Ultra-accurate, semi-auto varmint rifle?

[zahc]

My dad has a bean farm in OH, and kills a totally absurd amount of varmints. Dozens per week, easily, sometimes that per day. Mostly groundhogs with a sprinkling of deer (legally). He has a Winchester heavy varmint in 22-250 with a 12x fixed Leupold, and a Ruger heavy barrel 6mm Remington with a Leupold 20x variable varmint with rangefinding reticle. He has a Leica 1200 yard laser rangefinder. He uses the 6mm most of the time because it is very adequate for the occasional deer, unlike the 22-250, and the terminal ballistics more satisfying.

All would be well because his rifles shoot well but he has trouble with high target density situations. In the spring, the young groundhogs come out in multiples, and if he's far enough away they are stupid enough to hang around for a second or two after their sibling disappears. With luck, he can fire, work the bolt, and reaquire the target in enough time to shoot the second, but I think he needs a semi-auto. There have been times where the 5+1 capacity of his bolt guns has left him hanging, especially when misses are involved. I think he really could use an AR15-type rifle, but I don't think .223 is adequate. At 250+ yards the terminal effects are unimpressive even on groundhogs, and not good for deer at any range.

The thing is I don't know anything about semi-auto rifles. It seems like choices in varmint-caliber semi-auto rifles are limited to the AR-10 platform, things like the BAR, and the M1 (if 308 can be considered a varmint caliber). As far as AR-10s there are a multiple vendors and they are not interchangeable as far as I know. DPMS sells .243 Winchester AR-10s, but I don't know how accurate they are and it's hard to get an answer from salespeople. I know from the other safe-queens we have that if a gun is not nearly benchrest-accurate, it will never get used. Our accuracy needs are high since shots are typically long. 1" at 100 yards is just not good enough, period. His gravy shot is 200 yards; 300 yards is common, and occasionally 400+ yard shots are needed.

So my questions are...

What is the trajectory of 308 versus .243/6mm and does it make a suitable varmint caliber (disintegrating bullets are highly valued)? It seems to me that if the trajectory is similar to .243, then you might as well just go .308 for less wind drift, although the bullet situation might matter.

Are BAR and M1 rifles highly accurizable? We are kind of looking for an out-of-the-box solution, not a gunsmithing project.

Just how accurate are AR-10 platform varmint rifles? Do you have to crimp bullets and is that an accuracy issue? Does anyone have firsthand experience with the accuracy of these things?

Are there other semi-auto varmint caliber rifles that are extremely accurate?

[41magsnub]

The solution is claymores linked by... wait for it.....    detcord!

[Mabs2]

My uncle has an AR-10 that shoots very predictably most of the time.  I've seen him make 400 yard shots easy in the past.  The rifle got a little worn out and he had to replace the barrel, so he's working on new loads now.

[roo_ster]

What you need is a .264" bore AR.

In an AR15 package, that means 6.5 Grendel.  I hear very good things about this round and hte Alexander Arms uppers that go with it. 

In an AR10/SR25 package, that means .260 Remington (7.62NATO/.308Win necked down to 6.5mm).

For a while, my unit used SR25s in 7.62NATO in place of the M24 (Rem 700 .762NATO sniper rifle).  It did well and worked great as long as it was kept clean.  I am not nearly as knowledgeable abut the AR10s, but our good experience with the SR25s makes me lean in that direction.

The AR15 6.5 would be more easily packed, but the AR10 .260 better range.

Might I also suggest your dad invest in a suppressor?  I bet he'd increase the number of varmints per engagement with one.

Also, either 6.5 is great vs deer.

If it were me, I'd likely go with an AR15 in 6.5 Gremlin.

[zahc]

The .223-size 6.x rounds strike me as even worse than .223 because I assume they have a worse trajectory than .223, yet not a lot more downrange energy.

