243wssm or 6.5 Grendel for ar15 build

[ken6881]

So I am trying to decide on what caliber to build my next ar in. I am looking for something to carry some more energy than 223 will to kill groundhogs, prairie dogs, and deer at moderate ranges. And plink steel as far as possible. Any opinion between 6.5, 243wssm or even 6.8 spcII. Or any other cartridge?

[PDM]

My friend has a JP built 6.5 Grendel. I was super impressed with the accuracy. It would be perfect for your application. High quality ammo is a little hard to find. For a hand loader, the Grendel is a great choice.

[adayton]

So I am trying to decide on what caliber to build my next ar in. I am looking for something to carry some more energy than 223 will to kill groundhogs, prairie dogs, and deer at moderate ranges. And plink steel as far as possible. Any opinion between 6.5, 243wssm or even 6.8 spcII. Or any other cartridge?

I don't have any experience with the 243 chambering ... but I do with the 6.5 Grendel and 6.8 SPC II ...
I have built both in several variations ...
I prefer the 6.8 SPC over the Grendel, but both will reach right out there ... a heck of a lot further than the 5.56 and with a whole lot more energy ...
As far as ammo, handloading for either caliber is what you should strongly consider.
For more info on the two, there are forums dedicated to each ...
http://www.68forums.com (obviously for the Remington cartridge...)
http://www.65grendel.com
I am a member of both and would definitely recommend getting on there and gather as much info as you can before actually landing on a build ...
I may also be able to answer some questions for you... but if it gets too involved, I will defer to the forums as there are a whole lot of informed people out there that can and usually will answer most anything.
Thanx,
Allan

[son of liberty]

6.5 Grendel though I feel anything but 5.56 is a waste of time an effort in an AR15 , the return just dose not justify the loss.

[Whootsinator]

Given your stated mission, and assuming 'moderate range' to be about 300 yards, I personally wouldn't consider the juice of a different cartridge worth the squeeze from a practical efficiency stand point. I believe you would meet your goals most efficiently and simply (read: with the least headache) by buying a dedicated 20+ inch barreled long range upper receiver group in 5.56 and the appropriate buffer. That is also assuming you already have an AR with which to swap uppers.



Would it be less cool? Not to me, but maybe if you think so. Would another caliber have better ballistics? Yes, it probably would, but is it necessary? I think my recommendation would be the most logical option.

That said, if you have the resources to take on an arguably unnecessary new caliber for fun and cool points, go for it dude. Whatever you decide, make sure to take good pictures and show it off to us!

[ken6881]

Given your stated mission, and assuming 'moderate range' to be about 300 yards, I personally wouldn't consider the juice of a different cartridge worth the squeeze from a practical efficiency stand point. I believe you would meet your goals most efficiently and simply (read: with the least headache) by buying a dedicated 20+ inch barreled long range upper receiver group in 5.56 and the appropriate buffer. That is also assuming you already have an AR with which to swap uppers.



Would it be less cool? Not to me, but maybe if you think so. Would another caliber have better ballistics? Yes, it probably would, but is it necessary? I think my recommendation would be the most logical option.

That said, if you have the resources to take on an arguably unnecessary new caliber for fun and cool points, go for it dude. Whatever you decide, make sure to take good pictures and show it off to us!

You make a good point. I currently shoot a 5.56 20" upper and it does a good job (killed a dear with it this year)

I like the idea of a diversified ammo if for some reason 224 cal bullet become extinct.

I do hand load currently for 5.56/223 but my current upper is a 1-9 twist some I am afraid that I cannot stabilize a sufficiently heavy bullet but have not tried to yet.

I used moderate very generally for anything 175-450 obviously only taking only humane kills (depending on the animal, round and my ability)

Yeah I kind of like the cool factor as well but I am defiantly open to staying 223 if its a viable option. my impression was that 224 cal bullet is just not retaining the energy to make a good ethical kill at 300-450 yards. Over that range I would most likely be switching to my bolt gun 30-06 for anything deer sized no matter what round I choose for the ar platform.

[Whootsinator]

Given the new info, and with my CURRENT knowledge, I'll offer a new plan... Sell your current 20" upper, combine that money with the funds you had set aside for this different caliber project, and purchase a quality long range upper. If you have cheap/mediocre glass on your current upper, sell that too and make it a quality upper AND glass budget.

