Working up 1st 7PRC Load ... hmmm

[NorCalAOSHunter]

Working up my 1st 7PRC load. Shooting a Tikka with a 20" CarbonSix barrel. I am in California, so have to stick to Mono, thus trying the 160CX and 168 LRX. Have a couple powders, but everything seems to be saying "Try H1000, then something else if that doesn't work" ...

At this point I did a 16 shot ladder @ .3g increments:

160CX was:

Charge	Velocity
67.5	2808
67.8	2821
68.1	2830
68.4	2826
68.7	2848
69.0	2852
69.3	2869
69.6*	2894
69.9	2906
70.2	2875
70.5	2926
70.8	2931
71.1	2943
71.4	2949
71.7**	2995
72.0	2974

*Hornady Load Data had H1000 Max load at 69.5 @ 3100fps ... So I am essentially 200 fps below
** I got ejector marks on this one


168LRX

Charge	Velocity
64.3	2638
64.6	2610
64.9	2659
65.2	2642
65.5	2716
65.8	2707
66.1*	2749
66.4	2772
66.7	2755
67.0	2744
67.3	2850
67.6	2865
67.9	2861
68.2	2847
68.5	2909
68.8	2888

* Hogdon load data for the Barnes has Max Load @ 66.0 @ 2995 fps ... So, I look to be 250 fps below

I did not see any signs of pressure, in that ladder, even though I went almost +3g above Max

I was hoping I'd get something that would be a 700-800y gun, even with that barrel, given the hype of the 7PRC for performance. I am figuring out that I may not have realistic expectations ...

I have decided to try groups for:
- 168 LRX @ 67.9
- 160 CX @ 71.1

We'll see if either of those get near the 1/2 MOA CarbonSix says their barrel shoots. Which ever can get < 3/4 MOA, I'll likely go with. If neither, then will see what the factory 160CX groups at, and reassess from there.

 

[Brad Quarnberg]

Interesting data: thanks for sharing.
I have a Tikka 7PRC with a 22" Preferred Barrel Blanks barrel. With the factory 175 eldx I was running 2895-2905fps instead of the listed 3000fps. I know, just like yours, the shorter barrel impacts the velocity, but I plan on hunting suppressed with this build so I'm okay with the shorter barrel.
Hope to see more results as you work the groups for both rounds.

 

[NorCalAOSHunter]

Interesting data: thanks for sharing.
I have a Tikka 7PRC with a 22" Preferred Barrel Blanks barrel. With the factory 175 eldx I was running 2895-2905fps instead of the listed 3000fps. I know, just like yours, the shorter barrel impacts the velocity, but I plan on hunting suppressed with this build so I'm okay with the shorter barrel.
Hope to see more results as you work the groups for both rounds.

I got 2775 with the Factory Precision Hunter 175 ELD-X. Seems that I am seeing about a 50 fps/inch loss.

 

[Phil Rizzo]

If you want speed, either get a 24-26" or try some R23-R25-R26 or both. N560-565 also.
my 7ss shoots 160 Nosler's at 2995 with N565, and thats 100-150 below max, but 26"
You may have a slow barrel also. Get 100+ shots through it so it can hopefully speed up.
Good luck with it, you have options

forgot to add, H1000 is probably my favorite too!

 

[Dmagna]

Working up my 1st 7PRC load. Shooting a Tikka with a 20" CarbonSix barrel. I am in California, so have to stick to Mono, thus trying the 160CX and 168 LRX. Have a couple powders, but everything seems to be saying "Try H1000, then something else if that doesn't work" ...

At this point I did a 16 shot ladder @ .3g increments:

160CX was:

Charge	Velocity
67.5	2808
67.8	2821
68.1	2830
68.4	2826
68.7	2848
69.0	2852
69.3	2869
69.6*	2894
69.9	2906
70.2	2875
70.5	2926
70.8	2931
71.1	2943
71.4	2949
71.7**	2995
72.0	2974

*Hornady Load Data had H1000 Max load at 69.5 @ 3100fps ... So I am essentially 200 fps below
** I got ejector marks on this one


168LRX

Charge	Velocity
64.3	2638
64.6	2610
64.9	2659
65.2	2642
65.5	2716
65.8	2707
66.1*	2749
66.4	2772
66.7	2755
67.0	2744
67.3	2850
67.6	2865
67.9	2861
68.2	2847
68.5	2909
68.8	2888

* Hogdon load data for the Barnes has Max Load @ 66.0 @ 2995 fps ... So, I look to be 250 fps below

I did not see any signs of pressure, in that ladder, even though I went almost +3g above Max

I was hoping I'd get something that would be a 700-800y gun, even with that barrel, given the hype of the 7PRC for performance. I am figuring out that I may not have realistic expectations ...

