T/C Venture velocities?

Doing some load workups for a friend's hunting rifle, a T/C Venture in .30-06, and some of my velocity results have made me raise an eyebrow. Made me want to see if anyone else has velocity data for one of these rifles, to find out if my results are typical.

So, my loads started with a 165 Accubond over 56gr of H4350, which book says should run around 2700fps, and my past results have led me to find book numbers typically a little optimistic, so I figured I'd be expecting between 2650 and 2700.

So you'll understand why I was a little startled when the first round across the chronograph showed a velocity of 2906...

I thought, "Something's not right. Light angle, picking up muzzle blast, battery's low...that CAN'T be correct..." I bumped my chrony out a little farther from the bench, changed the battery, then sent a round each from my 7mm and my wife's 6.5 PRC; velocities right where I expected. So I picked up the Venture to send another.

2909.

Long story short, I ran my workups to a rather stout maximum load, that gave an average velocity of 3060fps with no pressure signs. Pristine primers, easy bolt lift, no case head deformation.

So, for any Venture owners out there: do you typically see ridiculously fast velocities from your rifle? Or is this one just special? I mean, I know that one of the touted advantages of 5R rifling is higher velocity, but 200fps over book speed?

jmr40 said:

I have data showing 59 gr as a max load @ 2938 fps. I've seen situations where a specific powder, in a specific rifle will reach the expected max velocity when still 2-3 gr below the max powder charge. But H4350 is my go-to 30-06 powder and I've not seen it happen with this powder in any of my 30-06 rifles.

Even though you are not SEEING evidence of an overpressure load, you are probably over pressure with the load at 3060 fps. Traditional pressure signs typically don't show up until you are WAY over.

In cases like this I'd consider around 2950 fps as max load regardless of what powder charge I used to get there.

Your scales might not be calibrated correctly. Different brass can make a difference. Some brands will generate more pressure and velocity than others with the same powder charge.

Also, in my experience you don't see rifles that shoot FASTER than expected. But getting one 100 fps SLOWER than expected is common.

Click to expand...

59 is where I stopped. I'm just one of those twitchy folks who doesn't like to post max loads by default, lest someone just go, "Sweet, I'm gonna just copy that load!"

And I actually use 2 different scales when I do load workups...literally. I have an RCBS 1010 that I do my trickle into, and a Frankford Arsenal electronic that I then drop the charge on to double check my beam scale, before funneling into the case.

Brass is brand new Lapua. Primer's a BR2, not mag. I mic'ed and case gauged fired cases at the 59gr load, they're EXACTLY the same as the low node at 56.5gr. in fact, here's one of each.


The rifle first broke 3k at 57.5... pretty sure that's not a massively over pressured load in anyone's book.

59gr at .140" jump gave a nice group with an ES of 22, too.



It's not a gnarly load, and the velocities are consistent and repeatable...just crazy fast.

I've also never seen a rifle outpace book numbers like this. Just wondered if it's common to other rifles of this type, or if it's just a unicorn?

Aside: I also load 6.5CM with the same keg of H4350 and see a 140 ELD-M just under 2850 from a 26" Savage barrel at 41.8...so it doesn't seem to be a particularly hot lot of powder, either.

I have a coworker with a different '06 who also has asked about me making him some ammo. Reckon if I start my workups in his Browning, it should at least give me a yardstick for where my pressures are at...if his velocities are more in line with what I'm expecting to see for the charge weight, I can more confidently say it's down to the individual rifle and not the load.

Thought I would follow up here:

Worked up loads in another .30-06, which also showed speeds slightly above book, though nowhere near what the T/C produced.

Second rifle is a Browning X-bolt. Where the T/C seems to have a pretty long freebore dimension (3.485" to the lands with the 165 AB) , and is OAL limited by the magazine, the Browning has the opposite issue, with a mile of magazine space but the Accubonds basically touch the lands at max SAAMI length. Loaded short to stay about .010" off, the Browning started to flatten primers at 57gr, at which point velocities are in the high 2800s. With velocities basically matching, and 1/2-3/4MOA groups at 56.5 and 57.0, I considered this load to be more than adequate for the task and took my unfired rounds home for downloading.

Conclusions I've reached:

1. My lot of H4350 is on the "hot" side of specs, producing higher velocities than listed in my manuals. With a short OAL and short throat, it produces pressure signs roughly 2gr below "book max," but also higher than listed velocities.

2. The T/C Venture barrel, on the example tested at least, is a "fast" barrel, likely as a result of the combination of 5R rifling and the old Roy Weatherby trick of using a half-mile of freebore to let the bullet get a head start and lower chamber pressures.

3. There's a reason some folks (myself included among them) are a little Leary of posting powder charges online, lest someone just copy the load and expect good results. In the T/C, a "max" load makes bugholes at 100yds with ridiculous speed and nary a sign of excess chamber pressure....but I can GUARANTEE that attempting to fire a round crafted for the Venture in the X-bolt I tested would be a recipe for a very bad day.

4. The oft-repeated mantra of "start low and work up" is repeated for a reason. I've known some people who like to open the reloading book, look up the max load, whip up some rounds and hit the range. Even in this day of manufacturers being spooky about legal liability, variations in specifications and tolerances can make a particular "safe" combination into a dodgy proposition if due diligence isn't practiced.

Anyway, I will concede what some have said about the initial load being above SAAMI max. Figured I'd come back here, cop to it, and take my lumps rather than slink off quietly, in case anyone here was curious whatever came of my testing.

I mean, probably not...nobody asked me, I'm just adding to the reams of unsolicited information on the internet...but I learned things, that might be of interest to someone someday.

rizbunk77 said:

I think you are running high pressure with those loads in the TC. That pic shows some cratering around the firing pin, deffinitely not a mild look. I would look at them side by side with some factory shot rounds to get an idea. I would back down to book maximum, Even if it is the highest book maximum you have. What about finding a milder load that works great in both your rifles?

Click to expand...

59.0gr IS book max for 165gr bullets, at least per Hodgdon's loading site, as well as the 8th edition Hornady manual I have at my bench. I never go over max for initial ladders, and while I have gone over max on some loads for certain guns, I don't proceed to that point unless:
a) velocity is well below anticipated, even when accounting for variations in barrel length, round count, etc.
b) there have been no pressure signs encountered up to that point
c) there is evidence that there is likely to be another accuracy node within the next .5-2gr (depending on case capacity), based on velocity trends (ES, SD) or group sizes.

Clearly, there was no shortage of velocity in this ladder, and coming to rest at book max showed best groups and an SD of 13. There's definitely no incentive to push any harder here.

And I would disagree about any cratering of the primers...I think I see what you're referring to, but the shiny sliver is actually just a reflection of the lighting in my kitchen. They pass the scratch test - there's no material extruding outward from the primer face.

By comparison, this is a round fired in the Browning at 57gr charge with identical components (bullet, primer, case). It's showing noticeable flattening and the first hints of cratering and imprinting. Since groups were already excellent at that charge weight, I called it a day. Velocities at that point were a still quick but more reasonable 2870, with ES of 20 and SD of 11.


Yeah, it's really quite bizarre to me. I mean, it's clearly a slightly spicy batch of powder to exceed book velocities by any amount. But in the case of the Venture, it really seemed to be happiest at max.