The online data for the 7mm Rem mag has become quite conservative
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"Softening" the loads for the 7mm Rem Mag has been a trend over a number of years now.
I read somewhere that it was because older chamber dimensions were a bit more generous, [and varied] and now that standards are tighter, some of the old loads are "hot" in newer offerings.
Don't know how much truth in that, but I use a 'graph to establish loads, watching carefully for pressure signs that may indicate a load too warm for use.
I expect about 3050 with a 160 grain Partition in a 24" barrel, and using the right powders, that is usually achieved safely.
Regards, Dave.
I read somewhere that it was because older chamber dimensions were a bit more generous, [and varied] and now that standards are tighter, some of the old loads are "hot" in newer offerings.
Don't know how much truth in that, but I use a 'graph to establish loads, watching carefully for pressure signs that may indicate a load too warm for use.
I expect about 3050 with a 160 grain Partition in a 24" barrel, and using the right powders, that is usually achieved safely.
Regards, Dave.
So when are these "pressure spikes" supposedly apparent, and with which powders/bullets? Why would the 7mm Mag be specifically prone to such?
I've been loading the 7mm Rem Mag almost since it's inception, in at least 10 different rifles so chambered, and with most suitable powders available then to now.
Add to that the bullets from 115 grains right up to the Barnes original 180 grainer.
I have chronographed several hundred 7mm Mag loads during that time.
Never experienced any of these so-called pressure spikes, even with stout loads of slow burners.
Now I'm not saying they do not happen, because practically any chambering can give such under unique circumstances.
However, I would conjecture that said "pressure spikes" are more powder specific than chambering specific. [Old Hodgdon's H205, for example]
One trend I have noticed is that of tighter chambers/throats in newer rifle models [even in North America] This would require that loads be backed off somewhat to keep things safe.
Regards, Dave.
Shamelessy quoted from the Speer #14 manual. (page 400)
"There is quite a variation in published loading data for this caliber. Differences betweencases, primers, and bullets all have an effect. This emphasizes our constant caution to always reduce loads whenever changing components from those used to develop the data.
Seldom will either handloads or factory ammo match nominal factory ballistics in a sporting rifle and there is a great deal of velocity variation amoung sporters in this caliber . Rifles in the Speer lab's collection posted velocities varying from 400 ft/sec under to 300 ft/sec over those posted by the SAAMI pressure barrel with the same ammo. Because of this, we have departed from our usual policy of showing velocities from a sporter. The velocities for the 7mm Remington are from a 24 inch pressure barrel.
These loads stay within the industry pressure limit of 52,000 CUP
Translation; they have pressure testing equipment and a lab and they still don't have a clue what a 7mm Rem is going to do in a rifle. When pressure tested loads vary 700 fps, its likely a good chance that pressures are all over the place.
It also explains why one guy thinks a 7 Rem is just a loud 30-06 on a good day, and the next guy thinks his a match for an STW.
"There is quite a variation in published loading data for this caliber. Differences betweencases, primers, and bullets all have an effect. This emphasizes our constant caution to always reduce loads whenever changing components from those used to develop the data.
Seldom will either handloads or factory ammo match nominal factory ballistics in a sporting rifle and there is a great deal of velocity variation amoung sporters in this caliber . Rifles in the Speer lab's collection posted velocities varying from 400 ft/sec under to 300 ft/sec over those posted by the SAAMI pressure barrel with the same ammo. Because of this, we have departed from our usual policy of showing velocities from a sporter. The velocities for the 7mm Remington are from a 24 inch pressure barrel.
These loads stay within the industry pressure limit of 52,000 CUP
Translation; they have pressure testing equipment and a lab and they still don't have a clue what a 7mm Rem is going to do in a rifle. When pressure tested loads vary 700 fps, its likely a good chance that pressures are all over the place.
It also explains why one guy thinks a 7 Rem is just a loud 30-06 on a good day, and the next guy thinks his a match for an STW.
burnt_servo
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not to derail things too far ...... something ive noticed with the 7mm stw , the load data seems to be getting slower too .
I load mine to about 2900 with 175 grain bullets. I do have the advantage of having surplus powder I bought as RP5, which another member told me is norma 105. I have no problem at that. I can pick brass at the range faster than I consume it. I do have an 11" twist, which may reduce pressure also.
