Safely reducing loads.

[Bill Steele]

I am starting to work on reduced loads for my .44/240gr SWC and wanted to make sure I didn't make a big Kaboom mistake.

I was reading in the Lee book on his rules of thumb on determining proper reduced loads for cast lead by using strength of materials versus pressures.

In his book (kind of out of left field) he cautions against reducing loads less than 80% of start loads when using slow burning powders. In that section he has a list of powders running from 50 BMG (slowest) to vv-N310 & Bullseye (fastest) and says you can reduce safely an additional 1% percent (from 20%) more from start loads for every step up in burn speed you go.

I was trying to figure out how this related to some recent posts by guys whose knowledge in this field I really respect on fast burning powders under heavy bullets causing an over pressure situation. I sensed it was two different concerns but couldn't reconcile the two concerns.

If the Lee book is correct, then it seems if I stick to the faster powders, reducing 50% or more from start loads (of the published .44 Mag start loads) should be no problem. Reading some recent posts by knowledgable guys on these threads, I am not so sure.

Way back in the past when I was loading for rifles, I had read about how reduced charges can cause "shaped charge" effects and all sorts of other way out stuff, but never read anything that seemed to jive with my limited knowledge of physics on the subject.

Any real world experience would be greatly appreciated.

[SixPointEight]

Well..I'm not 100% sure, but I thought the problem came from loading fast powders really low. If they fall against the bullet, you can get pressure spikes and a potential KB

[GeoffLinder]

If powder charge is so small that it ignites all at once instead of burning evenly you can get an over-pressure spike.

If the bullet never moves and case volume is real small, you can get a KB from an over-pressure spike that doesn't get relieved by bullet moving and creating more volume as powder finishes it's burn.

If a bullet just starts to release from case mouth and then hits lands and stops or slows too much for some reason and powder continues to burn a second over-pressure spike can occur.

Generally only an issue in centerfire rifle cartridges and pistol cases with very small volume (9mm, .380, .40SW, etc...).

.44mag and .44 special cases have a lot more internal capacity to start just like .45acp so the risk is way reduced here even though it can still apply in extreme cases hence the 20-80% warnings.

General rule of thumb in revolvers shooting large volume cases is "if the bullet leaves the barrel, you are pretty much OK". In Semi-autos using large volume cases, add "if the gun cycles reliably" to "if the bullet leaves barrel" and you will generally be OK with a reduced charge.

[Bill Steele]

Thanks guys, I appreciate the feedback.

Anyone want to hazard a guess why downloading slow burning powder is more of a problem than fast burning? I am stumped. I guess I will give Lee Precision a call on Monday and see if I can find out what the reasoning is for this caution.

[mif_slim]

humm.. I've never experiance any pressure signs as I've gone lower. Im talking about from 25gr in gradual steps all the way down to 2.0gr getting squibs... No pressure signs or spikes. Unless the powder Im using is stable and I've been lucky. I even used AA#5 with 3.0gr in 5.56 (not recommended for you ball-less folks! :P :P :P ) and I've seen no pressure signs either.

I've loaded about 1000 +/- of those, I experimented on AA 2460, 2230, 1680, #5 and RL-15. I havent done it with other powders so I cant say for them.

DISCLAIMER:
DO NOT TRY WHAT I DID, IF YOU DO DECIDE TO, YOUR ON YOUR OWN!

[sniper5]

H110 will flash over if it has exposed surface and spike pressures. You can call Hodgdon and ask them about this. Generally speaking, in fact more than generally speaking, with H110/W296 you need to fill the casing, and most loads are compressed with heavy crimps and heavy bullets.

With Bullseye, you NEVER fill the case. Which is one of the dangers of the powder. There is usually enough room for a double, and sometimes a triple charge. Pressures run higher per grain of powder, but the volumes are so low it keeps pressure within safe limits.

[Bill Steele]

humm.. I've never experiance any pressure signs as I've gone lower. Im talking about from 25gr in gradual steps all the way down to 2.0gr getting squibs... No pressure signs or spikes. Unless the powder Im using is stable and I've been lucky. I even used AA#5 with 3.0gr in 5.56 (not recommended for you ball-less folks! :P :P :P ) and I've seen no pressure signs either.

