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5.56 vs. 5.45 vs. 7.62 ; Input wanted please

Svartur_Skuggi

Private
Minuteman
Oct 22, 2010
22
0
50
Jefferson ; Texas
Well Hello Again Everyone;

Been awhile since my last post. Everyone was really nice and very helpful with my questions about rifles and build.

After spending some time with my new rig ( Blaser T2 ); I decided I wanted an AR or AK for home defense.

I have done alot of reading and this is what I have read about the 5.56 and 5.45 cal.
They stated that the 5.45 was Russia's answer to America's 5.56. Where the 5.56 works off of velocity, the 5.45 does not do to how it's made. So; from my understanding...... the 5.45 will topple no matter at what range you are at, where the 5.56 may not. Although neither round may kill your target flat out on impact, the 5.45 is more likely to kill than the 5.56 which may just mame.
I would like to know if these "facts" are correct? Because if they are, then the better round would be the 5.45.
But having said that..... knowing that both of those rounds could leave an intruder still alive and possibly still a threat, I looked into the 7.62x39.
From what I read the 7.63 can go through walls, car doors, and some vest. I also read that there is a possibility of the round just creating a clear and clean passing wound, so shot placement is important. But even if the shot did create an enter/exit wound only, the energy involved would/should stop the threat.

Now; I know that any round can kill if shot placement (and possibly follow up shots) are well placed. But from someone that has awakened to intruders in his home sometime back, I also know about the chaos that can effect the situatation. So; taking into account the possible chaos involved, which round would be the best for target stoppage and why?

My follow-up question then becomes........
Which AK or AR would be the best to buy? Best being = most accurate and reliable that wont fall apart after 1000 rounds lol.

Links would be very appreciated for places to buy the weapon in question.......

I'd like to thank everyone in advance for your advice and suggestions.

**SvarturSkuggi
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

12ga pump action with buckshot is what I would go with. Shot placement is not as vital with that combo.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

Thank you wfjames22.

I did buy one not a wk after the intruder broke in. However; I am still very interrested in an AK or AR as it will be playing a duel roll where I live.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

I think any of the chamberings you listed (among many others available in the platform) would work just fine for home defence. What else are you going to use it for? What is your budget?
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

Well then if it's going to fill a dual role, then how about stating what the other role is? I lost my psychic powers a couple years ago. HD and..... what?

Any of the listed calibers have first round stopping power. All you have to do is look the millions of dead over the last 60 years of warfare to know that. I would choose the weapon based on ergonomics and function, not on caliber. There's a big difference between using an AR and AK, and that is what you first need to realize and decide upon.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> the 5.45 will topple no matter at what range you are at, where the 5.56 may not. Although neither round may kill your target flat out on impact, the 5.45 is more likely to kill than the 5.56 which may just mame.........
..... knowing that both of those rounds could leave an intruder still alive and possibly still a threat, I looked into the 7.62x39.
From what I read the 7.63 can go through walls, car doors, and some vest.</div></div>

Now go back and ask the guy who fed you that BS how many people he's shot with the 5.56, 5.45, 7.62X39.

The only gurantee you're gonna get from any rifle or pistol round is no two will work the same way even under the same conditions.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

I personally feel that there will be issues here in America sooner or later. So I'd like to buy a HD weapon that could carry over into a protect the family/hunting weapon should things go to sh*t. I have shot a 5.56 and .308 AR. I however have not fired an AK. From my understanding the AR is more accurate where the AK is more durable.

And thanks for your reply
laugh.gif
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

For that much of a budget, why don't you go ahead and buy both and figure it out for yourself? AR for zombies and AK for Ruskies?
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

AR's are quite durable https://danieldefense.com/TortureTest What is your housing situation? Do you have other people in the house with you? Are there other houses nearby that could be struck if a bullet exits an exterior wall? Many of the AR-15 loads will do alot of damage to a human target but will break up in sheetrock and penetrate less than many handgun rounds or the 7.62 x 39. I would choose a good quality carbine length AR-15 over an AK for HD. If suppressors and SBR's are legal in your area, that would be even better.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

WOW!! Thanks Badshot308 for the link. That was very impressive!
As far as your questions.....
I have family living here, wife and 2 children.
We live about 45 min from town and have NO houses around us.
Yes; suppressors are legal here. But I'n not sure what a SBR is, so I can not answer that honestly.

