AR 10 243 Powders

TXCOONDOG

TXCOONDOG

Well-known member
I'm waiting on the rest of my AR 10 parts to come in to complete my build. I reload for a Trued 700 Rem Action in 243 with a CBI barrel and currently using H4350 and Fed 210 Primers with a 75 grain VMAX.

I also have 87gr Vmax as well. Of coarse, I will be running a Superlative Arms adjustable gas block and a can.

Never reloaded for the AR 10 so wondering if H4350 will cycle the action or is there a better powder choice?

Note: I prefer powders that are not temp sensitive.
 
I shoot a Christensen Arms AR in a 243 and have been shooting it for 7 years. H4350 has worked well for me from 80 to 100 gr bullets.
 
Lancer mags can handle 2.830 no problem.

They are twice the price and can be a bit finicky during the first few mags it would seem.

Magpul mags are 1/2 the price and not finicky at all.

I really like them both.
 
Not sure if your dead set on a particular bullet but Varget does great with the lighter and medium bullets in 243. Around 44gr will be what you want if you are running 55/58s. My load in 3 different 243 ar10 barrels (1 proof, 2 Xcaliber) is 43.8gr with a 58vmax. All 3 shoot 3/4 or better. This was my first year running that combo because it was available. I would think the Nosler would be better but they have been hard to find. Disclaimer as its definitely not fur friendly but honestly nothing in 243 really is!

Another thing to note is I put a medium crimp on them with the Lee FCD. The cycling action of an AR10 is pretty violent so to ensure the bullet doesn't get pushed in during cycling I recommend this extra step for the big ARs.

I wanted something fast and flat for thermal hunting, I killed 153 coyotes with that particular load this year and it works very very well. To 300yds is simply point and shoot.

I run H4350 in 243 but only with the heavies, it has a slower burn rate and is money for the 105 class stuff, but not fast enough on the light bullets IMO.

The Mapul 10rd mags is what I run and I've never had a failure of any kind so I see no need to change.
 
I've always used a crimp on my loads, anywhere from light to heavy depending on the caliber and/or application.

Haven't tried anything lighter than 75gr Vmax and 87gr VMAX as most of my shots have been within 225yds and under (most under 100yds). With the 75gr VMAX @ 3400 FPS, a 75 yd zero (scope height of 1.92") and a dead on hold has worked out great for me thus far.

Your input and the information provided is greatly appreciated.
 
Originally Posted By: arlaunchLancer mags can handle 2.830 no problem.

They are twice the price and can be a bit finicky during the first few mags it would seem.

Magpul mags are 1/2 the price and not finicky at all.

I really like them both.

Good to know. Thanks
 
Originally Posted By: Kino MNot sure if your dead set on a particular bullet but Varget does great with the lighter and medium bullets in 243. Around 44gr will be what you want if you are running 55/58s. My load in 3 different 243 ar10 barrels (1 proof, 2 Xcaliber) is 43.8gr with a 58vmax. All 3 shoot 3/4 or better. This was my first year running that combo because it was available. I would think the Nosler would be better but they have been hard to find. Disclaimer as its definitely not fur friendly but honestly nothing in 243 really is!

Another thing to note is I put a medium crimp on them with the Lee FCD. The cycling action of an AR10 is pretty violent so to ensure the bullet doesn't get pushed in during cycling I recommend this extra step for the big ARs.

I wanted something fast and flat for thermal hunting, I killed 153 coyotes with that particular load this year and it works very very well. To 300yds is simply point and shoot.

I run H4350 in 243 but only with the heavies, it has a slower burn rate and is money for the 105 class stuff, but not fast enough on the light bullets IMO.

The Mapul 10rd mags is what I run and I've never had a failure of any kind so I see no need to change.

I ordered five boxes of the 58 V-Max to play around with this summer.

Are you running a COL of 2.600" or?


