There's something to this ball powder...

[Nobade]

I have been messing with a 6.5 TC-U bolt rifle for a couple of years now. It shoots awesome with greasegroove boolits, but until today it never has worked with paper patched. So, what changed? Powder. I had been using IMR powders, mostly 3031. Reading here about good results with 760, I tried some loaded with 748 and some with 760. Boolit is the BRP 129 Kurtz, sized to .259" and patched back up to .2645. Seated to the base of the neck with the case completely full of powder, it put 20 rounds - 10 of 748 loads and 10 760 loads, into a 4 inch group at 200 yards. It has never done that, usually throwing PP boolits all over the landscape. The 748 loads were pretty snappy, the 760 noticably slower but all hit the same place. Looks like I'll have to be buying more ball powder to play with in the future.

[geargnasher]

Yes there is something to it! Double-base powders have always been very cast friendly at high loading density because they act like an inert granular filler behind the boolit until the boolit is fully engraved. Usually the kernels touching the boolit base don't ignite until the boolit is well on it's way, thus protecting the boolit from damage during it's most vulnerable state, during transition from case to bore. Cooler burning too in general, compared to SB powders.

Gear

[303Guy]

Mmm... very interesting! The question of ball powders has come up recently as being cast friendly. I'm now testing what's left of my AR2208/Varget and would like to find a suitable ball powder to replace it with. (Apart from the boolit base peening which is far less than that caused by AR2209/H4350, the AR2208 seems to produce lower pressure with higher velocity than the AR2209).

[CJR]

It's hard not to like lower peak pressures, lower burning temperatures, highest velocities, good bulk density loads without fillers, and excellent PPCB accuracy.

Best regards,

CJR

[303Guy]

Well, I've been looking for a ball powder to replace my AR2208/Varget. So far I have identified three candidates. Those are H335, BL-C(2) which has the lowest pressure of any powder and H414. (H380 could be a possible but it seems to have too much empty space in the case).

What troubles me with highest velocity and lowest pressure is that it means the mean pressure is higher and that means a longer barrel is called for. I want this for my short barrelled pig gun so I'm leaning towards H335.

On the other hand, BL-C(2) would be more versatile in so far as I could attain near 308 velocities using it in my mint bore two-groove No.4. (Not a bad plan since I have other 303's working at normal 303 Brit velocities).

So, which should I select?

( BL-C(2) is very similar to Winchester 748 ).

[frankenfab]

H335 is great in the .444, anyway.

surplus:

WC844 = H335

WC846 = BL-C(2)

WC852 = H414, but probably a little slower.

Don't know if you can get that stuff there, or not.

ETA: I'm proud to say I got some of all three!

[nanuk]

I remember reading that if one powder gives faster speeds than another, it will do so in shorter barrels also

I think this was taken down to shorter than 16 inch barrels.....

anyone else remember reading something like this?

[Doughty]

I've been using Accurate Arms 2520 in my high velocity (1800-2500) loads. Both patched and unpatched. A favorite load in my .38 Krag (.30-40 Krag blown out to .375) is 43 grains behind a 290 grain paper patched bullet. I have not tried any of the other ball powders in this burn range, but would like to, especially some of the surplus powders. I have tried the WC860, which is a slower burning ball powder, but can't get much velocity out of it, even with a duplex starter.

[CJR]

303 Guy,

It is possible to have the same AVERAGE pressure for a typical degressive powder and a ball progressive powder. However, the effects on a PPCB will be radically different. The digressive powder will peak quickly and then drop quickly. Kind of like setting off an explosion behind a PPCB. Since the PPCB has an inertial slowness in getting started to move , it will experience a peak pressure before it starts to move. Result? Excessive obturation/initial high temperature/may be lead vaporization.

However, a ball progressive powder will start the PPCB moving at low pressure and the pressure will be constantly increasing until PPCB muzzle exit. The result is gradual PPCB obturation at lower temperature, lower PEAK pressure, and maximum velocity. Maximum cartridge loads are typically based on PEAK pressures. Likewise, maximum progressive powder loads will typically have PEAK pressure that are 8000 to 10000psi lower than digressive maximum loads. Result? Progressive ball powder loads, with 8000-10000 psi lower PEAK pressure, will reach the highest velocities possible by having a higher AVERAGE pressure. Some side benefits are; one doesn't have to worry about a max. PEAK pressure excursion occurring on a hot day, and the gun operating at lower PEAK pressure will give a longer gun operating life (i.e. minimal bolt lug set-back, etc.), and all this at max. velocity. A win/win situation for PPCB.

Best regards,

CJR

[bbqncigars]

Doughty:
WC860 is one of the standard powders used in the .50BMG, so I imagine it might be a little too slow for some smaller calibers in shorter (<32") barrels. Now you got me thinking about trying it in the 45-70 Creedmoor, though. BTW, nice website and gorgeous looking molds.

