Any interest in a subsonic Copper projo?

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  • sneaky one
    Chieftain
    • Mar 2011
    • 3077

    #16
    You will find this to be a challenge guys- been there. txgunner has been there also- Rapier- from the previously hacked forum- Vegas dude- The leade is so short-. with them.

    One fellow forum member made it to 2230 fps, using a 160 .-BLC-2 was the choice. We made it thru bank- bulletproof glass- Laminated stuff= Very tuff. 1.25" thick.

    We do not-- as a disclaimer-- promote shooting thru bank glass- ,,, It was a small piece left over, and for fun--- I have some results in my email spot.

    moto x I found out thru a many trials - a Gmx Gilding metal pill= 95% copper, & 5 % zinc, ( which makes the copper closer to mild steel ), is very tuff.

    The 160's only protrude forward of the lip of the brass by 1/4--5/16ths ". One has to reduce the contact area -ogive by turning them down a bit. To gain any length.

    Make sense?
    Last edited by sneaky one; 03-26-2015, 11:42 PM.

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    • Klem
      Chieftain
      • Aug 2013
      • 3509

      #17
      Originally posted by motoxxx_ryder View Post
      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.
      Quickload lists the Hornady 160 RN as 1.243". Variable will know for sure however.

      Point taken on the bearing surface as an influencer on pressure. As long as there is 5,000lbs at wherever your gas block is situated on the barrel then it should cycle a normal BCG. The shorter the gas system the more forgiving it will be.

      I have found in Blackout that 210gn is the lightest threshold for reliable cycling in a 16" carbine length with suppressor. Any lighter and you have to choose between cycling and subsonic. Best I have found is the 220SMK as it tumbles immediately on impact with flesh. It over-penetrates as usual but at least it does some damage other than laser-beaming through like most other bullets. You hear a slap followed by a zing as it ricochet's out the back. The 240SMK is also an option - same profile, but ends up a heavily compressed load to fit in a magazine and they cost twice as much for no more ability to kill. Picture of a 220SMK round that hit bone and did not exit. you can almost reload it!


      I have tried the dedicated 220 hunting subsonic from Outlaw State. Blunt nose, solid lead with striations all the way to the base. I had high hopes for it. Some feeding issues due to the shape and very poor results on flesh. They laser-beam through without expanding.

      The Hornady and Sierra 220 Round Nose are similarly poor performers subsonic on flesh. Similar design to the .264 Hornady RN in Variables photo. I have the impression they need to be travelling much faster and aimed at a rhinoceros to expand properly.

      The Lapua 200gn dedicated subsonic is an FMJ stubby front with a lock base. The shape looks optimised for subsonic flight but again a very poor performer on flesh. It does not seem to be designed to do anything other than sail through the air.

      Your friends' design is similar to the 150gn .30cal LeHigh 'Controlled Fracturing' round. Even with the recommended 20gn 0.17 expander bullet jammed into the cavity it is still too light to both cycle and be subsonic in the Blackout. I have never tried it but it looks promising on flesh.


      Looking at the Grendel case compared to the Blackout I reckon the main problem will be filling up that space with enough powder to be safe yet still keep the bullet below the speed of sound. Hopefully there's also enough down-barrel pressure to cycle the action.

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      • Variable
        Chieftain
        • Mar 2011
        • 2403

        #18
        Quickie posting----

        The 160 Hornady RN bullets I have are around 1.238" long.



        They are .264" behind the cannelure, and .260" in front of the cannelure.



        They taper from there down to about .255" just behind the rounded nose portion.



        At the risk of sounding like a broken record--- Trailboss is the powder you seek for these loads as far as safe load density goes (IMO)..... I'll have to check, but IF I recall correctly--- you load Trailboss starting around 9 grains, and then work down from there. In my 10.5" it took around 7 to 7.5 grains to get approximately 1050fps. Don't quote me though-- it's been a number of years since I loaded any. Without tumbling or expansion it's like shooting field pointed arrows that never stop.LOL

        Expand on Rhinocerous in a supersonic load? Yep! Actually, I believe moose from a 6.5 Swede is the designed recipient.LOL Although historically, I bet they'd still work great from a 6.5 Swede on elephant headshots too.
        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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        • Klem
          Chieftain
          • Aug 2013
          • 3509

          #19
          Did the 7.5gn of TB cycle the action in the 6.5?

          I load 6gn of TB behind a 110VMax in Blackout for the quietest subsonic load suppressed. It's equivalent to a 9mm but does not cycle. Single shots only. The usual cycling load is 11.1gn of 2207 with 220SMK. Louder, but cycles.

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          • Variable
            Chieftain
            • Mar 2011
            • 2403

            #20
            Originally posted by Klem View Post
            Did the 7.5gn of TB cycle the action in the 6.5?

            I load 6gn of TB behind a 110VMax in Blackout for the quietest subsonic load suppressed. It's equivalent to a 9mm but does not cycle. Single shots only. The usual cycling load is 11.1gn of 2207 with 220SMK. Louder, but cycles.
            No, I never did find any load with any powder that would fully cycle the action. I was using a 10.5" SAAMI chambered barrel from AA (made by Sabre) with an M16 carrier and an H2 buffer.

            I can't remember offhand what the other powders I tried were, but I never felt comfortable with any of them. Some of them gave erratic velocities as well. I was going to try a duplex load of Trailboss with some other powders, but quit fooling with it before I got that far. I don't think that it would have changed much.

            I expect I'll probably see better results with a longer barrel (12.5" vs. 10.5") because of dwell time. Using a lighter bolt carrier and buffer will considerably improve my odds as well. A pistol length gas port would probably make it really easy, but I'd rather not go that route.
            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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            • Klem
              Chieftain
              • Aug 2013
              • 3509

              #21
              Originally posted by Variable View Post
              No, I never did find any load with any powder that would fully cycle the action.

              I expect I'll probably see better results with a longer barrel (12.5" vs. 10.5") because of dwell time. Using a lighter bolt carrier and buffer will considerably improve my odds as well. A pistol length gas port would probably make it really easy, but I'd rather not go that route.
              I think dwell time alone will not get it to cycle. A pistol length gas port perhaps, but then you can't shoot supersonic with pistol length gas systems. So, you either have two 6.5 uppers; one dedicated to subsonic and another supersonic, or have one upper and put up with single subsonic shots only.

              Like I said, my Quicktime does not have Trail Boss. If it did you could easily look along the time/pressure predicted curve and see whether there's 5,000lb at the 4" pistol gas mark.

              Comment

              • Variable
                Chieftain
                • Mar 2011
                • 2403

                #22
                Originally posted by Klem View Post
                I think dwell time alone will not get it to cycle. A pistol length gas port perhaps, but then you can't shoot supersonic with pistol length gas systems. So, you either have two 6.5 uppers; one dedicated to subsonic and another supersonic, or have one upper and put up with single subsonic shots only.

                Like I said, my Quicktime does not have Trail Boss. If it did you could easily look along the time/pressure predicted curve and see whether there's 5,000lb at the 4" pistol gas mark.
                I'm going to hope for subsonic cycling via the 2 extra inches of barrel combined with a reduction of the reciprocating mass by over half it's original weight. I'm fairly optimistic that that'll do the trick. I had movement without all of that, just not enough.

                Then to run supersonic loads---- I'll just turn the gas down. I wanted to use an adjustable gasblock like the Micromoa "Govnah", but they aren't interested in shedding any weight off of their block (it's over 4 ounces...). I'll be using an SLR adjustable block instead. Titanium if SLR ever releases the dang things, or stainless if they don't.
                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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