7 PRC and US869

waldo54

waldo54

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I have a swack of US869 that I used in my 7 RUM which I don't have anymore, anyway I have been trying to find some load data for US869 and the 7 PRC to no avail. I have a load for my 6.5 PRC with US869 and the 142gr NABLR which are now as hard to find as RL26 I think they are ferry dust. That load is very accurate however it's about 75 FPS slower than the load with RL25.

I see US869 is about 4 notches slower on the burn rate chart than LRT, there is load data available for LRT for the 7 PRC with 175gr and any data I find for any cartridge that shows both LRT and US869 in every case the max charge of US 869 is the same or 1 gr more. Keeping with that LRT shows a max 80gr with the 175gr in 7 PRC and I was thinking I am going to load some test loads with US869 starting around 74gr and working up 1/2 gr at a time until I start to see pressure.

I measured an empty case for the 7 PRC and filled to the base of the neck I can get 83gr US869 in it so should be able to load near max loads without to much compression.

I've been loaded for 50 years now but have always used published data as a starting point and going from there, am I on the right track here fellows or am I peeing into the wind, seeing that Alliant has suspended powder manufacture for a while anything RL is going to become more scarce than it already is, I have a couple loads that show promise for the 7 PRC with RL25 and H1000
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You should have no issues using the 6.5 prc load (assuming similar bullet weights) in your 7 prc with 869. Going up in caliber gives you a slightly easier path than going down, in terms of pressure. That should give you a starting point to work up from. Alternatively, if you have access, one of the programs for calculating loads (quickload etc) should help you out. - dan
 
Well yesterday I loaded up a batch of test loads with 175 gr ELDX and US869, LRT and US869 have a similar burn rate, data showed LRT max charge was 80gr with a 180gr Berger so I felt confident that using LRT data with US869 and 175gr bullets.

No signs of pressure all the way up to 80gr and probably could go to 81 or 82 without a problem but 80gr is a compressed charge so I don't want to push it more.

Hornady 175gr ELDX precision hunter factory loads average 2958 fps out of my gun and I was hoping to get up to that velocity but was skeptical given US869 is so slow, but as you see below I got to 2960, now to load some at 80gr and see how they shoot and collect the data from the Garmin Xero C1 for more accurate average velocity, ES and SD and hopefully shoot some good groups.

Below is the velocity of I guess what would be a ladder test, never did one before. All loads were in once fired Hornady cases with WLRM primers

72gr - 2522 fps
73gr - 2590 fps
74gr - 2673 fps
75gr - 2695 fps
75.5gr - 2729 fps
76gr - 2755 fps
76.5gr - 2808 fps
77gr - 2847 fps
77.5gr - 2851 fps
78gr - 2852 fps
78.5gr - 2885 fps
79gr - 2902 fps
79.5gr - 2905 fps
80gr 2960 fps
 
I did more testing with US869 and 175gr ELDX bullets yesterday, I loaded 9 rounds with 80gr and shot 3 each 3 shot group, average velocity was 2947 ES 40.9 SD 16.5 and the average group size was right around 1" which is not bad for a hunting rifle all things considered.

I also had some loads with H1000 and H4831 SC that showed real promise, 64gr of H4831sc produced an average of 2984 fps ES 9.6 SD 4.0 and shot into a .293" 3 shot group.
67gr H1000 produced an average of 2988 fps ES 8.7 SD 3.8 and shot into a .270" group

Based on these 2 loads I think my testing with US869 has run the gamete but at least I gave it a go hoping I would find a good load, 80gr has no pressure signs at all and I have a bit of room in the case yet so may try a few more loads at 80.5gr and 81gr to see if the groups tighten up and the numbers come down a bit.
 

Attachments

  • 7 PRC 175 ELDX - H1000.jpg
    7 PRC 175 ELDX - H1000.jpg
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  • 7 PRC 175 ELDX - H4831.jpg
    7 PRC 175 ELDX - H4831.jpg
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My testing of US869 has come to an end, can't get it to shoot as consistent as H4831sc or H1000 so be it I gave it an honest go and it's not to be, I have managed to trade off a bunch of US869, H4350, RL25 and IMR 4350 and now have a good supply of both H1000 and H4831sc so I'm set so quite some time
 
Thanks for posting this! I have a 7PRC coming and I am hoping to be reloading for it this spring. From the looks of your velocities I will be happy if I can repeat this. I have both powders and I was thinking of also trying N560.
 
Sounds like you have a couple of great loads!
What rifle do you have? Barrel length?
What brass, primer and COAL are you using?
Will have to try these in my new 7MM PRC (Fierce Carbon Rogue w/ 24" barrel)!
 
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The 7 PRC cartridge with any of the 160-190 gr bullets is in love with RL26 but being unless you have a supply of it your next choice is H1000 which is good and now Grand is here .
There’s LRT and Retumbo also . I’ve tried H4831SC in mine but found I got pressure too soon for the FPS . Just a bit too fast a Burn . I loaded Grand today to try out . JMO RJ
 
remington jim said:
The 7 PRC cartridge with any of the 160-190 gr bullets is in love with RL26 but being unless you have a supply of it your next choice is H1000 which is good and now Grand is here .
There’s LRT and Retumbo also . I’ve tried H4831SC in mine but found I got pressure too soon for the FPS . Just a bit too fast a Burn . I loaded Grand today to try out . JMO RJ
Click to expand...
RJ, look forward to hearing about your results with Grand
 
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