Odd Findings During A Velocity Test

[Cholla]

I am working up a load for my Ruger Hawkeye Hunter in 7 PRC. I chose RL-26 to start with. I started at 65 grains and eventually went to 67.5 grains, looking for what seems to be the mythical 3000 fps with the Hornady ELD-X 175.

I started to get good grouping at 66 grains, so I tried bumping up the velocity.

66 Grain RL-26
2711, 2715, 2759 fps

66.3 grains
2820, 2773, 2778 fps

66.6 grains
2797, 2786, 2785 fps

66.9 grains
2761, 2778, 2747 fps

67.2 grains
2870, 2854, 2835 fps

67.5 grains
2852, 2903, 2834.

I stopped there with no traditional signs of excessive pressure. I was fully expecting to reach 3000 fps. I guess one could say I found a "node," as I am not seeing much change in velocity with an increase in powder. 66.0, 66.3, and 66.3 were giving 1 MOA groups at 100 yards. The first 66-grain group was .6" MOA, but it opened to 1" MOA when I tried it again.

This is not what I was expecting.

 

[MagnumManiac]

If you look at other threads here, besides a few claiming that 3000fps with 175's is the norm, you will find PLENTY of vids, posts and other info claiming high 2800's to low 2900's is all this round is capable of.
I have never chased velocity just because someone has said it's 'supposed' to get xx FPS. This is why I got myself a pressure trace, so 'I' could see for myself what you can and can't achieve. Have I been disappointed? Sure, quite a few times, but I have also seen some astonishing results just by playing with throat length and throat design.

Cheers.

 

[Phil Rizzo]

Keep in mind, you have a 24?" barrel, and haven't found the upper edge yet.
I don't see another 100fps regardless.
How many rounds fired through that barrel?
What kind of brass?

 

[BenchLeg]

I'd chase the accuracy over velocity, what's the round count? You could get very close if the barrel hasn't sped up yet. My most recent was 70fps after about 90 rounds.

 

[Cholla]

The gun is at roughly 50-100 rounds. The barrel is 24". I am using Hornady once-fired brass.

 

[Dmagna]

Hornady brass is garbage and you will need ADG brass. I am running n570, ADG brass, fed 215m and getting close to 3100 fps with a 26" barrel with a Berger 180. I couldn't get anything over 2900 with any powder, I almost gave up on the cartridge until I tried n570. Then it really started to shine.

 

[Phil Rizzo]

Peterson brass is good also, but it's thick.
About anything beats H

 

[Mark37082]

This is interesting. If I want extreme velocity, I drop down on bullet weight. There are some claims out there very high velocity achieved with the 7PRC with 175's. RL26 and N570 seem to be king of velocity, but unless you screw on a 26" to 30" barrel, I am skeptical of the results.

 

[NW NM hunter]

I made it with n560, adg, cci magnum, 3050fps. I also tried h1000, rl23 but those where in the 2950ish range. I would think RL26 should also make it. 24 inch barrel

 

[bluedog69]

I have seen several 200 fps shy of the advertised 3000. I was looking at a 7 PRC, but may pass after all the reports I have seen.

 

[Dmagna]

I have seen several 200 fps shy of the advertised 3000. I was looking at a 7 PRC, but may pass after all the reports I have seen.

That's a factory loaded ammo issue not a cartridge issue

 

[choprzrul]

This load information was retrieved here The HHT terminal performance is from 1700 fps and up.

 

[bluedog69]

That's a factory loaded ammo issue not a cartridge issue

Yes, but the OP is .4 grain over Hornady max that they claim hits 3000.(handload data)
His hand loads only hit 2863, so that is still 137 fps below advertised with .4 grains over max load.
I just watched about 5 or 6 different youtube videos of guys getting the same results with handloads and factory.(several questioned if their chrono was off)

Yes I know that every rifle is different and he may hit 3000 with another grain of powder. May be safe may not. His barrel may speed up after another 100-150 more rounds down the pipe.

My suggestion would be to thoroughly clean and borescope it while going through the next 100 rounds and see where it goes.

 

[skipglo]

Other than your 66.6 gr load there are some Hefty ES differences...I know 26 is a preferred powder....but I would be looking to try maybe another powder here....just me