here are some common pressure signs i think i found on this forum a little while back!
-Case bulging, particularly near an unsupported part of the head.
-Case crack along side (may mean excess pressure, but may mean brittle, defective, draw mark scored, or worn out brass).
-Case head expansion (CHE; may mean high pressure, may mean nothing in isolated case).
-Case head separation (may mean high pressure, but may mean excess headspace or worn out brass).
-Case splits in body in fewer than 10 reloads-back loads down at least 2% (can also be due to ammonia vapor exposure or a brass defect in an individual case).
-Case mouth split (may mean high pressure, but more often means case needed neck annealing).
-Case pressure ring expansion (PRE; not much more reliable than case head expansion but may mean pressure is excessive).
-Case primer pockets getting loose in five reloads or fewer.
-Case, excessive stretching (this is actually visible pressure ring area stretching which may be due to excess pressure or to excess headspace).
-Case, extractor or ejector marks on head, especially after increasing powder charge. Most common in semi-auto rifles, but can happen with any extractor and ejector (may be high pressure or bad timing, or an extractor standing proud on the bolt face).
-Case, won’t fit back into chamber after firing.
-Gas leak (see Primer Leaking, below).
-Groups start to open up at or beyond a suspected maximum load pressure.
-Hard bolt lift.
-Incipient case head separation (starting or partial case head separation or signs of it).
-Increase in powder charge gets unexpected velocity. Look for an orderly progression of muzzle velocity vs. charge weight. If muzzle velocity stops going up or actually goes down, or if it goes up too much, you have a problem. The first two indicate steel is stretching. The stretch may just be due to uneven bolt lug contact, or it may mean you are stretching the receiver and fatiguing the steel abnormally. Unexpected velocity increase indicates unexpected pressure increase. With any abnormal velocity, you should back the charge off 5% from where it started. If, based on manuals, the load and its velocity seem too low for this to be happening, get your gun inspected or bolt lugs lapped and try working up the load again.
-Primer blown (primer falls out when gun is opened; same as loose primer pocket).
-Primer cratering (may mean high pressure, or it may mean a worn firing pin or firing pin tunnel, or may mean you have a new production Remington bolt with chamfered firing pin tunnel).
-Primer flattening (may mean high pressure, or may mean long headspace; some loads always make flat primers; softer primer cups (Federal) flatten more easily than harder ones (CCI), so it also can mean nothing at all).
-Primer, mushrooming (may mean high pressure, or may mean long headspace).
-Primer, piercing (may mean high pressure or may mean incorrect firing pin protrusion or incorrect firing pin nose shape).
-Primer, leaking gas around primer pocket (may mean high pressure, may mean loose primer pocket in case, may mean damaged primer was inserted, may mean primer backed out too far during firing, which excessive chamber headspace makes possible).
-Case, short life -back load off at least 2% (under 10 reloads in non-self-loaders or with military brass in self-loaders, 6 or less in self-loaders with commercial brass).
-Case, sticky or hard extraction (especially in revolvers this is a positive sign to knock the powder charge down at least 5%, in rifles also look for chamber ringing).
-Case, torn or bent rim (from hard extraction, see #24., above).
-Case, primer pocket expanded and won't hold newly seated primers firmly (PPE; this is likely no more accurate than CHE (3., above), but is a more sensitive measure for those with tools that can measure the inside diameter of a primer pocket repeatably to the nearest ten-thousandth of an inch).
-Primer, loose or falls out when opening the action or after (see # 26., above)
-Case, increase in required trimming frequency (this is an sudden increase in case length growth per load cycle, it can be caused by excess pressure, but can also be a sign of increasing head space due to some other problem. It is especially common as a pressure sign in lever action guns because the greater span from bolt face to rear lug allows more steel stretch when pressure gets excessive.)
-Case, increase in apparent headspace (this means the cases are coming out longer, including from casehead to shoulder. It can mean bolt lug setback, which is usually an extreme pressure sign. It can also mean a loose barrel or an improperly set Savage barrel. Whatever the cause, the gun should go straight to the gunsmith for inspection.)
-Gas or Flame Cutting of revolver top strap. (Can also be due to excessive barrel/cylinder gap that needs correction.)
-Gas or Flame cutting of rifle bolt face by gas leaks around primer pocket or of bolt face perimeter. (Can also be result of occasional leaks from normal rounds firing, as is observed in many military gun bolts.)
-Velocity higher than manual maximum load velocity for same powder and barrel length. For example: one fellow using a .243 Win load one charge increment below the manual maximum got velocity 200 fps higher than the manual claimed for its maximum load's velocity. His single-shot action was popping open at every shot. With QuickLOAD we were able to calculate he had about 77,000 psi. An alternate explanation, if everything else is normal, is that your chronograph readings are incorrect. It is not uncommon to get high readings due to muzzle blast when the chronograph is too close to the gun. I recommend 15 feet minimum, since that is what the manual authors typically use and is what you are comparing to. Some big magnum rifles need even more distance.
Hybrid Mode