I choose to read before buying, and will follow up my findings with those in the know before going further. Your link really placed my concerns about the AR's durability to rest.

Thanks very much
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

If you want a cheap reliable rifle go with the AK47 7.62X39 for home defence, but looking to the future I think an AR15/M4 in 5.56 will be the way to go, cost more but in the long run with the budget you have the AR will be a better choice and ammo will be more readily available. I like Armalite.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

SBR, short barrel rifle. Usually anything under 16" is considered a SBR. Not legal in my state but may be in Texas. Suppressors can save your hearing when shooting a rifle indoors and allow you to still hear what's going on around you after taking that first shot. I've fired 14.5" AR's with muzzle brakes in an indoor range and even with hearing protection, the concussion and muzzle blast was bad. If you combine a suppressor with a SBR, you can keep the overall length down a bit. With other people in the house, over penetration is a big concern. There have been other threads on the topic of various ammo and the over penetration issue. Here's a link to some ammo testing http://www.theboxotruth.com/docs/theboxotruth.htm Looks like the M193 load tumbled but still penetrated through several walls worth of sheetrock.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

badshot is giving very good advice. Here's another penetration test worth looking at...
http://how-i-did-it.org/drywall/results.html

Truth is, most modern hp loads in .223/5.56 will be light and fast enough to start tumbling/breaking up after their first drywall. Slower/heavier things tend to punch through and maintain momentum better. You can limit this with an ak with lighter hp rounds too, but if overpenetration is a concern .223 will pose less of a threat a couple walls over than even a handgun round.

Other truth is, ar's in your price range(noveske, daniel defense, larue, les baer, bravo company, spikes tactical...) will all be VERY durable and reliable. The big thing is just to keep the bolt carrier wet(with a lube...synthetic 0w50, breakfree clp or whatever u prefer...not militec, it's junk) and they'll run forever.

for home defense, a carbine will be pretty loud so you may want to consider a levang-type comp like a troy claymore or noveske kx3 flaming pig to project sound forward and spare your ears a bit. There may be legal considerations if you use a atf suppressor for a defense situation varying on your area. Also, much of what breaks up the light/fast projectiles of a .223 is the "fast" part. Getting an sbr would be very handy and maneuverable, but at the expense of velocity. 14.5" with a pinned kx3 or claymore would be the shortest i'd go.

As for a shotgun, you have to figure that when using OO buck...essentially you're letting go 9-15 shots of 9mm all at once with each pull of the trigger. that's a lot of potential liabilities in the air at any given time, especially since each one of those projectiles will penetrate drywall like a 9mm. They DO have a fantastic ability to end a threat...but so do ar's. Just be sure to pattern your shotgun at realistic defense ranges on a sihlouette and decide whether or not you're willing to let go 9 pellets each time you pull the trigger that you have a rough control over.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

I've owned all three calibers...currently, I only own 5.45. I really like how the AK74 shoots and how light it is compared to the AK47. Ammo is inexpensive and you can buy cases and cases with your budget. With your budget, you could get two Saiga 5.45 and mags and ammo. Once you do the Saiga conversion, you are probably looking at the same cost as buying an Arsenal version.

The AR15 is very modular and you can do a lot with it...I just tend to get bored with my firearms and went with the AK74.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

don't forget, you can get a spikes tactical completely milspec 5.56 rifle AND an adams arms 5.45x39 upper...feel free to shoot both and stay within your proposed budget.
http://www.adamsarms.net/details.asp?sku=UA-16-C-B-545
Again though, the 5.45 mostly gets it's "stopping power" from the nose crushing and causing the bullet to severely yaw within a couple inches of penetration. A decent hollow point has a different wounding mechanism. Of course, with a 5.45 depending on yawing, the bullets tend to be more fmj and stay together better through drywall than a .223 hollow point.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

5.56 or 5.45 will both work well. Feed them good SD Ammo and they'll work if you can put the bullet where you want it. Both calibers have 60gr VMAX loads for indoors, and Corbon makes some heavier duty SD loads.

