The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Rifles Wildcats And Their Development 6.8 SPC or 270-223?Go | New | Find | Notify | Tools | Reply | |
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It seems to me that you can neck up the 223 to 270, trim to the 6.8 spc length, use 6.8 SPC mags and get within 100 fps of the 6.8 SPC on 223 brass for a better CQC round than the 223 with just a rechamber, rebore or rebarrel. Any flaws with this brain fart? Will the mags need any fiddling? Call it what... 270 CQC? 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | ||
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Here is the 223, a poorly photoshopped 270-223 AKA 270 CQC and the 6.8 SPC The idea is to use the 6.8 SPC bullets get more smack down at the loss of long range but minimal changes to a 223 platform. Any thoughts  577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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It is not too difficult to put together a 6.8 upper and pick up some mags. Factory ammo available, especially from Silver State Armory. It's not like you to come up with such a small wildcat -- how's the 470 AR? ------------------------------- Some Pictures from Namibia Some Pictures from Zimbabwe An Elephant Story | |||
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The 470 is tho coolest! LOL yeah this is a small wildcat but I think interesting. Was thinking of a way to get more smackdown from a 223 with minimal headaches. 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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See, that's where I think you get with the 6.8 SPC. Minimal headaches. But then maybe I am just too lazy to go to the trouble of putting something else together. Taken a pig with the 470 yet? When you get old like me it seems the kids do most of the shooting... ------------------------------- Some Pictures from Namibia Some Pictures from Zimbabwe An Elephant Story | |||
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8 hogs have never kept in a 2400 fps 400 grain Speer gold dot yet! 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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I think using the 223 brass is better because it will be around forever. The only thing borrowed from the SPC is the mags and bullets. Was thinking 7.62x39 performance with higher mag capacity. It seems that in the modern theaters of war a 300 yard gun is what you need and if you need over 300 yards you want a different platform than the AR15 variants. 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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Nice work with the pigs! You can buy plenty of SPC brass now, but of course who can say if it will be around in ten years. I hope it will continue to be popular, but I agree the .223/5.56 outstrips it by a huge margin. ------------------------------- Some Pictures from Namibia Some Pictures from Zimbabwe An Elephant Story | |||
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7mm TCU maybe? Get away from any cartridge you cannot get brass for easily. Rich | |||
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Well the TCU is a blown out full length and might have OAL issues. The beauty with the 6.8 SPC bullets is functional impact velocities lower than the 7mm Was thinking 85 to 115 grain bullets going between 2400 to 2700 fps The 270 will give adequate shoulders without having to fireform. It is a K.I.S.S. wildcat (Oxymoron yes) Neck up, trim and stuff for more power with a barrel and mag swap. 90% of the SPC with minimal effort. 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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7mm TCU: 130gr bullet at 1900fps. How much more thunp do you want? Rich | |||
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Not much wrong with the 7mm TCU but I was thinking for an easy 223 power upgrade. The concept I envision here will have more benefits and less drawbacks for a AR15 platform. The 7mm TCU I think makes a great high BC subsonic round IMHO 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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A question. Why are you using 6.8 mags? I have both 223 and 6.8 rifles, and I thought the differences in the mags were due to the case head size, not the bullet. I understand that the case profile is a bit different in a 270-223 but I've never had a problem with a 6-223 in the mags. Thanks- I'm just curious here. | |||
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Was thinking that the larger neck diameter on the 223 case might need the 6.8 mags. The depth of the inside rib of the mag is the question. I don't know yet. 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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This would work well for 5.56 rifles like my SU-16 because there are no 6.8SPC bolts and barrels available for it. I've read on AR Forum.com that PMAGs work if the front rib is filed down. There is a fella named Kurt on ARF making a 6.8x40, I like Boom Sticks 43mm length better. I think it should have the same dimensions as the 6.8 SPC from the neck junction foreward which is 1.414" IIRC. This would move the shoulder back almost a .10 from the 5.56 location. My cartridge building software gives it a capacity of 29.3 gr. Probably lose 150-200 FPS to the improved 6.8 SPCII so expect 110s at 25-2600. Remember though that the nuetered 6.8 that Remington sent to SAMMI had about the same velocity as this one and the gel tests were done at this somewhat lowered velocity also so those defensive bullets will perform well. The 6.8 has some very good light for caliber bullets now. 85gr TSX, 95gr TTSX, 100 and 110 gr Accubonds. This would be a fine deer round with those. This would turn my SU-16A into a 5 lb deer rifle. | |||
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223Rem with taper blown out and 40deg shoulder is the '270HogHunt' here. Cheers... Con | |||
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From bolt actions or ARs Con? That sounds like the 7mmTCU necked down a bit, not sure if that would fit and feed well from a AR mag. Good to hear that it's powerful enough for hogs. I could head for California hog hunts with this and the TSX or TTSX. | |||
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The depressed grooves on the front of a .223 mag are deeper than those on a 6.8 SPC mag ... to allow the proper stacking of cartridges at the front due to the larger neck diameter of the cartridges carrying .277" bullets. I'd rather have the 6.8 case because that last 100 to 150 fps is worth having. SSA has been running specials on new brass for a while. I now have enough for a lifetime of deer hunting. Mike -------------- DRSS, Womper's Club, NRA Life Member/Charter Member NRA Golden Eagles ... Knifemaker, http://www.mstarling.com | |||
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Yes but the PMAGs are plastic. What they do is pull the baseplate off and file down those front ribs about halfway. They still work in 5.56 after that. I agree about choosing the 6.8 SPC for ARs but I shoot a SU-16 and a Daewoo AR-100 and the bolts and barrels are different. | |||
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 Thanks!577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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Yes the filed down ribs of the 223 plastic mags does sound like the best option. With a barrel swap you could go from 223 to 6.8 CQC with ease. Was thinking keeping 223 shoulder dimensions the same so no forming needed. just a tad shorter to accomodate the longer bullet.
