270 x 223

01 July 2015, 09:15

Hoot Murray

270 x 223

Has anyone done one of these? It would be just like a 7mm TCU only in 270 caliber. It seems to me that that would be a good cartridge on an AR platform almost the equal of the 6.8 but readily available brass.

Muchas gracias,

Hoot

01 July 2015, 19:22

ramrod340

Sure it would work. But the big question I have is why? A 6.8 has around 36-37grs of capacity. The 7TCU has around 31grs the 277 would have a touch less. To me taking the 223 case and necking it down to the 277 vs just going with a 7tcu just doesn't make sense. The cost of reamer custom dies etc???? If you want something like the 6.8 you are going to need a larger case. Otherwise go 7mm and be happy.

Just my opinion. Last comment build what you want to make yourself happy.

02 July 2015, 00:34

boom stick

IMHO the 257 is better than 264. 7 thou difference but the bullets in 25 have a much wider range of impact velocity. Not to mention the 25 is designed for shorter tip to crimp. If you are set on the 6.8 then I would consider the 222 necked up and shortened a bit.

02 July 2015, 01:23

TomP

quote:
Originally posted by Hoot Murray:
Has anyone done one of these? It would be just like a 7mm TCU only in 270 caliber. It seems to me that that would be a good cartridge on an AR platform almost the equal of the 6.8 but readily available brass.

Muchas gracias,

Hoot

A 7x45 mm chamber was the backup plan in case reboring my Savage 24V for 6x45 mm ran into problems. The 6mm rebore worked fine, so it was shelved, but it would have been an ok change. I wanted a combination antelope/sage grouse gun.

02 July 2015, 09:11

Hoot Murray

I was just curious as to if anyone had done this wildcat. So far it does not look like anyone has done this wildcat. I have a TC Contender Barrel in 7mm TCU and it shoots fine. Was just wondering what the ballistics would be going down to 270 cal and using it in a rifle with a 16 inch barrel. Thanks to all who responded to my post.

Muchas gracias,

Hoot

02 July 2015, 10:29

Mark Clark

270 Ingram, https://www.loaddata.com/membe....cfm?MetallicID=1687
I believe we have the reamer. We may have dies http://www.dvhcustomguns.com

Mark

02 July 2015, 13:36

Mikee-NZ

I have just ha a 6.5TcU built, very close to what you are interested in. Here is some data on the loads I have worked up so far. I would imagine the 270-223 would get very similar results

quote:
Ok, I have had my rifle for a few weeks now and here is some of the data from the loads I have found so far
OBVIOUSLY ALL USUAL DISCLAIMERS APPLY WITH THIS DATA

Brass was Winchester .223 necked up and trimmed to 1.740
Primers were fioochi small rifle
Chronograph is Ohler and rifle has 24 inch barrel

LOAD ONE, (5 rounds)
100gn Sierra HP / 27 grains IMR8208XBR
Velocities
Shot 1 2494fps
Shot 2 2521fps
Shot 3 2520fps
Shot 4 2477fps
Shot 5 2509fpa

Load 2 (4 rounds)

100gn Barnes TTSX / 28grains IMR8208XBR
Shot 1 2637fps
Shot 2 2632fps
Shot 3 2617fps
Shot 4 2601fps

Load 3 (4 rounds)
123gn AMAX / 28.5gns IMR8208XBR (MAX LOAD)
Shot 1 2617fps
Shot 2 2634fps
Shot 3 2609fps
Shot 4 2610fps

Load 4 (4 rounds)
100gn Sierra HP / 28.1gns Vihtavouri N530 (almost MAX load)
Shot 1 2763fps
Shot 2 2765fps
Shot 3 2777fps
Shot 4 2780fps

most accurate load was load 1 with approx 6mm group centre to centre @ 90m (100 yards)

going to work on load for hunting using N530 and the 100gn ttsx

04 July 2015, 14:15

Rule 303

quote:
Originally posted by Hoot Murray:
Has anyone done one of these? It would be just like a 7mm TCU only in 270 caliber. It seems to me that that would be a good cartridge on an AR platform almost the equal of the 6.8 but readily available brass.

Muchas gracias,

Hoot

Been done. The bloke in Aust who came up with the 35Sambar made one up. I think he called it the 270Egg????. He is the producer of Guns and Game magazine down here. Goodle the magazine and see what you can find out.

06 July 2015, 00:49

theback40

I just read that article, so it must be somewhere near at hand. The EGG stands for Efficient Game Getter, he did a 6.5 on a .221 case for a EGG short. I was impressed with the velocities he got with that little rig too. He shot a bunch of pigs with 120's and it did far better then you would guess.

11 July 2015, 16:37

hogfarmer

277 Wolverine is another. http://www.maddogweapons.com

11 July 2015, 19:31

boom stick

quote:
Originally posted by hogfarmer:
277 Wolverine is another. http://www.maddogweapons.com

http://forums.accuratereloadin...311091421#5311091421

Man, I thought that would have been good long ago. Seems it is working well.

12 July 2015, 12:08

Idaho Sharpshooter

cartridges need to have a niche they excel in to have any chance of acceptance.

I would not see this cartridge a good fit and feed in an AR.

13 July 2015, 09:01

Hoot Murray

Well, guys,

I think that it would work in an AR platform, but checking into it leads me to believe that there would be a lot of money to do it. No one that I can find supplies a barrel, so one would have to buy a blank and machine it down to the contour requires for an AR platform. So, my curiousity is satisfied> I won't be doing this.

My thanks to all who replied,

Hoot

27 July 2015, 21:22

bobmn

Ramrod: Please state your source for the 36-37 grains of water case capacity for the 6.8 SPC. I have an email from Billy at Remington who states "... the average case capacity to overflow the 6.8 Remington SPC is 35 grains of water". The Nosler load data shows a case capacity of 29.5 grains case capacity for the 6.8 SPC with a 115 grain bullet.
I have personally measured the water capacity to overflow of a 7mmTCU case formed from military brass (thicker than commercial cases) at 33 grains of water. I bet if you measured the capacity of a 7mmTCU with a 120 grain bullet seated in a commercial case to the same over all length as the 6.8 SPC, the case capacity would be within a half of grain of 29.5. The advantage of the 7mm TCU is that it has a .373 bolt face instead of the odd 0.421 bolt face of a 6.8 SPC while having the virtually the same effective case capacity.