Loading Data for AR30A1 Armalite 300 Win Mag

[LR65Pb]

I've looked, searched forums and googled for AR30A1 specific reload data and very little is available. If I missed it, I apologize, but since I'm new to reloading the 300 Win Mag, some of the information I'll be posting may help another newbie that has the same problem.

The gun is an Armalite AR30A1 Target version of the .300 Win Mag. It has a 24" barrel, 1:10 twist rate and a factory break. I've added an Atlas bipod as well as a monopod on the stock. It comes standard with a long 20 moa rail and I've mounted an SIII 10-50x62 mm Sightron Mildot reticle scope. What I could not find posted was the chamber length and at what point the COAL would touch the lands. I've spent several days, learning and reloading, using H-1000 and the Hornady 208 A-max bullet. I've had excellent results with the A-max in my 6.5 Grendels, so I stuck with it.
What I didn't know was best seating depth, COAL, powder weight, etc specifically relating to the AR30A1. I loaded 5 pieces of brass at each powder weight in increments of .5 grains, beginning at 74 and stopping at 78.5. I also loaded 8 each in the 77 to 78.5 grain range with various COAL varying from 3.545, .090 off touching lands, to 3.632, .002 off lands.

My range is next door to my house. A close friend owns 600 acress and I've set up AR500 silhouette steel at every 100 yds from 100 to 1300 yards. Same target is used for 400 to 1300 yards. I'm digressing, but wanted to layout that it sure is appreciated having a range next door for zeroing in a new load. Here's what I found.

First, I quickly eliminated the lighter loads with .200 jump. I'm shooting paper at 100 yds, so it hurt my feelings when my early groups were sometimes 1 to 1.5 moa. Finally, at 76.8 grains of H1000, the groups started to close a little. .75 moa, but not great. My last loads for day 1 was at 77 grains and the moa was better at .500. At that point, I was out of my first test loads, but at least I'm closer to having a load and now know what didn't work. Back to the bench.

Second time out, I'm now stocked with 8 each of 76.8 to 78.5 grains of H1000 and COAL from 3.545 to 3.632. Immediately, the groups were .75 moa at 76.8 and 3.545 COAL (.090 off lands). Next, I shot some 77.8 grains at the same COAL, 3.545. The groups tightend up and two groups were at .375 to .400. This was exciting, since I knew I was closing in on my load. Next group was shot using the same 77.8 grains, but the COAL was now at 3.625, .010 off lands. I skipped some loads at 3.595 and went straight to the .010 off lands due to some excellent posts by others. It worked. The group was now .300 for only 3 shots, but a followup group using the same 77.8/3.626 was .320.

Finally, I moved on to the 78.2, 78.5, 78.8 grain loads at same COAL of 3.625 and shots immediately went back to .75 moa. I'll be testing 78 tomorrow at different COAL, but suspect the 77.8 is where I'll end.

That's where I am now, and based on chronograph information from others with similar loads, I suspect velocities in the 2850-2900 fps range, maybe a little more, but I forgot my new Chrony Alpha when I went out for the 2nd trip. Tomorrrow, I'll have the opportunity to test velocity as well as the .003 off lands with 77.8 and 78 grains H-1000. Hope this helps others.

 

[alaska]

You have to try the 230 berger OTM and H1000 in your AR30

I have been using mostly Sierra 220 MK in my 300 Win with H1000, I did notice flatter traj with the OTM.

I switched to the OTM in my 338 Lapua also, the 300gr OTM in my AR30

 

[LR65Pb]

Thanks for that input Alaska. I also have an AR30A1 in the 338 Lapua and love it. I've been shooting factory Hornady 285 BTHP, but have recently purchased some 230 and 300 Berger Hybrids for each rifle. I haven't started loading any 338's yet but as soon as I can settle on a good 300 load, I'll begin on the 338. I've heard nothing but great things about the Berger hybrids. Most of my shooting is from 667 to 1150 yds, so the BC is going to really help on windy days. Hopefully, tomorrow I'll finish the 300 testing.

 

[alaska]

Sweet

I load 91.0 of H1000 with the 300 OTM
92.0 gave me 2833 and very flat primers.......a hot load at 2833 FPS at 29deg but OK in the AR 30 and Lapua brass.

But I backed off to 91.0

WLRM primer
H1000 @ 91.0
Lapua Brass
300 gr OTM
3.681" OAL

I use H1000 in both my 338 Lapua and 300 Win to keep it simple with the OTM
The OTM really start to shine past 1K yards with that great BC.
The 220MK are hard on the throat area.......at high vel. Great bullet the MK.........but I will never switch from the OTM.

 

[LR65Pb]

You're data will really help me get zero'd in on my 338. I just purchased 500 more 208 A-max's and a couple thousand Fed 215M primers along with a few pounds of Retumbo, but that's about the only exploring I'm going to do. The Bergers and A-maxes will be all I want for hunting or killing steel and the H1000 and Retumbo should do the trick for my powder needs. Can't wait to get out tomorrow and verify whether the .003 off the lands helps any or maybe 78 grains of H1000 will keep the groups together and add a little velocity on the 300. It's been difficult to find any information on the AR30's so I appreciate your help. I usually get to Alaska in July/Aug each year but I'm chasing halibut and salmon. Maybe one day, I'll make it up there to go for an Elk or Moose for my first time. This year I got an 8 point whitetail with one of my 6.5 Grendels but took down a doe with the 300 win mag at 702 yards. Should to shoulder shot, right through the heart. She walked out in my 742 yard target range at the wrong time. I had hunted the same range the day before but had so much fog, the deer were just silhouettes basically. Next day, it cleared a little and it was over.

