I have two AR15s in .223 Rem.  I have coyotes in my back yard which I’d like to be prepared to shoot BUT there are houses and a main road about ¼ mile away which (I believe) preclude me using a .223 Rem because it might travel too far.  Thus the quest for a subsonic round that shouldn’t travel as far yet get the job done.

I also have about 5000 rounds of .45 ACP (used to shoot IDPA and IPSC) and Redding carbide dies for my RCBS Rockchucker with a Piggyback II autoindex on it.

I'm "wishbooking" as to what I'd like to build next for an AR15.

Here's the dilemma:  

1)  IF I were to put a .45 ACP barrel in one of the ARs, I’d also have to buy magazines.  So the total expense would be quite high given that Olympic AR15 .45 ACP mags are around $40 to $50 each (and I like to have a minimum of four to six mags for any given caliber).

2)  IF I were to rebarrel an upper in .300 BLK according to everything I’ve read ALL of my .223 Rem mags will work without any modifications (which will save buying mags).  BUT I don’t have ANY .300 BLK ammo or dies (which from what I understand the only dies available are Forster or Lee dies which I prefer Redding dies over them).  I’m lead to believe that I can resize my .223 Rem cases to the .300 BLK case specifications (which I have NEVER done but am willing to learn).

It would be of immense help if you can expound on the cost of each conversion:  mags, dies, ammo, barrel, etc. so I can make an intelligent decision.

300 just because its easier. 45 would be a cool AR, I have an MP5 type and an FAL SBR in 45, very neat and fun, but not near as practical or useful as an AR in 300 would be.

Pic please of the SBR .45 FAL. Just the thought of it is giving me a woody...

I tend to agree with you that the .300 BLK is a better choice given that all I'd need is a barrel (Midway has one for $175).

I've never resized brass which I think that I had better learn how to do IF I do go with the .300 BLK.  

Can anyone enlighten me as to how to resize the .223 Rem rounds into .300 BLK and what tools are necessary to do that?  So far, I've found that "new factory" .300 BLK rounds are EXPENSIVE ($22 for 20 rounds!  YIKES!).

So far, I've found that only Forster and Lee make dies for the .300 BLK.  I sent an email to Redding (which is just up the road from me in Cortland, NY) asking if they had a set of .300 BLK dies.  I prefer Redding dies as they have always served me well when I need advice and/or help reloading.  My second choice is RCBS dies which were the only ones that I could find when I wanted to reload my .223 Rem brass.

300 BLK hands down IMO.  Nothing is proprietary except the barrel.  The .45 conversion will use a different bolt/carrier and magazines and will be blowback instead of gas operated.  Pistol caliber rifles are fun, but not terribly practical for most applications.

Having said that, I think you need to take into account that a big heavy subsonic round is more likely to richochet than a high velocity .223 round.  If you use a 60gr V-Max .223 round you are less likely to have problems with a bullet reaching the roadway than with a subsonic 300BLK.  If you go with the 300BLK you'd be better off with the 110gr V-Max at supersonic speeds I think.  

The problem is that the big heavy subsonic bullets won't fragment (or even deform in most cases) and are much more likely to skip off the ground.  I have a hole in my wood target backer from a 240gr SMK fired from my 300BLK that went through perfectly sideways after skipping off the dirt in the cornfield (I was trying to get on target at 300 yards and was hitting low).  A high velocity fragmenting round like the V-Max is far less likely to skip off the ground so it would most likely be less dangerous provided you were shooting from any elevation (if you miss, it will simply hit the dirt).  The fragmenting round is also less likely to exit the other side of the coyote, a heavy subsonic SMK will likely pass through and barely slow down.

As for dies, Redding makes a 300/221 die set, which is one of the names the 300 Whisper - 300 Fireball - 300/221 - 30/221 went by before Remington and AAC submitted the 300BLK for SAAMI approval.  I'd check with Redding for confirmation, but they should work fine.

