Real World VS Loading manuals

[demented]

I'm working on a load for a 7mm Remington magnum using H-4831sc, 150 grain bullets. I'm at 66 grains with no pressure signs, velocity averaging a sedate 2900 fps. Depending on what source followed I'm either at or four grains over recommended max, to be honest I'm not certain which direction to go from where I'm at. Rifle is a Browning A-Bolt Stainless Stalker, 26" barrel with B.O.S.S. system.

[7 loader]

The books are the base for wich your loads should be made. Any thing else is what you do. Keep doing what you are doing, but be carefull. So far it seems you are doing fine.

[Hntbambi]

Well, is your barrel 26" with or without the BOSS? If it's 26" with the BOSS, you have a 24" barrel or so for velocity figures. You will be a tad lower in speed compared to a 26" barreled gun.

There are many factors into what develops pressure. It's not so much the weight as the bearing surface of the bullet that interacts with the rifling that will determine the load. Not all 150 gr bullets will reach max pressure with the same amount of powder.

I have found the data books to be fairly close with my real world findings. The old addage of them being written by lawyers is BS. Without a personal ballistics lab you will not know for sure, so unless you really know your stuff, stick with the books.

[boomtube]

"Depending on what source followed I'm either at or four grains over recommended max, to be honest I'm not certain which direction to go from where I'm at."

Seems to me you're at a rational max. So, what direction do you think you should "go from where" you are, and why so?

[johnnyk]

I would proceed with caution. You should be able to easily get 3050-3100fps from a 150gn bullet. Your powder may be the culprit. Once you run out or switch to another lot you should definately back in on down and start over. JohnnyK.

[demented]

The barrel is 26" plus the Boss, probably close to 30" all told. My reason for posting is that 2900 fps really seems slow for any cartridge with MAGNUM in its moniker. Heck, I'm getting 2825 with a .308, 150gr. bullets, 22" barrel. That I'm topping out at 2900 with this 7mm using 30% more powder than a 308 to gain 75 fps just does not make any sense to me. I'd like to hit 3000fps, did not anticipate having trouble getting there with the powder I'm using. My primers are not flattened at all, no brass expansion. Actually pressure signs for my load with 66 grains a less than the Federal Premium I've been shooting. ??

[Stonewall2]

There are so many varibles when dealing with 7 mm Rem Mag rifles .
Case capacity , chamber -throat differences ,barrel diamensions,bullets all change pressure and the velocity .
See the 7 mm Rem data in the Speer manuals .

Both rifles shot with H-870 powder, ww brass , Fed 215 Primers ,160 Nosler .025 jump to lands.

One older Ruger 77 would not shoot 160 Nosler faster than 2950 but the best 3 shot group was .2 at 100 yards .

Another Ruger M77 with the 160 Nosler and H-870 using 80.5 gr would cronograph at 3075 fps at 32 degrees.

The companys that write the loading manuals have much experiance and equiptment to test the loading data.

Unless you have Pressure Trace strain gauge system and Quickload to meaure pressure in your gun load by the manuals and be very carefull.


What velocity do you get with the Federal factory loads?


Glenn