7-6.5 PRC

I updated my original post with more data. So click on the attachment and it is currently up to date. I attached it here as well.

I'm still waiting on one load with the 190ATIPs and H4831sc as well as the loads with RL16.

When all the testing is completed they will take some of the original rounds they used for baseline and barrel break in... and rerun some of that ammo. That will tell us if and how much if it did...the barrel speed up and give us a pressure correction etc...The barrel is currently from what I'm seeing have 200 or so rounds on it.

Later, Frank
Bartlein Barrels
 

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  • 7mm6.5PRC test data.pdf
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Cool that they are going to re-test with the different barrel condition. I wouldn't have expected better velocities from H4831 than N555 at similar pressures.
Virtually identical bud.

The 183smk with 58.0 of the H4831sc gave 2924fps at 64540psi.

With the N555 at 57.5 it gave 2958fps at 65495psi. So to be fair a max load with this powder would probably be 56.5 to 57.0. Which would drop the fps a smidge. If you would drop the charge a .5 or so… you will probably drop the pressure about a 1k psi and drop the velocity about 20 to 25fps would be a good guess. So basically the same velocity at the same pressure.

On the burn rate charts the N555 is two steps faster than the H4831sc. So if that is true… it would make sense that the N555 would use a tad less powder but either way…. They are very close.

I think anything slower than H4831sc would be getting too slow to get any meaningful velocity out of the round. I could be wrong about that.

I thought about loading some H1000 for the test but decided against it. I know RL23 is a popular powder for it also if I remember correctly but I don’t have any. As well as being as Alliant won’t be selling powder for reloaders until further notice… kind of a moot point to find any.
 
Virtually identical bud.

The 183smk with 58.0 of the H4831sc gave 2924fps at 64540psi.

With the N555 at 57.5 it gave 2958fps at 65495psi. So to be fair a max load with this powder would probably be 56.5 to 57.0. Which would drop the fps a smidge. If you would drop the charge a .5 or so… you will probably drop the pressure about a 1k psi and drop the velocity about 20 to 25fps would be a good guess. So basically the same velocity at the same pressure.

On the burn rate charts the N555 is two steps faster than the H4831sc. So if that is true… it would make sense that the N555 would use a tad less powder but either way…. They are very close.

I think anything slower than H4831sc would be getting too slow to get any meaningful velocity out of the round. I could be wrong about that.

I thought about loading some H1000 for the test but decided against it. I know RL23 is a popular powder for it also if I remember correctly but I don’t have any. As well as being as Alliant won’t be selling powder for reloaders until further notice… kind of a moot point to find any.

Yes, more specifically i figured N555 would be faster at similar pressures and H4831 would lag behind and be closer in velocity to H4350.

Great info and thanks for supporting this and sharing it with us all!
 
The VV guys actually called me yesterday as I was passing along the test data to them as well. They told me to try some N568. They think it would work really good with the heavy bullets. So they are sending me a pound. I'll get some loaded up when I get the stuff and get it down for testing as well.

Later, Frank
 
I left out of my original post.

Hornady also supplied me the reloading dies at n/c. Thanks Joe at Hornady. I didn’t ask for them at N/C either. Standard set and not even the match dies with bushings or the micrometer seater die and I didn’t have the seating stems for the ATIP bullets etc…. For nearly all of those loads so far running single SD’s as well as you should see some of the groups! Don’t forget the groups fired for testing are all 10 shot groups.

I do have a set of their match bushing dies on order. Wish I had them for the load testing to begin with but couldn’t get them as fast as I needed them.
 
as far as the 7x6.5prc goes there was a hunter at my place a year or 2 ago shooting that cartridge w/berger 180's. don't remember if it was mulie or wt season? don't remember how far the shot was that the deer was killed.
 
So I got the test data for the 190 ATIP's and the H4831sc load with 57.5gr.

Avg. velocity was 2900fps, SD = 8, ES = 25

Average pressure was 69,284! Most ran upper 69k and one round came in at 70,690!

See the updated sheet....

What I marked in blue where the most accurate loads. Keep in mind and don't go saying this or that bullet is better than the other. The difference in accuracy was at times only .050"! A change in a powder charge of say .2gr or changing the seating depth on the bullet can make all the difference. No load tuning was being done.

Notice how a 1gr powder charge increase with the H4831sc and the 190ATIPs bumped the pressure 5k psi.

Later, Frank
 

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  • 7mm6.5PRC test data.pdf
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All the testing is complete. RL16 and N568 was tested last.

See my foot note on the N568 powder...... and I'll add it here....

too bad you can’t get more powder in the case with the N568. Seating the bullet was already compressing the powder. Maybe you could stuff 58.0gr and get 2700fps or so. One of the smallest groups fired….3rd smallest group fired.

Also see notes like this....RL16 54.00 2942fps, SD 7, ES 18, 66228psi. This load exceeded the 65k psi limit. Highest pressure came in at 68040psi and the velocity on that one round was 2952fps. Only 10fps above the average for this load test.

From 53.0 to 54.0 of RL16 the pressure jumped 4k psi. One load was only 10fps faster in that batch of 10 rounds fired with the 54gr charge and pressure was another 2k above the average pressure of 66228psi. Could've been a variance in brass neck tension, bullet etc...

Becareful when your trying to get another 50fps or another 100fps out of your loads.


Later, Frank
Bartlein Barrels
 

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  • 7mm6.5PRC test data.pdf
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What are peoples thoughts on loading to short action mag length? 2.950? Which projectile would work best at that OAL?
168 Berger classic hunter. 2.94'ish OAL keeps the bullet just above the neck-shoulder junction. Puts it .020 off the lands in my chamber which is a .220 FB. Super accurate for me so far. 2915fps with 57.7gr n555 from a 22" barrel. It's the perfect bullet for the 7-6.5 to mag feed.
 
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