I recently shot a few handloads that caused a little bit of a hard bolt lift. These were shot with new WW brass. I then loaded a few more a half grain under the previous load and the "sticky" seemed to get worse, but this was with resized brass that were cleaned, lubed, and loaded. Could the lube cause a false pressure sign? I haven't been able to find to much out there about it. Thanks in advance!
Sticky bolt/Hard extraction newbie question
- Thread starter jsimonh
- Start date
make sure the cases are dry and clean on outside with no lube when you shoot them. A lubed case wont "stick" to the chamber walls like it is designed to and it therefore acts like a 50,000 PSI wedge pushing against your boltface, temporarily stretching your action, and when your action and chamber contract back to normal size, is pushing on the case.
BoydAllen
Gold $$ Contributor
Did you mean that there was lube on the loaded ammo? If there was, that was a big mistake, and it and the chamber should be cleaned till they are both dry of any lubrication. Lube is applied before FL sizing, and completely removed afterwards, before any other reloading steps are done.
Boyd
Boyd
The brass should be free of ALL lube prior to priming, powder loading, and bullet seating. I like to tumble my cases right after firing....spent primers in place. Then the brass is fairly clean of debris when you start to de-prime. You do not want dirt introduced INTO the die. (They are a pain to clean). The lube of course is applied before de-priming and neck/full length resizing. Clean the primer pockets and throw the brass back into the tumbler. I've never seen a tumbler clean primer pockets so any of the tools for cleaning pockets are needed. Now your brass is clean and ready for reloading. You can imagine what lube does to brass just by looking at any 'OIL' dents during sizing...and this is by hand! 50,000PSI causes fabulous problems!
The cratering around the firing pin indentation I've run into most all the time with CCI BR-4's with many different loads. I do not consider it a problem but maybe just an indication of approaching higher pressures. The sticking bolt is a real concern. Lube on the case for you but should it happen on clean cases you need to address a HIGH pressure problem.
The above has worked well for me for 45 years but I'm sure others have equally as good systems if not better.
The cratering around the firing pin indentation I've run into most all the time with CCI BR-4's with many different loads. I do not consider it a problem but maybe just an indication of approaching higher pressures. The sticking bolt is a real concern. Lube on the case for you but should it happen on clean cases you need to address a HIGH pressure problem.
The above has worked well for me for 45 years but I'm sure others have equally as good systems if not better.
holstil
Silver $$ Contributor
Once brass is pushed hard enough to cause the sticky, it is often done. A trick Greg Culpepper told me was to reduce the next two firings about 15%. I think it's the 1/2 thou. or less at the web that the die can't get resized once taxed.
About half of my cases worked ok after I did that. The rest are in my shiny pile collection of things that don't work anymore (until I learn of something new to fix them). I have a hard time throwing brass away. I think cases will be used as currency soon. 8) My wife likes jewelry, I was thinking of a brass neckless and 308 pendent with 45acp earrings for Christmas. What, brass is a precious metal.
Jim
About half of my cases worked ok after I did that. The rest are in my shiny pile collection of things that don't work anymore (until I learn of something new to fix them). I have a hard time throwing brass away. I think cases will be used as currency soon. 8) My wife likes jewelry, I was thinking of a brass neckless and 308 pendent with 45acp earrings for Christmas. What, brass is a precious metal.
Jim
BoydAllen
Gold $$ Contributor
Once, just for grins, I removed a couple of thou (from the diameter) of a case, starting at the top of the extractor groove, cutting parallel to the case CL, on a PPC case that had developed a click, and then fired it a couple more times with my top load....no click...no problem. I had read a story that mentioned Mr. Boyer doing something similar, at a match, with a file. My curiosity got the better of me. It seemed to work fine. The case had a lot of firings on it. The primer pocket was not loose.
Another thing that I have noticed is that some barrels are chambered so that a little of the case, just above the extractor groove shows at the back edge of the chamber. Perhaps this makes clicks less of a problem.
Another thing that I have noticed is that some barrels are chambered so that a little of the case, just above the extractor groove shows at the back edge of the chamber. Perhaps this makes clicks less of a problem.
bigedp51
NHgunNut said:
To this day it is a NATO EPVAT proofing requirement that oiled high pressure proof cartridges be used when proofing small arms. The oiled proof cartridge delivers twice the force to the bolt, bolt lugs and receiver lug recesses and simulates harsh combat conditions.
The British starting in the late 1800 used the axial copper crusher method of measuring chamber pressure. The copper crusher pellet was located at the very base of the cartridge which allowed for readings of direct pressure delivered to the bolt face.
Below the red arrow indicates the location of the British "axial" copper crusher pellet verses the American SAAMI "radial" location of the copper pellet or transducer. The axial copper pellet was hollow to allow the firing pin to strike the primer and allowed for a direct pressure reading of the force delivered to the bolt, bolt lugs and receiver lug recesses.
Below from the British War Office and the the warning about oil or grease in the chamber.
Pressures, Case Strength and Back Thrust
http://www.longrangehunting.com/articles/pressures-case-strength-back-thrust-2.php
bigedp51
effendude said:
As long as anyone tells someone to lube their cartridge cases I will present the printed "FACTS" on bolt thrust.
Recommended reading...................
BoydAllen
Gold $$ Contributor
Without getting over long, lubrication of ammunition that is loaded with cases that are the same shape as the chamber, or which differ only slightly, which is loaded to produce normal pressure in a dry chamber, is a very bad idea. On the other hand, in some specialized situations where the case being fire formed has significantly less volume than the chamber that it is being fire formed in, which limits the pressure with propellants that are normally used in the formed case, it can be done, with care, but I DO NOT RECOMMEND IT. The only example of this that I can think of is fire forming PPC brass using propellants and bullet weights that are normal to fullly formed case loading in that caliber. I should add that I have formed many of these cases dry with no problems and do not see any need to lubricate. The general rule, for the vast majority of situations is that ammunition and chambers should be free of all lubrication.
Posts on the internet are read by people of all levels of experience and ability. I think that it is irresponsible to recommend anything that an inexperienced shooter might misapply, and would suggest that those sort of things are better related in private conversations where the application and the background of the listener are known.
Posts on the internet are read by people of all levels of experience and ability. I think that it is irresponsible to recommend anything that an inexperienced shooter might misapply, and would suggest that those sort of things are better related in private conversations where the application and the background of the listener are known.
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