# Pressure too high?? Pictures



## jungle (May 10, 2008)

What do you all think? Are the case heads showing signs of excessive pressure? (7mm Remington Magnum)

Cases extract easily like factory. No cratering of primer. No backing up of primer. No flattening any more than factory ammo, still has good annulus area around primer. Very accurate. Approximately 3050 fps, approximately 100 fps above factory, and maybe more due to low light conditions for the chronograph (very overcast this afternoon).

There is an ever so slight "smile", hardly visible, on a couple of the rounds no more than some factory ammo.

However, the weather was cool when I fired them so I am thinking about droppng the load 0.5 grains. [attachment=0:2dpsmtyt]IMGP2522_zoomed.jpg[/attachment:2dpsmtyt]

Whats your assessment?


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## sawsman (Sep 13, 2007)

Let 'em "smile".  

I dont see any excess pressure signs from looking at the picture. No hard/sticky bolt lift... you're good to go.


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## Frisco Pete (Sep 22, 2007)

According to gunwriter and handloading guru John Barsness, who did an extensive article on reading pressure signs using standard pressure indicators vs. firing the rounds in a rifle fitted with pressure gauging equipment in HANDLOADER magazine - in summary he indicated that the chronograph is one of the most accurate indicators of high pressure. Other signs on the brass or primer are more hit and miss. He also said that if your velocities are 100 fps faster than factory ammo, particularly in a round already loaded to high pressure like the 7mm Rem Mag, that pressure is TOO HIGH according to all the research he did.

Actually the chronograph works _better_ in cloudy, diffused light conditions than in more direct sunlight according to Oehler Research. If the sun is not too low in the sky, your readings were most likely correct. So if you have chronographed factory loads of the same bullet weight in that particular rifle and your handloads are 100+ fps faster, then you should heed the warning your chrono is giving you.

I would therefore reduce your load at least 0.5 to 1.0 grains and re-chronograph. An additional benefit is that this will keep pressures from spiking in hot weather as well.


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## Loke (Sep 7, 2007)

What do your reloading manuals say? Are your loads in line with the velocities and pressures listed in them? Factory loads are lot usually loaded to SAAMI maximum pressures. You can get your handloads there, but without pressure testing equipment. A chronograph will be your most useful tool for guessing the pressures of your loads. There are too many factors that can affect the condition of your cases and mislead you in to thinking that you're safe. The condition of your chamber, the interface between the locking lugs and bearing surface of the action, the ****ing piece and the surface of the bolt body will all affect easily a case is extracted. The metallurgy of the case, the hardness of the primer cup, machine marks on the bolt face, and tolerances of the firing pin hole will affect the appearance of "pressure signs" on the bolt head.


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## Packbasket (Oct 29, 2009)

you are correct in there are no signs of 'too high pressure' under the conditions and at the location you were testing at.

you are also not wrong in dropping the load and re-testing at higher temps/alt but without knowing your loads, primer and bullet I'd be guessing at where you are in relation to the POSSIBLE high end of your load.

you are full length resizing or neck only? primer pockets reamed or factory? Sometimes in a MAX handload with non-uniformed pockets you can see signs of high pressure on primers that are not really there.

As pointed out above, the chrono is the best tool you have at your disposal for loading, second to your own brain ofcourse.

you are smart enough to look for pressure and ask this question, that's the hardest part to come up with in the formula.


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## woollybugger (Oct 13, 2007)

Always stick with published data. Call or email the powder mfgr. with one-off questions (i.e., primer substitutions, etc.) Never load above published data, never start at max loading. Find the most accurate load, not the highest velocity load. Reloading is fun! Keep it fun by not blowing up your gun or yourself. The 7mm mag is a high pressure cartridge with a large case volume, which means there is a lot of energy that has to go somewhere in a hurry. Flattened primers can be an indication of high pressure. You can also cut a case in half lengthwise (saw, then file it smooth to remove burrs) and mic along the walls to see if there is stretching near the case head. This will tell you if you have either head space issues or excess pressure, or both. 
From the pics posted it looks like there are no obvious signs of overpressure, but why guess? Like I said, start with minimum loadings, work up to find the most accurate load, and be happy with it. Gaining 50-100 fps isn't going to be worth the risk.


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## 10yearquest (Oct 15, 2009)

woollybugger said:


> Never load above published data


 I must object. I have an old speer manual number 10 and it says I can load a max of 27.5 grains of h335 in my 222 mag. In modern manuals it says 26.5 is the max. I have personally gone as high as 28 grains but now load 27 so my cases dont stretch. I have not had to trim my cases for about 4 loadings and my primers show no excess pressure. I think its ok to go above as long as it is done in increments and you watch for signs.


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