[220_SWIFT]

Don't underestimate the 223.  I used to kill truckloads of ground hogs every summer with a 223.  With a 55gr Ballistic tip, it is very effective out to 300 yards at least.  I never shot farther than that, but considering the damage at the rang I would venture it holds its own.  As for deer, it works fine as long as the criteria are met.  You need to use 60gr Nosler Partition, and the shots need to be broadside and under 200 yards.  I know this works very well.  My uncle in Georgia uses this combination and takes several deer a year.  He has never lost one, or had one go more than 50 yards.  However, he does let them walk if it isn't perfect.  It certainly isn't ideal, but it is doable.


The DPMS line have been very accurate from what I have seen.  A buddy of mine has a .243 for his 'yote gun.  It punches 3/4" groups at 100 yards with hand loads.  For an accurate semi-auto, DPMS is where I would start my searching.

[AZRedhawk44]

I think you're doing the .223 a disservice in your view, considering you're not limited to Hague convention rounds for killing varmints.

Step up to an expanding bullet between 50 and 60 grains, and go for neck shots on the deer when they come around.  An AR-15 can do the job you want.

[230RN]

roo_ster:

If you're not in a war zone, you need a light, disintegrating bullet for the flat angles at which varmints are shot.

My first "varmint" rifle was a .243, and (especially with solid-base bullets like the Noslers) about two-thirds of the shots resulted in a ricochet.  This is not good for the farmers to hear, especially if there's livestock in the area.

I therefore switched to light fragile bullets in .223 Remington  (favorite being the Hornady #2240, 50 gr SX) and never heard a ricochet once in many years of prairie rat shooting. Very accurate with my Savage 340 with a slow twist barrel.

Those bullets seem to evaporate if they hit a blade of grass.

I can attest to 220_SWIFT's comments on the 300 yard capability of the .223 on 6-inch tall targets, even though I use lighter bullets than he.

I haven't had the privilege of fast shooting at varmints, as zahc's dad has had, but I have hit four or five of them within a couple of minutes.  They aren't as spooky as all that, if you spread your shots around a little. At range, the sound of the shot is more of a dull boom, although the supersonic crack and the "whop" of the impact does get the attention of the ones close to your target.  Most of the time they make a couple of hops toward their holes and then look around a little, "kwee-ing" a warning signal. Some actually approach the downed prairie rat.

I frankly don't see the real need for an autoloader on varmints, completely apart from the fact that most varminters reload, and you can drop the cases from a bolt gun within a couple of inches of the gun, making salvage easy.

For larger game, I have no comment.

Terry, 230RN




 

[zahc]

If you're not in a war zone, you need a light, disintegrating bullet for the flat angles at which varmints are shot.

We always use Hornady Vmax or Nosler Ballistic Tip bullets. A 75grain vmax fragments very well even in 6mm. The Ballistic tips in .243 size seem to be a bit tougher and geared toward deer.

I never shot farther than that...As for deer, it works fine as long as the criteria are met.  You need to use 60gr Nosler Partition, and the shots need to be broadside and under 200 yards.

As you say, the .223 is not adequate for deer. Shots are not always under 200 yards; deer are big enough targets that we engage them at up to 500 yards. Plus, we do not usually carry two kinds of ammo. A 6mm Remington with 75gr Vmax does an OK job on both deer and groundhogs though.

[esheato]

https://www.volquartsen.com/products/1053-evolution

Volquartsen Evolution....gas operated, AR-15 mag fed, but Volquartsen quality. Price to match too.

[Jamisjockey]

Why not the DPMS AR10 in another caliber?  .308 comes to mind, but they also sell it in other calibers. 

[Ryan in Maine]

Remington R-25 in 7mm-08?
http://www.remington.com/products/firearms/centerfire/model-r-25/model-r-25-rifle.aspx

[Mabs2]

Remington R-25 in 7mm-08?
http://www.remington.com/products/firearms/centerfire/model-r-25/model-r-25-rifle.aspx

Aren't those just green DPMS rifles?

[Ryan in Maine]

Aren't those just green DPMS rifles?

*Shrug* Wouldn't surprise me. The cartridge might fit the bill though.