I've loaded about 1000 +/- of those, I experimented on AA 2460, 2230, 1680, #5 and RL-15. I havent done it with other powders so I cant say for them.

DISCLAIMER:
DO NOT TRY WHAT I DID, IF YOU DO DECIDE TO, YOUR ON YOUR OWN!

It is interesting, using Lee's ROT, all the powders you cite (except Reloader 15) are relative fast powders (or at least in the middle of the range) and will allow 70-80% reductions (again using his advice). The Reloader 15 is in the slower range and using his advice should never be loaded less than about 65% of the published start load. Strange.

H110 will flash over if it has exposed surface and spike pressures. You can call Hodgdon and ask them about this. Generally speaking, in fact more than generally speaking, with H110/W296 you need to fill the casing, and most loads are compressed with heavy crimps and heavy bullets.

With Bullseye, you NEVER fill the case. Which is one of the dangers of the powder. There is usually enough room for a double, and sometimes a triple charge. Pressures run higher per grain of powder, but the volumes are so low it keeps pressure within safe limits.

More puzzling, H110 is right in the middle of the range Lee uses in his book and using his Rule of Thumb you should be able to safely download 70% less than the published start loads and be fine. Really strange. In his explanation he doesn't mention H110 or W296, but he does include it in his list and rank order.

The only thing I can think of is maybe his advice was centered on rifle loads while trying to get a cast lead bullet to work and has nothing to do with hand gun loads with their relatively lower pressures and shorter barrels, etc.

Thanks again guys, it is really helpful to have experienced hands to bounce things off of.

[mif_slim]

I think their just afraid of squibs. A kb usually is resulted in too much powder or squibs.

[z-bob]

I am starting to work on reduced loads for my .44/240gr SWC and wanted to make sure I didn't make a big Kaboom mistake.

For reduced loads (you don't say how much reduced) you can use .44 Special or .45 Colt load data (but not .45 Colt +P or "Ruger Only" data) in .44 Magnum brass. Generally, bulky fast-burning or middle-burning powders will work best and be most economical. Red Dot, Green Dot, Universal, and Trailboss are good choices.

[6079Winston]

2400 pretty much covers the whole spectrum of .44 mag loads, also a nice powder for small rifle cases with lead bullets in case you need an excuse to pick up another mouth to feed. If you want to load under 800 fps you could probably load .44 Russian ammo instead. I have a mould for a .44 HBWC which I will someday try out in a mid range load in my 629.

[foesgth]

Donuts

Well guys I use a low tech solution. Trail Boss powder. It was built for cowboy shooting. It is shaped like little donuts or maybe Cheerios. I load 38spl loads for my wife that recoil like a .22. To illustrate how this powder works when you buy a regular 1 pound sized container it has 9 oz of powder in the same volume. Here is what IMR has to say about it:
Trail Boss is designed specifically for low velocity lead bullet loads suitable for Cowboy Action shooting. It is primarily a pistol powder, but has some application in rifle. It is based on a whole new technology which allows very high loading density, good flow through powder measures, stability in severe temperature variation and most importantly, additional safety to the handloader.

I also use it to build loads for my C&R surplus stuff that doesn't beat you to death.

[Bill Steele]

Yes, I think maybe the KB comes after the squib, that probably would feel like a shaped charge that.

I am shooting for about 900-1000 fps range for my 240gr SWC's. Soft enough to allow me to shoot it alot without these old hands getting sore. I am planning to stop at the range on the way home from the FFL, so I will load up some with about 10 gr of AA-7 to start things off. I have some Bullseye, Unique, 231, #9 and TB coming. Should arrive mid-week and give me something to play with the following weekend.

Thanks again guys, I really appreciate it.

[EmmaGoldman]

900-1000 fps is still hotter than most standard .44 special loads for that bullet weight. You're still well above the level of reduced load that causes problems. Any of those powders will be fine. Just pull data straight from the manual for .44 special and load it in either special or mag brass. My first choice would be Trail Boss, then 231, Unique and #9 (as a group) then bullseye (I just don't really like that stuff).