cast boolit powder

[XWrench3]

i have noticed that most of the powder recomendations, mostly for rifles, given for cast boolits is different than for jacketed bullets. there are a few, but for the overwhelming majority, the powders just seem to be different. is the reason for this less that some powders burn cooler than others, or is it due to pressure reasons, or something else?

[Buckshot]

...............Pressure reasons in part. You can shoot cast lead very well from a 30 carbine at 40K psi, but you won't get many bragging targets shooting cast out of a 300 Win Mag at 40K psi.

..................Buckshot

[SierraWhiskeyMC]

Usually the cast boolit powders are a good deal faster than for the J-word bullets.

The J-word bullets can be driven to significantly higher velocities than cast boolits.
Faster powders generally help to obturate the base of cast boolits so that leading is less pronounced.

However, there is a limit to everything. Too much of a fast powder is definitely not a good thing. Fast powders tend to have a "quick" pressure rise, which is good for initial obturation, but can lead to dangerous overpressures quickly - and that line is often not very well defined.

Some powders need to be used in a very narrow load range.

Some powders are rather "forgiving", and can be used in a rather wide load range. The more "forgiving" powders tend to be bulky, but are good for beginners.

For example, H4895 can be started off with as little as 60% of maximum load. You can work up from there. BTW, H4895 is salvaged IMR4895 powder; not exactly the same (the IMR version is hotter) but they are close. Still, treat them as separate powders.

Each powder is unique upon itself, and should be approached as such. (that is not an endorsement for Alliant Unique, but one could do worse.)

Powders are all different. Different burn rates, different levels of smoke, fouling, etc.

You'll develop preferences over time. Some powders work better in certain calibers. Some are more economical. It's what your goals are and your firearm selection that will drive your powder selection.

[JIMinPHX]

As a general statement, j-word bullets operate at higher pressures, which tends to make them work better with slower powders. There's more to it than that, but that is the oversimplified, cliff's notes version of it.

[Shiloh]

As a general statement, j-word bullets operate at higher pressures, which tends to make them work better with slower powders. There's more to it than that, but that is the oversimplified, cliff's notes version of it.

That is a good condensed version of whats happening.

Shiloh

[HammerMTB]

I had some interesting results of yesterday's shooting. I was trying a slower burning powder in some .44 loads. I was looking for a similar velocity from the boolit, but hoping I might find a slower powder than the 700X I was using.
I found the vel I wanted from it, but the SD was poor. The accuracy was worse, but only marginally. What surprised me was the felt recoil. It was obviously more sharp from the faster powder.
Just some things to think about.... :Fire:

[Shuz]

I had some interesting results of yesterday's shooting. I was trying a slower burning powder in some .44 loads. I was looking for a similar velocity from the boolit, but hoping I might find a slower powder than the 700X I was using.
I found the vel I wanted from it, but the SD was poor. The accuracy was worse, but only marginally. What surprised me was the felt recoil. It was obviously more sharp from the faster powder.
Just some things to think about.... :Fire:

For many years I've used Green Dot as my 1000 fps loading powder for my .44 mags because it's approximately 1/2 the amount, therefore cheaper in cost, than 2400 or H-110/WW296. Only WC-820 can approach it for shot to shot cost. However, I noticed early on, as you have, that a comparable speed with the slower powders has much less perceived re-coil than Green Dot or Unique loads.

[felix]

Well, the acceleration curve is steeper with the faster powder. Force is a function of acceleration only. So, recoil is not only perceived by many, it is actual for everyone. ... felix

[44man]

As a general statement, j-word bullets operate at higher pressures, which tends to make them work better with slower powders. There's more to it than that, but that is the oversimplified, cliff's notes version of it.
This is the answer.

[geargnasher]

Well, the acceleration curve is steeper with the faster powder. Force is a function of acceleration only. So, recoil is not only perceived by many, it is actual for everyone. ... felix

...IF the mass of the boolit is a constant for each powder.
Force is a function of acceleration and mass.

Like the force the track experiences trying to start a 20K-ton train at 3mpm versus the force my shoulder experiences launching a 150-grain boolit at 750mpS.

If either mass or acceleration of the boolit were increased, at some theoretical point the experienced force would be equal to the train.

And then you have to factor in relativity and plate tectonics.