I'll ask around and do some digging to try to find the absolute maximum effective range of 5.56 in regards to terminal ballistics against live targets.

[ken6881]

Thanks wootsinator
I just bought some good glass SWFA 10X42MQ mil mil scope has yet to come in.

I will do a little research on good high BC 224 bullet but is still good for hunting. Mag length is a concern but I know there are some mags that load single stack and allow for longer seating depths of long bullets.

[Whootsinator]

I can't come up with how single/double stack would make any difference to maximum COAL, but I don't believe COAL is a serious issue. The longest bullet I am personally aware of is the Barnes 70gr TSX, and loaded it will fit in a PMAG, Lancer A5AWM, or STANAG magazine.

Bullet lengths:
Barnes TSX 70 grain - 1.040"
Hornady Match 75 grain - 0.992"
Sierra MatchKing 77 grain - 0.985
Nosler Competition 77 grain - 0.982
Barnes TSX 62 grain - 0.945
Nosler 69 grain - 0.900
Sierra 69 grain 0.890

[ken6881]

There is a mag that the case sits directly into the center and sits back into the "fin" of the mag thus allowing longer oal

I know the bullets will phisically fit but to increase case volume and get closer to the lands it would help to seat the bullet longer in the case

[son of liberty]

There is a mag that the case sits directly into the center and sits back into the "fin" of the mag thus allowing longer oal

I know the bullets will phisically fit but to increase case volume and get closer to the lands it would help to seat the bullet longer in the case

My handloads are capable of sub MOA in my good barrels , loaded to 2.253. The difficulty is in the wind call, even squeezing every last drop of accuracy and velocity , with a 223 bullet the difficulty will still be the wind call.

[ken6881]

I have never really tried to tighten up my groups with my current load when I get a decent scope on it I will start playing with some good hunting bullets, and varget to see how it goes.

[ken6881]

After doing some looking I cant find any of the mags I was talking about last I knew dpms bought the right to make them but I cant find it on there site. I can modify a mag to fit up to 2.350 overall length. Looks like I am going to buy some 62-70gr TSX and 55-70gr GMX bullets to try out of my current upper and if I don't like it probably just re-barrel what I have to a 20-24 Stainless heavy barrel with a 1-7/8 twist and be done.
Ran some numbers through the ballistic calculator and looks like to stay above 500ft-lb of energy for deer 450yds looks like the edge with max loads suggested in my Hornady reloading manual for the GMX 55-70gr bullets

[Whootsinator]

The GMX projectiles are harder (they're gilding metal instead of pure copper) than the TSX bullets. The TSX's should offer more reliable expansion considering they should have a lower minimum expansion velocity.

Long COAL 70gr TSX's, allowing more powder to be used, feeding in an AR-15 sound AWESOME. I'm excited to hear how everything plays out for you, from the projectiles to your modded magazines. Do you have a chronograph? Keep us posted.

[ken6881]

I do not have a Chronograph been looking hard at the magneto one but my dad told me my uncle has one so I may try and borrow his to do some testing before buying one. I have been holding out for a LAB RADAR but I have yet to hear anything about its production date otherwise I would have bought a crony this summer and been done with it.

On a side not my 30-06 bullet drop FAST compared to what the book says for muzzle velocity and BC and plugging it in to a ballistic calculator so I am anxious to get it in front of one to see how it is really doing.

[son of liberty]

Here are a few pics of a 75 grain Hornady BTHP match recovered a few years back when I started using them in all my serious ammo

Its about 53 grains recovered weight, about 178 meters to target

Load is as fallows
75grain BTHP Match Hornady
23.5 grains of varget
2.253 OAL
Crimped
MV 2500 fps out of a 20in ER shaw, 1/8 twist stainless barrel at an ammo temp of 59.0F
1043.8ft lbs at muzzle
500ft lbs at 375 yards

Load is sub MOA in my good barrels and will hold a consistent 2 MOA in most of my carbines though velocity is decreased.

[ken6881]

What kind of target? Results look okay.

I personally shot a 308 190 gr hpbt at a deer and had very poor results no exspansion exit woond same size as entrance. Shot placement was good and deer walked 5 steps. I'm just Leary of match bullets on live targets.