Home Forums Reloading Big Game Rifles Compressed loads and velocity

I have a .35 Whelen, rebarreled an old Wby. Vanguard 30-06.

I worked up loads with 225 grn TXS bullets using Re15. Got about a 25-50 fps increase for each grain added then stopped at 58 grains, which is over the book max. Never saw signs of pressure but got good groups and was happy with about 2550 fps.

But I keep reading about heavier loads than I'm using even withg 250 grn bullets and people getting higher velocity. So I loaded some up to 59 grns and WOW! I got 2770 fps, more than 200 fps increase with that last one grain. To make sure it wasn't a fluke I fired a couple of rounds I had with the 58 grn load and got just what I was seeing before.

That last grain did put me into a compressed load. Could that have been why it made such a big difference?

??

Definitely not an expert here, but a large jump in velocity at over book max makes my sphincter tight.

Well me too maybe, but the primers looked good and bolt was easy to lift.

What chronograph, and was it sunny or cloudy--or mixed?

It's a Shooting Chrony F-1. Afternoon was sunny but our range has covered benches. I set the chronograph on a bench under the roof so it was completely shaded.

My results were repeatable and as I said, I chronoed a couple of the loads I had with 58 grns and got the same results that I expected. I think I did about all I could to rule out some the chronograph.

If anyone is concerned about the safety of my load, here's a thread I bookmarked a while back

Reloading for the Whelen

You can see some guys are using 58-59 grns of Re15 with 250 grn bullets and someone using 60 grns with 225 TSX like I'm using. In fact, check out the last post on that thread Muledeer.

Lots of folks around here shoot Whelens because they are legal for primitive season in a break open rifle. Most that handload use 59-60gr of RL15 for 225gr SGKs and Accubonds.

The 35 Whelen runs at a Max pressure of 62K psi. At what psi would you expect to see these "pressure signs"? 63K, 65K, or 70-80K?

The 62 kpsi is SAAMI's spec for factory ammo right? Maybe I don't understand your point, but SAAMI's MAP for the .45 Colt is 14 kpsi. I'm sure I've gone way over that with my new Freedom Arms Revolver with no signs of pressure.

Of course the SAAMI spec for .45 Colt considers guns built in the 1870s that were designed for black powder cartridges. And when the Whelen was standardized in 1988, there were already six decades of wildcat rifles in use.

I did have another thought on my big velocity increase. The older loads used Remington brass. These new ones with the one additional grain used once fired nickel plated Federal brass I bought from someone here on the Fire. I wonder if the type of brass can make such a difference?

Yes it can. Internal capacity has an influence on pressure. More internal capacity allows for higher velocity at similiar pressure, but at the cost of additional propellent, all else being equal.

McInnis, what Steve4102 was alluding to is that pressure signs do not appear with an individual cartridge once SAAMI max is reached, but rather at the limits of the brass, regardless of chambering.

A good example is a .30-30 Winchester, which has a max of somewhere around 38.5 Kpsi. Brass and primers will not exhibit the traditional "high-pressure" signs until this maximum is grossly exceeded, possibly to the point of catastrophic failure of the firearm.

Granted, with a SAAMI max of 62 Kpsi, the Whelen will show the traditional signs soon after said limit is exceeded, but it could also show up at lower pressure with softer brass.

The best field confirmation of safe pressure is a chronograph. If you have more velocity than you should and the chrono is working properly, then you are very likely running excessive pressure. With six decades of loading data, velocity parameters are well established.

I am getting a higher velocity than any of my reloading manuals show, but at heavier powder loads. But they aren't high compared to what others on that old thread I posted, or this other one I found:

Reloading for the Whelen

I do know this for sure, this rifle has a very long throat. A local gunsmith reamed a .35 barrel for me and I cannot even come close to touching the lands with any bullet. I'm guessing that probably reduces pressure buildup and velocity with a given load, but would like someone who knows to let me know if that's right or not.

Roy Weatherby made millions on that idea. Freebore requires more powder, but also allows for more velocity.

Like Ringman said, the freebore will lower pressure.

I'd still want to know why one grain gave such a huge jump in velocity.

Did you fire the followup rounds immediately, or had a day or two lapsed? If the rounds that your fired were done so consecutively, and if it were a false high, whatever influenced the false reading would still be present.

If done later, and the chronograph had been broke down and reset up and weather had changed, then I would most likely eliminate chronograph error as a cause for such a huge jump.

How was ambient temperature between strings?

Were the one-grain-higher charges from another lot of RL15? Even so, that's a big jump.

There's a reason for such a huge jump, and I'd be inclined to expect a somewhat linear increase in velocity, but if it turns out that the increase is real, I'd kinda be thinking about backing it back down.

Vic has given excellent advice!

Thanks vic, well said.
Next question is, at what PSI do these signs appear? We are all taught to look for them. Once we find them, back down a 1/2 or a full grain so they basically go away. Are the loads now safe and withing safe pressures for that cartridge? How would we know if we do not know at what PSI they develop in the first place?

Pull a bullet from one of the old rounds. weigh the powder. Look at the powder bottle/jug for the old load, is it the same lot from the same factory, as the new load.

Traditional excessive pressure signs such as extractor marks and stiff bolt usually appear around 70,000+ psi, already over your rifle's mechanical limit. Primer signs are completely unreliable. The safest way to go about things is to chrony your loads and keep your loads at the same velocity or a little under what published maximum is. More pressure = more velocity, so if you're faster than the velocity for published data, you're also creating more pressure. If you chrony your loads and you're under the target velocity, then you can add powder until you reach the listed velocity for that load (if you have the same length barrel used in the data, if not, subtract about 75 fps per inch less of barrel you have), but call it good there, anything over that is most likely gonna be too hot and damage your rifle and quite possibly your face.

OK, I have read this a few times, but I have never found any real test data to confirm this. Got any real tested data?

Ok, obviously the safer method isn't gonna work for you, so just add powder until the firearm explodes, buy a new one, and back off 1/2 a grain on that load.

Also, do you have any "real tested data" to confirm the contrary?