Gear

[felix]

Right on, Gear! ... felix

[runfiverun]

what the heck?
i do this wrong too... i use the slowest powder i can reliably work with.
hammer 800-x works nicely in the 44 mag...

[MakeMineA10mm]

We may be talking in too broad of a sense. There's replies both about pistol and rifle rounds above. I think what everyone has said is true, but the different replies may apply to different situations.

For example, being a 444 Marlin loader and fan, I've spend a LOT of time researching loads, reading about others' successes and failures, and doing testing of my own. My tests, others' anecdotal reports, and tests documented in several sources have all indicated that IMR-4198 is a VERY difficult powder to beat in the 444 with any jacketed bullet under 300grs. Likewise, H322 is the powder to beat when you step up to 300gr+ jacketed bullets. HOWEVER, with cast boolits, Reloder 7 is almost always the best choice. (Beartooth Bullets, Ken Waters' Pet Loads, and at least one other publish source - can't remember off the top of my head right now - agree with this, as well as my own testing and unverified testing I've read from others.)

Now, I defy anyone to tell me how RL-7 and IMR-4198 are THAT different in burning rate. Yes, RL-7, generally-speaking, is faster than IMR-4198, but on most burn rate charts they are next to each other, and the loading levels of the two powders in the 444 Marlin would make you second-guess that RL-7 is faster than 4198 with cast boolits. Some of this is explained by the fact that cast boolits offer less resistance in the bore, and therefore either develop less pressure, or allow one to load heavier loads resulting in the same pressure. THIS is what I think is happening in the 444 with these powders, and it demonstrates another factor to take into consideration.


Now, we can also go at things from another direction entirely, and look at shotgun powders in the 30-30...

[smilie=6:

[felix]

Use RL7 when you need to get more 4198, in lieu of the latter, in the case. ... felix

[Whitespider]

I generally try to use the slowest propellant that will fit the case and still produce consistent ballistics, at the intended velocity; which means, for some applications, I use slower powders than a lot of the guys do. In many cartridges, such as the .22 Hornet, 30 WCF, .44 Magnum, .44 Special, etc., I use powders in the same burn rate range whether I’m shooting cast or jacketed. Larger and/or higher pressure (jacketed) cartridges, such as the .30-06, require some sort of compromise for good results with cast (at least for me). But, this isn’t a hard-set rule; it doesn’t always work out that way... For example, I could easily fit a slow burning pistol powder in the .38 Special and .357 Magnum cartridges and get consistent ballistics, but I just can’t beat the overall performance of W231 in those cartridges, cast or jacketed.

[JIMinPHX]

...IF the mass of the boolit is a constant for each powder.
Force is a function of acceleration and mass.

Like the force the track experiences trying to start a 20K-ton train at 3mpm versus the force my shoulder experiences launching a 150-grain boolit at 750mpS.

If either mass or acceleration of the boolit were increased, at some theoretical point the experienced force would be equal to the train.

And then you have to factor in relativity and plate tectonics.

Gear

I think that the force required to crush the boolit into the shape of the lands & grooves plays into this too. Boolit hardness does make a difference.

[Dale53]

When just a lad, there were rather limited choices of powders for reloading. Speaking ONLY of pistols and revolvers, I early on chose Bullseye for Target loads, Unique for medium loads and, at first 2400 for high velocity loads.

I did not particularly like 2400. When H110 and Win 296 became popular I readily transferred my heavy loads to H110. I consider W296, H110, and WC 820 the same powder understanding that in the case of WC 820 it cannot be used with the exact same loads. It is ESSENTIALLY the same but not EXACTLY the same. In other words, it is not a canister powder and you have to run tests (a chronograph is REALLY useful for this purpose) to determine proper loads. In my case, I have a quantity of WC 820 and it is ½gr faster than H110 in the .44 Magnum. I load accordingly.

Unique is hard to beat for full loads in the .45 ACP and medium loads in the .44 Special, .45 Colt, and .44 Magnum. However, 231 works well in those categories also and burns cleaner, if that is a consideration. Also, I like 231 for target loads, these days. Most of my loads are run with a progressive loader and I like ball powders for its repeatability in the powder measure.

I guess that I could sum up by saying that there are several considerations when picking a powder for a specific purpose:

Among those, but not limited to them, are burning rate, sensitivity (unwarranted pressure peaks), ease of measuring, and last but not necessarily least, cost.

FWIW
Dale53