Range Report 300 SAUM (Picture added)

long450

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I made it to the range today to shoot the Accuracy Systems 300 SAUM upper I had built. Here is what I had them build:

Complete new flat top upper, stainless barrel 1X12 twist 24" plus brake.
I had the barrel fluted, a 3 port Maxi Brake, and a quad forend .
Cost was $2099 (expensive I know) and it was delivered within the 8 week estimated time frame.

This is a nice piece of work and it shoots well under their guarantee of 1 MOA!

Today was 101 degrees when I headed to the range. All targets were shot at 200 yards..

Proir to going to the range I had thoughly cleaned the barrel using solvent and gray JB compound recommended by Accuracy Systems. I used the JB compound in three different applications. I also mounted a Leupold LR 8.5x25 scope on the rifle and attached my DPMS 300 SAUM lower with the JP trigger to the upper.

Once I arrived at the range I bore sighted the rifle and fired 3 fouling shots to get sighted in.

First up was 180 gr Accubonds with 65 grains of Reloder 22 powder and a 215M primer. All fired rounds were seated magazine length.

The wind was not strong, but the mirage was running strong. I ingnored it as for as compensating for it on any of the shooting.

I fired 2 shots and could not see where they impacted the target until the mirage slowed down and changed directions. Once this happened, I could see the two shots and later determined that they were 1.887" vertically and 1/2" wide. I put this rifle aside to let it cool and shot something else while I waited.

Once the barrel cooled, I fired two shots (all I had of this load) with same load except for the bullet was a 180 Hornady IL. These two shots were .835 inches tall by 1/2" wide.

I then fired 3 shots using 64 grains of Reloader 22 with 165 Hornady IL and 215M primers. These three were 1.124 wide by .893 tall.

The brake made the rifle easy to shoot. I would compare it to a 243 with an 80 gr bullet.

I did not take the chrony with me today, but I expect these loads should be around 2900 Fps for the 180's and 3000+ for the 165's. Not hot loads. All were shot in
Norma brass.

I will get some pictures of the rifle and provide the weight in a later post. A copy of the upper can be seen on Accuracy Systems website as a 325 WSM upper, but with the Maxi brake

Needless to say I am pleased with the outcome on this project. I will repeat this test with the same loads in the next couple of weeks.
 

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The 1x12 was what Accuracy Systems recommended. It shoots very accurate with 190 SMK, and down bullets, which was used in their test target of 3 shots in .165 inchs. That is very accurate. They did not say how they test it, other than factory ammo with 190 SMK at 100 yards. . The magazine is a limiting factor on the AR 10. The large heavier bullets take up too much case powder capacity.
 
Man that is a nice rifle. It inspired me to inquire a quote to convert my existing upper. $500 to rechamber my .308 (zoinks!) or $700 for a barrel (jenkies!), $100 to open the ejection port, and $200 for the bolt (Ruh-roh Raggie!). I can see how you paid $2100 for an upper.
 
Spotting impacts with a .300 of any sort at 200 yards would be pretty nice. I bet when you get to stretch it's legs you could even read your own trace with a proper follow through. Sounds like the brake is working pretty well, that coupled with the weight. That thing has got to weigh a ton with that 24" heavy barrel and Mk4 mounted on it. My unloaded sporter weight barrel .308 AR weighs 8 lbs without a scope or any other accessories.
 
14#'s wouldn't be too bad, I just weighed my .308 and it's 12.6 with scope, bipod, sling and empty 20 round mag. Good luck with it and keep us updated.
 
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