Low Velocities After New Barrel

[Wiley2019]

New here so obligatory apologies if this is in the wrong place. I recently had a Carbon6 barrel made in 6.5 PRC for an old trued 700 short action. 22” 1:7.5 twist, button rifled. It shoots lights out, several groups at 1/4” during break in and sight in. 123 rounds down the pipe as of right now. After break in I chronod it at an average 2720fps, essentially the same as the creedmoor I intended to replace with the PRC. All testing has been done with hornady factory 143gr ELDX Precision Hunter and 140gr ELDM Match.

Now I knew cutting the barrel down to 22” would result in lower than published velocities, and I expected that but not such a significant drop as I know folks with the same length that are touching around the 2900 mark. I do not currently reload but I’m not opposed to it if I can get the desired velocities safely.

I guess my questions are, is there anything I can do to help speed it up and make the PRC shoot like a PRC? I’m a decently capable backyard tinkerer so I’m not afraid to do a little work on it, this is just an issue I’ve never run into so severely. Is it worth investing in the reloading equipment to make up the speed or am I stuck with 6.5 PRC prices to get 6.5 creedmoor balistics? If I can’t get much improvement I’d rather just sell the gun and start over with a custom action and everything.

 

[Simonsza1]

Some barrels are just that way. Some slow some fast, could still change. I had a criterion barrel that jumped close to 100fps at 250 rounds. I thought my break in was way over and then it decided to let loose. Btw it’s been a laser beam ever since and the velocity hasn’t changed a bit.

 

[just browsing]

123 rounds is nowhere near broken in. Need at least 250 on that bitch before it finally settles in. So you will pick up some speed yet.

That said, the primary limiting factor is going to be factory ammo. Hornady PRC is notoriously slow.

 

[DJL2]

Huh... wouldn't have thought Hornady would be handicapping their own cartridge. Seems odd for the same folks that load Superformance and squeeze a good 100 fps more out of 168 grain .308 as compared to Federal (who, in my experience, is on the light side).

 

[Wiley2019]

Huh... wouldn't have thought Hornady would be handicapping their own cartridge. Seems odd for the same folks that load Superformance and squeeze a good 100 fps more out of 168 grain .308 as compared to Federal (who, in my experience, is on the light side).

It’s probably a little of both the ammo and barrel, the same ammo gets close to 2900 in my cousins Savage.

 

[Wiley2019]

123 rounds is nowhere near broken in. Need at least 250 on that bitch before it finally settles in. So you will pick up some speed yet.

That said, the primary limiting factor is going to be factory ammo. Hornady PRC is notoriously slow.

Well since you twisted my arm I guess I’ll just keep pulling the trigger haha. Good to know, I’ve just never had a barrel slow enough to really be concerned since I’m hunting and not shooting matches.

I guess I’ll keep putting rounds through it and possibly purchase some hand loaded ammo to see if it helps velocity before I start purchasing reloading supplies if that makes sense.

Is the issue the type of powder that Hornady uses or are they loaded light? I shoot factory hornady in my 300PRC and I’m getting velocities right on the advertised number.

 

[wade2big]

The Precision Hunter and Match ammo was only slightly faster than what you are seeing out of my 24” Tikka. I think there is some slow Hornady ammo out there. What was interesting to me was when I pulled down different lots, there was different powder used. I posted photos a while back of the powder. If I can find them I will post in here as well.

Your fix is to load your own.

Update for photos of powder from two different lots of precision hunter ammo. Unfortunately I only shot and doped the ammo from the first photo and didn’t the second.

 

[Wiley2019]

The Precision Hunter and Match ammo was only slightly faster than what you are seeing out of my 24” Tikka. I think there is some slow Hornady ammo out there. What was interesting to me was when I pulled down different lots, there was different powder used. I posted photos a while back of the powder. If I can find them I will post in here as well.

Your fix is to load your own.

Really? I’ve never had issues with factory hornady, I run Hornady precision hunter and match in 6.5 creed, 6 creed, 308, 7mag, 300PRC, and this 6.5PRC. The only issue I’ve had with consistency or velocity has been in the 6.5PRC, but I suppose that could be because the PRCs were my first full builds so maybe I’m being pickier with them. Seems like a reloading setup is in my future despite trying so very hard to not add another expensive hobby to the list.

Edit since you added pictures:
Wow that’s wild, makes me want to open up a few and see what’s inside them.

 

[wade2big]

Really? I’ve never had issues with factory hornady, I run Hornady precision hunter and match in 6.5 creed, 6 creed, 308, 7mag, 300PRC, and this 6.5PRC. The only issue I’ve had with consistency or velocity has been in the 6.5PRC, but I suppose that could be because the PRCs were my first full builds so maybe I’m being pickier with them. Seems like a reloading setup is in my future despite trying so very hard to not add another expensive hobby to the list.

Edit since you added pictures:
Wow that’s wild, makes me want to open up a few and see what’s inside them.

I’ve shot lots of the 6.5cm american gunner and hornady black that was consistent across lots. Something is off with the PRC stuff. Look at the photos I posted above. Thats Two different powders from hornady precision hunter 6.5prc. There was a difference of over 2 grains of powder between the two as well.

 

[Wiley2019]

So I’ve got some custom loaded ammo on the way, from a guy I’ve had great luck with in the past, the load I got is a 143gr ELDX, new Bertram brass, hogdon powder and a fed 210 primer.

Now I don’t really know what any of that means because as I said I’m not a loader, but he says he gets 3040fps in a 26” tube so hopefully once I shoot a few more boxes of factory to get around that 250 round count, I can throw some of the handloads in and get closer to the velocities I was expecting. I stuck with the ELDX because it shoots so accurately in the factory loads so I know my barrel likes the bullet, hopefully the speed can get close to what I’m wanting so I don’t just have to sell the rifle and start over.

Apart from that does anyone have any other ideas?

 

[kthomas]

1. Your barrel is not broken in yet, it's still going to speed up.
2. Some barrels are faster than others, just the way it is.
3. Factory Hornday 6.5 PRC is slow. My buddies Tikka was getting similar velocities to yours, ~2770 fps.
4. You will probably have to reload to realize the full benefits of the 6.5 PRC cartridge.

 

[NW Valkyrie]

I have a 24" Proof Carbon barrel for my 6.5 PRC deer rifle build. Using Hornady factory ammo I get 2950 fps with the 143gr ELD-X Precision Hunter. So pretty much on spec.

For reloads using 56.4 grains of R-26 I get 3,000 fps with Lapua brass and 3,030 with Hornady. This is below maximum per Hornady load data, and similar to your custom load.

Suspect you got a slow barrel, but you'll find out for sure with the custom load.

 

[dimar1492]

Just a reference point. That same factory load shoots 2940 fps out of my 6.5 PRC.

24" Krieger 4 groove that was previously a 6.5 Creedmoor and I chased with a PRC reamer.

 

[Wiley2019]

My experience with Carbon Six barrels is they are slow to start with and are slow to speed up. But after they do it's a significant difference from first rounds fired. I started out with 58gr of H1000 on a 6.5SST to get 3000fps. Slowly over time I had to keep backing the charge down as it sped up. Currently I'm at 54 something grains. Massive difference.

Good to know, do you have a rough idea of how many rounds it took for you to get there? I’m very happy with the accuracy, weight, and look of the barrel, just not happy with a PRC shooting creedmoor speed with extra recoil.