Home Forums Hunting & Shooting Ask The Gunwriters Gunwriters and Others--Ramshot Hunter Temp Sensitivity

Went to the range today with my 30-06 loads I used this fall for deer. The weather here in Leavenworth, KS today is 10 F above, with 25 mph winds gusting to 35 mph, with a wind chill of -10 F. Not as cold as many places today.

I put the rounds in the back of my truck this morning before church, and they stayed out until I made the range trip after church. The rounds were in the shade all day also, even at the range, as the shooting positions are covered and were shaded today.

The rifle is chambered in 30-06.
The load is 58.8 grains Ramshot Hunter, CCI 250 (magnum) primers, Nosler brass, 180 Nosler Partitions.

When I last ran this load over the Magnetospeed this summer (about 85 F), the load averaged 2760 fps, with about 8 or 9 rounds shot for the average.

The Magnetospeed picked up every round today, no problems with the batteries. I had a set of spare batteries in my shirt pocket in case I needed to make the switch.

Average today, with 8 rounds shot for the average: 2590.

Quickload says if I increased the powder to about 61 grains I would get back to "normal" velocity. Quickload is wrong, of course, because all models are wrong. But it's interesting nonetheless.

Is that about a normal amount of velocity loss based on your observations? If I did the math right the velocity loss is only about 6%, really pretty reasonable.

Do you increase the powder in your case for winter hunting (like cow elk depredation hunts, etc.)? You could just work up a load at 10 degrees and use it for your cold weather hunts? One could also switch to another powder, like H4350, but I would think a cold weather load using the same powder would be just as good as switching powders.

Not that this matters, as I'll be hunting elk in September this year. But I thought shooting this load in cold weather would produce interesting results.

Very curious: What was ES for both the warm and cold firings?

I'd expect no worse than what you got today, from 760/414 in the '06, and that powder ain't great for temp-resistance.

While I haven't found Hunter (or Magnum) to be as temperature-resistant as TAC and Big Game, that much velocity change surprises me. I would have expected at most half that.

ES for the "hot" firing was 40 fps

ES for the "cold" firing was 80 fps

I played around with Quickload some more (again, wrong info), and it says a load at 85 F of 2760 with Hunter should be moving around 2730 at 70 F. If that were true, you'd have a difference of 140 fps instead of 170 fps.

I will add all shots today impacted within 2.25 inches of point of aim. 6/8 were within 1/2 inch of point of aim. If I were hunting instead of shooting over a chrono, I would never have known the difference.

Could also be faulty data--a test including 1 event isn't exactly statistically significant...

That's because you did your load development well in the first place.

FWIW, Ramshot's ballistics people (not the tech sales rep) say that their stick powders are more resistant than the sphericals, and always will be.

One thing I haven't found out is how the Magnetospeed performs in cold temperatures. I was supposed to be sent one for review about 3-4 months ago, but it hasn't shown up, probably because they're selling too many to bother. But I can't find anything on their website about cold performance, or anything on any on-line reviews either.

The ES figures speak to temp resistance, and at least imply that the magnetospeed is operating as it should.

A conventional chronograph is very resistant to temperature change. You are counting ticks of a crystal controlled clock. While not perfectly immune to temperature change, it's close enough for most practical purposes.

I have no idea how robust to temperature change the Magnetospeed is.

With that much change, I would be suspecting measurement system error.

I should also add that I had some extra Dyna Bore Coat, as I ordered a new bottle for a 25-06 Redneck put together. As I hadn't given this rifle a good scrubbing for a while, and since I had some DBC left over, I followed JB's procedure to "Clean to Bare Metal", and reapplied DBC to the barrel.

These were the first 8 shots through the tube since re-applying. However, I would think if the DBC caused the error (or, more like no copper deposits in the barrel), the first shots would have been slower/more affected than the last shots. However, the shots were 2566, 2564, 2609, 2642, 2562, 2605, 2587, and 2590. The first two shots are slower than 5 others, but they're not the most extreme slow shot. However, if I throw them out the average would be 2599 fps.

I would believe the Magnetospeed could have problems with the cold.

I would believe some copper deposits in the barrel would reduce the ES a bit, and maybe bump the velocity up a bit.

And a good suggestion about Big Game--I have a keg on backorder for a bunch of 150s/155s I have waiting here for it. If Big Game is more stable in the cold, I could just hunt in cold weather with 150 gr Partitions instead of 180s.

I would bet no elk or deer would survive a 150 gr Partition through the heart/lung area. Even the mythical elk that wear body armor I read about on the internet.

The first few shots with DBC are usually much like shooting a freshly-cleaned bore, both in velocities and fouling. It's not until after the bore is cleaned again that the coating's effect really starts working.

Thanks for the tip, and the cleaning procedure.

I hope to get back to the range more this winter, and this combo of 180 PTs and Hunter will get more testing--I have around 450 x 180PTs and probably 7 lbs of Hunter left. This whole test really sounds like I need more data for any real significance.

In that case, I will patiently wait until you have the chance to re-shoot with a not-freshly-DBC'd bbl.

Thanks for your posts--I'll let you know what happens.

Unfortunately, the range here is only open from noon to 4:30PM in the winter, but I'll do what I can for cold weather. That's why today was perfect--a high of 10. I'm sure we'll get some cold weather days still.