its a mauser small ring (mexican mauser), custom made about 10 years ago well known gunsmith douglass barrel, 7mm08 worked fine, suddenly it started very very very flat primers and now its separating heads (new brass) stoped shooting it what is happening??? load h414 45 grains 140 sierra std primers federal hulls... what do I look for???

2 questions
Have you recently changed lots of powder?
Have you checked to see if the lugs / lug seats are dammaged (pounded back, excessive headspace issue).

I have overloaded dozens of calibers just to see what happens.
I can typically get 15% overload and nothing bad happens with high pressure rifle cartridges.

I get ~1% variation with powder lots.

My guess is the bullet is slow in getting started.

The thing that really gets the pressure up fast is pinching the bullet:
1) ramming the bullet into the lands
2) crimp from hell
3) donut in case neck from necking down
4) tight neck chamber and thick necked brass
5) bullet squished to a larger diameter from compressing powder
6) oversized bullets that are tight in the neck or throat

--
A society that teaches evolution as fact will breed a generation of atheists that will destroy the society. It is Darwinian.

Check the case length. May have stretched to the point on being too long for the chamber. The throat of the rifle could cause the case neck to crimp on the bullet when chambered resulting in much higher pressure.

Several good ideas as to what has raised pressures, but if you are actually getting head separations, dollar to a donut you have very excessive headspace. A strong action with proper headspace and overloads will usually melt down a case and blow it out before it separates. My guess is the action is soft and has suffered lug seat setback.

Maybe several things have happened. Lug setback, brass too long, different powder, etc.
I'd check the throat area, a carbon build-up can cause pressures to spike. That added to some of the other problems mentioned could be compounding things.
Let us know what you find out, we all learn from this stuff.

Miss read it thought it said 06 not 08. sorry

TAILGUNNER.. its done the same with other powders and normal loads, will check other things recomended by you and other fellow members it gives me a great start as to what to look for... thanks a lot guys will post results as I find them

oops..I left the rifle at the ranch, will be a few days before I have the gun in my hands and give you guys a rundown on your tips and futher inspection of the gun, I can tell you with confidence that the reloads ar ok, have done it for 30 years and am very carefull on every aspect of reloading and can read a hot load pretty good. thanks again

A couple of thoughts:

Your brass may be growing into the barrel throat causing hyper pressures. When is the last time you trimmed you brass?

Barrels have been known to accumulate so much metal fouling that it in effect makes the bore undersize for the bullet causing hyper pressure. When is the last time you used Sweets 7.62 and clean the barrel down to the steel.

Case seperations tell me that either:

1. You sizing die is adjusted wrong and you keep setting the shoulder back on the case.
2. You have a longer that standard chamber which results in excessive headspace and No. 1 above.

I could come up with a few other notions, but chances are your problem is found in one of the above.

I'd be checking for excessive headspace.....

It could be something as simple as a die set on the short side of the normal tolerances and a chamber cut on the long side.. How do you set up yours dies? Turn them in until they contact the ram or until the sized case's shoulder is just touched by the sizer? The second scenario can make cases last a lot longer.. A bit like neck sizing.. Call it partial sizing.. Check cases that haven't seperated for an incipient seperation ring just in front of the case web.

The very flat primers don't go with a normal load. And head separations are worse with hot loads as the case walls stick to the chamber.

I would change the lot of powder. Use some other suitable powder that you have for that rifle until you sort it out. Also order a no go headspace gage from grafs.com They only cost a little and it will give you peace of mind with that chamber and others. With the instruction sheet that comes with the Foster brand and a shim made from a beverage can you can determine if your headspace is in a workable range.

This could also be caused by a new lot of primers going so flat and not be relevant to another problem that's causing the head separtions. Make sure that you didn't switch shell holders.

Don't shoot the rifle again until the headspace is checked.

Are those loads producing head expansion? Mic the head just in front of the extractor groove and compare it to an unfired round of the same lot.

Is this a new lot of brass? Maybe the necks are too thick? Will a new bullet fall into the neck from a fired case now?

[ 11-23-2003, 17:49: Message edited by: Savage 99 ]

Very flat primers are often an indicator of headspace. The initial pressure of ignition pushes the primer out to the extent of the headspace present. As pressure increases the case head is pushed back against the bolt face, reseating the primer. Since the primer cup is under considerable pressure, it doesn't seat easily and is flattened right out. This mimics a high pressure appearance but the real cause is headspace.
Generally, with a mauser, if the lugs are setting back into the receiver it will be apparent because of the ridge of metal which is left under the ejector slot.You can feel this when you manipulate the bolt.
If the lugs are deforming instead, you can measure across the lugs at front and rear and see the amount of displacement of metal at the rear. One thing is certain. There is something drastically wrong and the rifle shouldn't be fired until the problem is identified and corrected (if possible). Regards, Bill.