velocity myetery

[stevea]

Hi, folks. I'm new to the forum but not new to Ruger products. I have a mystery I hope someone can me with. I recently got a Ruger BH in 44 special, and I am very pleased with it. The mystery has to do with some reloads. I used the Alliant manual and loaded the recommended 6.3 gr. of Unique underneath a 240gr. Oregon Trail LSWC. That should have given me about 820 fps, acc. to the manual. Instead I got an average velocity of 1035--more than 200 fps faster than predicted. I went back and looked at the scale setting, and it was right on. Figuring the scale was somehow off, I started weighing other things. A 158 gr. bullet weighed right at 158 grains; a 230 gr. bullet weighed just under 230 grains; a 155 10mm bullet weighed exactly 155. So the scale was on. It's an old RCBS 5-0-2 that I've used for years. So the mystery is this: if the scale is not off, and my setting was correct, how am I getting 1035 fps. Did I get an unusually frisky cannister of Unique? On the plus side, the load is very accurate, primers are not flattened, and case extraction is easy. It does buck and roar a bit for a .44 spl, though, and I'd prefer something in the 800-900 fps range, as predicted. Any theories?

Oh; on the chance that the chronograph was off, I also clocked some CAS loads from Winchester, and they were all in the 750-760 range, so that's not the problem either.

Cases were Winchester, primers Winchester large pistol, bullet the "laser cast" 240g. swc from Oregon trail.
Thanks for any help, or even guesses.
Steve

 

[Rick Courtright]

Hi, and welcome to the Forum!

I can't answer your question directly, but there are some things in your recipe that attract my attention.

So I looked it up on Alliant's site and see a couple of things to consider there: they call for a MAX charge of 6.3 gr of powder, a CCI 300 primer, and a Speer LSWC bullet. First off, it looks like you're loading the MAX charge--did you start there, or have you worked up from the "starting" load Alliant recommend of 5.5 gr?

Then I see a Win primer was used. Remember, the Win WLP is ok'd for "standard AND magnum" loads, so it could be a bit hotter than the standard CCI.

I also noticed an Oregon Trail bullet in your post. Someone will correct me if I'm wrong, but I seem to remember reading that some of the bullets in Oregon Trail's catalog are a bit "hard" compared to some other cast bullets, and I don't even know if Speer's bullet is cast or swaged. If swaged, it could be considerably softer. That could make a difference, as can primers.

It's also possible you did get a "frisky" jug of powder, but that's not really likely. Not impossible, as I've seen it myself, but not the first thing I'd look at. There's also the possibility that the gun you're using is "just perfect" for maximizing velocities. Again, not likely, but not impossible.

So I'd suggest you go back to the basic adage when working up a new load, or even using a "known" load in a new gun: start low, work up!

Since you've checked your scale and chrono against known items, how about you go back and put together some ammo using Alliant's STARTING load of 5.5 gr as your ONLY change in recipe, chrono them, and see what happens? If they're within range, you know you're on the right path. If they're STILL hotter than desired, you may want to drop ever so slightly on the powder charge (Unique's pretty forgiving compared to some powders) and check again.

Remember, too, that EVERY item we use that is not a "book recipe" item is a "component change" that should trigger the "start low, work up" response. For example, I've used a recipe that calls for Win brass, Win primer, and Win bullet, but MY version was assembled using Starline brass, Win primer, and Rem bullet, so I made THREE changes, each of which should be "tested" and adjusted for!

Seems like a lot of work, but you want to be safe AND produce ammo that does what it's supposed to all at the same time!

Good luck...

Rick C

 

[Rclark]

That is a mystery.... My 'standard' .44Spec 7.5g Unique load under 240g Bullet chronographed at 1033fps out of 5 1/2" barrel .44Spec BH. I don't have any sub-7.5g data as I went directly to the Skeeter load. That said... Tested with Starline brass.

The primer shouldn't be a factor. I did some tests with CCI-300, CCI-350s and got only 8fps difference using Unique (.45 Colt load test) .Testing with 2400 powder I found the WLP between the CCI-300 and CCI-350 in power. Basically Unique is primer independent.

I'd grab another can of Unique. Just to see....

It sounds like your scale is ok. But maybe buy a set off check-weights and check the exact weight you are trying to load.... Just a thought.

 

[greenmtnguy]

What brass are you using?

Most of my reloading is with STarline brass. I find that, because it is thicker and holds less water than, say Winchester brass, loading the same powder charge will net a higher velocity in the Starline brass due to its smaller capacity. It doesn't take much to make a difference in pressure.

Also, how far ahead of your muzzle is the chronometer? If it isn't far enough out, your measurement might be including propellant particles.

 

[Iron Mike Golf]

Might be a combinations of factors:

1. Barrel length. A quick check of the downloaded Allian manual does not reveal to me what gun or barrel Allian used and you don't say what your gun has.
2. Bullet alloy. Laser Cast are hard, they put silver in their alloy to make it harder. I think Rick C is right about the Speers being swaged. Harder raises pressure.
3. Bullet diameter. I don't have any Speer 44s, but their sight lists them as .430. Laser Casts are listed as .431. What's your gun's groove dia?
4. Lubes are different, too, right? Dry film on the Speers (I have some Speer .38 plinkers like that) and waxy in lube grooves on the Laser Cast. Just reaching for differences here.

 

[Rclark]

Barrel length. A quick check of the downloaded Alliant manual does not reveal to me what gun or barrel Allian used and you don't say what your gun has

Very true. You cant take much stock in the velocity given in the 'manual'. But it should be in the ballpark regardless. Given that the Skeeter load (7.5g Unique) is around 1000fps out of a 5 1/2" barrel (my tests are in the same type of flattop .44Spec BH as the OP is using except he might have the 4 5/8 barrel which should have even less velocity) . So 6.3g should be way less than 1000fps. I guess I should setup the chronograph again and load down to get some data for my files just for posterity . I do like the Skeeter load.

One thing, you didn't say you weighed the 240g bullets.... Maybe 200g or the 180g by mistake? (Oregon Trail do make these size bullets).

[edited for update]
Shot some test loads Saturday afternoon (27F, cloudy, slight breeze) for my satisfaction with Ruger 5 1/2" .44Spec Flattop:

6.0g Unique, 240g SWC, CCI-300, 874fps, 11 SD, 31 ES, 15 shots
6.5g Unique, 240g SWC, CCI-300, 933fps, 12 SD, 42 ES, 14 shots
7.0g Unique, 240g SWC, CCI-300, 969fps, 14 SD, 46 ES, 14 shots
and of course :
7.5g Unique, 240g SWC, CCI-300, 1033fps, 10 SD, 29 ES, 12 shots

FYI,
7.5g Clays Universal, 240g SWC, CCI-300, 1037fps, 10 SD, 36 ES, 29 shots