[Mabs2]

*Shrug* Wouldn't surprise me. The cartridge might fit the bill though.

I'm quite sure they are.

[zahc]

Why not the DPMS AR10 in another caliber?  .308 comes to mind, but they also sell it in other calibers. 

From what I can see they sell it in .243 and .308. .243 would be perfect, and I'm not sure about .308. Never had one. I suspect good varmint bullets are hard to find in .30 caliber.

[sanglant]

.444










sorry, couldn't resist.

[sumpnz]

From what I can see they sell it in .243 and .308. .243 would be perfect, and I'm not sure about .308. Never had one. I suspect good varmint bullets are hard to find in .30 caliber.

Maybe not from DPMS but you can get AR-10 pattern rifles in just about any .308Win based caliber.  And if you can't get it off the shelf it wouldn't take much more than a barrel change and maybe some gas system adjustments to acomplish that.

Personally my choice would probably be an AR-15 in 6.5 Grendel or one of the 6mm options (PPC, x47, etc).  That or an AR-10 in .260Rem, or 6.5x55 (if you can do that).  The Swede get you a bit more velocity for the pressure, at least according to my reloading manuals.

[MechAg94]

Anyone know if that .204 Ruger round is any good?  

It sounds like most of the times he needs more rounds, it is with smaller animals.  So that tells me 223 should be more than adequate for most cases.  I think you might be able to find AR's in lots of other calibers though.  Heavy 223 rounds are supposed to be able to reach out there pretty good.

Would it make sense to carry an AR and keep a small lightweight bolt action in 308 for longer shots at deer?  I would suggest a good 308 AR, but those can get very expensive if you want to go beyond DPMS. 

[roo_ster]

The .223-size 6.x rounds strike me as even worse than .223 because I assume they have a worse trajectory than .223, yet not a lot more downrange energy.

Your understanding does not match what I have read.  Matter of fact, what you wrote is the exact opposite of the usual 5.56NATO vs 6.5Gremlin comparison.  The 5.56mm starts with greater velocity(1)  (though less energy) and proceeds to shed velocity and energy faster than a prom dress, while the 6.5G holds what its got.  The advantage, trajectory-wise, at the 300+m ranges goes to the 6.5G. 

There is a great energy graph I saw a while back on wikipedia, that holds the 6.5G 142gr pill as 100%  and places all the other pills relative to it, percentage-wise

<looks for graph>

Here it is:
http://en.wikipedia.org/wiki/File:AssaultRifleCartridgeComparisonChart.PNG

Here's a velocity chart comparison a fellow on the Beartooth Bullet forum did:
http://shootersforum.com/showthread.htm?t=8865

My understanding of your problem is accuracy, the longer-ranged targets (300-400m), and energy to dispatch deer.  If the shooting is shorter ranges, the 5.56mm will be adequate, even for deer given a decent broad side presentation and a quality pill (Nos Partition, etc,)

Any of the beefier 6.5mm rounds (.260Rem, 6.5x55) will be even better, if you want to go that route.

(1)  In the 62gr & less pills.  Use anything heavier and stating velocity will be close enough to be determined by handloading and individual gun characteristics.


230RN:

Very good point on ricochet avoidance. 

Thing is, anything that will hold together enough to dispatch deer at moderate range will not disintegrate at long range.  The farmer in question will likely have to settle on either having to do a mag change to use different bullet types or settle on a compromise load.

Frankly, the requirements listed are going to be very tough to meet:
* 400m varmint-accurate
* Powerful enough for deer
* Rapid firing (semi-auto)

Tossing other requirements into the mix will result in no rifle/cartridge combination being up to the job.  This actually points toward a semi-auto with different mags loaded with different cartridges for different applications.

[zahc]

Would it make sense to carry an AR and keep a small lightweight bolt action in 308 for longer shots at deer?

Yes, but I doubt it would happen. Too much trouble wrangling even one gun in the truck. I imagine I/dad would always be left holding the wrong rifle.

