And if you cannot open the action after your lapse in reloading judgement, don't make things worse by beating on the bolt handle with a 2X4. Swallow your pride, take the rifle to your gunsmith and tell him what your dumb brother-in-law did to your rifle. Chances are good the gunsmith can put things aright without further damage.

I have not blown primers but have had a few that cratered. Have also experienced the dreaded difficult bolt lift and associated hard-to-extraxt case. I avoid this by charging with powder one case at a time immediately before bullet seating to avoid double chanrges. I also weigh each and every powder charge. I look at the primer after every shot at the range looking for pressure issues. I also carry a spare shellholder to the range to see if there is any case head expansion. When loading I only load one powder at a time and keep that bottle on the bench so that there is no confusion as to which powder I am using. I also don't take breaks when re-loading so as not to lose my place.With handloading I have found it wise to try to anticipate where a screw-up can happen and try to avoid it by not taking shortcuts. I assembly line all reloading tasks; decapping, tumbling, inspection, full length case forming and priming. But when it comes to powder charging and bullet seating those are done one case -at-a-time!

Primers seem to be the first thing to look for. But overpressure can be seen in bulges and out of perameter base measurements. I recently bought 1000 once fired brass. They came from a (unknown) firearms manutacturer. They were all painted red on the base. I was told that they were all "over pressure" loads. The factory uses them to test their firearms. So far, I've reloaded 400 of them and rejected 20 for overpressure signs. The first signs were them not going into the case holder for depriming. These same cases wouldn't hold a primer (stretched out of shape). I measured all the deminsions and found varying deminsions, up to 20/1000 out on the base deminsions. There were no outward signs of overpressure. The primers looked fine and the cases looke fine. All 1000 needed trimming about 1/1000 (which, of course, is a little long for once fired cases) So, sometimes, you will not see anything on the outside that screams at you. It may be the little suttle things that need a micrometer to identify.
The next test will be when I fire the reloaded rounds. Lets see if there are any failures or problems in a "second firing".
Another note: These were all Lake City 5.56. They all had a military crimp. They appear to be heavier (stout) metal, but I don't have a way to measure it. I wonder if these were loaded at the factory, as special hi pressure test rounds. Anyway, the ones I loaded look goood and measure good on all their deminsions.

Never assume that what works in one gun will work in another ! Never force a bolt closed on a tight handload. Idahoguy; Pistol cartridges are easy to double charge and I think that may be the reason for blown pistols. Some powders must not ever be loaded under what the manuals call for.

If you manage to "shatter" a modern bolt action rifle - High number '03 Springfield, Arisaka, 1917, 98 Mauser and later, you are in pressures above 145,000 PSI absolute.

High number '03s have been tested to 125,000 PSI CUP without showing more than a few thousandths setback of the locking lugs/shoulders, and some none at all.

You will get blown primers long before reaching such pressure levels. Recently got a blown primer with factory Remington 270 130 gr. SPCL. Remington replaced the box of ammo.

In all my years, never heard of anyone managing to destroy one of these "modern" bolt actions without actually trying to do so. Handguns are a different matter entirely.

I agree with you Harold up to a point I would say never use handloaded ammo made by someone you do know. I handload ammo for a few friends but they all know me very well. I do not handload ammo for people that I do not know personnaly

Hey, guys! A better explanation of high-pressure spikes with so-called light loads is, because the powder lies, as you said, along the bottom of the cartridge case, the flash from the primer travels unencumbered over the top of the charge, causing it to burn much more rapidly. Modern smokeless powder, especially slow-burning powder, is intended to burn progressively, starting from the rear surface (by the flash hole), burning steadily as the front of the charge, like the bullet, travels down the bore of the firearm. With a half-empty case, the primer flash ignites the entire top surface of the powder charge, causing a tremendous pressure spike.

Back in the day, we were taught that if you want to use a light charge, place a piece of kapok on top of the powder charge to keep it in place at the rear of the cartridge.

Dave, your knowledge of the topic is thorough... Did you learn that on your own or from Ackley's book?!?!

Absolutely no exceptions I do not load ammo for other people. Deadeye, if a gun blows they will blame you. Maybe even sue you. Don't take a chance for anyone..

I thought when I started reloading 40+ years ago I was going to save 50% on ammo, instead I have found I shoot twice as much.

Never reload for a friend, get him into reloading instead.
Never shoot someone else reloaded ammo, unless they are a reputable re-manufacture company.