185-gr SWC, Chap. 3: Some WW296 Trials

[pitted bore]

Part 1

After results from Chapter 2, I was pretty much convinced that without some radical change in loading technique, such as heavy crimping, using Lil'Gun powder was not going to produce satisfactory results. At the end of that thread, Wildcatter suggested using WW296/H110. Based on his experience with the cartridge, I decided to give it a try, and dug a can of 296 out of the locker.

Based on some suggested loads for a 200-grain bullet from the calguns thread, I settled on 40 grains as a starting load. Again, the loading protocol was pretty much that used for the loads in Chapter 2, Part 1, with two loads each at charges of 40, 41, 42, 43, and 44 grains. The barrel started out pretty clean for this series. I fired the loads from a bench through the chrono screens, and obtained these readings:

WW296 . .Trial 1 .Trial 2
-------------------------------
40 gr - - - 2150 - - - 2311
41 gr - - - 2305 - - - 2322
42 gr - - - 2324 - - - 2429
43 gr - - - 2421 - - - 2119
44 gr - - - 2494 - - - 2502

On the second and third shots, notable hangfires of a least a half-second occurred, and a shorter hangfire happened on the last 44-grain shot. After the first two, I began to tilt the rifle up, to settle the powder into the primer end of the case, before gently lowering it to fire the shots through the chronograph.

There were no signs of excessive pressure. In fact, most of the cases as sooting, back to the extraction groove in some instances. Some powder grains were left in the bottom of the bore after firing.

It appeared that an increase in powder charge was appropriate for further tests with this bullet.

[Siringo]

For light bullets, maybe we have to go to faster powders. Such as 2400. I have had the same thing happen with light bullets. Seems like the load peaks out and then drops off. Pressure is not high enough to get a good burn.

[pitted bore]

Siringo-

What weights of lighter bullets have you used? Have you tried some faster powders?

I would rather not throw bullets and powder downrange and fire off currently irreplaceable primers to find out what you already know.

Thanks.
--Bob

[pitted bore]

Part 2

As in the trials with Lil'Gun, the lack of pressure signs indicated that an increase in powder charge might produce an increase in velocity. I made another trial series with two cases each at 45, 46, 47,48, and 49 grains of 296.

The rifle was set up as in Chapter 2, Part 1: in the padded gun vise, sandbagged, and triggered via a string. The chronograph was set up similarly. I expected no disasters, but again I put a good-sized tree between myself and the rifle, because the copay on my medical plan had been raised recently.

Here's what the chronograph showed:
WW296 . .Trial 1 .Trial 2
-------------------------------
45 gr - - - 1939*- - - 2445
46 gr - - - 2610 - - - 2570
47 gr - - - 2031*- - - 2584
48 gr - - - 2392 - - - 2316
49 gr - - - 2426 - - - 2203

The readings with asterisks(*) are unexpectedly low, but are not wacky enough to be disregarded as a malfunction of the measuring system.

There were no signs of excess pressure, and the sooting that showed on the cases indicated insufficient pressure.

Again, as with Lil'Gun, velocity appears to be a max with this bullet at about 2600 fps with 46 gains of 296, and any powder above that is not contributing to velocity.

[pitted bore]

Part 3

Because it seemed obvious that the loads with 296 were not producing enough pressure, I decided to try a strong crimp, which can increase bullet pull and therefore pressure. I loaded up a series of two cases each with the same powder charge as in Part 2: 45 through 49 grains.

For this series, I applied the maximum crimp that the Hornady taper crimp die produces. When I did this, the bullets were visibly distorted from the case pressing inward; in fact, after the case brass had sprung back, I was able to turn the bullets in the cases. The case mouth was considerably under the SAAMI minimum of 0.474. Since the cartridges passed the "thunk" test (although maybe with a grade of D-minus), I decided to proceed with firing.

The gun was set up, sandbagged, and string-fired as in Part 2. These were the readings:

(Heavy taper crimp)
WW296 . .Trial 1 .Trial 2
-------------------------------
45 gr - - - 2521 - - - 2413
46 gr - - - 2584 - - - 2374
47 gr - - - 2547 - - - xxxx
48 gr - - - 2465 - - - 2397
49 gr - - - 2324 - - - 2441

Again, the operation of the rifle, and the appearance of the cases showed no signs of excessive pressure. The soot that appeared on the cases indicated insufficient pressure.

