cartridge pressure?

[Dekker]

Hey guys, I have noticed that when I shoot my rifle (7mm wby) the bolt is a little tough to lift up to eject the shell.  I'm assuming that this is due to the pressure of the cartridge?  I'm shooting standard loads (not reloads) and was wondering if there is anything I can do to improve this?

thanks

[Heredoggydoggy]

Look at the primers on your empties--if the primer is flattened, or the firing pin dimple looks like a crater on the moon, = signs of high pressure.

[Dekker]

I hadn't thought of that.  If this is the case, do you think I could lower the pressure (starting to reload) enough to fix the problem or is it a problem with the caliber size in general?

[Heredoggydoggy]

Any cartridge can be loaded to excess, but large capacity cases are more sensitive.  Reloading lets you tailor the load to the gun for best accuracy and shootability.  Besides being fun.  When I work up a new load, I start at the bottom load in the data, load 5, then increase the powder charge 1/2 grain for the next 5, and so on up to the max load on the chart.  Once at the range I shoot them in the same order, watching for best group and signs of excessive pressure as indicated by the primers.  Usually when the bolt is hard to open, it's a sign of high pressure, but it might also be the design of the gun.  Weatherby touts its multiple fingered bolt lockup, but it's unusual for more than 4 or 5 of the fingers to actually be contacting on lockup.  If more are contacting, the bolt can be harder to open.  If they are ALL contacting, you will need a hammer to open the bolt.  I would put some good gun lube on the bolt locking lugs, and be sure the contact surfaces are clean.  Weatherbys are great guns.

[Dekker]

Thanks for the great info!

[Bofire]

 :)Make sure your chamber is clean.
Carl

[JackOfAllTrades]

Back to the original question..  If there's excessive pressure build with factory ammo, then there could be issue with the assembly of the action/barrel.  Is this gun new, or has it had many hundreds of rounds fired through it? Is it a custom build?

If the head space of the bolt/chamber is set incorrectly, then that could lead to sticking cases, but not necessarily high pressures. (or both) I've also recently witnessed a new rifle that had a very rough chamber throat. His 300wsm cases were sticking terribly, but there were no signs of over pressure on the cases. Look for scratches at the belt, neck and shoulder of your fired cases. A re-ream of the chamber and re-setting headspace makes that particular gun shoot like a dream now. A high pressure cartridge like the 300WeMag, can wear on the action to take the headspace out of spec. Having the headspace checked by a gunsmith would be money well spent, as even reloading, you could still experience the same issue. If you want a light loaded 300WeMag... Buy a 30-06.  Reloading to reduce pressue as an answer to your issue is like putting a handfull of gauze on a paper cut.

-Steve

[Heredoggydoggy]

  More good info for ya.  There should not be a problem with factory ammo.  Recently a friend had a custom rifle built, and had to send it back because the chamber was too tight to close the bolt on factory ammo.  Factory ammo is as close to spec in dimension and pressure as possible.  Jack's right--most likely it's the gun, not the ammo.

[Heredoggydoggy]

Factory ammo is loaded to SAAMI specs, whatever that may be currently.  If you've been reloading for a while, you will notice that the published load data is more conservative than it used to be.  Damned ambulance-chasers have put the scare  into everybody!