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Thread: Reloading observation

  1. #1
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    I've been reloading for over 25 years and recently learned something I betting most reloaders are unaware of and should take into consideration, especially regarding revolvers. Most of us I'm guessing that bullets with a canlure should be be seated using the canlure as the depth guide for the most part. However I've noticed that depending on the bullet, (I only load jacketed bullets) type and seating depth I'll get an excessive amount of pressures blowing back through the entire cylinder so much so that it will sometimes cause a near permanent imprint of the case head on the recoil plate and dislodge rounds from the case and,or, seat them deeper no matter how tight I crimp them. I couldn't find the cause for this until consulting with a person who is a certified expert regarding propellant physics. Apparently if the distance from the bearing surface of the bullet to the bearing surface of the cylinder lands is more than should be the magnum or heavy charges of slow burning powders will allow high pressure gases to escape past the projectile and out the front of the cylinder because seating depth and bullet design will leave a gap between the mouth of the case and the bearing surface of the cylinder. To eliminate this rather disturbing occurrence it is essential to seat as shallow as can be done without creating a chambering issue and still having some canelure to utilize for crimping purpose. I'm noticing the problem more so with the lighter projectiles in my .357 mag as the bearing surface of the bullet is either very short or non existent all together forward of the canelure. Another contributing factor is trimming my brass shorter than maximum specification which sets the bullet even further from the cylinder lands. I also noticed on that note that with the larger bullets, 158 grain, I'm getting near zero blow back because the bullet is contacting the cylinder lands while still inside of the case mouth giving the powder more time to finish its burn before becoming oxygenated by the free space or gap which is another good reason to try and eliminate as much free space or gap between case mouth and bearing surface during the powder burn.

    When seconds count, the police are only minutes away!

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    Good info to have. I am fairly new to reloads myself, but try to keep mine shallow as well. We have a group of 5 that get together for a good time reloading. Due to the process, someone is always left out. His job is to verify each bullet is seated properly, primers are in correctly, and mic each bullet that comes down the production line. We try to keep our error within +/- 10%. Periodically stopping to do a barrel test. Drop into barrell, drop out of barrel, and cycle through magazine and chamber with no problems. Yeah alot of steps, but don't want anyone being bored.

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    in every reloading manual is not only information about how much and what kind of powder to use, but also OAL, or over all length. That information is there for a reason. HEED IT. If your loaded cartridge is the correct length and you are having problems, then the problem is not that the bullet is seated to an incorrect depth.



    Whatever you do, NEVER seat a bullet deeper than reccommended since this will effectively reduce case volume and easily cause an over pressure situation. Additionally, seating a bullet too shallow will cause it to be held less securely than it should by the case. This could allow the bullet to be cocked which could lead to a failure to feed in an auto loader, and flying lead in a revolver.



    Follow the data tables in the reloading manuals VERBATIUM. If you still have a problem then you need to get a gun smith to check your gun for defects. Or perhaps have someone observe you while you reload and spot something that you are doing wrong. NEVER EVER give out bad reloading advice. Some newbie might read it and get himself injured or killed.



    Lastly, cylinders do not have lands, barrels do.

    edited for typo's and such




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    edited to remove double post

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    You are completely missing my message. I never said load out side of the recommended specifications! I only stated that it should be observed that certain bullets don't have a bearing surface above the canelure and this allows gasses to blow by. I always crimp within the canelureand the depth according to casing over all length spec.. My point, and I'll state it once again for yourignorantpurpose is to not over trimthe brass and only trim it to max length if you are encountering this blow by issueso to keep the free space as minimal as possible! How long have you been loading? Do you even know what free space is or bearing surface is on the bullet or the revolver? What is meant by a magnum charge of slow burn rate powder? Why excessive high pressure gases blow by in certain circumstances but are minimal in others? Anyone who has the most minimal knowledge of reloading knows that pressures rise when you seat deeper than stated in the book and that if a canelure exists crimping within this area is a must do. In fact my point I was making was to not seat deeper than recommended and that if brass is trimmed to min. length with some cartridges it makes it impossible to seat at stated casing overall length with bullets of lighter weight v.s. heavier ones. However, if your brass is trimmed to min. length you will have difficulty crimping within the canelure which is why I stated to trim to max length for that cartridge. Try listening and know what you are talking about before you go running your mouth about things you never listened to in the first place and insulting others who have not deserved such criticism.

    When seconds count the police are only minutes away!

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    Yes barrels do have lands, but for the individual who may not know what the bearing surface is it is sometimes necessary to describe in both terminologies as I did! And over all length is never exceeded in my post but only stated that if the case is trimmed to its acceptable max length it will decrease free space decreasing and containing full pressures to within the case while the burn finishes with as little oxygenation as possible.Unless proper steps are taken that don't include changing recommended seating depth, EVERas I've described,high pressures will blow backand score the recoil plate, possibly cause re-seating or dislodging of the projectile as can and does happen with full magnum charges with slow burning powders,which is the cause of lower barrel fracturing on those revolvers such as S&W that have that flat area on the entry point or back of the barrel, and accelerate pressure cutting on the top front of the frame which is always a problem with revolvers to some extent. The pressures in a .357 heavy magnum loadreach as much as 42,000 cup and you don't want that in its full degree slamming into your other chambered rounds the barrel flat spot, or any other area of the weapon not intended to contain those pressures. Dimpled primers is a clear indication of this happening which is when the case is shoved back with extreme pressure and causes the spent primer to become indented by the firingpin hole because peak burn is occurring during free space traveland can as well damage that part of the gun!And further more I am only referring to jacketed projectiles as they have a shorter bearing surface on the smaller or rather lighter bullets and in some of those lighterbullets their is no bearing surface above the canelureat allincreasing the dilemma.If we are speaking of an auto loading pistol this does not apply nor does it apply to high powered rifles. With high powered rifles it is best to seat the bullet to just off the lands, .001" - .002"for increased accuracy, lower pressures, and decrease throat erosion.