It's seems that another approach will have to be tried if 185-grain bullets are to be workable.

Please let me know what needs to be added for clarification.

--Bob

[Siringo]

Siringo-

What weights of lighter bullets have you used? Have you tried some faster powders?

I would rather not throw bullets and powder downrange and fire off currently irreplaceable primers to find out what you already know.

Thanks.
--Bob

The lightest that I have gone was a 200 gr. Barnes. I had the same wild swings in velocity using Lil'Gun and WSR Primers. Using CCI SR Mags, my velocities dropped off 100 to 200 fps. Other than using 296 and 110 on 240 gr. bullets, I have not delved into the faster powders. By the way, the group sizes with the 200 grain were more or less patterns and testing was suspended. I think the logical step would go a notch or two up on the quicker powder. Maybe it would light better too with the small rifle primers.

On a side note -- primers are beginning to show up again.

[Siringo]

I was looking at loading data for the 460 S&W (this cartridge operates at 60K psi) and seems the powders of choice are same we are using. Although there is some 4227 and 5744. Big difference though is the use of Large Rifle Primers.

[BD1]

I have had much better luck using large rifle primers in cut down .284 brass to light both H110 and LilGun. I also believe that the "body" crimp into a lube groove on the cast boolits has raised the start pressure enough to get a consistent burn.

Two things I'd be tempted to try if I had a bolt gun with a claw extractor:
1. A hard roll crimp into the cannelure using a 45 Long Colt die.
2. A max COAL with the bullet seated into the lands.

The bolt gun should give you the ability to ease a cartride in being held by the extractor, or to chamber one into the lands without knocking it out of round.

BD

[Siringo]

AH!!! Headspacing on the bullet!

[pitted bore]

Two things I'd be tempted to try if I had a bolt gun with a claw extractor:
1. A hard roll crimp into the cannelure using a 45 Long Colt die.
2. A max COAL with the bullet seated into the lands.

The bolt gun should give you the ability to ease a cartridge in being held by the extractor, or to chamber one into the lands without knocking it out of round.

BD1-
Thanks for both of these suggestions. I'll reply to your #1 here. I'll have to make some measurements to address your #2.

A minor problem with suggestion #1 is that the 185-grain Encapsulated SWC by Hornady doesn't have a cannelure. Neither do the 160-grain Barnes bullets that I wanted to try next. I'd be interested in learning whether there exist on the market any 451 or 452 jacketed cannelured bullets of less than 200 grains.

Of course, a cannelure can be applied with a cannelure tool ($65 new from C&H and $130 from Corbin). I'll probably try making a cannelure on my 185s with the clever device that Wildcatter described on 10-18-2008 in the calguns thread; he made it from an ordinary tubing cutter.

I'm still leery about using a roll crimp. Because this cartridge headspaces on the case mouth, playing with that critical area makes me nervous. That's why I used a heavy sandbag over the action and a long trigger string when I tried out the cartridges with the shrunken mouth diameter from the heavy taper crimp described above.

If I feed a cartridge from the magazine, the rim does slide in behind the claw of the extractor, and the case will certainly be held in place before firing. What concerns me about this approach is that the claw might allow some forward movement of the case. This might cause trouble if (1) the firing pin blow is sufficient to drive the case far enough forward in the chamber to put the roll-crimped mouth over the edge of the chamber cut, or (2) the rearward pressure from the primer might be sufficient to force the case forward similarly. I'm uncertain about the slop of tolerances built into the rim-claw arrangement. Holding the case against the bolt face is not what the extractor was designed to do.

If there's enough forward movement of the cartridge, the bullet could become pretty firmly wedged by the case mouth wall backed up by the ridge at the front end of the chamber, and pressures might become really excessive and possibly destructive.

The Hornady seating die has a roll-crimp shoulder built in. I could possibly use that rather than seeking a .45 LC die if I decide to try the roll-crimp solution.

However, I think I'll first play with cutting a cannelure and trying Wildcatter's side-crimp technique. I'm uncertain if this will solve the problem with the light bullets, however.

More later.
--Bob