fps

                    Bear also in mind that a 170grain 6.5mm round travelling at 1050fps is little different to a 9mm pistol round. A 220gr Blackout round is essentially an accurate .45 handgun round. If the nose is pointy to aid feeding then it will be even less effective than a decent flat-nose handgun hollow-point.

                    Quickload predicts peak pressure using a 170gn 6.5mm bullet around 11,500lbs to keep it under 1050fps. This is a quarter of the energy potential of the calibre and this 'underload' will be evident in results on flesh. Just like hunting with Blackout cures you of all the media hype of 'silenced killing', so will subsonic Grendel if you can get it to work.

                    With 37.5gr of water capacity in a Grendel case you'll be looking at 50% fills using popular supersonic powders. Trail Boss which my Quickload does not have has the bulk needed to fill the case without blowing it up. TB will probably get you 80% fill and still be subsonic but whether it cycles the action is anyone's guess.

                    My experience hunting with subsonic Blackout is that heavy subsonics are over-penetrators. The subsonic 30cal round is already an underload with 2/3 the available peak pressure and this is further diminished when the round continues on out the back of the animal and into the sunset taking precious energy with it. typically the animal runs off to bleed out somewhere else or if it drops on the spot it will be alive when you approach it requiring follow-up shots. Hunting subsonic is hard work with the range and energy handicaps you impose on yourself...but it is fun when it's a bit quieter (a cycling supressed AR is louder than a 9mm H&K MP5SD).

                    Comment

                    • Variable
                      Chieftain
                      • Mar 2011
                      • 2403

                      #11
                      Originally posted by Klem View Post
                      I'm thinking the Grendel's compound throat will be the least of your worries. Over 100-150metres which is about the realistic range of subsonic rounds you won't even see the difference on an animal, let alone when practicing on paper.

                      What will be of concern is;

                      1. Having enough pressure at the gas port to cycle (5,000lbs min).
                      2. Filling the case to at least 80% to prevent Secondary Explosion Effect(SEE) and Flash-Over.
                      3. Having a shape of tip that reliably feeds up the ramp (RN tips in Blackout are notoriously unreliable. Pointy tips are better).
                      4. Long supersonic barrels of 18+ inches will make more difficult keeping it under 1050fps

                      Bear also in mind that a 170grain 6.5mm round travelling at 1050fps is little different to a 9mm pistol round. A 220gr Blackout round is essentially an accurate .45 handgun round. If the nose is pointy to aid feeding then it will be even less effective than a decent flat-nose handgun hollow-point.

                      Quickload predicts peak pressure using a 170gn 6.5mm bullet around 11,500lbs to keep it under 1050fps. This is a quarter of the energy potential of the calibre and this 'underload' will be evident in results on flesh. Just like hunting with Blackout cures you of all the media hype of 'silenced killing', so will subsonic Grendel if you can get it to work.

                      With 37.5gr of water capacity in a Grendel case you'll be looking at 50% fills using popular supersonic powders. Trail Boss which my Quickload does not have has the bulk needed to fill the case without blowing it up. TB will probably get you 80% fill and still be subsonic but whether it cycles the action is anyone's guess.

                      My experience hunting with subsonic Blackout is that heavy subsonics are over-penetrators. The subsonic 30cal round is already an underload with 2/3 the available peak pressure and this is further diminished when the round continues on out the back of the animal and into the sunset taking precious energy with it. typically the animal runs off to bleed out somewhere else or if it drops on the spot it will be alive when you approach it requiring follow-up shots. Hunting subsonic is hard work with the range and energy handicaps you impose on yourself...but it is fun when it's a bit quieter (a cycling supressed AR is louder than a 9mm H&K MP5SD).
                      Some excellent points Klem.

                      I don't expect any hollywood results, and really expect it would pan out somewhere between a mediocre archery broadhead and a handgun bullet for terminal performance. There definitely isn't going to be any hydrostatic shock.

                      With the design MotoXXX Ryder posted above, I expect you would get a pass-through with some decent bleeding involved. It'd take some extra care with shot placement that's for sure.