One recommendation. If going 5.56 stay in the AR platform. If you decide to go 5.45 stick with the AK platform. 5.45 AR Mags suck donkey balls, and avoid Tapco unless it's the G2 trigger for the AK. Either will work.

7.62x39 - Again stick with AK Platform. This would only be my choice outside of the home. I sort of like my neighbors and don't want to put any holes into them.


AR - ScottMilk a vendor here on the hide can build you one, Bravo Company or Daniel Defense have full models ready to go. If you're handy you can buy the parts and build your own. It's up to you.


AK - Simplest answer is to buy an Arsenal in 5.45 or 7.62 - You can check K-var or go to Atlantic Firearms to see what they have in stock. For a lesser expensive model that's been getting good reviews for reliability is the AK74 (5.45) by IO - (It's a fixed stock configuration). I personally prefer side folders on the AK.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: smokey0118</div><div class="ubbcode-body">As for a shotgun, you have to figure that when using OO buck...essentially you're letting go 9-15 shots of 9mm all at once with each pull of the trigger. that's a lot of potential liabilities in the air at any given time, especially since each one of those projectiles will penetrate drywall like a 9mm. They DO have a fantastic ability to end a threat...but so do ar's. Just be sure to pattern your shotgun at realistic defense ranges on a sihlouette and decide whether or not you're willing to let go 9 pellets each time you pull the trigger that you have a rough control over. </div></div>

I believe 9mm is .355" and 00 buck is .33" across, with 00 buck being about half the grain weight of typical 9mm projectiles. FPS is fairly close between the two, with the 9mm in a +P offering, but the decision goes to the HD 00 buck shell in its ability to blanket the patterned area, QED.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

I normally lurk here as I'm just getting into long-range, but I do know enough about this area to share a few thoughts. Apologies in advance for the long post...

As to the original question, seek out info from Gary Roberts (who usually posts as DocGKR on other forums) about the terminal ballistics of those 3 rounds. The 5.56 generally has much better terminal ballistics at close range when intermediate barrier penetration isn't needed.

In a nutshell:

- 5.56 in military loadings will tend to turn 90 degrees before breaking at the cannelure and fragmenting after traveling 5-6" in gelatin.
- 5.45 will tend to turn 180 degrees but not fragment in 10-12" of gelatin.
- 7.62x39 in military loadings will generally not turn or fragment in gelatin within the distance of an average human torso.

Rifle bullets become unstable upon hitting the target but don't actually tumble. They instead flip 180 degrees, stabilize then continue traveling base first until they stop. Bullets fragment when the shear forces of the bullet traveling sideways tear the jacket apart, causing much larger wound channels. HP or ballistic tip bullets tend to fragment more readily, but there are more and better load choices in 5.56 than in either 5.45 or 7.62. Fragmentation will also reduce (but not eliminate) risk to your family and neighbors.

All three certainly 'do the job', but 5.56 makes a lot more sense, especially in this country with ammunition availability, than either of the others.

Shotguns are certainly very effective, but just go to the range and pattern it at 10 yards (probably the longest shot in your house). Even with a short cylinder bore, the pattern is probably not more than 2 or 3" across, meaning you still have to aim precisely to make solid, safe hits. That, combined with ergonomic issues and the risk of over-penetration cited earlier, make it a less optimal choice.

For a home defense gun, you'll want 1) a sling 2) a light mounted to the gun and 3) a red dot optic. The sling is needed because you'll likely need to use your hands to do stuff and need a place to put your rifle. The light is needed because the vast majority of nastiness is going to happen at night, and you need to be able to positively identify your target. The red dot sight provides such a huge speed and accuracy advantage over irons (remember, it's nighttime) that I don't think they're optional unless funds are ridiculously tight.

