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#11
05-22-2017, 09:59 PM
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Quote:
so it appears fireforming these little puppies yielded a noteable gain in capacity. now their 16.3gr avg h2o. did some more loading yesterday and it seems that things are coming together between the fireformed brass and getting the pressures higher up. getting 3260 avg with 13.5gr lil gun with a 40gr v-max and still not seeing any signs of pressure. The barrel is a factory sporter savage take off in .223 that I cut .635" off the chamber and rechambered into .223 short. also shortened the barrel as i'm going to thread it for a suppressor once ptg sends my range rod. 
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#12
05-23-2017, 03:41 AM
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Hi squirrel_slayer,
I looked pretty hard at the 223short several years back. I lost all the saved data, bookmarks, etc for it due to ransom ware virus killing my last computer. If I remember right, the original designers wanted a cartridge that was just made by shortening , and cutting the oal of a mil spec 223 or 556 case, and having the throat large enough so no neck turning was necessary. Seems like the throat was around .260 or so. Sound about right? Did you keep the large throat? If so, what are your impressions of accuracy with the thick necks? Good luck! Hope everything turns out to your expectations. 
Last edited by strkr; 05-23-2017 at 03:44 AM.
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#13
05-23-2017, 03:07 PM
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strkr you are correct. it is a form/chop/ trim and load cartridge.
I actually started this project with different intentions. I'm currently in the process of making super short barrels for my SBR'd AR15. My main goals are for it to be an economical option as far as brass is concerned, I wanted smaller case capacity to use more appropriate powder burn speed for the short barrel (talking 5-6" long) then lastly I'm hoping to get subsonic operation with the heavies (starting with 80gr smk) I debated between the tcm and the short and decided to go with the short for the added pressure capabilities and ultimately velocity I'm hoping. the short also has a more aggressive case taper which is very similar to the 22 reed express which is another trait I'm hoping will work for me as I'm going to be running the supersonic loads via ppsh 43 magazines. the savage barrel was more of a after thought. I just so happened to have a barrel laying around so into the lathe it went. lol I don't expect a lot accuracy wise from it both from the thick neck and factory sporter barrel but 1 load thus far is printing right at moa. actually shot a ground squirrel on sunday and I was very happy with the results. very mild report and it wrecked that squirrels day! granted that was only at 40 yds with a 3150 ft/sec muzzle velocity.
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#14
05-23-2017, 03:27 PM
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Here's my real intentions. finally got my stamp back a month ago. still waiting on my two suppressors. I've always had a love affair with the mp5 so I wanted this build to be like a mp5k but with a cartridge that could defeat soft body armor. will be mostly a range toy unless it proves to be reliable then if it does i'll find a FFL to load me some "factory" ammo for legal protection.
 here's a mockup of where I'm at so far. barrel isn't finished yet still need to thread the tennon and headspace it to the extension, thread the muzzle, and drill the gas port. I will be buying a sig mpx handstop/VG once I can find one is stock while I have gun money. lol always one or the other holding me up. I will also buy or try and shorten the magazine to be roughly the same length as the grip so should end up around 15-20 rounds with the short mags and 35 for full length as pictured. Last edited by squirrel_slayer; 05-23-2017 at 03:30 PM.
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#15
05-23-2017, 03:35 PM
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strkr
all is not lost! http://www.go2gbo.com/forums/89-wild...t-project.html He also has a page on face book. think it's called .223 short chat Last edited by squirrel_slayer; 05-23-2017 at 03:44 PM.
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#17
05-23-2017, 05:22 PM
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tried to fulfill the desire with a 7.5" .223 AR pistol several years back and I agree the concussion wasn't very pleasant.
between the smaller case capacity and the suppressor this go around I'm thinking it will scratch the itch. lol
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#18
05-23-2017, 05:32 PM
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Here's a photo with a .223 rem with two shorts next to it, one with a 40gr armscor jhp and the other is a 80gr smk that i'll be trying to get running subsonic suppressed hopefully from stock AR mags. the 40 armscor will be ran from the ppsh mags with a mag block adapter.
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#19
05-23-2017, 08:49 PM
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What twist does your 223 Short have? I tried some of the 80gr SMK in my M70HVSS several years ago, but it couldn't quite stabilize them, even at cooler temperatures. That was in a nominal 1:9 twist, full (max) Sierra book load of W748 or IMR4895, as I recall. They didn't keyhole, but were yawing in a roughly 3" diameter at 200 yds. I think the 75 or 77gr SMKs were designed to make a 1:9 work at 223 velocities, but I never tried them. The hunting intended Sierra 63gr GK or the Winchester 64gr SP are much shorter, and should stabilize okay at lower velocities. My point is that you may need to go to a faster twist barrel, if you really want to make the 80gr bullets work and be subsonic.
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#20
05-23-2017, 09:19 PM
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the savage barrel is a 1:9 but I have no plans to run the 80's subsonic in that rifle. if anything i'll try the 55gr lead cast bullets from a lee mold I bought subsonic. The heaviest I plan to try in the savage supersonic is the 53gr v-max, depending how they fair I may just stick with the 40 armscor and v-max. the 34gr dog town or varmint nitemare are also on the radar.
the AR barrels are 1:7 which are what I'm going to try the 80gr subs in. generally speaking 69gr is the max for .223 and a 1:9. the 75's-80's need a 1:8-1:7 twist generally. velocity does play a small part in it. Sierra graciously donated some 90gr smk's for testing purposes that I will try in the ar barrels as well.
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