5.56 based upgrades?

[Switchblade]

I have been looking at upgrades in caliber for the AR. There are obvious choices in 6.5 Grendel, 6.8SPC, 6mmAR, 458SOCOM, and 450 Bushmaster. Are there any upgrades that use the base 5.56 case or is it a moot point? Reason I am looking is I have a bunch of 5.56 P-Mags and any 6mm based upgrade requires new mags.
I figure that with the allowable powder volume in a 5.56 case, bumping up to a larger bullet would make the larger bullet not quite fast enough. Not quite sure, but I think I am headed in teh right direction with my thinking

 

[our gang]

Re: 5.56 based upgrades?

Have a bud who has a well tricked out RR 6.8 SPC and loves it. Shoots as well as any military style AR with considerably more "whup ass" factor. He is not a reloader and there is some quite good factory ammo out there.

 

[Jedi]

Re: 5.56 based upgrades?

Switch
I,m with ya looking to do same thing, original plan was 6.5grendel
but i,m thinking 6mm would be better choice

So im going with 6mmAR complete upper that way if SHTF i can drop original 5.56 upper back in and have easier to find mil cal.

Dont think i will go with turbo version as fire forming just irks me... thou the numbers look impressive

I will do the varmint upper on 24" barrel
http://www.6mmar.com/6mmAR_New_Products.html

One stop shopping i like that to, just saving up my pennies.
Stick the 5.5x22 NXS from 08 on it, should be fun.

 

[Switchblade]

Re: 5.56 based upgrades?

I figure the 6.5 Grendel or the SPC willbe the way to go,and buying mags for it will have to be the way also. I just really hate the 5.56 unless you can get the serious bullets for it

 

[300LW]

Re: 5.56 based upgrades?

There is the 6.5 MPC

http://www.sskindustries.com/6_5mpc.htm

Don't know much about it, though.

 

[slapshot.308]

Re: 5.56 based upgrades?

What are you looking to use for? There are upgrades concerning external and terminal ballistics but is comes down to what you want "it" to do and how much of "it" you want it to do.

 

[Switchblade]

Re: 5.56 based upgrades?

Ah, 6.5MPC looks pretty good if the 5.56 mags are used. Basically I am looking for something that will use the existing mags but offer more power out to 300M. Still looking at all the options but was curious if any one of them used the basic 5.56 mags with no other changes outside of the basic barrel.
The 6.5 Grendel or 6.8SPC still looks to be the best of the breed with the 458SOCOM being a kick ass thumper.
I see this as a future project to make the platform a better suited all around rifle. AS I said, the 5.56 was, and still is a prarie rat caliber

 

[260shtr]

Re: 5.56 based upgrades?

I'm somewhat bigger than a prairie dog, but I still don't want to catch a 55 gr Ballistic tip at 3000fps at 300 yards or 500 for that matter.

 

[260shtr]

Re: 5.56 based upgrades?

The 6.5 MPC with a 100 gr BT and a 20" barrel would fit into the kick-ass category. If you are gonna reload for it, you can use any bullet you want.

 

[mdesign]

Re: 5.56 based upgrades?

Interesting thread. I have a 5.56 but am interested in the 6.5 Grendel as a hunting cartridge. It has great ballistics, very low recoil and I think it could be a good mid-range deer cartridge.

I also heard the rumor that the military is considering going to a similar cartridge because it has more power than the 5.56. If the use of the 6.5 Grendel was more wide spread, it might give us better options.

 

[our gang]

Re: 5.56 based upgrades?

I'm not sure the 6.8 will use 223 mags. My bud's RR magazines are marked 6.8 and are not the same as my DPMS 223 mags.

 

[Switchblade]

Re: 5.56 based upgrades?

As was stated by Mega Cab in another thread,"I do not want to be shot with a sewing needle out of a straw". I have to agree, being shot with anythign would suck. My end goal is to just make my own M4gery a little more whoop ass with more thump and minimal cost. Converting to 6.5MPC would only really require rebarreling and a headspace adjustment on the upper I have, then a set of dies with my existing brass. I do know if I want a killer set up, the 6.5 Grendel/6.8 SPC would be the way to go.