A high quality AR carbine (from Colt, LMT, BCM or Daniel Defense) with a VTAC sling, Surefire light and Aimpoint should run $1500-1700. That would leave you enough left over for ammo and a carbine class from a top-flight instructor, which frankly is probably the most important thing of all. Both Paul Howe (CSAT) and Jim Smith (Spartan Tactical) are local to you. I have trained with Jim and know a few people who have trained with Paul. They were both Delta force operators involved in the Battle of Mogadishu in 1993, have incredible experience to share and are excellent teachers to boot.

With a basic carbine spec'ed like the above, top tier training and some diligent practice, you will be a bad-ass, and all within your budget.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: squinty-andy</div><div class="ubbcode-body">I normally lurk here as I'm just getting into long-range, but I do know enough about this area to share a few thoughts. Apologies in advance for the long post...

As to the original question, seek out info from Gary Roberts (who usually posts as DocGR on other forums) about the terminal ballistics of those 3 rounds. The 5.56 generally has much better terminal ballistics at close range when intermediate barrier penetration isn't needed.

In a nutshell:

- 5.56 in military loadings will tend to turn 90 degrees before breaking at the cannelure and fragmenting after traveling 5-6" in gelatin.
- 5.45 will tend to turn 180 degrees but not fragment in 10-12" of gelatin.
- 7.62x39 in military loadings will generally not turn or fragment in gelatin within the distance of an average human torso.

Rifle bullets become unstable upon hitting the target but don't actually tumble. They instead flip 180 degrees, stabilize then continue traveling base first until they stop. Bullets fragment when the shear forces of the bullet traveling sideways tear the jacket apart, causing much larger wound channels. HP or ballistic tip bullets tend to fragment more readily, but there are more and better load choices in 5.56 than in either 5.45 or 7.62. Fragmentation will also reduce (but not eliminate) risk to your family and neighbors.

All three certainly 'do the job', but 5.56 makes a lot more sense, especially in this country with ammunition availability, than either of the others.

Shotguns are certainly very effective, but just go to the range and pattern it at 10 yards (probably the longest shot in your house). Even with a short cylinder bore, the pattern is probably not more than 2 or 3" across, meaning you still have to aim precisely to make solid, safe hits. That, combined with ergonomic issues and the risk of over-penetration cited earlier, make it a less optimal choice.

For a home defense gun, you'll want 1) a sling 2) a light mounted to the gun and 3) a red dot optic. The sling is needed because you'll likely need to use your hands to do stuff and need a place to put your rifle. The light is needed because the vast majority of nastiness is going to happen at night, and you need to be able to positively identify your target. The red dot sight provides such a huge speed and accuracy advantage over irons (remember, it's nighttime) that I don't think they're optional unless funds are ridiculously tight.

A high quality AR carbine (from Colt, LMT, BCM or Daniel Defense) with a VTAC sling, Surefire light and Aimpoint should run $1500-1700. That would leave you enough left over for ammo and a carbine class from a top-flight instructor, which frankly is probably the most important thing of all. Both Paul Howe (CSAT) and Jim Smith (Spartan Tactical) are local to you. I have trained with Jim and know a few people who have trained with Paul. They were both Delta force operators involved in the Battle of Mogadishu in 1993, have incredible experience to share and are excellent teachers to boot.

With a basic carbine spec'ed like the above, top tier training and some diligent practice, you will be a bad-ass, and all within your budget. </div></div>

Dude... Great 1st post... Seriously...
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

I read a little bit, then skipped to the end to add my .02

If you have a shotgun, excellent. You have a great HD weapon.

As for having a dual roll weapon that can be used as HD and hunting? Forget the dual roll and purchase a hunting weapon but if you're concerned about threats while you're out hunting and want stopping power, accuracy and auto-loading...then with the budget you listed, get a nice 7.62 AR.

