pressure signs (updated with picture)

[teampete]

Hey all, well I just shot my new rifle and my first handloads ever!! Now I have questions on pressure signs. I have a 300wm and I loaded 210 berger vlds. Berger says max load is 75.5 grain of h1000 and start load is 71.5. Well I went from 71.5 to 75.5 in small increments. I noticed a small mark on the brass coming from the bolt face. This mark apperared at every powder charge. Is this a sign of excessive pressure?? I don't think so because it even occured at the starting load and I hear berger doesn't even publish real max values for there own sake. Please chime in

 

[WyoElk2Hunt]

Re: pressure signs

A picture of mark would be nice. Were the rounds hard to chamber? Were they hard to extract? What did primer pocket look like? Sorry for so many questions but will help answer you questions.

 

[teampete]

Re: pressure signs

No they were not hard to chamber or extract. I will try and post pics tonight. Primers looked ok I think but this is my first time doing this stuff so... I'm usind fed 215m primers if that makes any difference

 

[Buffalobob]

Re: pressure signs

Was the chamber degreased? Residual oil in the chamber will give the "impression" that there is high pressure.

Some brass such as Norma is softer than others and will mark easier.

 

[teampete]

Re: pressure signs



Here is th epicture guys. Sorry, this is the best picture I could get. One on left is start load of 71.5 and right is max load at 75.5. What do you all think?

 

[Greyfox]

From your picture you have a flattened primer acccompnird by an ejector mark. Typically a sign of high pressure. Since you mentioned that it occured early on, as you were increasing your powder charge there are a couple of things I would check:

Check your seating depth. Make sure your Bergers are not being pushed into the rifling, or just out too far. Try seating them .025-050" further into the case.

Double check you powder weight or scale and make sure it's accurate.

Try a factory load. Your rifle chamber/headspace could be excessive. Do tou have any rings around the case slightly higher than the base.

 

[teampete]

Greyfox, I used a hornady oal gauge which I then used a comparator to get my measurement to ogive. Then I backed it off .010. Would only backing it off that short amount cause the high pressure signs?? I wonder if my primers were seated well enough. I have a nad primer tool and compress it almost all the way in which should seat the primer in the corrext spot? I know the federal primers I am using seem a lot harder to seat then the cci ones I also had

 

[Greyfox]

My 6.5x284 shows pressure signs at .010 with Berger 140 VLD's. At .050 they go away. My max accuracy is at .075. Hard to tell if this is the issue but work a try to see what happens. Its easy to check out to see if the primer is the issue.

 

[Broz]

Teampete, It looks to me you are right at the max pressure and flattening primers. If you get any increase in effort to open the bolt after a shot is fired I would back it off. This may occur more so on hot days or in a string of shots with a hot chamber.

I have and do load extensivly with 210 Berges and H-1000 in 300 WM's. I have seen factory Sendero's that are at max at 74 grains and some go to 78 grains just fine. My custom action 300 will go above that safely. All rifles are different. Also I have seen the same velocity from different rifles with 74 gr as ones with 77. Hard to imagine but this is what I have seen ,and proven, with confirmed actual drops to 1000 yards.

Jeff

 

[teampete]

Hey all, its me again. I had a guy look at my brass today that has a side business of hand loading ammo for people. He said I am real close to the max. He said I could probably even go up a grain if I like. Im not ready to do that but he said the flattened primer is probably because this is a magnum cartridge and I am too close to the lands. He said for magnum cartridges he usually sits them atleast .020 of the lands. I was at .010. Have any of you heard about this in magnum calibers?

 

[Long Trang]

Teampete,
You are wise to decide against adding another grain of powder to an already near max load which is showing possible high pressure signs. I seat loads .010 off the lands of my custom 300 WM, however, (as mentioned before) every rifle is different. What may help you to understand is the 'jump' a bullet is allowed offers the burning powder the chance to build pressure and thereby giving the bullet a 'running start' to take the rifling. If your bullet is jammed or too close to the rifling, it will likely produce a pressure spike. With loads that are not near max, this is typically safe and acceptable, but with a near max load to begin with, you are adding to the pressure with this spike and risking dangerous pressure levels. I would suggest either lowering your powder charge and play with your seating to the lands (this would lower your MV, but most likely improve accuracy) or keep the max load and seat the bullet deeper to eliminate the pressure spike (this would take a little away from accuracy, but offer higher velocity).
Keep in mind, magnum cartridges tend to burn barrels with hotter loads, which is why I tend to reduce my loads for the time being. Considering you are using heavy projectiles, they will go much farther than your lower weight bullets anyway.
In addition, many primers do flatten (slightly) in magnum cartridges. This was a concern I had when I first began reloading for my 300, then I found out it is usually normal and not necessarily an indication of high pressure.
Good luck and be careful.