Alternate-caliber AR-type rifles

[zahc]

What calibers can you get in a match-accurate semi-auto rifle?

My dad has the terrible, terrible job of (legally) shooting deer out of his bean fields on a weekly basis.

He doesn't really have a proper deer rifle, though, because in OH deer are only legally hunted with shotguns. He's been using his epically awesome early-model Ruger 6mm Remington to great effect on both groundhogs and deer out to 400+ yards. It's probably the perfect round for both groundhogs and deer. But now he wants a semi-auto, for target-rich environments.

I know you can get AR-10 style rifles in .308. Now, .308 will kill deer, but might not be the best universal round for groundhogs, especially since he likes to use light fragmenting bullets on groundhogs to reduce ricochet danger. Of course .223 will kill deer too at closer ranges but at 400+ yards it does not give satisfactory performance. In AR-style rifles it seems he's stuck between two calibers. I have heard about ".223 but with a bigger bullet" rounds chambered for AR-15s but I don't know about their ballistic performance. What he really needs is a 6mm remington (or similar) semi-auto.

I told him he might be able to find one of those old Browning semiautos in 6mm or .243 or something, so that he could use his current reloading equipment, but I don't know how accurate those are. He's spoiled with some very accurate bolt rifles, and I know an even 1.5MOA rifle will sit in the safe.

[Viking]

6.8mm Remington perhaps?

[roo_ster]

6.5 Grendel sounds like a good tool for the job.

[Boomhauer]

Research 6.5 Grendel or 6.8 Remington, which are two of the popular chamberings for the AR-15. I've done a bit of research, and I'm leaning towards 6.5 Grendel for this type of application. I just have not been ready to commit dropping the ducats for a new upper and the shortage of reloading components has also played a factor in my hesitation.

AR-10 style rifles are also chambered in .243, by I think Remington and DPMS (Since Remington is connected to both DPMS and Bushmaster, one of them makes Remington's AR style rifles, I think).

[El Tejon]

BAR in .270 Winchester?

[Gewehr98]

I don't get it.

Can he or can he not use a semi-auto to shoot deer in Ohio?  

[SADShooter]

Strictly speaking, an AR in .243 probably strikes the best balance for varmints and deer. That being said, the likelyhood of a semi offering a worthwhile speed advantage against deer (at least the skittish Texas whitetails I'm familiar with) over a well-handled bolt/lever gun doesn't seem to justify the effort. If your dad just wants it, cool.

[Balog]

I've been wondering; since the 6.5 Grendel is based on 7.62x39 (or a cartridge that's based on it anyway) will they feed from standard AK pattern mags, if one were to either rebarrel an AK or use an AR pattern modified for AK mags?

[Marnoot]

I don't get it.

Can he or can he not use a semi-auto to shoot deer in Ohio?  

Sounds like for sport-hunting, it has to be a shotgun. But this is pest-removal so anything goes.

[zahc]

Sounds like for sport-hunting, it has to be a shotgun. But this is pest-removal so anything goes.

Correct.

That being said, the likelyhood of a semi offering a worthwhile speed advantage against deer (at least the skittish Texas whitetails I'm familiar with) over a well-handled bolt/lever gun doesn't seem to justify the effort. If your dad just wants it, cool.

More importantly, he has wife approval for it. But I know from experience that it could be useful. At 300+ yards, dropping one deer often causes the others to flit around a bit and then stop and wonder what happened to their friend. Usually by the time you can jam another round in a bolt rifle and reaquire a sight picture, it's too late. Even more familiar is the scenario of missing a groundhog. Miss one and they usually just look dumb for a second or two if they are young and dumb (they don't live to be old and wise around my dad). I've often wished for a faster follow-up shot.

[El Tejon]

I don't get it.

Can he or can he not use a semi-auto to shoot deer in Ohio? 

Ohio sounds like its neighbor Indiana.  Shotguns (mostly) for deer tags, centerfire rifles for predation tags.

[41magsnub]

out of the box suggestion:

command detonated claymore mines laid out in zones.

Might be kind of hard on the beans though....

