I'm looking at some data here before me talking about 7mm bullets. Now I'm curious, how does a 139 grain jacketed bullet warrent different powders and charges then a 140 grain jacketed bullet? I think I must be missing somthing here. 
One grain difference ?!?
- Thread starter pharaoh2
- Start date
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the amount of surface contact, bullet design, not unlike Barnes x etc
A 140gr sp will be shorter than a 139gr hpbt, seating both of them to the same COAL results in less case capacity with the hpbt, thus requiring different charges. Jacket hardness also varies from manufacturers, same result, different loads.
pharaoh2, pm me, I have been reloading for 30yrs and would be happy to drop by and share my experience with you if you like.
In a box of 100 bullets, the heaviest one could be one grain heavier than the lightest.
I would disregard any difference in loading them.
It is only in the last thirty years, or so, that loading books distinguished between different bullets. Before that, it was all by bullet weight, only. And for practical purposes, a 139 bullet weight is a 140 grain.
I would disregard any difference in loading them.
It is only in the last thirty years, or so, that loading books distinguished between different bullets. Before that, it was all by bullet weight, only. And for practical purposes, a 139 bullet weight is a 140 grain.
H4831, I agree, 1 gr difference in bullets out of the same box is no big deal. I do not reccomend using the same data for a round nose 180gr and a 180 gr VLD, effective case capacity will be different and affect pressure accordingly IMO. Not trying to ruffle anyones feathers, just promoting safe reloading practices.
For others reading this thread, and as mentioned above. The references apply to rifle bullets and generally to bullets of approximately the same length.
If you are talking about small volume handgun cartridges or short, non-bottlenecked cartridges, the length of the bullet can vary between designs, even if they are the same weight. Seating them to the same OAL can affect pressure.
If you load to max pressure and minimum OAL, it can make a difference. IE, a longer bullet seated to the same OAL, compared to a shorter bullet of the same weight, will decrease volume inside the case, and WILL increase pressure.
If you are talking about small volume handgun cartridges or short, non-bottlenecked cartridges, the length of the bullet can vary between designs, even if they are the same weight. Seating them to the same OAL can affect pressure.
If you load to max pressure and minimum OAL, it can make a difference. IE, a longer bullet seated to the same OAL, compared to a shorter bullet of the same weight, will decrease volume inside the case, and WILL increase pressure.
I guess when you start out reloading on this kind of loading charts and get used to using such information, you don't get too excited about a slight change in bullet design.
Notice there were just four headings; charge, powder, bullet and velocity.
The bullet was given by weight only. Also, no overall lengths. You seated the bullet to give about the right appearance, as long as the bolt would close, and for repeat firing, if it would cycle through the magazine.
The "charge," the powder weight, was what was deemed would bring the pressure up to SAAMI standards, in the average rifle.
In later loading books this term "charge," was changed to, "maximun." The word maximun has a somewhat sinister sound and it, along with other word additions and changes, changed the attitude of reloaders, forever.
That word "maximun," means exactly the same as the word "charge" once meant. It means the amount of powder deemed to raise the pressure to SAAMI standards. Nothing more.
And by the way, those SAAMI standards we're talking about is the same, that is the same pressures, as loaded in the factory loads for that cartridge. Thus, the powder charge given as a "maximum" load, will be the same as a factory loaded cartridge.
See what I mean about the word maximum being looked on as something sinister. I have yet to hear of a shooter that is afraid to shoot factory loads in his rifle, yet every newer handloader thinks it is a stupid idea to just load the "maximum," load given in the book for his rifle and shoot it. In reality that load will be the same pressure as loaded in factory loads.
Sorry for the long rant, but just think about it.
Notice there were just four headings; charge, powder, bullet and velocity.
The bullet was given by weight only. Also, no overall lengths. You seated the bullet to give about the right appearance, as long as the bolt would close, and for repeat firing, if it would cycle through the magazine.
The "charge," the powder weight, was what was deemed would bring the pressure up to SAAMI standards, in the average rifle.
In later loading books this term "charge," was changed to, "maximun." The word maximun has a somewhat sinister sound and it, along with other word additions and changes, changed the attitude of reloaders, forever.
That word "maximun," means exactly the same as the word "charge" once meant. It means the amount of powder deemed to raise the pressure to SAAMI standards. Nothing more.
And by the way, those SAAMI standards we're talking about is the same, that is the same pressures, as loaded in the factory loads for that cartridge. Thus, the powder charge given as a "maximum" load, will be the same as a factory loaded cartridge.
See what I mean about the word maximum being looked on as something sinister. I have yet to hear of a shooter that is afraid to shoot factory loads in his rifle, yet every newer handloader thinks it is a stupid idea to just load the "maximum," load given in the book for his rifle and shoot it. In reality that load will be the same pressure as loaded in factory loads.
Sorry for the long rant, but just think about it.
Thanks all. I'm planning on using the 139 data for 140 grain bullets. The data reads just that, 139 grain jacketed and 140 grain jacketed. I never paid attention to that before and just thought was was stupid that they would list different powders and different charges for the same bullets and if anybody else noticed anything like that.
Which 7mm cartridge? My Lyman book only gives 139 grain data for the 7mm Mauser, .280 Rem and .284 Win, but 140 grain data only for 7mm Mag. Velocity isn't about the bullet diameter. It's about the cartridge. Bullet construction matters for a 7mm Mag. Not as much for one of the others.
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They are all .284 some bullet makers i.e hornady do 139 others i.e nosler do 140
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- Daysland AB
umm yea ok then ?
I don't know about one grain but in my 7mm mag 5 grains makes a ton of difference. When I was trying differnet loads and bullets I could not load the speer 145 grain bullet no matter what I did or used. However, load any 140 grain or 150 grain bullet ( sierra, nosler...etc) was easy and now I either use the 150 scirocco or the 140 grain accubond, both of which work excellent.
Pudelpointer
CGN frequent flyer
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Most cup-and-core style bullets should be able to utilize load data for other manufacturers. If, as earlier stated, you are changing the profile drastically - say round nosed flat point to VLD in the same weight, it would probably be smart to find some data for the bullet you are changing to. If you are going to change bullet construction, say from cup&core to something like a failsafe, tsx, xp3, solid or something with a steel insert, you should definitely find appropriate data for that specific bullet.
Just my opinion.
Just my opinion.
