Starting loads...useless?

[Oly]

Just wondering if anyone has ever found that their rifle shoots best within a grain of the powder manufacturers suggested starting load?

[One on top of two]

Yes and a lot of the time just over ,

but your missing the point . 

Only a tool doesn’t work there loads up . 

Start low and work up , 

👍👍😁

[Laurie]

There are starting loads and starting loads depending on the source. A generation ago, Hodgdon only gave maximum charges with the instruction to subtract 6% to get a starting load, an exception being H110 where only 3% should be deducted. Over many years, I've concluded Hodgdon got that pretty well right so a 46gn maximum 308 Win load should start around 43.2gn and a 24.5gn 223 max would be ~23.0gn.

This approach was apparently too technically demanding for some customers and/or the lawyers didn't like it, so Hodgdon now quotes staring loads in grains like everbody else. Taking some of its 168gn 308 Win loads at random its current starting loads run from 5 to 9% below the stated maximum depe3nding on the powder grade.

Look at Hornady's manuals though and you get a very different approach. The lowest loads quoted are much more than a 10% reduction. Its 7th edition (sticking with 308 and 168gn bullets) lists H. Varget from 32.6gn to 44.0gn - a difference of around 23% which I find ludicrous. Apart from taking forever and wasting a lot of barrel life in working a load up by 11.4gn, the lowest charges will be grossly inefficient and most likely inconsistent as they are running at well below the powder's 'happy' pressure band.

Other manufacturers / sources quote ranges anything in between these extremes.

The original Hodgdon advice remains pretty valid. Unless the bullet or powder manufacturer says otherwise in relation to a particular cartridge-powder combination, something in the 6-10% band below maximum is usually a suitable reduction. There are exceptions either because the powder is very low-pressure intolerant and/or it is a high volume case design as in many over bore capacity magnums being loaded with very slow burning propellants. In such cases the quoted starting charge is also the minimum charge and must not be reduced further. Doing so risks very inconsistent results and in extreme cases a dangerous one that sees charge detonation instead of burn and pressures that will destroy the firearm.

Sierra Bullets whose people know more about safe load development than most say that charges should be worked up in step sizes that are c.1% of the quoted maximum, so 0.4-0.5gn for max loads of say 46-49gn, 0.2-0.3gn for 223 Rem size charges. On approaching maximum loads, reduce that further to say 0.2-0.3gn for 308 Win size charges, 0.2gn for 223 size.

On precision, traditionally it was said that maximum loads / pressures rarely or never gave the best groups and this has become a handloading 'rule'. This was largely down to the poor quality of most mass manufactured rifles after WW2 where locking lugs didn't bear evenly on the receiver, or in many twin lug Mauser type actions, one lug didn't touch the receiver at all until pressures approached maximum, then it would touch randomly producing fliers. This condition shouldn't apply to modern factory rifles hopefully and certainly not at all to custom stuff built on small production volume actions. Often such rifles group very well indeed somewhere near maximum loads and MV extreme spreads are generally smaller with higher charges. However, any individual rifle's best precision occurs in a series of charge / pressure / MV 'nodes' or bands as charge weights rise, usually 1-1.5gn apart in a 308 size cartridge / charge weight. So a starting load may or may not be right on a 'node' and could give superb groups. As charges rise, groups open up until the next node appears. Often the very highest allowable charges / pressures fall between nodes, so a lower charge weight gives best results. That's what on-range load development is about / for - ie finding precision and small MV spreads at an optimum velocity for the firearm and the application.

As One on Top of Two says, the reason for quoting starting charges and working loads up from them is primarily about safety as individual barrels / chambers and cartridge component choice other than the powder can see considerable pressure and hence usable / safe maximum charge variation between individual rifles. Only a fool starts with the maximum - but there are fools out there sadly.

[Popsbengo]

9 hours ago, Laurie said:

..... any individual rifle's best precision occurs in a series of charge / pressure / MV 'nodes' or bands as charge weights rise, usually 1-1.5gn apart in a 308 size cartridge / charge weight. So a starting load may or may not be right on a 'node' and could give superb groups. As charges rise, groups open up until the next node appears. Often the very highest allowable charges / pressures fall between nodes, so a lower charge weight gives best results. That's what on-range load development is about / for - ie finding precision and small MV spreads at an optimum velocity for the firearm and the application.

I found this with my .308 working up N140 and Lapua 155gn and it was very noticeable.  I almost stopped close to my starting load as it was so good at 100m (but poor velocity).  The groups got worse as load increased but thankfully came back on at 1.0gn under "max" with good MV.  (I would note here that I saw no evidence of the so-called plateaux effect discussed elsewhere).

I'm pretty sure the corporate lawyers will insist on uber safe starting loads suitable for complete numpties with poor equipment.  I know what I do, and it's very similar to Lauries' excellent advice  but it's not for me to recommend 🤔

[VarmLR]

The best loads for most of my rifles are somewhere not far-off 3/4 the way between (recommended) starting and max loads.  To save load development time and budget, I usually start 5 to 6% under max and use OCW to get to the nodes quickly.   I'll often have two good nodes within that band.  This seems to work for me irrespective of the calibre and it's probably no small coincidence that some of these loads tally fairly well with recommended accuracy loads.

I have loads for 223 and 308 which are almost smack on what Sierra recommend as their accuracy choices using the same powders/bullets.  I've generally found their recommendations to be reliable.

As Laurie says, it's rarely worth starting at min, partly for economy but also because obturation is sometimes not properly achieved as witnessed by the carbon fouling of the brass beyond the neck area for some chamber/brass combos, which differs from rifle to rifle of the same make and calibre.  No-one in their right mind would start at max, but there's a few about who will take that risk, somewhat bizarrely. They are possible candidates for the Darwin awards. 

I recall a story (haven't many of us?) where an elderly farmer, now long since gone, used the same powder for years with his .308 which he used for deer control.  When asked what loads he used, he shrugged and said that he filled it up to the base of the neck and smacked the bullet home (I think using a Lee Load All).  Whilst this seems like madness, truth is that with some powders and 150 to 155grn bullets, you're probably pretty safe with .308 but it's not to be recommended!!!  

 

[Oly]

On 3/22/2019 at 12:12 AM, Laurie said:

There are starting loads and starting loads depending on the source. A generation ago, Hodgdon only gave maximum charges with the instruction to subtract 6% to get a starting load, an exception being H110 where only 3% should be deducted. Over many years, I've concluded Hodgdon got that pretty well right so a 46gn maximum 308 Win load should start around 43.2gn and a 24.5gn 223 max would be ~23.0gn.

Interesting, many thanks. 

I'm reloading 308 with RS50, Reload Swiss recommend starting load of 39.0gns and maximum of 46.0gns for 168gn bullets...hence the question as it seemed quite a large range. At 6% reduction from max load that would only be 43.2gn.  However, they are now loaded in half grain increments from 39.0gn, but it'll be interesting to see how they fair. 

To my knowledge none of the reloading manuals cover Reload Swiss do they?