AR-15 80 grain A-MAX

mph621 · March 25, 2015, 12:43 PM

I loaded some 80 grain A-MAX bullets last night for my 223 set the oal too 2.390 to single load. I used 25.8 grains of 748 before I realized that was for bolt guns only. Does anyone know what a good and safe load is for a 80 grain A-Max .224 I have a 1-8 twist 24 inch bull barel. Any help would be appreciated!

nemesiss45 · March 25, 2015, 12:56 PM

My book says 21.8-24 gr of 748 and 2.550 OAL

The way i load for my ar is to do 5rnds ever 1gr in the allowable charge weights, shoot it all, srap any that dont feed well, then choose the most accurate. I have not, however, loaded with 80 gr. Bullets, so i couldnt recomend a sweet spot for it.

scsov509 · March 25, 2015, 01:19 PM

Quote:

My book says 21.8-24 gr of 748 and 2.550 OAL

I've got the same data and and also show Sierra lists the 80 grain HPBT over 21.3-23.5 grains of 748 at the same OAL. FWIW, I played with the 80 grain pills a little bit but finally gave up and switched to the 77 grain Sierras since they can be loaded to magazine length for the AR. I also found that powders like Varget, TAC, and IMR-4064 gave me a lot better velocity with those size bullets.

JeepHammer · March 26, 2015, 07:35 AM

I don't know if it will work for you,
I've found seating the bullet just a little deeper in the case *Usually* improves accuracy with heavy bullets.

Giving that heavy round a little 'Free Bore' before it hits the rifling.
That long, heavy bullet has PLENTY of load bearing surface to hold the rifling,
So a head start on getting all that load bearing surface into the rifling SOMETIMES helps...

The problem with ARs is there are SO MANY different chambers out there,
Barrels marked 5.56 usually have longer free bore before the bullet hits the rifling,
But that's not even a given, every one is different...

I mention this because the prevailing thought is to get that bullet REALLY CLOSE to the rifling,
And that doesn't always work best since so many different companies crank out AR barrels and every one of them have a different way of chambering...

If I may ask,
Why the heavy bullet? Are you shooting large game, or really long ranges?

mph621 · March 26, 2015, 07:53 PM

I plain too try 959 yards next Saturday just for kicks I will be shooting that with my 300 win mag and 50 BMG so I thought I would load 10 or 20 up to try. Thanks for all that great info from you all!!!

skizzums · March 26, 2015, 10:05 PM

i don't know how many you loaded, if just 100 rounds, then use them for long distance shooting an load single shot. i don't think you can seat those deep enough into the case for the magazine without starting to go over the ogive of the bullet. lots of folks use them for single shot in the AR though. if you have a 5.56 barrel, you'' have plenty of room. chamber an unchamber a few rounds to make positive your not running into the rifling, but your prob okay unless shooting a .223 only barrel

Damon555 · March 26, 2015, 10:14 PM

According to the manufacturers data (which goes no larger than a 69 grain bullet with 748) you are several grains over the max load for the heaviest bullet that they list.

How did you come up with the load you chose? Did you do a load work up to get to that point?

I could be wrong but I think your loads are unsafe.....best to cut your losses and start over.

skizzums · March 26, 2015, 10:58 PM

this is from hornaday
WIN 748 -- START 20.2gr@2200----- MAX 23.6gr@2600
but know that manuals have data maxing out under 55kpsi, if you have a 5.56 nato barrel, you can go to 62kpsi pressures, but you really need to do a work up. your entering dangerous territory.

I think we are all curious where you got your data to start at almost 26gr? not to harp on you, but just curious

scsov509 · March 29, 2015, 12:38 AM

Quote:

this is from hornaday
WIN 748 -- START 20.2gr@2200----- MAX 23.6gr@2600
but know that manuals have data maxing out under 55kpsi, if you have a 5.56 nato barrel, you can go to 62kpsi pressures, but you really need to do a work up. your entering dangerous territory.

