which .223 based cartridge?

[justin22885]

as the .223 just doesnt have the potency i look for, i was looking into other cartridges like 6.5 grendel and some obscure wildcats.. but doing some ballistics calculations and playing around with some load data ive discovered that if you build 6mm TCU, 6.5mm TCU, or 300 blackout upon 5.56 brass and load to higher pressures the performance increase actually brings these cartridges right into the realm of 7.62x39 and 6.5 grendel

so, i tested all loads except the 30 cals with speer hot core bullets, 100 grains for 6mm, 120 grains for grendel and 6.5mm TCU, and for the 30 cals it was the 150 grain SPBT from speer and all five calibers were producing around 1,550ft/lbs at the muzzle and around 550ft/lbs at 600 yards.. time of flight and drop were different on the three of course with the heavier bullets having more drop

so this has me thinking of finding a .223 based cartridge, considering how dirt cheap once-fired 5.56 brass is, to play around with.. but which one? and why? (id consider any caliber based on .223/5.56 so long as it the efforts to resize the brass are minimal)

 

[68wj]

I like the 6mm and .277 (6.8) options.

I prefer the performance of the 6.8 SPC and don't mind the less common components since they continue to become easier to find, but the .223 cased .277 Wolverine gets close using normal bolts and common brass. Here is a write done by AR15Hunter.com http://ar15hunter.com/277-wolverine-range-and-hunt-report/

 

[justin22885]

i'll check it out.. in my opinion 30 cal bullets have to be pretty long to have a decent BC when compared to the overall cartridge lengths being discussed and they do generate a lot of drop and longer time of flight when fired from anything less than a .308

 

[jim in Anchorage]

Well you may want to reinvent the .17 Remington.

 

[justin22885]

i want bullets heavier than what .223/5.56 provides

anyway, i did some reading on .277 wolverine, it claims a 110 grain bullet at 2,500 which exactly matches load data of the 6.8SPC... 6.8SPC being a bit lower pressured than what 223 and 5.56 can generally do, it seems like it may really match 6.8 SPC in something easier to find (make) brass for and suitable magazines... so i'll consider this one along with the others.. however 6mm and 6.5mm TCU do offer higher BC with the 6mm bullets only being 10 grains lighter than the short 6.8 bullets and being easier to find

 

[eldon519]

The .277 Wolverine looks very promising to me too. There is also the 6.5 Patriot Combat Cartridge but that super-short neck makes me uncomfortable. Looks like bullet setback just waiting to happen.
http://rifleshooter.com/2014/11/6-5-patriot-combat-cartridge-6-5-pcc-6-5mm-wildcat-for-the-ar15m-16/

 

[justin22885]

seems this is one of those too many cooks in the kitchen type of problems.. which 223 based cartridge.. meh, theres about 2 dozen of them that all do the same thing

 

[mshootnit]

The late Greg Rodriguez authored a very good article regarding the 6mmx45 titled A Modest Proposal, Shooting Times
Here is the link: http://www.shootingtimes.com/ammo/ammunition_st_proposal_200808/

 

[Gtscotty]

You can load 6.8 SPC for modern chambers almost 200 fps faster than the cited .277 Wolverine load (I've done it without pressure problems in an 18 in barrel) . That is a significant difference, but it might be a tradeoff you're willing to make for bolt and magazine commonality. On the other hand, 6.8 loaded rounds and components are becoming more and more common. I see a lot more brass and factory ammo out there on the shelves in 6.8 than in 6.5 G, for example. It's not as exotic as you're looking for, but regular old 6.8 would probably meet your needs pretty well.

 

[justin22885]

uuh, so what exactly is the difference between a 6mm TCU and a 6x45mm?

also, if i cant get 6.8SPC for under 40 cents a round then im not interested, i can easily get a .277 or 6x45 for under that

 

[justin22885]

i found a really old thread on a different forum of people discussing the differences between 6mm tcu and 6x45.. said the TCU has even less of a taper with sharper shorter angles and require fire-forming.. the sharper shoulder angle and less taper would translate into even less reliability in a semi, and firefoming is the kind of extra steps im looking to avoid, so 6mm TCU (and other TCU cartridges) are out of the question

which leaves me to 6x45, 25-45 sharps, 277 wolverine, and 300 blackout and im preferring a projectile in the 100-125 grain range with a ballistic coefficient of over .400, preferably in an expanding type of projectile, no hollow points or FMJs

 

[mavracer]

If you're just looking to shoot supersonic 30s you might look at the 7.62 X40 Wilson tactical

 

[Gtscotty]

uuh, so what exactly is the difference between a 6mm TCU and a 6x45mm?

also, if i cant get 6.8SPC for under 40 cents a round then im not interested, i can easily get a .277 or 6x45 for under that

PSA has loaded fmj for $.49/Rd, and loaded bonded soft points for $.64/Rd. Where can you get loaded .277 or 6x45 for anywhere near that price? If your talking reloaded costs, you could reload any of the three rounds for under $ .40.