[Doughty]

Digressive ball powder loads, with 8000-10000 psi lower PEAK pressure, will reach the highest velocities possible by having a higher AVERAGE pressure.
CJR

CJR, Did you mean to say "Progressive ball powder loads." If "digressive ball powders" is whay you meant, would you give me a few examples of those types of powder. Not trying to be critical, I just don't know that much about powders.

bbqncigars, For use in .45-70 is why I originally got the WC860. Got rid of all the .45-70s except for an old trapdoor, so am wanting to use the powder. (Thanks for the kind words regarding the website and molds.)

CJR, since I've wandered into the area of duplex loads with ball powders, what does that become? A digressive-progressive?

Richard

[CJR]

Richard,

Thanks for catching my typos, which I've now corrected. Ball powders are "progressive". Let me see if I can post a powder reference I've used in the past.

As to your question; I would think that a digressive/progressive mixture becomes a "neutral" powder.

Best regards,

CJR

[CJR]

Richard,

Here you go. This should be helpful; http://www.fas.org/man/dod-101//navy...c/ballstic.htm It shows the pressure curves for the different powders.

If that doesn't work, do a search for "Introduction to Naval Weapons Engineering". Then select "ES310 Introduction to Naval Weapons Engineering", then go down list and select "Ballistics". It should open up then.

I forgot to mention that this link shows the technique of controlling the burn rates with "geometrical shapes of granules. Ball powders control their burn rates by using different deterrent chemical coatings.


Best regards,

CJR

[Doughty]

CJR,
Thanks for the link. Interesting stuff.

[303Guy]

Thanks, CJR.

Which type of propellant to use depends on the application. If the barrel cannot be made very long, it is better to use a degressive propellant to achieve the maximum exit velocity in a limited distance ...

I've been looking on the net for specific powder pressure curves but couldn't seem to find any.

The message I am getting is that these ball powders need enough pressure to burn well. Unburned powder at the muzzle is not so bad if the boolit flies fast enough and straight enough. I can't seem to get BL-C(2) in my parts so I need to look at the other remaining choices. Ball powder does sound like a good choice for cast and paper patched.

So the question is, which ball powder would be better in a short barrel?

[CJR]

303 Guy,

I've evolved to two (2) ball powders for my PPCB loads; W748 & W760. W748 is faster burning than W760, so for a shorter barrel I would think that W748 would work best. You won't know untill you try it in your particular gun.

Best regards,

CJR

[303Guy]

CJR

Thanks for the help and advice. I located some W748 and did some double checking and confirmed that the W748 fell closer to AR2208/Varget than anything else and that is would likely be the 'optimum' powder for the short barrel and paper patched boolit. So far I have fired exactly one test round and this single test seems to confirm that it is as close for as can be hoped for. I checked against pistol loading data for the 308 Win and that indicated just about optimum too even though case capacity for heavier bullets is smaller.

Pistol data for rifle calibers confirmed what nanook said;

I remember reading that if one powder gives faster speeds than another, it will do so in shorter barrels also ...

Thank you all. Thank you Nobade for starting the thread.

P.S. It's a neat looking powder! And it is almost a direct substitute for Varget which I was looking for also. In fact, I tried the same powder measure setting which threw 44.8gr W748 as opposed to 33gr Varget/AR2208. That load seems to produce the same pressure and velocity. Perfect!



The L/H primer was with AR2208/Varget - shown for comparison. The base is way less damaged than would be with Varget. It was fired without a wad. A bit of the patch base ring was recovered in the sand - that's interesting as I haven't been finding any pieces of patch with AR2208.

The bore is super clean and shiny!

Things are looking good!

[geargnasher]

303guy, Winchester 748 is my all-time favorite for .30-30, 34.5 grains for any boolit/bullet that will chamber in a levergun. Absolutely stellar in my Marlin 336 with an 18" barrel! Nearly 2200 fps with excellent accuracy from 165-grain GG/GC boolits shoots flat, shoots far, and fills the freezer. I would assume that it would also be ideal in the .303 British at velocities of 2,000 fps and above.

Gear

[CJR]

A tibit of info about W748 & W760. It is my understanding that when W748 & W760 powders were first introduced, they were designated as "Benchrest" powders, i.e. "BR". Then somewhere along the way, Winchester dropped the "BR" designation. For me, these two powders work very well for my PPCB efforts!

Best regards,

CJR

[Nobade]

Have you guys had good results with less than a case full of ball powder and PP boolits? Most of what I have done shoots best with a case full to the base of the boolit. But Quickload says I will overpressure the 30-06 if I do that with 760. Does the "buffer" effect work even though there is some airspace or will it need filler on top?