577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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6.8-223 is less than ideal. The case is too long. The bullet ogive is down in the neck at magazine length. This is why the 6.8 is shorter. | |||
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Boom Sticks case length is the same as the SPC. Ummm I think, the new 95 TTSX(sweet bullet BTW) and Accubonds were designed for the 1.676" case length any longer and the best bullets won't work.
That what this fella did but the neck length looks way to short to me. From the pic it looks like his case length and OAL is too long. http://www.defensereview.com/6...r-urban-warfare-ops/ On the other hand the 6.8x40 has a short neck too. The comparison pics are 2/3 down the page http://www.ar15.com/forums/top...=121&t=397161&page=4 I'd steal everything about the SPC Murray chamber from the neck juction forward, leade, twist, 45 degree leade angle(whatever the proper name for that is. They screwed it up on SAMMI SPC and SPCll) but it's your baby. That short neck might work. | |||
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Well it seems the 1.686" length of the 6.8 CQC in this idea being the same length case as the 6.8 SPC is probably the Goldilox length. It was good to read that article. Thanks! Since the same oal restrictions the performance should be the same. Yes a shorter neck but no compromise on performance. The necked up 223 case is just too long IMHO 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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Was looking at the 222 case. If necked to 6.8 and neck shortened it would give a longer neck than a shortened 223. Could even cut it back more to say 1.6" or 1.625" Would lose a tad on capacity but have a good neck length. 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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To obtain a .270/.223 round of AR-15 magazine length, you will have to seat the long .270 bullet pretty deep in the case (reducing the .223s aready small case capacity). And once you had this round, what .270 bullet could provide adequate penetration and expansion at the velocities this cartridge could produce? I think your desired 2,400 fps with a 115gr. bullet is probably a little bit optomistic for a magazine length .270/.223 round. I would just go with the tried and true 6.8 SPC. | |||
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I am taking the easy road on this one. www.deltacompanyarms.com is run by a disabled Iraqi veteran. Look at the 300 BLK. Mine is going to be an 11" barrel on one of my pistol receivers. The focus will be a 247gr cast bullet at 1050fps with a suppressor. Phftt-klack! You may be thinking of the 270 Ingram, circa 1979 or so for contenders. Rich | |||
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Rich... The 358 gremlin is better than the 300 BLK or 300 blackout. Pistol bullets to 35 rem bullets to subsonic heavies up to 300 grains. Same concept but better IMHO. 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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Boomie, normally I applaud your creative thinking. I believe you are off on a tangent this time. You have to work within the parameters of magazine internal dimensions with the AR firearms when you start drawing on restaurant napkins with detachable magazine weapons. Working within those limitations is what got us the 300 BLK in commercial form, and SAAMI approval. There are two million or so AR's in citizens hands, and a hundred million 223 magazines. Make use of them. My spec 300 with the 247gr bullet at 1100fps delivers nearly 700ft/lbs of ME. Thirty of them out of a standard thirty round magazine. regards, Rich | |||
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The 358 Gremlin works. If you go to BFG cartridges website you can see this works. Yes magazines are modified or special order. He has an order for a special run of magazines to make this work at full capacity. The 270-223 has some kinks I admit. 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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Boomie, perhaps, but you need to look at the original 300 Whisper with jacketed bullets to properly compare. Rich | |||
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Boom, is BFG Cartridges Fireball168? | |||
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Si 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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I might send him my specs for the widened 6.8 SPC and see if he wants to chamber a barrel, set up dies, etc. Gotta get an email program installed on the PC with the scanner first though, danged Win 7 upgrade wiped out my email. The 222 brass makes good sense. Cut it down, neck up and load. You could set up the reamer so it fireforms the shoulder forward to the same neck length as the 6.8 but it isn't important. I ran both versions in my software and the difference was .2 grains water, not enough to matter. Assuming that they fit in one of the new quad-stack mags imagine a 50-60 rd magazine full. Serious firepower. Would be real nice if one of Hodgdon/Hornadys Superperformance powders work in that. They'll release more versions in the future and the blend for the 5.56 case size should be a good seller. | |||
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Well a necked up and trimmed 222 case would give the best neck. Easier still would be just utilize the 25 copperhead reamer and dies and trim that long neck back to say about 1.6" ish to keep it close to 2.25" oal. Both would be sweet. If the case was 1.6" long a rimmed version could be sweet for a contender using 357 Maximum brass.
577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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