Home
Posted By: ChaseA1 Is my Load to hot??? - 12/18/20
I am using a 140 grain Sierra game king in a 7 mm Remington Magnum CCI 250 magnum primer and federal Brass My only concern is I am thinking about using 67 grains of IMR 4831 that is one grain over max give or take than what most manuals say But what I was thinking is I have not set my bullet as deep as I once was. I was setting my bullet to the depth that the Sierra manual said to set it at but I have checked where the bullet touches the lands of the rifling and I have found that I was jumping it Just over a tenth of an inch So now I am wanting to jump it 20 thousandths of an inch so I would have more capacity in the case now so I figured it would equal less pressure so I was thinking about trying one grain more of powder than what the load data says. Is this dangerous? Give me your thoughts? Thanks
Posted By: mathman Re: Is my Load to hot??? - 12/18/20
Putting the bullet closer to the lands will raise pressure.
Posted By: 300Winnie Re: Is my Load to hot??? - 12/18/20
^^^^This
Posted By: ChaseA1 Re: Is my Load to hot??? - 12/18/20
OK I thought this was true mostly with harder bullets like solid copper bullets or sirocco/A-frame?
Posted By: 300Winnie Re: Is my Load to hot??? - 12/18/20
True with all bullets.
Posted By: ChaseA1 Re: Is my Load to hot??? - 12/18/20
OK I’ll agree with you But I thought the more case capacity the less the pressure and the less the case capacity with the same powder charge & bullet weight caused more pressure
Posted By: DigitalDan Re: Is my Load to hot??? - 12/18/20
Internal ballistics is a fair bit more complicated than that.
Posted By: ChaseA1 Re: Is my Load to hot??? - 12/18/20
Yes Your right but I’m just wondering if it’s going to explode on me?
Posted By: Seafire Re: Is my Load to hot??? - 12/18/20
Originally Posted by ChaseA1
Yes Your right but I’m just wondering if it’s going to explode on me?


With one grain over present day "MAX"....

Check and older manual and I'm sure it is higher than they are publishing nowadays....

and there is no real records of massive deaths....

Trust common sense, unless ya don't have it, over what some lawyer approved manual is telling you to do...
They are a reference, not a Bible...
Posted By: Vic_in_Va Re: Is my Load to hot??? - 12/18/20
[Linked Image from live.staticflickr.com]
Posted By: Blacktailer Re: Is my Load to hot??? - 12/18/20
What does your chronograph say? If you don't have one, stick to what the manuals say. And why do you want one more grain of powder anyway? If you don't have enough velocity, buy a RUM.
Posted By: JGRaider Re: Is my Load to hot??? - 12/18/20
Originally Posted by ChaseA1
Yes Your right but I’m just wondering if it’s going to explode on me?


One good reason to use a chronograph.
Posted By: HuntnShoot Re: Is my Load to hot??? - 12/18/20
The SAAMI pressure spec for the 7mmRM isn't near the top of "safe" pressures in modern bolt guns. As others have said, seating the bullet closer to the lands will boost pressures more. You could even back off further, and reduce pressure a bit more. Eventually, the pressure curve goes the other way as you decrease case capacity.

You are likely nowhere near dangerous territory, but I have to ask: what do you hope to gain by running even more powder? Sierra 140 Game Kings aren't very stout bullets, and thus don't benefit from more velocity. You'd be better off to slow them down than to speed them up. Or, if what you've got so far shoots well, don't mess with it.
Posted By: Dude270 Re: Is my Load to hot??? - 12/18/20
As stated above, getting closer to the lands increases pressure.

You also didn't move the bullet out of the case enough to change capacity in any meaningful way.

If the loads you had before shot well I would leave well enough alone.

Also, If you want to tinker with your loads, a chronograph is your best friend
Posted By: Bugger Re: Is my Load to hot??? - 12/18/20
Loads from the manuals have changed over the years and I wonder if the early manuals were pressure tested, if they were, they were tested by copper crushing method.

My Sierra #1 manual suggests 67.5 gr 4831 is max (H4831, I'm sure.)

My Hornady #7 manual says 65 grans of H4831 is max

Ken Waters in January 1981 said 68 grains of H4831 was a "good all-around" load for the 7mm RM with 140 grain Nosler Partition and 65 gr IMR4831 was max

Lyman manual #45 & #46 says 67.5 gr 4831 (H4831) is max

Nosler manual #2 & #7 says 66 grains of IMR 4831 is maximum

Speer manual #11 says 63 gr of 4831 (H4831) for their 145 grain bullet is max

Hodgdon manual #23 says 64 grains of 4831 (H4831) is max behind 140 gr bullet

If I were to find the max in my rifle, I'd run a few rounds past my chronograph. I think I'd stop at 3,100 fps unless there were pressure signs with less powder. I shoot 7mm RM's and in my notes, I either used RE 22 and RE 26 . I didn't find a record in my 7mm RM's of either 4831's, which is odd because I like both powders.
Posted By: FWP Re: Is my Load to hot??? - 12/18/20
I would forget about playing with "max" loads and strive for the most accurate load.
Originally Posted by ChaseA1
Yes Your right but I’m just wondering if it’s going to explode on me?