ETA:  If there are houses 1/4 mile away in the line of fire, nothing would be safe to use.  I would hesitate to shoot a .22LR with houses that close in the background.  It is unlikely that a round would make it that far after hitting an animal or the ground, but the consequences of that 1 in 1000 shot could be catastrophic.  There was a man killed while sleeping in his bed a few years back in the Indianapolis IN area by a .45 ACP round fired several hundred yards away.  The bullet came in through the roof and struck him in the heart.  His wife thought he was having a heart attack, it wasn't until they got him to the hospital that they found the entry wound.

I was having this same exact debate myself.  I went with the 300 BLK 8" Noveske Upper.  I do/did really want a .45 upper/SBR but ran into the same roadblocks that many have.  The fact that I only need a barrel and can use the same bolt/mags/lower as my other AR calibers made the decision simple for me.  The 300 BLK will launch a 220/240gr bullet about the same velocity as a .45 SBR would a 230gr bullet making suppression very easy.  You can buy formed brass fairly cheap or new brass at a reasonable price.

That's the 16" SI Defense M4-type barrel, and it's not in stock.

The 16" CMMG is in stock, though, and it's $200.

They also have the factory Remington 220gr OTM sub ammo in stock (right now)...

I vote for the 300 BLK.
You can use your existing mags, though I prefer the Wilson/Lancer AWM 7.62x40 WT( Basically a Lancer AWM 5.56 with the ribs filed down to ensure reliability when loaded a round similar to the blackout).
I also have a .45acp build in the works as well.  It's a Ron Williams DI upper with a Bazooka Brothers lower.
Since you have two ARs in .223, you can convert one them and all you need is a barrel assembly instead of a whole new upper and mags.
As for dies I'm using the Redding 300/221 Deluxe die set.  Using loads that AAC recommend on their website for 220 subs with great results.
As for brass you can go to quarterbore.com forums and buy brass from a couple of members there or even have them convert your brass for you.  Either way it's fairly inexpensive.
$22 for a box 20 is cheap for subsonic rifle ammo.  They use 220 Sierra Match Kings bullets which if you plan on loading these you'll find out that they are not cheap.  Look up Engle Ballistic Research's .308, 5.56 subsonics and Corbon 300 Whisper subs and you will see that $22 is a bargin.
Of the two the .300 will be my primary pig, coyotes, pest gun while the .45 will a range/plinker gun.  You could do a lot more with the Blackout.
Here is a couple of short videos of me first trying it out:
http://www.youtube.com/watch?v=vht2DalAedI
http://www.youtube.com/watch?v=I7aUgOqy5b4&NR=1

With your requirements and with your supply of .45 acp it's a no brainer for me. I already shoot .45 asp as well so I would go that route if it were me.

300BLK

Prior to learning about 300 Whisper / Blackout I intended to get a cav arms lower (with its wider well to use grease gun mags / avoid franken mags) and Oly45 upper.  Glad I found and bought my 10.5" Noveske 300 barrel first.  Makes much more sense for many reasons than AR45.

Here are a couple. the OSW is a little different now, ditched the FWD grip and its been painted black. The SBR 45 has a cheap $20 red dot, and its fun. It has an Aluminium reciever and I had 2 versions, grease gun mag and thompson mag. i like the thompson mag, freed up my grease gun mags for the SW45.  Both FAL's have 11 in barrels. The 45 is blow back and uses a modified FAL bolt and carrier. It was a PITA to get to run and not slam fire. Especially with the GG mag version, but the Thompson mags work out better, and I have finally got it running. Its fun to plink with. The SW45 is very nice, very smooth.  Also the PWS brake on the 308 is VERY effective. And a vortex  will even kill the flash from the 11 in 308 when its installed. The Vortex on the 45 is just a 308 one reamed out to .460 or so.