I run Lapua brass in my Bolt Actions. However, I'm concerned that the AR might be hard on brass. Just curious what everyone is running in your 10 and how has brass life been?

 
Brass life in mine is excellent, I run adjustable gas blocks so it isn't so violent. I also run Lapua in one of them, my brass is over 20 years old lol and I long ago lost track of the firings but you can barely read the headstamp on some of them. I think Lapua pays for itself, having said that my other rifle I'm running dogtown I bought at a super bargain covid year, and after that I have a pile of Fiochi I got at a super bargain and I'm sure it will do fine also. I won't ever need to buy 243 brass again I'm sure.

2.6" sounds about right for the 58's, I'm with Keno on Varget for those, H4350 is what I run with 87's, which is what I'm using right now and they work great imo. About an inch less flat at 300 with a 200 yd zero, but much less wind deflection, but mainly I have a pile of them too and they outshot the 58's in my rifles.

Mags, it's hard to go wrong with pmags, I use them in one rifle and Amend2 in the other to keep the ammo straight.
 
Just waiting on my barrel. I bought a Superlative Arms adjustable gas block and Magpul mags.

Who knows what the rifle will like best. I've been happy with the 75gr V-Max but want to play around with various combos.


I greatly appreciate the response 204 AR.
 
X-Caliber got my barrel corrected and back to me. Fire Formed the brass (Lapua) as I performed the barrel break-in.

Die set to bump shoulders .003"-.004" and bullets are .015" off the lands with the 87grainers using a med-heavy crimp (LEE FCD) to prevent the bullets from moving forward when chambering.

Using H4350 with the 87 grain V-Max and worked my way up. Groups were great at .300"-.560" at 100 yds. 41-42 grains (node) seems to be the sweet spot @ 2900-2966fps out of the 20" (Suppressed). Anything above that starts showing swipes and 43gr has nasty burrs and leaking around the primers.

Tried 58gr V-Max (COL 2.600") with Varget and the max velocities that I could reach were 3600 fps (Suppressed) before swipes and burrs get bad. Groups were around 3/4-1" @ 100 yards.

PS: I'm running a JP high pressure bolt.
 
Varget, IMR-4064, H414, H/IMR-4350, and Ramshot Hunter, all have a strong place when loading the .243 Winchester.
 
An old reloader told me once ...... "If your .243 won't shoot with IMR4064, well then ... it just won't shoot."

I found over the years that with reasonably sized bullets he was correct.
 
You're right on the money between 41 and 42 gr H4350 with the 87s. I would have expected another 100 fps though but it might speed up after a few rounds. My DPMS is at about 3070 with 42 gr. You can also expect dirty cases shooting suppressed as I'm sure you know, however that load won't leave a lot of bore fouling in the way of carbon. I put about 50 rounds thru mine last weekend fine tuning the Eliminator on p-dogs and the bore, as usual with this powder, cleaned up very easily. Varget tends to be clean also. I wish I could find a small case powder that burned as clean.

The downside to this round is that you come to appreciate the efficiency of the rounds based on the Grendel and 6.8 case, as they'll send an 87 at 2900 with 28 gr of powder with double the barrel life. I just haven't had one that's as consistently accurate as my 243's.
 
I noticed with H4350 and 87 V-Max, first shot the case ejects at 1 and the next four shots ejects perfect at 3, any ideas?

No issues with running, just curious as I haven't experienced that with my 6.8 SPC II or 30 Saborcat AR's running suppressed.

There is definitely less port noise with the 20" barrel w/rifle length gas system vs 16" barrels w/ mid-length gas system.


All AR's have a SA adjustable gas block but the 243 has a SA GB with the bleed-off which I don't run it in that position. The gas blocks are adjusted just enough to lock open on the last round with an additional click for reliable function.

Possibilities/Thoughts:

Maybe the difference is 16" barrels with mid-length gas system vs 20" rifle length gas system?

Fouling build-up and the first round has more pressure (slight obstruction) which clears some of the fouling.
 
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