Frankly, the requirements listed are going to be very tough to meet:
* 400m varmint-accurate
* Powerful enough for deer
* Rapid firing (semi-auto)

The first two are easily handled by .243. The problem is that I'm not sure the semi-autos are still varmint-accurate.

[86thecat]

Borrowed this list from another site, might be able to find something here that will work-

AR-15 calibers-
.204 Ruger
5.56/.223
6.5 Grendel
6.8 SPC
.30 Remington
7.62x39
.450 bushmaster
.458 SOCOM
.50 Beowulf

AR-15, without bolt modification
.17 Remington
.17/223
.20 Tactical
.20 Practical
.20 Vartag
.204 Ruger
.221 Fireball
.222 Remington
.222 Remington Magnum
.223 Remington (5.56x45mm)
.223 Remington Ackley Improved
6x45mm
6mm TCU
6x47mm
6mm Whisper
.25x45mm
6.5mm Whisper
7mm Whisper
7mm TCU
.300 Whisper (.300/221, .300 Fireball)
.338 Whisper

AR-15, with bolt modification
223 WSSM
5.45x39mm (.21 Genghis)
243 WSSM
6mm PPC
6mm WOA
6mm BR Remington
6mm Hagar
6.5mm PPC
6.5 WSSM
6.5 WOA
6.5mm Grendel
25 WSSM
6.8x43mm SPC
.30 Herrett Rimless Tactical (6.8x43mm case trimmed to 41mm and necked up to .308; the 6.8mm version of the .300 Whisper)
7.62x25
7.62x39mm
.30 RAR
300 OSSM
.357 Auto
.35 Gremlin (necked up 6.5 Grendel to 358)
.358 WSSM (various names, but all are some form of a WSSM necked up to 35 caliber, some are shortened to make them big game legal in Indiana)
.458 SOCOM
.50 Action Express
.50 Beowulf

AR-15 using a simple blowback operation
.17 HMR
.22 LR
.22 WMR
9x19mm
9x21
9x23
30 Carbine
357 Sig
40S&W
400 Cor-Bon
41 Action Express
10mm Auto
45 GAP
45ACP
45 Super
45 Win Mag

[bedlamite]

There is a great energy graph I saw a while back on wikipedia, that holds the 6.5G 142gr pill as 100%  and places all the other pills relative to it, percentage-wise

<looks for graph>

Here it is:
http://en.wikipedia.org/wiki/File:AssaultRifleCartridgeComparisonChart.PNG

Don't believe everything you read. That was part of a series of propaganda graphs done by someone on the Grendel Forums a few years ago, He used a 28" barrel bolt gun, and it was way over pressure for an AR-15. Also, the Grendel has problems chambering bullets over 130gr in an AR-15. The Grendel, Using Hunting Bullets, has a realistic range of about 250-300 yards for deer. If you need to reach farther than that, step up to something based on a 308 case.

[KD5NRH]

The first two are easily handled by .243. The problem is that I'm not sure the semi-autos are still varmint-accurate.

Remington 7400 in .243 works fine with a good scope.  .243/6mm also gives you a nice range of bullet weights to play with, from 55gr on up to a moderately wind-resistant 115gr.

55gr .243 bullets  In my experience, there's not much left of the 55gr 6mm after hitting a target.  Especially at close range when it's still going around 4,000fps from 45gr of Varget.

[MechAg94]

The first two are easily handled by .243. The problem is that I'm not sure the semi-autos are still varmint-accurate.

I have a Rock River Predator Pursuit upper with a match grade barrel with a DPMS lower in which I installed a match trigger.  I have shot 1/2" groups with some 68 grain reloads my brother cooked up for me.  Black Hills match ammo of the same weight got under an inch.  I guess you can find a bolt action that can do better, but not by much.  That upper wasn't all that much money either compared to some of the tactical choices out there.

They make a Predator upper in 308 also, but I have no idea how accurate it is.

If you weren't including deer, I would suggest something like 17 HMR or 17 HM2, but those aren't for much beyond small game.