The Safety Of Starting Loads

[spinconn]

I know we must work up our own loads, and that manuals are only a report of results achieved by the loads tested therein with their barrels, etc., and that we work up to maximum loads carefully and slowly. However, what about starting loads?

Is it safe to assume that one can always start with a starting load listed in a Manual? Assuming, of course, that the load is measured accurately and is not erroneously lower than the listed load, will the listed load always prevent a squib?

Is there any margin of error that tolerates a .1 grain less of powder, for instance?

 

[joshb]

I save components by starting in the middle. You can “assume” that starting loads are safe. The companies producing the manuals have TEAMS of lawyers yelling at them!

 

[JSH]

My findings, smaller calibers 17’s and 20’s can be pretty picky.
If 1/10 grain puts you in a high pressure zone, your playing with fire so to speak.

 

[FeMan]

You are not going to have a squib from using a starting load in a reputable reading manual. Changing components, load characteristics, starting jammed against the lands, etc will change pressure. While it may be possible to change enough things to make a min Manual load a max load in a given rifle, the min loads are far enough down that accomplishing that would probably require a lot of creativity.

Not sure why you asked, but stick to starting loads and as close to the listed components as possible and work up from there. If you change things, stick to one thing at a time, measure results and then move on.

 

[ballisticxlr]

If you're loading book and components are all identical to the book load, you can start in the middle or even pretty near the top once you have a feel for things. Hell I usually start within 1-2 grains of where I plan on ending up and I usually am ending up within a couple grains of a max charge. There's too many corner cases to answer your question really simply but like JSH said, if .1gr is going to be a problem either way, you're already in a bad way and should put the tools down.

A lot of people here would probably pee down their leg if they saw the way I've been known to work up a load where there's not readily available reference data but I betcha quite a number of them do it the same way because they have as much (or usually more) experience than I do. I wouldn't probably explain that method in detail to anyone who's not been at it for 20-30 years though because bad things can happen in pretty extreme cases.

Squibs will happen when you don't add any powder or have contaminated powder that doesn't burn. Squibs don't happen because you loaded 24.5gr for a starting load instead of 25gr.

 

[Coyotefurharvester]

If your shooting a factory rifle, starting loads can be dirty(brass after firing as necks may not seal) and primers may move out and flatten if you are not careful with headspace/sizing.

 

[D-4297]

In order to avoid the pitfalls of this issue , and as someone else said , loading manuals are created for the purpose of giving direction to reloaders . The minimums ; and Maximums are established by those companies through testing , and generally approved by their Legal Weenies , to avoid lawsuits . I develop my initial .308 TR loads by "finding" the 70 - 75% of Max figure , and starting there . Carefully adding powder to reach a desired "Node" , or velocity window . And as always ; considering that TR shooters ALWAYS load longer than SAAMI specs , in order to reduce chamber pressure . Minimums are just that . A starting point .

 

[JASmith]

D-4297: Good advice!

 

[Laurie]

For many years Hodgdon didn't publish starting loads, only maximum values with the injunction to start at 6% below that figure, H110 aside where this was reduced to 2%. Some of today's starting load values are well over 20% below max, guaranteed to give inefficient results, sooted cases and actions, and if work up is done carefully from those levels take forever and use a good chunk of barrel life up.

I just noticed a new 'requirement' the other day in the general loading advice in Lyman's new Long Range Precision Reloading Handbook. As well as always starting at the published starting load, never exceeding maximum etc, an instruction has been added to "develop the load slowly, carefully, firing at least ten shots at each incremental propellant charge weight". If one takes Sierra's excellent advice to use 1% of the max load for increment size, that could see 10-12 steps in the process - each of 10 rounds. Got to hope your first powder choice works for you!

 

[spinconn]

Thank you for all the help. I would like to add some info. I recently blew up a new S&W640 shooting a minimum charge. As I do not have the cartridge left to examine I am assuming I must have had a double charge, despite my being a very cautious reloader. I always try to stay within the manual limits and not experiment. In my 70's now, I reload low charge loads for minimum recoil, especially considering most of my shooting is with small, light snub nose revolvers.

I can live with the possibility that I erred by mistakenly putting in a double charge, but I do not have proof that this was the case. The only other possibility is a charge too low. I weigh each and every load and check each case with a flashlight. This might tell me if I had a double load, but it would not tell me if I had too light a load. I have never understood how a load too light could detonate, like a load too high, but I do understand it can cause a squib, hence my original question used a squib as an example, but I have read of low loads causing detonation. My original question was really to determine if I need to take the extra precaution of starting my loads somewhere in the middle rather than at the lowest end.

