This is why we have "starting loads".

[Leslie Sapp]

I recently acquired an almost mint 1980 Remington 700 in 8mm Remington Magnum with a 24" barrel. Not having many elk here, I decided to get some 160 gr Barnes TTSX bullets and set it up as a long range deer rifle.

Barnes load data shows a starting load of 76.5 grs of Hybrid 100v giving a velocity of 3132 fps out of a 24" barrel, and a max load of 83.5 grs giving 3430 fps.

Knowing that Barnes recommends a bit of a jump, and I didn't want to start chasing the lands just yet anyway, I loaded up a few 76.5 gr starting loads to their recommended C.O.L, 3.6", and walked down to the range to try them out.

The first one came out the spout at 3436! Eek! Checked for pressure signs, none found. Touched off two more, with a velocity of 3406 and 3423, respectively.

I'm glad I didn't decide to save a little powder and bullets by starting somewhere in the middle. The good news is that I'm already at the velocity I wanted and those 3 shots went into 1.1" at 100 yards.
It's likely that once I've got some fire formed brass to work with and start tweaking things, I can improve on that group.

Be careful out there guys, and follow the rules - they're there for a reason.

 

[Pdvdh]

I was expecting some fireworks.

Glad you're safe and all is well.

 

[Leslie Sapp]

Didn't mean to false advertise.
I for one am glad I don't have any graphic pictures to go with this post.

 

[Pdvdh]

I had a similar experience recently with Speer load data for their 200gr Trophy Bonded Bear Claw bullet in my 300 Win Mag.

Max Load data from Speer is 74.5gr IMR 7828 with a MV = 2836fps. I loaded 72.0gr 7828 and recorded a MV = 2984fps, with some signs of excess pressure on the Lapua brass.

I backed down to 71.5gr with a MV=2970fps. I'm using 3gr less powder and I'm 135fps faster than their maximum load. And this is with HBN coated bullets, which normally require some additional powder to reach equivalent pressure/MV.

My MVs were chronographed over three separate chronographs. One being an Oehler 35P.

Speer may have changed their design of this bullet? Or they may have an error within their reload data? Dunno... They don't offer this bullet for the reloader any longer. I had an old box of 25 bullets in my reloading room.

 

[Corey Schwanz]

Glad this wasn't a picture of a blown up gun! Always good to start low and work up! Never know what speed your rifle might like the bullets moving at and besides, it means more range time and shooting is fun!

 

[Bravo 4]

Yep always start low. The max load before pressure signs for my 7mm RemMag was a book staring load.

 

[HARPERC]

It's always amazing to look at info from various reliable sources, only to find a maximum load in one, is minimum elsewhere. Glad your rifle is OK, and especially glad you can still type.

 

[Jokostel]

Good deal. You took the intelligent approach.

WORK to the velocity with a known set of conditions , and watch your signs.

This is why load shoppers are so dangerous..... and why chronographs are so invaluable.

 

[MagnumManiac]

I recently acquired an almost mint 1980 Remington 700 in 8mm Remington Magnum with a 24" barrel. Not having many elk here, I decided to get some 160 gr Barnes TTSX bullets and set it up as a long range deer rifle.

Barnes load data shows a starting load of 76.5 grs of Hybrid 100v giving a velocity of 3132 fps out of a 24" barrel, and a max load of 83.5 grs giving 3430 fps.

Knowing that Barnes recommends a bit of a jump, and I didn't want to start chasing the lands just yet anyway, I loaded up a few 76.5 gr starting loads to their recommended C.O.L, 3.6", and walked down to the range to try them out.

The first one came out the spout at 3436! Eek! Checked for pressure signs, none found. Touched off two more, with a velocity of 3406 and 3423, respectively.

I'm glad I didn't decide to save a little powder and bullets by starting somewhere in the middle. The good news is that I'm already at the velocity I wanted and those 3 shots went into 1.1" at 100 yards.
It's likely that once I've got some fire formed brass to work with and start tweaking things, I can improve on that group.

Be careful out there guys, and follow the rules - they're there for a reason.

This amazes me.
Unless you are using EXACTLY the same components, you can quite easily exceed the manuals velocity and still be in safe pressures. Why? Because your barrel is most likely looser in every tolerance compared to a pressure barrel, number of grooves, their width etc will not be the same as the barrel the testing was done in. I have a pressure trace, some rifles ARE faster than others due to groove number mostly, but also rifling type, width and looseness or tightness of those grooves and lands. Narrow grooves are generally faster than wide types.
If you work up until the rifle TELLS you the pressure has become excessive, such as slight sticky bolt lift, then back off 1-2%, you are safe, no matter what the chrony says.
Why do you think no 2 manuals mirror each other in the results with the same powder charges?

Cheers.
lightbulb

 

[Deleted member 46119]

So glad you are ok!

Yup. Starting loads = good.

With no pressure you may be blessed with a "fast" barrel. I hope for you it tightens up a little more with fireformed brass or a little tweeking. How cool would that be.

 

[Greasyspork]

As another note, that 100V can be some flakey powder with a lot of variance from lot to lot and temperature.

 

[Frank in the Laurels]

You picked up a jem of a rifle !! It's my opinion that the big 8 mm mag is one of the best kept secrets in the big game hunting world. It's a shame big green screwed this cartridge up when it was introduced with junk bullets. Put some nosler partitions in it or an X bullet and your ready to take on anything in North America including brownies. I bought that same rifle the second it was introduced and use it for bear hunting only. Pickup a big ole' bag of brass when you see it and enjoy one of the best kept secrets in cartridges.