No room for error?

[Mgderf]

Perusing the Hodgdon load data web-site for .300 Blackout data I found several entries that do not list any start data, only maximum loads.
Are these no room for error loads?

 

[SSGSAD]

I am going to guess, depends on the powder .....

can you link, or post the data ?????

 

[O'Shark]

Alliant's load data tends to be like that on several calibers. I believe their site says to reduce by 10% for starting loads.

 

[Mgderf]

I am going to guess, depends on the powder .....

can you link, or post the data ?????

My I.T. skills are all but non-existent.
That said, I picked the .300AAC data for a 208gr projectile and came up with the following,
Powder Projectile C.O.L. Start Max
IMR4198 .308" 2.260" 11grs
H4198 .308" 2.260" 11.2grs
IMR4227 .308 2.260" 10.3grs
W296 .308" 2.260" 9.4grs
H110 .308" 2.260" 9.4grs
Lil' Gun .308 2.260" 8.3grs

Well the site smooshed everything together.
Suffice it to say there are no numbers for start data, only max loads.

 

[SSGSAD]

My I.T. skills are all but non-existent.
That said, I picked the .300AAC data for a 208gr projectile and came up with the following,
Powder Projectile C.O.L. Start Max
IMR4198 .308" 2.260" 11grs
H4198 .308" 2.260" 11.2grs
IMR4227 .308 2.260" 10.3grs
W296 .308" 2.260" 9.4grs
H110 .308" 2.260" 9.4grs
Lil' Gun .308 2.260" 8.3grs

Well the site smooshed everything together.
Suffice it to say there are no numbers for start data, only max loads.

JMHO, the ONLY 2 powders that CANNOT be reduced, is W296 & H110,

the others, reduce by 10% and work up looking for pressure signs .....

 

[Yeah]

What sources of error do you anticipate?

 

[SSGSAD]

What sources of error do you anticipate?

Some powders, have very little "wiggle" room .....

Say one powder lists a load from 5.2 gr. - 7.5 gr., and any load in between is "safe" .....

Another powder may list a load from 5.2 - 5.5 gr., so less "wiggle" room .....

 

[Yeah]

Some powders, have very little "wiggle" room .....

You don't say?

I've no experience with wiggly powders. What characteristics determine this wiggle room? How does one extrapolate it from listed maximums?

 

[Mgderf]

You don't say?

I've no experience with wiggly powders. What characteristics determine this wiggle room? How does one extrapolate it from listed maximums?

Precisely my questions. I'm new to reloading. I don't like to vary from listed data, and I've not yet loaded anything to full max loads.
When I run across data listed as max, with no starting data, I get a little nervous.

 

[midget]

Someone would have to look it up in QuickLoad or a reference manual, but I'm willing to bet that the h110 range maybe around 1gr. You have to be very careful with that one as you will have major pressure issues if you undercut the load.

 

[Broom_jm]

Smart reloaders never rely on just a single source of data. If you choose other bullet weights, from the same website, you get a range of charge weights. With this data, and others, you can begin to reasonably extract starting charges from the MAX charges shown for the 208gr bullet.

H4895 has all kinds of "wiggle" room; any published rifle load can be reduced a full 40% from the MAX charge to create reduced recoil loads.

H110 and W296 are the same powder, placed in different cans. When two different charge weights are listed from them, it is a result of different lot numbers of powder, which brings me to my final point.

ALL LOAD DATA is presented as a guideline or starting point. In the past, it was very common for load books to show only the MAX charge. It was left to the reloader to know what to do with that data, even with powders like H110/W296 that should not be reduced past the minimum charge weight. For most bottle-necked rifle loads, it is understood by knowledgeable reloaders that you can reduce a MAX charge by around 10%, provided it's a suitable powder for that cartridge. For pistol loads, 5% is usually more the norm.

Looking at the other H110/W296 data for the 300AAC on the Hodgdon website, it is evident that a 7% reduction from MAX will get you to a starting charge. This actually makes sense, since this cartridge is somewhere in-between a rifle and pistol cartridge. Further effort with a calculator and other MIN/MAX charge numbers (for different weight bullets) reveals that 8% of MAX is frequently given as the MIN charge weight.

Bottom line: Some things in life, reloading absolutely being one of them, require an ability to read, understand and actually assimilate information. Be safe! KNOW what you're doing. Part of that is knowing how to extrapolate, within an observed percentage range for each powder. If that skill set is not one you possess, you might consider reloading for more common cartridges, if at all.

 

[Woobie]

You're also being given a load that is intended to be sub-sonic. There really isn't any reason to go up into supersonic, so they don't list it, even though it may well be safe. I would just shoot the published load. Chronograph it or listen to see if it is subsonic. Then check your accuracy. If it's good enough for you, then great. If you are supersonic, (and I'm kind of assuming you have a 8-10" barrel) then you may be able to reduce your charge by .8 grains or so, as broom_jm implied. Just remember, if you reduce it past a certain point on certain powders, you'll be supersonic again, and that is definitely not good. If you don't like reducing the load, or it is t working, you can always switch powders, so don't get married to one until you've tested it.

 

[bstewrat3]

Another caution when working at the subsonic level is avoiding sticking a bullet in the bore. Some of the loads are fine in the 8"-16" barrel lengths, but when you get to 20"-24" you risk sticking some of the longer match bullets. JD Jones actually recommends starting high and working down for subsonic loads in his 300 Whisper when used in rifles.