Blue Mountain Precision upgrade

[.300 Dakota]

Good evening, all. Waited 15 months to get a new 6.5 SAUM build from Straight Jacket Armory, bought up 250 pieces of ADG brass, I've shot it 17 times working on barrel break-in (25" Bartlein 3B straight fluted), and nothing has gone more that about 7/8 MOA apart during that process. Using 120gr Noslers on break-in. I've ALREADY made the decision (i.e. plunked money down) after calling Blue Mountain Precision to replace the 6.5 SAUM barrel with a 27" 3B Hawk Hill in 8.25" twist chambered in 7mm PRC.

I'm a speed freak, and just don't think I'm going to get what I want out of the SAUM. This should be a drop in fit. It will also fit a little better in the long action magazine. Hawkins Hunter bottom metal using Ultra Mag magazine, Kelbly Atlas Lite action and Mesa Precision carbon fiber stock. Not sure how well the 195s would do here at sea level out of that 8.25 twist, but was planning on more or less sticking with the 160 - 180gr weights anyway. Am I crazy in thinking I will get a little more umph?? Obviously it's a hunting rifle. Don't care about ringing steel or setting a group accuracy record, but I do expect at worst 1/2 MOA and 3000 ft/s. Was getting a little over 3100 with the 120s in 6.5 and hadn't found the ceiling yet. Not sure it would get there with 140s and heavier.

Any new info on Blue Mountain? They are 8 - 10 weeks behind, so somebody is keeping them working. Must be somebody that knows something somewhere. I've been watching them for months now and decided to call before I took the plunge. The site showed 1 in stock. There is a very nice and professional young lady there who said she had JUST taken inventory and assured me the barrel was still there. Of course, 2 people can be adding to the cart at the same time and buying. Then one will get it, and one won't unless their inventory system is high-speed and integrated.

Correct me if I'm wrong, but as long as the machining is right, I'm not really losing anything by going to Hawk Hill, right??!

 

[6.5saum/300rum]

What are you planning to hunt with this rifle?
The 6.5 saum with a 25" barrel should get a 140 grain bullet to 3100-3200 fps. I have two one is a 24" and it shoots 140 elite hunters at 3115fps and the other is a 26" shooting 140 vldh at 3200fps.

I haven't loaded for a 7prc yet but looking at load data you would be lucky to get 3100-3150 with the 180's in the 27" barrel.

 

[6.5saum/300rum]

Reloading for 7 PRC - Hawkins Precision

Reloading 7 PRC - Learn how six different powders work in Hornady's new 7 PRC. Powders include H1000, N565, H4831SC, RL23, and Retumbo.

hawkinsprecision.com

The picture is hornady load data with a 24" barrel. I'm sure some other members will give some real world data.

 

[.300 Dakota]

SHOULD. Yes. It has given ZERO indication that it will be able to do this. I could tell by the primer I was getting close to the ceiling on the 120s at 3126 ft/s. It has a SHORT throat in it. SAAMI reamer, I'm sure, if not GAP 4S reamer, which has even less. I sent in a dummy round, which was declined. I believe the 7 PRC has a bit more generous throat to it? It's definitely longer, which fits the magazine better. I firmly believe based on my initial impression that I'd be down right blessed if I got 3000 out of the 6.5 with a 140gr.

 

[.300 Dakota]

For reference, I killed my high desert mule deer with a 26" 6.5x284 Norma using the 120 grain Nosler at 3300 ft/s out the end. It was a HOT load, yes, but was quite comfortable at 3200. Maybe I shoulda built a 6.5x284 Norma.

 

[6.5saum/300rum]

SHOULD. Yes. It has given ZERO indication that it will be able to do this. I could tell by the primer I was getting close to the ceiling on the 120s at 3126 ft/s. It has a SHORT throat in it. SAAMI reamer, I'm sure, if not GAP 4S reamer, which has even less. I sent in a dummy round, which was declined. I believe the 7 PRC has a bit more generous throat to it? It's definitely longer, which fits the magazine better. I firmly believe based on my initial impression that I'd be down right blessed if I got 3000 out of the 6.5 with a 140gr.

What powder, primers and brass are you using? My 24" is a gap 4s on a short action. My 26" is on a long action but it doesn't need to be it's only 2.865 oal.

 

[.300 Dakota]

Tried RL 26, N565, IMR7977, and the thing that's done best is an old metal can of MRP. Fed 215 Gold Medal Match primers, and have duplicated these loads between both ADG cases and GAP 4S cases (Hornady or rebranded ADG anneal line?). FYI, the identical loads show the 2 cases to be completely interchangeable. No statistical difference in weights, concentricity, or velocity avg or ES. They even go to the same POI on the target. I'm guessing the 4S cases are rebranded ADG.

 

[.300 Dakota]

OAL = 2.784 - 2.797". I'm 18 thou off the lands at 2.797. I'm sure you're using a VLD-type bullet, though, so your OAL will be much longer than the 120gr Ballistic Tip that has all of its weight in bearing surface.

 

[6.5saum/300rum]

Tried RL 26, N565, IMR7977, and the thing that's done best is an old metal can of MRP. Fed 215 Gold Medal Match primers, and have duplicated these loads between both ADG cases and GAP 4S cases (Hornady or rebranded ADG anneal line?). FYI, the identical loads show the 2 cases to be completely interchangeable. No statistical difference in weights, concentricity, or velocity avg or ES. They even go to the same POI on the target. I'm guessing the 4S cases are rebranded ADG.

I thought the gap 4s was hornady but I could be wrong I use adg in one with f210 and Norma 7saum f215 necked down and neck turned in the other. I use h1000 in both.

 

[.300 Dakota]

N565 is the most accurate of the bunch. Also the slowest, so far.

 

[.300 Dakota]

I will try H1000 to see. I also have some Magnum in it's wheelhouse. I'm not sure N568 would do anything but go slower. My 7mm SAUM loved Supreme 780, but I don't have enough of it to sustain if it worked.

 

[.300 Dakota]

N560, might be an improvement.

 

[6.5saum/300rum]

I've only ever tried h1000 and rl23. Are you set on using the 120 bt bullet? If i remember correctly they have a really long bearing surface. I'm shooting 61.5 grains in adg brass and 62 in the Norma they are different lots and definitely max in my guns so work up.

 

[huntinfool18]

If you're a speed freak, you're not gonna get what you want out of the prc. It's not even close to breaking any speed records. You'll need to step up in to the 28 nosler territory