PPU Factory .308 - Over Pressure?

[phaedra1106]

Thanks chaps, that makes perfect sense :)

I hadn't considered the de-capping pin as I've never seen it on any of my CCI, Magtech or S&B primers. Next range date is on the 17th so will see what happens, he's shooting it "bare" with no mod or brake fitted.

[R.G.C]

The two primers on the left are softer brass than the third. All have been pushed out by the de-capping pin and the convex shape is due to that. Only primers still in the cases after firing will give a true indication of anything untoward.

If the loads were within the specified limits it is unlikely that ammunition is over pressure. My suggestion is, as Iain suggests, get your headspace and chamber checked, then, with a scrupulously clean rifle (especially the chamber, if as you,say, he has been shooting dirty ammo that alone could cause problems) with a clean rifle, repeat the test and check each primer after firing.

Here is a good explaination

http://bulletin.accurateshooter.com/200 ... -pressure/

HTH

:cheers:

John 25,

The CCI are quite soft as compared to brass cups. It is to consider the cup thickness difference as well. If the ammo was mil surplus, they could well have been with thick cup primers?.

For what I can see; FP indentation are also different and this can make a lot of changes in pressure rises and cup deformation.

It would have been inportant to look for otther more obvipos signs of pressure, should there have been any?
R.G.C

[John25]

There are a number of indicators of over pressure ranging from hard extraction (which could just be a dirty chamber) to primers blown completely out of the case and it would take me all night to go through them all in full. As the pub is already open I'll give you this link

http://www.youtube.com/watch?v=orJdUR_X ... ata_player

Which will lead you to a number of similar videos.

I would need to see the gun and the cases fresh from the chamber after firing to make an accurate diagnosis.

Did you say that you had chrono'd them? I can't remember.

Hope this helps,

J

[phaedra1106]

I think we're going with the de-capping pin pushing them out of shape option, obviously I'll have a look at the reloaded rounds as they are fired at the range to check for any signs.

Saw him today and the originals were 145gr. Also it was a new Bipod not moderator, so possiblity of scope, muzzle brake (now removed) or Bipod or just the ammo, looks like our range date on the 17th may be put off until the 24th so will have to wait until then to see.