 

[justin22885]

yeah, ill be reloading my new cartridge, so far im looking mostly at the 6x45 and 25-45, any decent 6.5 cartridges that dont require fire forming?

 

[jmr40]

You're not going to get significantly, if any better performance on anything based on a 223/5.56 case. The better 77 gr 223 bullets will do just about anything a 243 will do. The 6.8 is one of the few rounds used in AR's that is an improvement, but it isn't based on the 223.

 

[eldon519]

Is anyone actually loading SPC II anymore now that SSA got bought up? I've read their "5.56" is now much more watered down, more .223-ish.

 

[Zerodefect]

Don't know anyone doing 6.8spc now that modern 5.56 is all fixed up for 14.5"+.

And .300blk owns 7-10.5" Ar15's. Wouldn't mind trying supersonic .300blk in a 14.5" just to see what kind of power it would have.

 

[Gtscotty]

Is anyone actually loading SPC II anymore now that SSA got bought up? I've read their "5.56" is now much more watered down, more .223-ish.

The velocities listed on most of the 5 Nosler 6.8 loads indicate they are for Spec II or later, don't know how they chrono though.

 

[Gtscotty]

Don't know anyone doing 6.8spc now that modern 5.56 is all fixed up for 14.5"+.

Don't know what you mean, lots of folks use 6.8 for dedicated hunting MSR's. There are 20 loads under 7 different brands listed at Midway. That's more than most of the less common bolt cartridges people sometimes pine over (e.g. 257 Bob, 260 Rem, 6.5 CM, . 338 Fed, . 358 Win, 35 Whelen etc.).

 

[Zerodefect]

Ok, I'll go along with "hunting". But aside from that, everyone's building 5.56/.223wylde and .300blk's.

 

[Gtscotty]

"Hunting" was always the strong suit for the 6.8. You don't need more than 5.56 for gun games and home defense, and if you're going to be a silent commando 300 blk is the only way to fly.

 

[justin22885]

.223/5.56 in weights above 65 grains is almost entirely match ammo, not any good for what im looking for as my preference in bullet selection would be either for a high BC soft point boat tail such as those from speer, or a polymer tipped expanding projectile.. something that is both accurate with superior internal ballistics to an FMJ

the specific bullets ive found that i like are the speer spitzer SPBT in 100 grains for 6mm, 120 for .25 cal and 130 for 6.8... i believe 100 grains is about the max for the 6mm, how well would the 25-45 sharps handle the .25 cal selected and can the .277 wolverine handle the 130 grain projectiles?

and no, im not hunting, looking for something that can beat out the 223 in energy, momentum, barrier penetration, that can also beat the 7.62x39 in accuracy made from cheaply available once fired brass (5.56 once-fired is very inexpensive) requiring minimal efforts to reform (no fire forming) for the purpose of stockpiling as a potential go-to caliber

 

[justin22885]

it looks to me, judging from the specs i found on .227 wolverine that while coming pretty close to 6.8 SPC ballistics, it seemingly has a slightly shorter case too.. if you were to seat the .277s bullet just a little less deep to add a bit more powder, i bet you could match 6.8SPC ballistics spot on especially using 5.56 brass and higher pressures.. so it kind of renders the 6.8 SPC not worth the extra cost in reloading components, magazines, and barrels

anyone know how i can add this cartridge to quickload so i can play around with some load ideas a bit?.. im wondering with the slightly shorter case if the .277 wolverine could load a longer, higher BC bullet than the 6.8 SPC.. ultimately though it seems like its a heavier, slower bullet compared to something in 6.5, or the 6x45, wouldnt have nearly as flat a trajectory and would add minimal gains to barrier penetration especially when youre comparing a 100 grain 6x45 to a 110 grain .277 wolverine

just curious, but why was the 6.8SPC capped at 55,000? is it due to the brass it uses or is that pretty much the safe bolt thrust limits of the standard AR locking lugs?

 

[eldon519]

I'm not sure if I actually see what you plan to use these rounds for but here is a thread with stories and pics of AR15 .223 deer kills. Seems they've had pretty good luck with the Barnes 70gr TSX (as well as the lighter variants) and the 75gr TAP.

http://www.ar15.com/forums/t_1_5/13...raphic_Pics_11_30_update_with_son.html&page=1

 

[justin22885]

not for hunting deer.. for a general purpose go to weapon, for ANY occasion, id rather rely on something a bit more potent than .223/5.56 and right now i think im mostly interested in 6x45, 277 wolverine, 300 blackout.. and if i could use them in standard magazines id jump all over the 7.62x40 WT, which in my simulations can deliver MORE power than 7.62x39