I have decided to try groups for:
- 168 LRX @ 67.9
- 160 CX @ 71.1

We'll see if either of those get near the 1/2 MOA CarbonSix says their barrel shoots. Which ever can get < 3/4 MOA, I'll likely go with. If neither, then will see what the factory 160CX groups at, and reassess from there.

I have a CarbonSix on my 7prc. N570 was the ticket, H1000 didn't do it for me. N570 gave me really good speed and accuracy. N565, N560, N568, h1000 we're all slow.

 

[NorCalAOSHunter]

I have a CarbonSix on my 7prc. N570 was the ticket, H1000 didn't do it for me. N570 gave me really good speed and accuracy. N565, N560, N568, h1000 we're all slow.

Which bullet? Mind sharing load data and velocities? What length barrel?

Thx

 

[ncwg2boatguy]

I love H1000 but a few buddies are running RL26 getting extra speed like 100+ fps I think

 

[NorCalAOSHunter]

I love H1000 but a few buddies are running RL26 getting extra speed like 100+ fps I think

I looked all over for RL26 … like unicorn farts … non-existent

 

[VinceMule]

Those N500 series of powders burn so hot, that you may not have much barrel left in 600 rounds, so count the cost, which I learned the hard way. The back pressure of a Can does not help matters either.

 

[Dmagna]

Which bullet? Mind sharing load data and velocities? What length barrel?

Thx

I have a 26" barrel and never reached 3000 fps with anything other than n570. I am using adg brass with 180 Berger hybrids I got all the way up to 3150fps with n570 and stopped. I am using 3080 fps for my load getting about 1/2-3/4 moa consistency

 

[Phil Rizzo]

570 is good stuff for velocity, and accuracy no doubt.

If you don't mind the accelerated erosion and
excessive amounts of fouling it produces, not to mention the challenges it can pose metering. The suppressor will collect carbon quickly, FYI.

I've seen chunks fall out of one and get jammed in the lugs, talking about a puzzler.!

Just depends on how much you shoot the gun, really.

 

[quigley257]

Also hard to find, but I have been using 70gr of Retumbo and getting right at 3000fps shooting the 175ELDX with great accuracy and consistency.

 

[NorCalAOSHunter]

Finally got to Grouping today. I tested 2 loads that I had found "nodes" on in a ladder test:
- 168 LRX, 68.1g H1000 COAL 3.20
- 160 CX, 71.1g H1000 COAL 3.29

I shot 3 shot groups. Let barrel cool to touch in between each group. Same setup for rest etc. I shot in this order:

1. 3 Factory 160 CX - Chrono with MagnetoSpeed to see what they were at, AND to heat up the barrel so my hand loads could be as "similar conditions" as possible - Note the Factory 160 CX: 2869, 2853, 2845 ... so essentially 2855 out of my rifle
2. 3 Hand load 160 CX: Shot 1 & 2 were .099 MOA, 3rd shot turned it into a 1.265 MOA group
3. 3 HL 168 LRX: 1.785 MOA
4. 3 Factory CX: Shot 1 & 2 .290 MOA, 3rd took it to 1.091 MOA
5. 3 HL CX: Shot 1 & 2 .216 MOA, 3rd took it to .622 MOA (I am noticing a trend here, not sure of ammo/rifle or shooter getting lazy on #3)
6. 3 HL LRX: 1.722 MOA (confirms first group)
7. 3 HL CX: At this point, I knew the CX was the load for this rifle until I can get some diff powder to try with the LRX, because I WANTED the LRX to win. Slapped the MS Chrono back on and: 3010, 2974, 3011 ... Avg ~3000

So at this point, since I want to bear hunt with it, I am going to stick with the 160CX. I will load up another 100 and do some more shooting and chrono to get better data, and to see if the 1,2, then 3 issue is a shooter or rifle issue.

Primary Load: 160 CX @ 71.1g H1000 and COAL 3.29, ~3000 fps out of a 20" Carbon Six barrel.

Now to Zero with that load, as you can see my impact and POA were consistently off.

 

[FireFlyFishing]

I'm curious what a 145 LRX would zip along at with that caliber.