223 w/ 80g A-Max - how short can I go?

[glock24]

I'm musing with the idea of a short-barreled bolt rifle in 223 Remington. Assuming proper barrel twist, I'd like to push an 80g A-Max to at least 2500 fps.

Does anyone know if a 16" barrel will do it? How about 18 inches? I'd like to keep the barrel under 20".

Thoughts? Advice? Criticisms?

Thanks

 

[ChrisGarrett]

Re: 223 w/ 80g A-Max - how short can I go?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: glock24</div><div class="ubbcode-body">I'm musing with the idea of a short-barreled bolt rifle in 223 Remington. Assuming proper barrel twist, I'd like to push an 80g A-Max to at least 2500 fps.

Does anyone know if a 16" barrel will do it? How about 18 inches? I'd like to keep the barrel under 20".

Thoughts? Advice? Criticisms?

Thanks </div></div>

I'm playing with 75gr AMAX, 80gr SMKs, 80gr AMAX and 77gr Nosler CCs in a 20" 1/7" AR and I don't think you'd get the velocity out of a 16" tube to make it a super long range weapon.

You might just stick with the 69s, or the mag length 75/77 HPBTs.

Chris

 

[glock24]

Re: 223 w/ 80g A-Max - how short can I go?

Chris,

What kind of velocities are you getting out of your 20" barrel using 80 grainers? And with what powder?

I'm not looking for a super-long range setup, that is why I can live with an 80 grainer at 2500 fps. I'm just curious if I'm in the ballpark with a 16-18" barrel.

 

[ChrisGarrett]

Re: 223 w/ 80g A-Max - how short can I go?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: glock24</div><div class="ubbcode-body">Chris,

What kind of velocities are you getting out of your 20" barrel using 80 grainers? And with what powder?

I'm not looking for a super-long range setup, that is why I can live with an 80 grainer at 2500 fps. I'm just curious if I'm in the ballpark with a 16-18" barrel. </div></div>

Just an FYI, with these long VLDs, you're not going to be feeding them from a magazine, as they're single feed only.

These are 'my' loads in 'my' rifle and I had no major pressure signs with these, but start low and work up. I did have a batch of 69gr SMKs pierce 7 primers out of 50, so shit can happen even when keeping in line with the books.

This is a beginning attempt and some of my data was lost due to my chrono glitching over the past half dozen sessions.

80gr AMAX:

23.0 gr VV-140, LC89, Rem 7.5, 2.517": 15/15 shots, 2561 fps, SD: 18.8
23.5 gr VV-140, LC89, Rem 7.5, 2.517": 15/15 shots, 2633 fps, SD: Ooops!

80gr NOSLER CC:

23.5gr Varget, LC89, Rem 7.5, 2.525": 15/15 read, 2550 fps, SD: 15.0
24.0gr Varget, LC89, Rem 7.5, 2.525": 15/15 read, 2611 fps, SD: 21.5

75gr AMAX Moly:

23.8gr VV-140, LC97, BR-4, 2.500": 15/15 read, 2593 fps, SD: 42.0
24.1gr VV-140, LC97, BR-4, 2.500": 15/15 read, 2666 fps, SD: 15.5
24.4gr VV-140, LC97, BR-4, 2.500": 10/10 read, 2709 fps, SD: 23.4
24.7gr VV-140, LC97, BR-4, 2.500": 10/10 read, 2746 fps, SD: 20.2

That's really my first effort in reloading heavies for the 223. I've since got some bushing dies and I'm kind of laying groundwork for further fine tuning.

I haven't shot much this summer and in July, I did the 15 min. trigger job on the Stag lower (Bushy 20" Gov. 1/7"upper) and cleaned the trigger up a bit, so now it's more than adequate to target shoot with.

Chris

 

[olympian]

Re: 223 w/ 80g A-Max - how short can I go?

24,
Should not have a problem getting 2500fps with the 80gr in a 18-20" bolt gun. Service Rifle shooters can get it with Reloder 15 and 2520 is a powder to consider, too.

 

[olympian]

Re: 223 w/ 80g A-Max - how short can I go?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChrisGarrett</div><div class="ubbcode-body">Just an FYI, with these long VLDs, you're not going to be feeding them from a magazine, as they're single feed only.
</div></div>

Mine feeds 80s without a problem, so it depends on the gun.

 

[ChrisGarrett]

Re: 223 w/ 80g A-Max - how short can I go?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: olympian</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChrisGarrett</div><div class="ubbcode-body">Just an FYI, with these long VLDs, you're not going to be feeding them from a magazine, as they're single feed only.
</div></div>

Mine feeds 80s without a problem, so it depends on the gun. </div></div>

It's not a question of feeding them, as ARs have long throats, especially the ones with 5.56 NATO chambers.

The issue is, is in seating the bullets to mag length: ~2.260".

You just can't do it safely with the 75gr AMAX and the 80s/90s, as the ogive sits well below the case mouth, they're that long and the bearing surface is that short.

The 77gr SMK and the Hornady 75gr HPBT are both mag length tolerant.

Chris

 

[Niles Coyote]

Re: 223 w/ 80g A-Max - how short can I go?

glock24,

With a 21" rock 7t I am getting 2790 with varget, I can load it hotter but that is where the accuracy is in my rifle with that bullet. The chamber is throated for 75 amax and I have a OAL near 2.5 with the 80 grain which runs fine with AICS mags.

As for barrel length. You should be fine getting 2500+ out of a 16". I have had several barrels (handguns and rifles) in lengths of 21, 20, 16, 14, 12 and 10. I saw a large drop when going shorter than 16".

My two cents, I would not go shorter than 18". You will have good velocity and reduced muzzle blast; I detest shooting my 16" and shorter barrels simply because of the blast/pressure wave.

Of course you can tame that with the powder you use but then you loose velocity as well.

 

[Niles Coyote]

Re: 223 w/ 80g A-Max - how short can I go?

Oh, and may I add that 80 A-max at 2790fps reached 1k steel with 34.5 moa and hits were easy and predictable in the winds that I had Tuesday. Only problem was hearing the impact, they are not as easy to hear at that distance as 308 impacts.

 

[glock24]

Re: 223 w/ 80g A-Max - how short can I go?

Thank you gentlemen! Good info!

 

[ChrisGarrett]

Re: 223 w/ 80g A-Max - how short can I go?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: glock24</div><div class="ubbcode-body">Thank you gentlemen! Good info! </div></div>

Sorry, when I was touching upon, or focusing on, the mag length issues with the long VLDs, I was thinking you were wanting to shoot these out of an AR, which you don't.

You'll still have to be aware of how long your particular mag box is, but ususally you get to load them a bit longer than you would in a standard AR mag.

As you can see, one can seat them quite long. I'll actually try things a bit longer the next go-round, if you can believe the, lol.

Chris

 

[glock24]

Re: 223 w/ 80g A-Max - how short can I go?

I'm planning on using AI's new 10-round 223 magazine. They designed it very smartly, as it accomodates a COAL of 2.57". I should have plenty of room.

Thanks

 

[glocker17]

Re: 223 w/ 80g A-Max - how short can I go?

I am at 2.480 OAL with the 80 A Max's. Over 24.7 of VV540. Very mild load, 2800 fps but shoots fantastic. Can sub 24.5 Varget as well.

Mag mod to a Rem 700 is simple and will feed the long rounds.