I think we are all curious where you got your data to start at almost 26gr? not to harp on you, but just curious

My Sierra manual lists 25.8 grains of 748 as a max load under the 80 grain MatchKing for a bolt rifle. Not a good load to have started with if that's what the OP did, but in answer to your question it is in fact a published load for a bolt action rifle.

skizzums · March 29, 2015, 02:25 AM

okay, if it's in fact published that's great. amazing the differences in data.

March 25, 2015, 12:43 PM	#1
mph621 Junior Member Join Date: March 25, 2015 Posts: 2	AR-15 80 grain A-MAX I loaded some 80 grain A-MAX bullets last night for my 223 set the oal too 2.390 to single load. I used 25.8 grains of 748 before I realized that was for bolt guns only. Does anyone know what a good and safe load is for a 80 grain A-Max .224 I have a 1-8 twist 24 inch bull barel. Any help would be appreciated!

March 26, 2015, 10:05 PM	#6
skizzums Senior Member Join Date: July 1, 2013 Location: Douglasville, Ga Posts: 4,615	i don't know how many you loaded, if just 100 rounds, then use them for long distance shooting an load single shot. i don't think you can seat those deep enough into the case for the magazine without starting to go over the ogive of the bullet. lots of folks use them for single shot in the AR though. if you have a 5.56 barrel, you'' have plenty of room. chamber an unchamber a few rounds to make positive your not running into the rifling, but your prob okay unless shooting a .223 only barrel __________________ My head is bloody, but unbowed

March 26, 2015, 10:58 PM	#8
skizzums Senior Member Join Date: July 1, 2013 Location: Douglasville, Ga Posts: 4,615	this is from hornaday WIN 748 -- START 20.2gr@2200----- MAX 23.6gr@2600 but know that manuals have data maxing out under 55kpsi, if you have a 5.56 nato barrel, you can go to 62kpsi pressures, but you really need to do a work up. your entering dangerous territory. I think we are all curious where you got your data to start at almost 26gr? not to harp on you, but just curious __________________ My head is bloody, but unbowed

March 29, 2015, 02:25 AM	#10
skizzums Senior Member Join Date: July 1, 2013 Location: Douglasville, Ga Posts: 4,615	okay, if it's in fact published that's great. amazing the differences in data. __________________ My head is bloody, but unbowed

March 25, 2015, 12:56 PM	#2
nemesiss45 Senior Member Join Date: February 6, 2014 Posts: 526	My book says 21.8-24 gr of 748 and 2.550 OAL The way i load for my ar is to do 5rnds ever 1gr in the allowable charge weights, shoot it all, srap any that dont feed well, then choose the most accurate. I have not, however, loaded with 80 gr. Bullets, so i couldnt recomend a sweet spot for it.

March 26, 2015, 07:35 AM	#4
JeepHammer Junior member Join Date: February 27, 2015 Posts: 1,768	I don't know if it will work for you, I've found seating the bullet just a little deeper in the case Usually improves accuracy with heavy bullets. Giving that heavy round a little 'Free Bore' before it hits the rifling. That long, heavy bullet has PLENTY of load bearing surface to hold the rifling, So a head start on getting all that load bearing surface into the rifling SOMETIMES helps... The problem with ARs is there are SO MANY different chambers out there, Barrels marked 5.56 usually have longer free bore before the bullet hits the rifling, But that's not even a given, every one is different... I mention this because the prevailing thought is to get that bullet REALLY CLOSE to the rifling, And that doesn't always work best since so many different companies crank out AR barrels and every one of them have a different way of chambering... If I may ask, Why the heavy bullet? Are you shooting large game, or really long ranges?

March 26, 2015, 07:53 PM	#5
mph621 Junior Member Join Date: March 25, 2015 Posts: 2	I plain too try 959 yards next Saturday just for kicks I will be shooting that with my 300 win mag and 50 BMG so I thought I would load 10 or 20 up to try. Thanks for all that great info from you all!!!

March 26, 2015, 10:14 PM	#7
Damon555 Senior Member Join Date: January 11, 2012 Posts: 384	According to the manufacturers data (which goes no larger than a 69 grain bullet with 748) you are several grains over the max load for the heaviest bullet that they list. How did you come up with the load you chose? Did you do a load work up to get to that point? I could be wrong but I think your loads are unsafe.....best to cut your losses and start over.