Unusual Chrono Readings with cast bullet 35 Whelen loads and Trail Boss powder

I was doing some load testing with my 35 Whelen Encore and the NOE 358009 clone (big 280gr RN cast bullet). I was using Unique, Trail Boss, and IMR 3031. The chrono was 10-12 feet in front of the muzzle.

The Unique loads did what I expected (low 1000fps range, mild report and recoil). The lighter Trail Boss load, 14gr, was about like the lighter Unique load (11gr).

But, the 17gr Trail Boss load did something weird on the chrono. The recoil and report felt only a little greater than the 14gr Trail Boss load, but velocity was ~2200fps across 5 shots, nearly double the lighter load! The "wrongness" of that wasn't apparent until I shot the 3031 load (40gr I think, need to check my notes). The 3031 load gave me just over 2000fps, but recoil and report were significantly greater than the other loads, which was expected.

For comparison, the 280gr 2000fps load using 3031 felt close to my hunting load which is a 250gr @ 2400fps load.

So, I either have a "magic" load in 17gr of Trail Boss that gives me high velocity without the associated noise and recoil or something was causing a chrono mistake that was consistent across 5 shots. I *think* the difference in charge weight between 17gr of Trail Boss and 40ish grains of 3031 may have been part of it. The weight of a powder charge does impact felt recoil and 40gr is quite a bit heavier than 17gr, but I wouldn't have expected that much difference.

As far as accuracy is concerned, none of them were great, though the 11gr Unique load showed promise. Some tweaks to it (+/- a grain or two and some extra care in casting the bullets) may deliver acceptable 100yd results.

Chris

I've never had it happen, but I've heard that sometimes a chronograph can read the cloud of gas that comes out of the muzzle instead of the bullet. Sometimes moving the screens out a bit or putting up a baffle between the screens and the muzzle will fix it.


Okie John

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Originally Posted by okie john

I've never had it happen, but I've heard that sometimes a chronograph can read the cloud of gas that comes out of the muzzle instead of the bullet. Sometimes moving the screens out a bit or putting up a baffle between the screens and the muzzle will fix it.


Okie John

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I thought about that, but it was very consistent and not repeated with the other loads. I would have expected more fluctuation if it was measuring gas.

Next time I'll put it out further.

Chris

Quote:

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Originally Posted by okie john

I've never had it happen, but I've heard that sometimes a chronograph can read the cloud of gas that comes out of the muzzle instead of the bullet. Sometimes moving the screens out a bit or putting up a baffle between the screens and the muzzle will fix it.


Okie John

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I've had it happen with an in-line muzzleloader. IIRC I moved the chrony to 15' in front of the muzzle instead of 10'.

ETA: In my case it presented as wildly disparate readings, like an extreme spread of 1000 fps.

Is your 17gr load compressed? Hodgdon cautions against compressing Trail Boss because it can lead to erratic performance. See Hodgdon's statement quoted Terry Wieland's article "Trail Boss Revisited" in the June 2016 issue of "Handloader" magazine, Issue 302, page 72.

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Originally Posted by oregon45

Is your 17gr load compressed? Hodgdon cautions against compressing Trail Boss because it can lead to erratic performance. See Hodgdon's statement quoted Terry Wieland's article "Trail Boss Revisited" in the June 2016 issue of "Handloader" magazine, Issue 302, page 72.

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No, it's not compressed. I've been using Trail Boss since it hit the market and know the formula for starting loads with unlisted cartridges (of which the Whelen is one).

Besides, if this was a compression-related pressure spike, it was the most consistent and well-behaved pressure spike imaginable. :)

Chris

You could try a piece of cardboard with a hole cut in it between the muzzle and the chrono.

I hope that this might be the best thread to discuss light .35 Whelen loads. I'm getting started on a rifle project, and one of my goals is to have .357 Magnum JHPs loaded lightly in addition to the more typical full-power rifle loads.

Is there a bullet type, shape, or weight that anyone has found that minimizes or mitigates any feeding issues? I value smooth feeding, and if there's a load development that helps feeding out, I'd like to begin by starting down that particular path.

Quote:

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Originally Posted by Bergeron

I hope that this might be the best thread to discuss light .35 Whelen loads. I'm getting started on a rifle project, and one of my goals is to have .357 Magnum JHPs loaded lightly in addition to the more typical full-power rifle loads.

Is there a bullet type, shape, or weight that anyone has found that minimizes or mitigates any feeding issues? I value smooth feeding, and if there's a load development that helps feeding out, I'd like to begin by starting down that particular path.

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No clue. My Whelen is a single shot, so feeding from a magazine isn't a concern.

Chris

I have been experimenting with Trail Boss in my .44s and have gotten some weird numbers(high) when shooting max loads with the crony set up at 10ft. Pushing back to 15ft solved the issue. I'm thinking it is unburnt powder passing the bullet but it wasn't consistent.