Not trying to Hijack your thread here OP, but I guess I did a little. Sorry. I have a little experience with the 45 cal carbines and honestly, they are more of a fun gun than a serious use weapon unless i hole myself up in my house.....  I might try squirrel hunting with one, maybe, but I do believe you will get more use and less hassle/cost from a 300. It has a much wider envelope of operations than a .45 And probably more accurate. Go with the 300.

i would use the blackout if you want something quiet.  .223 with light vmaxs would be safer. Nothing is safe without dirt behind it.

Panzer, Awesome, both pics and sticks. Now I won't be worth $h!t all day. I need that 45 SBR FAL.....

Use frangible ammo on the coyotes

Frangible ammo often will not come apart unless it impacts something very hard like steel.  It can still ricochet and won't necessarily wound very well.  It is designed to come apart well during training when you are shooting steel targets.

Ammo designed to fragment, like the V-Max, will come apart more reliably when it encounters intermediates like tissue or dirt.  It is designed for use againts small game where penetration isn't a major concern.

I just got an email from Midway USA:  

Per your request for notification, we received the following:

SI Defense Barrel AR-15 300 AAC Blackout (7.62x35mm) 16" M4 Contour 1 in 8" Twist Matte

Supplies may be limited and are first come first serve. Don’t wait until they’re gone.  

To view this item, click on the link in the next section.

Thanks for Your Business,

Larry Potterfield,
Founder and CEO of MidwayUSA

I got the following email from Redding:

We are shipping those to our dealers as they order them.

The part number is 80327 for a two dies set (full & seat) or 84327 for a three die set (full, neck & seat).

We have also made a Type S Bushing Neck, as a Custom Series die, for bolt action guns.

The two die set is recommended for semi-auto rifles and the three die set is best for bolt action rifles.

These dies are marked 300 BLK (300 AAC Blackout) but will work for the 300/221 Whisper if the seating die is readjusted for the crimp ring.

(Conversely, the 300/221 will work for the 300 Blackout if the seater is adjusted for crimp.)

If you call Graf & Sons, Midway, Midsouth, Natchez, Gunstop, etc. they can get the dies if they don't happen to have them on the shelf.  

We can sell them directly, but it will be at full suggested list price and you must send a check as we do not take credit cards

Thanks to all for all of your input.  

IF I had an unlimited fund for buying a new AR it would be for an AR in 45 ACP.

BUT I don't have an unlimited budget so I'm probably going to buy the .300 BLK barrel and convert one of my uppers to that.

As for ricochet bullets, there is a THICK stand of pines about 100 yards from my back yard that will stop any rounds that might get that far.  I forgot to factor them in with my concern about the main road across the valley.

I also bought a box of #4 16 gauge shells that a good friend of mine who hunts coyotes recommended.  I have retinal detachment on both eyes so using a high power rifle or a 12 gauge shotgun (I have a 30-06  and a Winchester 1300) are OUT of the question hence the 16 gauge, .223 Rem, 300 BLK, .22LR and 45 ACP pistol will have to get the job done should it become necessary to eliminate a threat from the coyotes.

Pics are required when you complete your build :)

I know this idea is going to go over like a lead balloon, but what I have for a subsonic load is for my single shot 30/30 NEA "though any other action type or 30 cal. would suit" I cast a 210gr gas check semi pointed bullet loaded with a light charge of Red Dot which pushes the round at roughly 1025 fps.. It is quieter than a 22LR but carries a lot more momentum than any subsonic rounds I've read about. The only additional expense I've encored is a set of dies for the bullet, that can also be loaded at higher velocities as a hunting round for big game.
I know this won't change your mind but I though I'd throw it out there since expense is a consideration to you. How many times do you normally shoot at a coyote?

There's nothing wrong with using a 30/30 for subsonics but it wouldn't carry any more momentum than any other 210gr bullet going 1025fps.  The standard 300BLK load is 220gr, so it would have more momentum and a better BC so it would carry more momentum farther.  The 240gr SMK's I use would have quite a bit more.

Momentum is just speed times mass.  Since subsonics have a built it speed limit, you can only increase energy or momentum by increasing mass.