That's what I'd do but because the shotgun is so long, I feel more comfortable grabbing my handgun. Thus the Glock 23 by the bed and the shotgun is in it's case.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

The great point in 5.45's favor is that as surplus it's still cheap as dirt in comparison to 5.56, which seems much more sensitive to the ups and downs of supply and demand. The drawback is that, while it's inexpensive in comparison, you can't find it everywhere (as in Wal*Marts, Dick's, Academy Sports, etc.) and you have to lay in your own supply. Another thing about 5.45 is that it has an extremely light recoil, and you can carry more of it than other calibers per pound.

I'm sort of platform-agnostic when it comes to the caliber, so as feed for AKs of ARs, both are fine, although AK74s will most likely be more ready-to-go out of the box, especially if yours has a plate for an optics mount. 5.45x39 ARs can be a bit of a pain to get running (magazines and hammers, especially), but once they do, they're reliable enough. Milsurp AK74 magazines can be had for as little as $10 a pop; AR magazines can be hard to find consistently and go for up to a time-and-a-half to two times as much.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

AK 47, AK 74, AR 15 all of these could be used for what you describe. I would recommend go and shoot one of each and get a SBR version of whatever one you wanted. With your budget you could afford a really nice SBR of either one you choose. Like you already stated shot placement is essential but if you didn't get off good shots all three of the examples have magazines that hold a plenty of rounds to stop the threat. You can make valid points for each of the choices. Find what one you like and shoot well. I personally love the ergonomics of an AR and you can get one in those rounds.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

Well. From Ruskies point of view it's strange that when you can have a pistol you still opt for a rifle.

1. If home defense is the first reason - you may consider 10" barreled tromix saiga shotgun conversion http://www.tromix.com/saiga.htm. At least with 2 mags you've got 14 .12ga rounds in relatively compact package.

2. About AR-AK-545-762-556 issue - buy they gun that will shoot good groups.
If gun can't hit chest target at 300 yards you'll won't like it and will not train hard with it.

Ak vs. AR - technically there is no good fast trigger for AK. So double tap time is very limited to the TAPCO G2 Trigger possibilities. With AR you can go with Giesselle or Wilson combat. Second issue is muzzle break. You don't have PWS or AAC or Surefire option for AK. (I mean you don't have it in US)

556 vs 545 - both are good rounds and will give you +- same groups from same platform. There is no recoil.

762 vs 545/556 - it has recoil (compared to 545/556) and combined with standard muzzle break gun will go on 8 o'clock. Fast double-tap? No way from ak platform with standard muzzle break without "wraping" yourself around it.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vtb</div><div class="ubbcode-body">Ak vs. AR - technically there is no good fast trigger for AK. So double tap time is very limited to the TAPCO G2 Trigger possibilities. With AR you can go with Giesselle or Wilson combat. Second issue is muzzle break. You don't have PWS or AAC or Surefire option for AK. (I mean you don't have it in US)</div></div>

You're discounting the RSA trigger. Set right, it's just as good, if not better. Moreover, the problem with suppressors wouldn't seem to be making them or getting them, it's being subsonic. Those options seem close to zilch commercially.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

OMG!!!!
Thank you everyone for all your input.
I have looked at the links provided and was amazed at what out there.

Now I dont wanna drag the thred out seeing that my questions hvae been answered, however, I was sent two private messages and would like to offer up their suggestions and get input on it.

One message suggested a bullpup.
Their arguement was that a bullpup could be configured with the light and laser/scope set up. This would allow me to have very good manuverability in any inside situation, while fulling the duel roll I wanted.

The second message offered the suggestion of using sub sonic bt hollow point.308 rounds. Then explained that the hollow point coupled with sub sonic should take care of over penetration, while still leaving me the option to use other ammo so the same weapon can fulfill other roles.

The two weapons offered as suggestions was the Kel-Tec RFB and the Steyr Stg.77 AUG.
I have looked online for reviews, and both seem to have followings.
I would like input on these suggestions and if you are a follower of another Pup, by all means share
laugh.gif


Thanks again everyone ....... you all are awesome to those still learning
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

Holy Moly this thread is all over the place.