                      1.) Port pressure---- As far as my intended use would be I plan on cheating somewhat by using a very light BCG (Ti or Al), and perhaps even an empty buffer (if necessary) to lower the pressure needed. I'm guessing running wide open gas with a suppressor would add up to enough. I start to get movement with Trailboss behind a Hornady 160gr. now in my 10.5" suppressed. Two extra inches of barrel in front of the gas port (in process 12.5" build), and anywhere from four to six ounces less reciprocating mass in the BCG and buffer should help tremendously I'd think.

                      2.) Case fill---- Trailboss all the way for me baby! If it would cycle, I'd be in heaven.

                      3.) Tip shape---- My 160 Hornady round noses cycle okay manually in my 10.5" Grendel, but I know that doesn't mean they definitively would in semi. I agree a pointed nose would likely feed better. The problem comes with interfering with them ooening up correctly, and how the shape affects the necessary length/weight ratio. I suspect 170 grains might not actually be practical. I'd guess a reasonable length would more likely net us 140-150 grains. Just guessing though...

                      4.) 18" barrels---- Yeah, that would be a real bear. I wouldn't want to even try to figure out getting that to cycle. Perhaps it's possible, but I'd expect it to be way more finnicky.


                      MP5SD??? You set the bar pretty high with that one.LOL I'd take the tradeoff in sound to keep the Grendel though.

                      ETA: "Donuts of Death" pic of Trailboss with a 160 grainer. (Yeah I know they wouldn't hold a candle to a supersonic load, but they're still fun!)

                      Last edited by Variable; 03-26-2015, 01:00 PM. Reason: Add picture
                      Life member NRA, SAF, GOA, WVSRPA (and VFW). Also member WVCDL. Join NOW!!!!!
                      We either hang together on this, or we'll certainly HANG separately.....

                      Comment

                      • JASmith
                        Chieftain
                        • Sep 2014
                        • 1620

                        #12
                        Originally posted by Klem View Post
                        I'm thinking the Grendel's compound throat will be the least of your worries. Over 100-150metres which is about the realistic range of subsonic rounds you won't even see the difference on an animal, let alone when practicing on paper....
                        Apologies, the points in the post were ones that were discussed at length in earlier discussions, but may have disappeared because the hacks and changes to the operating software.

                        The comment about the throat is directed at the bullet designer, and the throat configuration is a major worry for him. The point about the nose is that the OP will not be able to get to magazine length if the copper slug is a straight 0.264" cylinder with a hemispherical nose. There are other subtleties that influence the likely bore riding design.
                        shootersnotes.com

                        "To those who have fought and almost died for it, freedom has a flavor the protected will never know."
                        -- Author Unknown

                        "If at first you do succeed, try not to look astonished!" -- Milton Berle

                        Comment

                        • Variable
                          Chieftain
                          • Mar 2011
                          • 2403

                          #13
                          Originally posted by JASmith View Post
                          Apologies, the points in the post were ones that were discussed at length in earlier discussions, but may have disappeared because the hacks and changes to the operating software.

                          The comment about the throat is directed at the bullet designer, and the throat configuration is a major worry for him. The point about the nose is that the OP will not be able to get to magazine length if the copper slug is a straight 0.264" cylinder with a hemispherical nose. There are other subtleties that influence the likely bore riding design.
                          The Hornady 160 RN bullets are a bit undersize up front too. That's how I got away with seating them out so far.
                          Life member NRA, SAF, GOA, WVSRPA (and VFW). Also member WVCDL. Join NOW!!!!!
                          We either hang together on this, or we'll certainly HANG separately.....

                          Comment

                          • motoxxx_ryder
                            Warrior
                            • Mar 2015
                            • 180

                            #14
                            for those who are wondering about the weight, pressure is based on bearing surface length and not bullet weight. so if a sub 160 cycles then we should be able to get a lighter copper projo of similar dimensions to cycle. Ill reach out and see if hes willing to hop in as there seems to be a bit of interests if we can get a bullet that expands reliably and cycles at sub sonic velocities.

                            Comment

                            • motoxxx_ryder
                              Warrior
                              • Mar 2015
                              • 180

                              #15
                              he mentioned he has a pill that might work, its 1.35 inches long not sure on the weight. i may see if i can throw some funds his way and get something started. If all goes well ill have a epic caliber that i can narrow down my list of rifles.

                              ETA - Can someone give me the OAL of the 160gr Bullet. I want to get an idea of how long a bullet we can use.
                              Last edited by motoxxx_ryder; 03-26-2015, 07:10 PM.

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