7mm PRC Build........I know I'll explain!!!

Longtine88

Well-Known Member
Joined
Nov 22, 2020
Messages
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Location
Sulphur Springs, Texas
Yes I know I have always said it doesn't do much of anything against my favorite as everyone knows the 7MM Saum, but there's an explanation.....................................................................> It's not for me!!!!!! 🤣🤣🤣🤣🤣🤣🤣🤣

It's my nephews graduation present and since this forum is all about information I'll post my results. Basically he doesn't reload and he's 3 hours from me and fixing to go to college so he wanted a 7mm that he could find ammunition for. So after deliberation we settled on the 7mm PRC. Yes I have a reamer!

The build:
Proof Carbon 24" 8" Twist
Defiance Classic Action Nitrided
Manners LRH Stock
Trigger Tech Diamond Gold
EC Gen 3 Tuner / Brake
Hawkins DBM Hunter bottom metal

Throated very long for the 195's. Breaking in the barrel I shot Hornady's Precision Hunter ELDX. Let's just say in my opinion it's trash! Maybe the long free bore had something to do with it but still 100 yards 2" groups.....come on.

Load:
Berger 195 EOL
New ADG Brass
Fed 210M
N568 74.3 grains
CBTO: 2.669" at -0.007" off lands COL: 3.430"

Only brass prep I did was running a mandrel through the new necks to expand out to get the 0.002" tension.

Pressure testing:

67.0 2,523 fps
69.0 2,628 fps
71.0 2,727 fps
72.0 2,756 fps
73.0 2,802 fps
73.5 2,829 fps
73.8 2,845 fps
74.0 2,857 fps
74.2 2,860 fps
74.4 2,866 fps
74.6 2,865 fps
74.8 2,877 fps

Shot 74.2 74.4 and 74.6 at 500 yards. 74.2 and 74.4 were no vertical dispersion and only 2" Horizontal same poi. 74.4 Had the same 2.3" horizontal but the vertical dispersion was 2.7". So I chose the 74.3 grains to land.

Confirmed the seating depth by shooting 2 shot groups from 0.005" OL to 0.030"OL and ended up at 0.007" off lands.

Next tuner adjustment. This is where I recorded my ES data. Moved in increments of 2 on the tuner starting at 4 where I did all the testing at 500. Don't ask I just didn't adjust it to 0 initially, my bad.

0: 2862 2866 .7 moa
2: 2865 2866 .4 moa
4: 2866 2867 .2 moa
6: 2869 2858 .6 moa
8: 2858 2863 .6 moa. adjusted it to 5 hole

3: 2865 2867 one hole like maybe .08 moa

Shot 4 groups of 3. Letting barrel cool down between each of the 4 strings. All were one hole group clover leafs.

Thoughts: The barrel is gonna speed up and hit the 2,900 fps mark for sure. That was my initial goal. I have been playing with he 7mm saum on a sped up barrel that is 28" and I'm getting the same bullet to the 2,900 mark and a little over. All and all it's not a bad round. I think it was a marketing ploy for sure. It's just not that much more than a saum to me. I was not impressed with the Hornady ammo and fyi it was only getting 2,740' in this barrel average. I ran 20 shot's through it breaking in. The ES on the ammo was around 40 fps. Which is insane. Thank God I reload lol. I'm certain with good handloading and planing you can get the 175's and 180's which I think are perfect for it to over the 3,000 fps mark especially in a a good 26" barrel.

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Hope this helps somebody!!!!

Not one word Richard!!!
 
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Hahahah. Funny👆
Ive never known 568 to be a screamer concerning velo but it does seem to be excellent for accuracy. I run it in a 300win.
I sure didn't have any Uncles like you!
 
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If I understand correctly, the numbers on the left are the EC tuner settings. If so, why would 5 give you a better tune than 3?

0: 2862 2866 .7 moa
2: 2865 2866 .4 moa
4: 2866 2867 .2 moa
6: 2869 2858 .6 moa
8: 2858 2863 .6 moa. adjusted it to 5 hole

5: 2865 2867 one hole like maybe .08 moa
 
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