All of the rounds listed in the OP have killed people that you could stack a mile high. They all work. None are magic bullets.

With a huge budget like that I would look into a quality AR in 5.56 (don't mess with 5.45x39 or 7.62x 39 AR's as the mags for both are not uber reliable). BCM, Colt, LMT, DD, Noveske, and on on. Set it up simply at first add a quality light (surefire) and perhaps a red dot (AimPoint IMO). Shoot the snot out of it. Decide if you think there is anything you want to change. If it was my money I would look into a 16 mid-length gas system for a first AR. If you want to drop $200 on an SBR (short barreled rifle) be prepared to jump thorugh the legal hoops and wait a long time.

If you want an AK, get an Arsenal chose your caliber 7.62x39 little more punch than 5.45x39 but more recoil and not as accurate at range. Almost all 5.45 ammo is corrosive and will require some special treatment and more cleaning.

I own both AR's and AK's. I like both but if I were to choose only one I would get an AR. Stay away from anything Kel-Tec. AUGs work but are completely different animals and have some serious limitations.

FInal note- don't buy what looks cool. DO your research and by that I mean you sound uninformed about basics of the weapons you are considering. If you plan to use something in SD, you should know as much as you can and get some quality training.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SvarturSkuggi</div><div class="ubbcode-body">OMG!!!! One message suggested a bullpup.
Their arguement was that a bullpup could be configured with the light and laser/scope set up. This would allow me to have very good manuverability in any inside situation, while fulling the duel roll I wanted.</div></div>

The bullpup design has sort of a "trigger by wire" arrangement, and the execution in an example like the CAI has a rep for being gritty and unpleasant. If you want multiple attachment points on an AK, look into an Ultimak rail system, with which you can either just replace the gas tube/upper guard, or the lower guard, as well. Certain red dot sights will cowitness (allow you to see iron sights through the glass) on top of an Ultimak, and it allows for the possibility of a vertical grip. Krebs sells an adapter that allows you to hang it off the side of the rails where it won't get in the way of a dynamic magazine change.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

Thanks for all the answers.

You are correct BBJones in the fact that I'm not informed on these weapons. This is why my original question was about ammo, then went on to weapons.

When I first decided to get into some long range shooting, I started off not knowing anything in that area either.

I do think I will take some more time before buying any of the above weapon systems, and do abit more research. I understand the fact that what works for one shooter may not work for another. LOL I know this from testing someother rifles at the range.

I dont know anyone with an AK to borrow, so I do need to shoot one before chosing either weapon. I will post pics and my thoughts on whatever I get for all those that took their time to help me out.

I have a good base of information to start off from thanks to everyone that helped out.

I am doing some more searching in The Hide forums for additional information. There are plenty of awesome post/topics here.

Thanks;
Shane
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

I think it has been mentioned, but you are going to lose some hearing if you shoot an unsuppressed AR indoors.

With home defense, the hands-down choice is a shotgun with buckshot. You said you have a $2500 budget....my goodness man, you don't need to spend that kind of money for a home defense weapon. Get a Mossberg or Remington pump in 12 or 20 gauge with 00 or #4 buckshot respectively and call it a day. You will have the most effective home defense weapon available for about $250. Oh ya, put a Fenix flashlight on that puppy. Now, since you only spent $300, you have plenty of budget for a nice AR to round out your collection. Spend $900 on an AR an put the extra $1200 into college plan for the kids.
 
Re: 5.56 vs. 5.45 vs. 7.62 ; Input wanted please

556 will do the trick as long as you feed it some good ammo. I had my last 556 loaded up with some 64gr soft point federal tru t223l. That ammo is pefect for indoor soft target shooting. I ran a piston LWRC m6a2 and it was rock solid. That being said, I now run a LMT mws 308 full of red box TAP 155 amax. Recoil is not bad at all but it is a bit hefty for indoor work. I've gone back to handguns with lights for HD.