Because of the Kaboom I went back and checked all my existing handloads and the logbook entries for them. I have found one error I cannot explain. I have a box of 38 special rounds with Starline brass fired once before, CCI500 primers, 1.445 OAL, 140gr Missouri Bullet Co SWC Plated bullets and 3.3 grains of HP38. I cannot find this load in any of my manuals. The lowest charge I can find is 3.7gr HP38 for a 135gr Cast bullet (lighter bullet), 3.5gr HP38 for a 148gr LHBWC (heavier bullet) and 3.9gr 231 for a 140gr JHP (different shape and jacketed bullet).

I do use loads I find online with manufacturer data, such as Hogdon's reloading center data but now I cannot find that load of 3.3gr of HP38. It is not like me to make up a load of my own, so two questions:
1. Is it likely that a 3.3gr load would be so low as to detonate and destroy a revolver?
2. Is anyone aware of a published load this low, and if so, who published it?

Sorry for the length of this but I didn't know how to explain it with brevity.

 

[6ShotsOr5?]

For many years Hodgdon didn't publish starting loads, only maximum values with the injunction to start at 6% below that figure, H110 aside where this was reduced to 2%. Some of today's starting load values are well over 20% below max, guaranteed to give inefficient results, sooted cases and actions, and if work up is done carefully from those levels take forever and use a good chunk of barrel life up.

I just noticed a new 'requirement' the other day in the general loading advice in Lyman's new Long Range Precision Reloading Handbook. As well as always starting at the published starting load, never exceeding maximum etc, an instruction has been added to "develop the load slowly, carefully, firing at least ten shots at each incremental propellant charge weight". If one takes Sierra's excellent advice to use 1% of the max load for increment size, that could see 10-12 steps in the process - each of 10 rounds. Got to hope your first powder choice works for you!

Great advice from component sellers, . Always consider the source.

 

[Jager]

A couple things...

First, sorry to hear about the S&W 640. I know that had to be a scary experience. And not knowing what caused it understandably brings its own anxiety.

Your kaboom was not a squib. It was either a double charge or secondary detonation. Secondary detonation is a rare, odd effect related to very light charges with very slow powders. Think H110/W296 in handguns or IMR-4831 in rifles.

Fast handgun powders such as Bullseye have historically been used for very light loads. They are quite safe in that application.

I don't have any experience with HP-38. I wouldn't think it was slow enough to worry about secondary detonation. But I could be wrong. I've used a lot of W231 - which has a similar burn rate to HP-38 - for many mid-range loads. For truly light loads like what you're doing I have always used a faster powder.

A double-charge is the likeliest explanation for your unfortunate incident. It is the singular risk that comes with using such tiny amounts of powder.

The Starting Loads published in reputable load manuals are as safe as anything in handloading ever can be. All the labs producing those manuals are familiar with secondary detonation and will not have a starting charge anywhere close to where they have observed that phenomenon.

Best of luck...

 

[spinconn]

Thank you Jager, that answers all my questions clearly and completely. I appreciate it.

 

[divingin]

Because of the Kaboom I went back and checked all my existing handloads and the logbook entries for them. I have found one error I cannot explain. I have a box of 38 special rounds with Starline brass fired once before, CCI500 primers, 1.445 OAL, 140gr Missouri Bullet Co SWC Plated bullets and 3.3 grains of HP38. I cannot find this load in any of my manuals. The lowest charge I can find is 3.7gr HP38 for a 135gr Cast bullet (lighter bullet), 3.5gr HP38 for a 148gr LHBWC (heavier bullet) and 3.9gr 231 for a 140gr JHP (different shape and jacketed bullet).

I do use loads I find online with manufacturer data, such as Hogdon's reloading center data but now I cannot find that load of 3.3gr of HP38. It is not like me to make up a load of my own, so two questions:
1. Is it likely that a 3.3gr load would be so low as to detonate and destroy a revolver?
2. Is anyone aware of a published load this low, and if so, who published it?

I haven't loaded 231/HP38 in decades, but routinely shot 148HBWCs in a S&W Model 52 over 2.4 to 2.7 grains of WW452AA, and more recently about 2.5 Titegroup (these typically shoot in the 600fps range.)