Anyone who works up loads properly and doesn't just dump powder into the case should never have to worry about that.
Originally Posted by ChaseA1
OK I’ll agree with you But I thought the more case capacity the less the pressure and the less the case capacity with the same powder charge & bullet weight caused more pressure


As it applies to cases as the variable, it's true.

Historically, on average in hunting rifles chamberings, Winchester brass was thinner then Remington. So in an .06 sized cartridge you could stuff in another grain of powder with equal pressure signs and a bit more velocity. So it's a good rule of thumb as it applies to the case itself, but as previously mentioned, when you introduce additional variable it can get more complicated.
Originally Posted by Bugger
Loads from the manuals have changed over the years and I wonder if the early manuals were pressure tested, if they were, they were tested by copper crushing method.

My Sierra #1 manual suggests 67.5 gr 4831 is max (H4831, I'm sure.)

My Hornady #7 manual says 65 grans of H4831 is max

Ken Waters in January 1981 said 68 grains of H4831 was a "good all-around" load for the 7mm RM with 140 grain Nosler Partition and 65 gr IMR4831 was max

Lyman manual #45 & #46 says 67.5 gr 4831 (H4831) is max

Nosler manual #2 & #7 says 66 grains of IMR 4831 is maximum

Speer manual #11 says 63 gr of 4831 (H4831) for their 145 grain bullet is max

Hodgdon manual #23 says 64 grains of 4831 (H4831) is max behind 140 gr bullet

If I were to find the max in my rifle, I'd run a few rounds past my chronograph. I think I'd stop at 3,100 fps unless there were pressure signs with less powder. I shoot 7mm RM's and in my notes, I either used RE 22 and RE 26 . I didn't find a record in my 7mm RM's of either 4831's, which is odd because I like both powders.



Sierra, Hornady, Nosler, and Spear bullets, all with different bearing surfaces. Weight is only one bullet specific variable.
Posted By: smokepole Re: Is my Load to hot??? - 12/19/20
Originally Posted by JGRaider
Originally Posted by ChaseA1
Yes Your right but I’m just wondering if it’s going to explode on me?


One good reason to use a chronograph.


Yep. For some rifle/brass combos, one grain above max is no big deal, for others it is.

Velocity = pressure.
Posted By: longbarrel Re: Is my Load to hot??? - 12/19/20
Other than direct pressure measurements via psi or cup. probably the most accurate (potentially) was Ken Waters' method of measuring the "pressure ring" just ahead of the solid part of the case head, to 0.0001" I suggest that you do this for your lot of brass in your gun's chamber to see what is the case expansion for "normal" pressures and if you go beyond, noted by how much the pressure ring expands. If you go too far, you get signs of excess pressure--primer pocket looseness, brass flow into the ejector cut, stiffer extraction, etc. If you take pressures far enough to get any of those signs, you are on your own and can get a facefull of gas or worse, especially at higher ambient temperatures, etc. Some of us explored the outer limits when young, and some of Ackley's recommendations treaded on that territory, especially to get more velocity from his "improved" cartridge cases. As we got older and more conservative, most of us stay a bit undeer the loading manuals' max recommendastions for a particular powder and projectile.
Originally Posted by longbarrel
Other than direct pressure measurements via psi or cup. probably the most accurate (potentially) was Ken Waters' method of measuring the "pressure ring" just ahead of the solid part of the case head, to 0.0001" I suggest that you do this for your lot of brass in your gun's chamber to see what is the case expansion for "normal" pressures and if you go beyond, noted by how much the pressure ring expands. If you go too far, you get signs of excess pressure--primer pocket looseness, brass flow into the ejector cut, stiffer extraction, etc. If you take pressures far enough to get any of those signs, you are on your own and can get a facefull of gas or worse, especially at higher ambient temperatures, etc. Some of us explored the outer limits when young, and some of Ackley's recommendations treaded on that territory, especially to get more velocity from his "improved" cartridge cases. As we got older and more conservative, most of us stay a bit undeer the loading manuals' max recommendastions for a particular powder and projectile.


This old wives tales been disproven.
© 24hourcampfire