 

[alaska]

My AR 30 in Lapua
Leupold MK 4 8.5x25 TMR illuminated Ret
ARMS # 44 rings low

m4 Extension with LMT SOPMOD stock

I use this rifle mainly on the ATV as a mobile shooting platform (MSP) while moose hunting.

 

[LR65Pb]

Nice. I love the idea of your mobile platform. I have one too but I don't think it can make it to the same places yours probably goes. I use mine to keep these old bones off the ground and to elevate above the brush a little. I purpose built it just to shoot from. I made the entire stake bed and cover my self. New remanufactured Super Hurricane engine and the front pto winch even works. Love taking it out when I shoot. The other pic is my long range. The stake is 1125 yds to target.

 

[alaska]

That is one cool veh.

I bet that crawls like a ATV........and easy to work on.

 

[LR65Pb]

Today was a good, long day of testing. For 6 hours I loaded and tested groups from .030 off the lands to .010 jammed, in .005 increments. At each of those increments, I used powder weights from 77.7 gr to 78.5 in mostly .1 gr intervals. This made for a lot of shooting and loading, but it was worth it.

Before starting, I fired 2 Factory Hornady 180 SST's through the chrony to verify it's data and it read 3111 and 3118 fps at the same 15' distance. Since the Armalite AR30A1 300 win mag uses the same magazine as the 338 Lapua, COAL can pretty much be anything and still have the 5 shot capacity mag.

Based on yesterdays results, I had an idea of what might work, but as it turned out, I picked up more velocity and at the same time, a tighter final group. I wrote down every shot and group which came in handy when at the end of the day, I decided to revisit the two tightest groups. One of those groups was at the starting charge weight of 77.7 and the other was at 78.4. One thing that became apparent during the testing was the gun liked having the bullet close to the lands. As I moved it in from .030, the groups generally got tighter. At the 77.7 gr and .003 off the lands, I shot a .25" group, with several in the .375 range (guestimated). By running the COAL to 3.635, just barely off the lands, maybe .001 at most, and using 78.4 grains of H1000, I had my best group of the day. Actually, it was only a 3 shot group at the end of the day, but I'll take it. When I looked at the Chrony on the second shot, I thought that it hadn't registered the shot because it was 2918, the same as the first shot. On top of that, the poi was right on top of the first shot. After verifying that the log did have two shots in the string, I loaded the 3rd cartridge. Again, the chrony showed the exact same velocity, 2918. I checked it again and it absolutely had 3 shots logged for a 3 shot average of 2918 and 0.00 and 0.00. No way did I think it was possible. Several times I had 2 of 3 shots in the same hole, but usually one of the 3 would deviate and I'd end up with a small gap between shots or a lightly touching clover leaf looking like 2 shots. The final group was quitting time and the 3rd shot barely opened up the 2 shot hole. At worst, a .125 moa.

I think all of the testing and running back and forth was worth it. My best group ever with a 15' velocity of 2918 fps using the 208 Amax, 78.4 gr of H1000, bullet seated right at the lands, multiple fired Hornady brass with a Fed Match Magnum 215M primer.


Thanks for all of the previous posts in other threads. It certainly has helped me get a grip on reloading again.

 

[socaltroy]

Hi LR65Pd,

I have the same rifle with a Nightforce 12x42x56 scope. I just started to collect all the goodies to start reloading and have been searching for somebody like you for info. Its great to see someone else out there to chat with. Thanks for all the great info. I do have one question on your COAL. My calipers are showing a factory load length in the 3.2 range. How are you getting 3.635? Thats a huge difference. Also what bullet are you using? Im new to reloading so I was hoping you could shed some light on this.

 

[LR65Pb]

The above pic shows the difference. I very quickly measured the COAL and Ogive to Base of both the Hornady 82193 (180 gr SST Superformance) and my reload which measures .005 Off the Lands using the 208 AMAX.
The factory 180 measured 3.323 COAL with 2.696 Ogive to Base.
The reload 208 AMAX measured 3.631 COAL with 2.904 Ogive to Base.

The .005 was measured several months ago with a different caliper and set-up, so my hurriedness may be off by a couple of thousandths.


Hope that helps. Yes, the reload is quite a bit longer. Especially with the 208 gr.

 

[LR65Pb]

I've been looking for my best 3 shot group and found it on my phone. Again, 208 Amax, 3.635 COAL (.001 off the lands), 78.4 gr. H1000, Hornady brass, 2918 fps at 100 yds. Measured .430 maximum edge to edge, probably more like .427 but hard to tell. Certainly, I can't do that very often. Just a good indication of the load. All 3 shots measured the exact same velocity.

http://i43.photobucket.com/albums/e354/ubbugb8/Edgewater/20150319_200901.jpg