The 6.5 Grendel, 6.8 SPC, and 7.62x39 have to have their own mags. The .450 Bushmaster, and .458 SOCOM need the mag lips 'adjusted'. This is because they use .30, or .45 based cases. The 6.5 MPC is the only one that uses a 5.56 based case and fits baseline 5.56 mags like the P-Mags or stock AR mags(all based on my research so far)

 

[Scimitar]

Re: 5.56 based upgrades?

A 223 with the right bullets like a Nosler BT or Hornady Vmax
will say hello loudly. A Barnes TSX will penetrate and expand.
Milspec stuff ain't that hot though. Other than .223 what I like is a 300 whisper. The CQB cartridge IMO! 240 flippin leave a path.

 

[slapshot.308]

Re: 5.56 based upgrades?

+1 on the 62gr and 70gr TSX. The 60gr Nosler Partition is pretty good too. The Swift 75gr Sirocco II is pretty evil too, but at around $1 per pill it's expensive medicine.

 

[MR3GUN]

Re: 5.56 based upgrades?

The Grendel is a great LR round from the AR platform. The 6.5 is a great CQB round. The two are really designed for two different roles IMO.

 

[sandwarrior]

Re: 5.56 based upgrades?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Switchblade45</div><div class="ubbcode-body">I have been looking at upgrades in caliber for the AR. There are obvious choices in 6.5 Grendel, 6.8SPC, 6mmAR, 458SOCOM, and 450 Bushmaster. Are there any upgrades that use the base 5.56 case or is it a moot point? Reason I am looking is I have a bunch of 5.56 P-Mags and any 6mm based upgrade requires new mags.
I figure that with the allowable powder volume in a 5.56 case, bumping up to a larger bullet would make the larger bullet not quite fast enough. Not quite sure, but I think I am headed in teh right direction with my thinking</div></div>

The only 'contender' I knew of, no pun intended, for an upgrade was the 6mm/5.56. Straight neck up of the 5.56 to 6mm. Aparrently the sharper shoulder and straighter walls of the 6nm TCU were supposed to be too much for the AR rifle to handle smoothly. I don't know I never had one. it launched an 80 gr. bullet @ 2900 fps. About 300 fps lower than a .243 can do it in the same 20" barrel.

As far as the other choices I went back and forth on the 6.5 Grendel and 6.8 SPC. I chose the Grendel for the long range capability as well as improved performance in 0-300 yds terminal ballistics over the 5.56. As far as I was concerned the 6.8 and the 6.5 were about dead even in the 0-300m range. But, the fact that good long range bullets are made for the 6.5 and not the 6.8 decided it for me. The other issue was also that you can seat good long range bullets out a ways in the 6.5 case whereas you can't in the 6.8 As my reasoning denotes the advantage went to the 6.5. And, that's what I bought. I worked up a bunch of loads for it and found that I could get the velocity from factory and reload alike that was advertised. I then came to realize that I never was going to hunt with the round and what it was to me was an experimental, so I sold it. I was satisfied it could do what was advertised.
The two .458 SOCOM and .450 Bushmaster make very good close up ballistics but needing any range is not an option with them.

 

[Greg Langelius *]

Re: 5.56 based upgrades?

Going up in bullet mass is not necessarily going to deliver more punch. Terminal peformance is a product of mass, velocity at distance, and the ability of the bullet's construction to transfer the remaining energy in the most disruptive manner.

The way to decide this is to look at ballistic performance to determine bullet velocity at the target distance, then take that info to the handloading manual (if it provides such data, as the Sierra manual does) and use it to look up the specific bullet's terminal energy at that terminal velocity. Then that velocity/energy info must be weighted against the bullet's construction factors to determine whether bullet deformation will effect the desirable degree and rate of energy transfer.

This is by no means an easy process, and often there are gaps in the information one needs to complete the task.

Techniques like using .357 pistol bullets for .35 (.358) caliber rifle cartridges come to mind. Although the bullet construction may be explosively expansive at actual pistol distances; at extended distances, their lighter construction can work more ideally once the initial velocities have bled off.

It's not a science, it's an art, and there are not a lot of really accomplished practicianers of this art.

Personally, I like the .223 with a 50gr or 55gr Nosler ballistic tip. It's ballistically very effective, can be tuned to match accuracy, and as a tissue disrupter, it's very effective at distances out to 300 or so yards, beyond which I would be switching over to my .30-'06.

Greg