[Gewehr98]

Large doses of strychnine sprinkled liberally throughout the foliage?

[zahc]

Does anyone know of any cool online ballistics calculators, so that I could compare rounds side-by-side? There is a decent one on Remington's website, but it only lets you choose factory loadings, of which there are approximately zero in 6mm Remington, all tailored to deer. I don't know anything about .308; I assumed that since it was a 30 caliber, it would have a rainbow trajectory, but I'm not sure.

I guess you can fit .243 WSSM in a AR-15 size rife, too.

[Gewehr98]

They're ALL rainbow trajectories, if you get right down to brass tacks.

http://www.eskimo.com/~jbm/calculations/traj_basic/traj_basic.html

http://www.beartoothbullets.com/rescources/calculators/balistics/index.htm

[bedlamite]

6.8 SPC. The advantage of the Grendel is that better BC match grade target bullets are available in 6.5mm. That disappears when the target is made of meat instead of paper, and the SPC is about 200-400 fps faster depending on the ammo and gun specs. 6.8 is much more commonly available, Cabelas even stocks it, good luck finding Grendel ammo. There is no broken bolt club for the 6.8 either.

http://www.huntingnut.com/index.php?name=News&file=article&sid=3

[Tuco]

BAR in .270 Winchester?

Along the same lines, Remington Woodsmaster in .243 or .270 or .308 or .30-'06

http://www.remington.com/products/firearms/centerfire_rifles/model_750_woodsmaster_specs.asp

Match accurate?
no.
Deer accurate?
yes.

[AJ Dual]

They're ALL rainbow trajectories, if you get right down to brass tacks.

http://www.eskimo.com/~jbm/calculations/traj_basic/traj_basic.html

http://www.beartoothbullets.com/rescources/calculators/balistics/index.htm

Yep, any bullet is falling at 9.8m/s^2, some just run faster towards the target than they're falling than others. 

I too would probably go with the 6.8spc, it's the round that makes use of the "AR-15 infrastructure" and parts commonality the most. 6.5 Grendel has the long skinny bullet and better BC on paper going for it, but 6.8 will get the job done nicely, and be a little more common in terms of ammo, and upper availibility etc.

And you might want to look seriously at a suppresor. It'll do nothing for the trans-sonic crack of the bullet, but it might allow your father to rack up an extra deer or two, since they won't know what way to run when the shootng starts.

I would also invest in a low power 4x optic with a wide FOV.

[PTK]

Since he's culling, do point out that he can use a silencer. Ohio Valley Outdoors does transfers on the cheap, or at least, they did back in 2007.   

[AJ Dual]

Geez... this and the guys down south dealing with feral pigs are making me jealous.

[MechAg94]

Hasn't there been an issue with some 6.8 SPC uppers having the chamber sized wrong or something like that.  Made them less reliable?  I thought I read something about it, but I haven't looked into it seriously.   

[bedlamite]

Hasn't there been an issue with some 6.8 SPC uppers having the chamber sized wrong or something like that.  Made them less reliable?  I thought I read something about it, but I haven't looked into it seriously.   

Remington screwed up the chamber specs when they submitted it to SAAMI. There was never an issue with reliability, it was just that the leade was so short that the bullet was sitting on the lands, so you couldn't load the round to it's full potential. Silver State Armory has made ammo to two different levels because of this. The difference in chambers between the SAAMI and SPC2 is very similar to the difference between the .223 rem and 5.56 NATO chambers.

The only company still selling the old SAAMI chamber now is Model 1 Sales. Everyone else has changed to SPC2 chambers, with a few notable exceptions using the DMR chamber.  Even DPMS and Bushmaster dropped the SAAMI chamber this spring. If you do manage to get a SAAMI chamber upper from old stock, it can easily be reamed to SPC2.

[zahc]

I would also invest in a low power 4x optic with a wide FOV.

Not for the kind of shooting my dad does. He regularly shoots at 400+ yards, and usually uses a Leupold with the range-compensating varmint reticle and leaves the scope at the 18x 'delta' mark.

[280plus]

Groundhogs at 400 yds? Ooo, can I come over to play?