    Most auto loading pistols head space to the case mouth and bullets must be seated to exact specification for various reasons of which all are critical.

    When seconds count, the police are only minutes away!

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    well, sounds like you know it all and have it all figured out. guess that's why you're not having any overpressure problems. Since I've only been reloading since the '60s I'll just quit running my [ignorant] mouth and let somebody more experienced chime in. cheers,
    roN

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    I always write down the OAL of factory rounds, and use that as a reference. I do not load to those spec's, I just write down the info in case I ever need it.

    I do most of my loading for rifles,I use a tool named the "OAL Gauge" from stoney creek. you get a case in SAAMI spec, and the primer pocket is drilled and tapped so you can use their gauge to seat your bullet to have an OAL so you know exactly how far off the rifling lands that you are.
    I have a 22-250 that likes the bullet just touching the lands, and I have a 30-06 that likes a little bit of "Bullet Jump" before it engages the lands for best accuracy. (Weatherbys riflingare something totally different, so you may not be able to use an OAL gauge for them)

    I believe stoney creek makes an OAL gauge and brassfor pistols, but I do do not know how one would do that measurement of revolvers,

    Now here is a weird problem a buddy had with his rifle, he found the OAL where the bullet was just touching the lands, the rifle was more accurate then he has ever seen out of it just from loading to that length, but one day when he went to eject a round that was not fired, it would not clear the ejection port due to the length of the loaded round.
    What to do?? Give up accuracy by shortening the OAL, or grind the ejection port to accept the longer rounds he needed to get greataccuracy out of the rifle??
    He ground open the port!!



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    6L6GC wrote:
    Lastly, cylinders do not have lands, barrels do.
    gamestalker wrote:
    Yes barrels do have lands
    Actually, neither do. People and gov'ts have lands.

    Firearms have "lans".

    FTW

    :celebrate


    ETA: I thought I better come back and add, before someone flames me instead of chuckling with me, that yes, I know that both the words "lans" and "lands" are used re: rifling.
    Bob Owens @ Bearing Arms (paraphrased): "These people aren't against violence; they're very much in favor of violence. They're against armed resistance."

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    Wow, its funny you mentioned that. I was just reading one of my Speer books last night and they were referencing various problems of that type and said to go with your gut. Sometimes it will be the magazine that won't let them fit and other times it will be the ejection port. Is it an auto loading rifle? If so I wouldn't imagine a problem with making room for the round to eject. I had an old 700 back in the early 1980s that was seating very shallow and would nearly make ejection of a live round impossible but it was a nail drive at that seating depth. I used to question how shallow is acceptable but some 20 years a go I was reading an article written by Vernon Speer that stated if the round will stay in the case mouth it is not a problem and to go with what brings you optimum accuracy! I load mostly compressed loads anyway for my high powered rifles and as well some of my magnum revolvers which is why seating depth is of such importance to me and others such as yourself. Some of the hand loaders out there are simply loading for economics and don't really get into to the meat of it thus don't understand what we consider to be high pressure v.s a nice accurate high velocity load. Whats nice is the choice of components that are now available as opposed to when I started loading in the late 1960s, what a difference. The data and standards for such is so much more consistent now as well.

    When seconds count, the police are only minutes away!

  11. #11
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    Naw, I'm happy to hear some good spirited remarks! Ya buddy!

    When seconds count, the police are only minutes away!

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    Actually you can measure the distance from the case mouth to the bearing surface of the cylinder by shallowseating a bullet into an unprimed case of course and then find the point where the bearing surface on the bullet touches the same on the cylinder. From that point you can measure with a dialcaliper the amount of free space you are dealing with and decide how much to trim off your brass to custom fit your rounds to that particular revolver. Make sure you use the bullet you are intending to load with or all will be in vain.I don't think it is possible to completely eliminate free space but it can be effectively reduced thus decreasing the amount of blow by of high pressures caused by full magnum loads that are creating havoc. The worst case I encountered was with a Sierra 110 grain HP that didn't have any bearing surface above the canelure. I'll never buy those bullets again unless I'm going to load for 38 special to be fired from a 38 special due to the shorter cylinder. I'm always being chastised for loading super magnum loads but that is what gets my juices going. I like it when the chronograph says I'm getting 2,100 fps from my .357 and I'm still not at max charge for that powder and bullet. With those kind of velocities one has to examine each load and its characteristics to find the sweet spot which is why I get so detailed about my bullet type, crimp, seating depth, case trimming, and other stuff. I'm not blowing primers or cases, and other than unwanted excessive blow back from using the wrong choice of bullet for that recipe, all is safe and good. Yesterday I made some adjustments to brass length and nearly all of my unwanted blow back went away and my velocities went up a smidgen.

    When seconds count, the police are only minutes away!

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