As far as I'm aware, with just about any fast pistol powder, you can drop the charge to the point that the bullet won't make it out of the barrel, and still not get any kind of detonation. The powder ignites too quickly to get the kind of delayed combustion that causes the catastrophic failures that a light charge in a rifle can cause.

I recently moved to WST from Titegroup, and worked up loads for 32SWL, 38Spl, and 45ACP by choosing a random light charge and increasing in steps to get action cycling, close to a velocity of 700fps, and without excessive recoil impulse. By "light charge", I mean a charge that wouldn't eject the case in an auto.

Bottom line: I kind of doubt it was the low charge that caused you problems.

 

[NorCalMikie]

Starting load is??
Max load is??
Me? I start mid way between start and max and adjust from there.

 

[miningshawn]

This one falls pretty close to home for me - but a different set of circumstances. I am creating a wildcat and starting from scratch, no load data at all. Knowing a couple of basic engineering principles (F=MA, PV=nRT, Boyle's Law, and others) I looked at cartridges that are very close in case volume - in both directions - and calculated a "window" of probable charges.

I also had to account for parent case SAAMI pressure, mine being significantly higher.

In all cases- reloading books, manufacturer's websites for powder and bullets, and other people's experience (internet) are invaluable.

The toughest part is determining the lower\lowest safe charge. It's easy to find high pressure - not nearly as easy to find the low end safely.

 

[Rsadams]

I save components by starting in the middle. You can “assume” that starting loads are safe. The companies producing the manuals have TEAMS of lawyers yelling at them!

+1...

 

[Laurie]

The issue of how most pistol powders burn is a very interesting one. As @Jager and @divingin say, it's impossible to go too low with the very fast burning flake or rolled / flattened ball types - as long as there's enough pressure to ensure every bullet exits the barrel. Some magnum revolver types, especially H110, need full or near full pressures to perform consistently, but the old classic Hercules / Alliant grades not so.

There is a hypothesis somewhere on this site

http://www.gmdr.com/lever/lowveldata.htm

about how these powders burn, that's worth considering. This site covers use of small charges of such powders in much larger capacity rifle cases including 444 Marlin and 45-70.

Over-pressures in pistol loads are nearly always regarded by investigators as a being the result of an inadvertent double charge, but it has to be speculation given the absence of evidence usually (unless the next round in the ammo box lacks a charge). Nevertheless, I've read many times that it was the frequency of blow-ups from double or even triple charges of the powder-puff loads used in CAS that was the spur for the development of Trail Boss making this event impossible.

There is another cause that has featured in some blow-ups on our (UK) side of the Atlantic in recent years - failure to completely empty the powder measure after the previous session, so the first 'throw' in the next one gets a load of what was being previously loaded. But that's nearly always a rifle issue where the handloader switches from pistol to rifle powders between sessions, or from a very fast burning rifle grade to a medium or slow burner.

 

[D-4297]

I can attest to what Laurie said . I was teaching my Lady-friend to load for her Glock 17 , 9mm Comp gun , with a Compensated barrel . Loading for 115gr THP , using Alliant Red Dot . When she had it going good , I watched , and she loaded . When finished , I showed her how to clear the measure , dump the Trickler , and clean everything up , as I always do . Good to go , Right ?.....Wrong ! The next morning I set up to load 4064 for my .308 , and everything was good . Right up to the third load , where I found little tiny RED dots in the pan . The "sticky" Red Dot was clinging inside the cavity of the measure , so I got to dis-mount the measure , dump the 4064 , and dis-assemble and clean the measure completely . Lesson learned , to be much more careful in the future .

 

[danny]

In order to avoid the pitfalls of this issue , and as someone else said , loading manuals are created for the purpose of giving direction to reloaders . The minimums ; and Maximums are established by those companies through testing , and generally approved by their Legal Weenies , to avoid lawsuits . I develop my initial .308 TR loads by "finding" the 70 - 75% of Max figure , and starting there . Carefully adding powder to reach a desired "Node" , or velocity window . And as always ; considering that TR shooters ALWAYS load longer than SAAMI specs , in order to reduce chamber pressure . Minimums are just that . A starting point .

Maybe you'd be better off by getting rid of the "BS" established by the "Legal Weenies" and start right at their maximum load, saving a lot of time.

Danny