New AR build, caliber choices...

[451_Detonics]

My new Zombie Squad Ar lower is on it's way but I am in a quandary as far as caliber. It will not be a .223, I have enough of those. This will be an intermediate range rifle for 400-700 yard work. I want it to use standard AR mags as well and preferably a standard BCG. This means I am looking at the .221 fireball brass family. Rounds in this family include

.221 Fireball
.222 Remington
6mm Whisper
6.5mm Whisper (the leading round in my thoughts)
7mm Whisper
6mm MPC
.300 Whisper (already have one)
.338#2 Whisper

The 22 calibers I have pretty much eliminated due to the lack of an ability to buck wind well. The .338 may use too heavy a bullet for the ranges I am considering. The 6.5 however will allow use of the great VDL bullets for longer range use, and from a 20 inch barrel 2400 fps is reasonable. It could also be loaded subsonic for a suppressor later on. Brass is easy to convert and it is an easy round to load.

This rifle will be built up using parts with an eye on quality, not on price...most specifically the barrel.

I have considered the 6.5 Grendal but due to it needing specialized mags it is out of the running for consideration so no need bringing it up.

Any thoughts on caliber i may have missed and why would they do better than the 6.5 Whisper.

 

[Limpy88]

how about 6mmx45 same case as 223 but bigger bullet but it may not reach your range wanted. there is also the 30 ossm. but it is only offered by olympic arms. you also have the 6mmAR similar to 6mm ppc performance
6mm AR Home Page
keep a normal bolt may be hard for a good long range bigger bullet.

 

[451_Detonics]

Well...after doing some further research my considerations are moving from the 6.5 Whisper towards the 6.5 MPC. This cartridge will easily push a 95 grain at 2800fps from a 20 inch barrel and requires very little work to form the brass. (ready to load brass is also available from SSK) As I have no intention of this being used as a CQBR I am looking towards a 24 inch barrel if that will gain me addition velocity, something I will have to discuss with JD.

The 6.5 MPC (multi purpose cartridge) is simply the .223 brass opened up to 6.5 and trimmed to 42mm.

 

[worksalot]

I guess I don't see an advantage of the 6.5 whisper over the 300 whisper.

 

[451_Detonics]

I have a 300 Whisper with suppressor, the 6.5 would be for supersonic rather than subsonic. The 6.5 Whisper has better long range ballistics in this case but as I said after doing more research I think the 6.5 MPC would better suit what I want.

This will not be a go out and blast 300 rounds at the range gun but rather more of a precision rifle for competition as well as a coyote gun.

 

[malern28us]

I know that the beginning of the page says that they are not currently taking custom orders at this time but....
Match grade customs
The plus is that it is fun to see what Harrison can do! (scroll further down the page to read about some of the 6mm offerings.)

 

[451_Detonics]

If I go with the 6.5 MPC I will talk with JD Jones first and either buy my barrel through him or see who he recommends. I have shot enough of JD's stuff to know he builds top rate gear. (the 500 Whisper is a blast to shoot)

I have talked with a couple of people who load the 6.5MPC and the consensus is with a 300 yard zero and a good mil dot scope you can easily hit anywhere from 100 to 700 yards.